# pos

id: cord-330266-uypjqif7
pos: NNP
token:
  https://www.who.int/docs/default-source/coronaviruse/realtime-rt-pcr-assays-for-the-detection-of-sars-cov-2-institutpasteur-paris.pdf?sfvrsn=3662fcb6_2

lemma:
  https://www.who.int/docs/default-source/coronaviruse/realtime-rt-pcr-assays-for-the-detection-of-sars-cov-2-institutpasteur-paris.pdf?sfvrsn=3662fcb6_2


# ent

id: cord-001769-2sdg5ll7
type: ORG
entity:
  the Third Military Medical University Institutional Animal Care and Use Committee Supporting Information S1 Text Reagents


id: cord-001017-4qfhltg4
type: GGP
entity:
  Alzheimer s disease AD Parkinson s disease PD amyotrophic lateral sclerosis ALS and multiple sclerosis MS 2 While AD PD


id: cord-003378-0ozhye9q
type: DNA
entity:
  polyclonal rabbit anti mouse Fgl2 antibody 1 100 Proteintech USA polyclonal rabbit anti mouse fibrinogen antibody 1 1 000 Abcam EngLand polyclonal rabbit antimouse Fas antibody 1 50 Abcam


id: cord-003378-0ozhye9q
type: DNA
entity:
  monoclonal mouse antihuman mouse Fgl2 1 750 Abnova a monoclonal mouse antihuman HBP1 1 100 Santa Cruz USA


id: cord-003378-0ozhye9q
type: CELL_LINE
entity:
  reverse 5 GCCA CCA CGC TCT TCT GT 3 mIL 1β forward 5 TGT AAT GAA AGA CGG CAC ACC 3 mIL 1β reverse 5 TCT TCT TTG GGT ATT GCT TGG 3 mFgl2 forward 5 GCC AAA TGT GAG TCC CTG GAA 3 mFgl2 reverse 5 TTC CAC CCA AGA GCA CGT TTA AG 3 hFgl2 forward 5 ACA GTT CAG GCT GGT GGT 3


id: cord-003378-0ozhye9q
type: ORG
entity:
  the Cell Institute of the Chinese Academy of Sciences Shanghai China Human Umbilical Vein Endothelial Cells


id: cord-017613-va4ft5we
type: CL
entity:
  stem like part beneath the knob 36 S1 and 2 units are associated by non covalent linkage and they can be easily dissociated from each other by denaturing reagents


id: cord-017613-va4ft5we
type: CHEMICAL
entity:
  N terminal domain interactions structural analysis of the binding site Crystal structure of murine sCEACAMla 1 4 a coronavirus


id: cord-254871-qmx74umk
type: CELL_LINE
entity:
  MHV JHM infected infant mouse brain emulsified in Freund s complete adjuvant The following tissues were specifically examined for MHV antigen


id: cord-254871-qmx74umk
type: DISEASE
entity:
  genitourinary organs bone salivary glands or intestinal mucosa In nose lung and lymphoid tissues MHV antigen


id: cord-019076-4qu9j953
type: PROTEIN
entity:
  RNA polymerase TM1 TM2 TM3 transmembrane domains 1 2 and 3 respectively HEL helicase ExoN 3 0 to 5 0 exoribonuclease


id: cord-103306-1wc3f1rl
type: GGP
entity:
  bioRxiv DOI 10 1101 2020 09 17 302877 sha a959bea3f3b11260ff9e27a209b46a55b2a5fb8d doc_id 103306 cord_uid 1wc3f1rl Mouse


id: cord-252882-2qhoqa88
type: CHEBI
entity:
  amino acid substitution A pair of recombinant viruses that replaced the MHV A59 cleavage signal with the corresponding MHV 2 sequence


id: cord-259095-mfptcw8t
type: CHEBI
entity:
  amino acid carboxy terminal truncation of 3CLpro rendered it inactive in atranscleavage assay Thus MHV 3CLpro was able to cleave at a site within the putative full length proteinase but the entire predicted 3CLpro domain


id: cord-259580-fn5pkec9
type: ORG
entity:
  Rat Plasma and Its Application in a Pharmacokinetic Study of Orally Administered Xiaoyao Powder Generation


id: cord-259580-fn5pkec9
type: CHEMICAL
entity:
  Radix Bupleuri Radix Angelicae Sinensis Radix Paeoniae Alba Rhizoma Atractylodis Macrocephalae Poria Rhizoma


id: cord-253024-b393ea2u
type: PROTEIN
entity:
  RNA mutants LA7 LA1 2 3 0 x lo7 1 0 x 103 3 3 x 1o 4 1 1 x lo 1 0 x lo2 1 0 x 10 6 5 5 x 107 1 3 x lo 2 4 X 1O 6 5 5 x lo7 9 5 x lo4 1 7 x 10 3 3 5 x 10 4 3 x lo3 1 2 x 1o 4 7 8 x 10 1 4 x lo4 1 8 x 1O 4 6 9 X 10 8 7 x 10 1 2 x loo 7 3 x lo7 7 2 X 10 1 0 x loo 9 1 x 10 9 5 x lo7 1 0 x loo 2 1 x lo7 2 0 x 10 9 5 x 10 l 8 5 X lo 5 5 x 10 6 4 X lo 9 1 x lo7 7 2 X 10 7 9 x 10 Z 2 2 x 10 2 4 X lo7 1 1 x loo 4 0 x 10 2 0 x lo6 5 0 x 10 2 8 6 x 10 8 4 X 10 9 7 x 10 l 1 2 x lo8 1 2 x lo8 1 0 x lo0 1 2 x lo8 1 2 x 108 1 0 x loo 9 4 x 10 1 2 x 108 1 2 x loo 8 2 X lo7 9 2 x lo7 1 1 x lo0 1 0 x 108 9 0 x lo7 9 0 x 10 l 9 2 x 10 8 5 x 10 9 2 x 10 l 2 8 X 10 3 2 X 10 1 1 x loo 5 2 x lo7 4 5 x 10 8 6 x 10 J 4 7 x 10 4 6 X 10 9 7 x 10 l 5 9 x 10 4 8 X 10 8 1 x 10


id: cord-253024-b393ea2u
type: PROTEIN
entity:
  monoclonal antibodies 1 Viral Poliovirus genetics Coronavirus transcription subgenomic mouse hepatitis virus


id: cord-022324-tcltmhi7
type: CELL_LINE
entity:
  human or mouse origin of coronaviruses isolated from multiple sclerosis material passed in mice or mouse tissue 143


id: cord-021499-up5vftj4
type: CL
entity:
  stem and peri ependymal areas Lesions in peritoneum bone marrow thymus and other tissues can be variably present Mice


id: cord-021499-up5vftj4
type: ORG
entity:
  Microbiologic Monitoring of Laboratory Animals Viral and Mycoplasmal Infections of Laboratory Rodents Effects


id: cord-259374-m7q1roay
type: DISEASE
entity:
  monolayers infected with terminal passage p30 culture supernatant was used to generate RT PCR products for consensus Sanger sequencing of the complete viral genome Genewiz Changes


id: cord-263658-dlmzcl9g
type: DISEASE
entity:
  coronaviruses in organ culture varied markedly in their antibody responses to the CF antigens used in this study One such patient


id: cord-259603-bh198xgl
type: PROTEIN
entity:
  nsp6 NiRAN nidovirus RdRp associated nucleotidyl transferase nsp12 RdRp RNA dependent RNA polymerase


id: cord-259603-bh198xgl
type: PROTEIN
entity:
  ZBD zinc binding domain nsp13 HEL1 superfamily 1 helicase nsp13 ExoN exoribonuclease nsp14 N7 MT N7 methyl transferase


id: cord-259603-bh198xgl
type: PROTEIN
entity:
  coronavirus nonstructural proteins 3 and 4 Virology 458 459 Structural basis for proofreading during replication of the Escherichia coli chromosome


id: cord-256444-grw5s2pf
type: DNA
entity:
  L leader sequence HE hemagglutinin esterase S spike E small membrane protein M integral membrane protein N nucleocapsid protein An poly A tail G


id: cord-256444-grw5s2pf
type: TAXON
entity:
  bovine coronavirus BCV turkey coronavirus TCV bluecomb virus feline coronavirus FCV canine coronavirus CCV


id: cord-256444-grw5s2pf
type: SO
entity:
  L leader sequence HE hemagglutinin esterase S spike E small membrane protein M integral membrane protein N nucleocapsid protein


id: cord-256444-grw5s2pf
type: CHEMICAL
entity:
  N linked glycosylation of the N terminal domain Identification of the coronavirus MHV JHM mRNA 4 product Complete sequence 20 kilobases of the polyprotein encoding gene 1 of


id: cord-259671-7de21oaq
type: PROTEIN
entity:
  viral N protein heterogeneous ribonucleoprotein hnRNP family members polypyrimidine tract binding protein


id: cord-259671-7de21oaq
type: PROTEIN
entity:
  protease ADP ribose 1 phosphatase NTPase 5 to 3 helicase RNA 5 triphosphatase RNA polymerase guanosine N7


id: cord-259671-7de21oaq
type: RNA
entity:
  SARS coronavirus RNA cap 2 O methyltransferase nsp10 nsp16 complex Coronavirus nonstructural protein 16


id: cord-259671-7de21oaq
type: CHEMICAL
entity:
  Octanucleotide A B C Fig 5 Alignment based secondary structure prediction of betacoronavirus 3 genome regions The viruses


id: cord-259671-7de21oaq
type: DISEASE
entity:
  coronavirus transcription A contemporary view of coronavirus transcription Selective replication of coronavirus genomes


id: cord-264848-wl29jk16
type: PROTEIN
entity:
  primary antibodies rat anti BrdU 1 200 Accurate Chemical and Scientific Corporation mouse anti APC CC1 1 20 Oncogene Research Products San


id: cord-266138-yibbiiij
type: DISEASE
entity:
  coronavirus induced demyelinating encephalitis Dt rries R 1991 The immune system response to viral infection


id: cord-266018-8bhnlsgy
type: DNA
entity:
  APCconjugated rat anti mouse CD8 PERCP conjugated rat anti mouse CD4 Pharmingen San Diego CA PE conjugated D b S510 518 MHC class I tetramer Beckman Coulter San Diego CA


id: cord-266018-8bhnlsgy
type: GGP
entity:
  Th2 associated cytokine IL 10 Table 1 Therefore the data indicate that cytokine production rather than the type of CD11c cell


id: cord-271526-14nfqusv
type: PROTEIN
entity:
  coronavirus packaging signal J Virol 66 3522 3530 Holmes K V 1991 In Fundamental Virology B N Fields and D M Sequence specific sequences


id: cord-268139-tgpsu4qz
type: DNA
entity:
  fragments B and C NciI and BsmBI for fragments D and E BsmBI for F and SfiI and BsmBI for fragment G Gel purified restriction fragments


id: cord-264884-ydkigome
type: DNA
entity:
  P1 and mouse hepatitis virus MHV persistence exemplars Villarreal 2006 Villarreal 2007 Since viruses are ancient numerically dominant and the most diverse biological entities on Earth


id: cord-270814-krw8zmr5
type: PROTEIN
entity:
  measles virus hemagglutinin and CD46 Pathogenic murine coronaviruses murine coronavirus spike protein


id: cord-269011-230p8rsf
type: PROTEIN
entity:
  MHV N molecule Fig 6 Masters 1992 Also the leader binding property was assigned to this domain this activity was initially mapped to the area containing the two highly basic regions


id: cord-269011-230p8rsf
type: PROTEIN
entity:
  coronavirus surface glycoprotein Coronavirus IBV glycopolypeptides Locational studies using proteases


id: cord-269011-230p8rsf
type: GGP
entity:
  carcinoembryonic antigen related cell adhesion molecule cellular receptors Angiotensin converting enzyme 2


id: cord-281552-zfjy3m3i
type: DISEASE
entity:
  coronavirus assembly Retention of the avian coronavirus infectious bronchitis virus envelope protein


id: cord-271763-cual2qv4
type: CELL_LINE
entity:
  TATAGGCAC YAQHCFKAPSNFCPCKLDGSLC VGNGPGIDAGYKNSGIGT T T 1570 1580 1590 1600 1610 1620 1630 1640 1650 1660 1670


id: cord-271763-cual2qv4
type: PROTEIN
entity:
  GACTC G AC G LvGIGEHCScLAIKsDYC cNPCTCPPqAFLGWSVDSELQ _ _ _ 56b 1810 1820 1830 1840 1850 1860 1870 1880 1890 1900 1910 1920 GGGATAGGTGTAATAmTTGCTAATmATmGCATGATGATGTTAATAGTGGTACTACTTG CTACTGA AC ATC ACACAGACAT


id: cord-271763-cual2qv4
type: PROTEIN
entity:
  SPKVTIDCSAFVCGDY 800 2530 2540 2550 2560 2570 2580 2590 2600 2610 2620 2630 2640 CAGCATGTAAATCACAGTTGG G TATGGTAGCTTCTGTGACAATATTAATGCTATACTCACAGAAGTAAATGAACTACTTGACACTACACAGTTGCAAGTAGCT TA T GA


id: cord-271763-cual2qv4
type: CHEMICAL
entity:
  1670 1680 52b 1690 1700 1710 1720 1730 1740 1750 1760 1770 1780 1790 1800 TAGTTGGCATAGGTGAGCACTGTTCGGGGTC


id: cord-285676-4kgy20o9
type: DNA
entity:
  human coronavirus 229E RNA polymerase locus Mouse hepatitis virus strain A59 RNA polymerase gene ORF 1a Heterogeneity among


id: cord-285676-4kgy20o9
type: CHEMICAL
entity:
  N terminal 198 residues of the 1a polyprotein of FIPV specifically recognized products of 12 83 and 100 kDa in FIPV infected


id: cord-285676-4kgy20o9
type: CHEMICAL
entity:
  N terminal ORF 1a proteins of the coronavirus MHV A59 requires multiple proteolytic events Identification and characterization of a 65 kDa protein processed from the gene 1 polyprotein of the murine coronavirus MHV A59 Identification of the polymerase polyprotein products p72


id: cord-286332-cdg4im5h
type: DNA
entity:
  NGS rabbit anti MHV polyserum k134 diluted 1 400 and chicken anti IBV H120 serum diluted 1 400 or rabbit anti MHV polyserum k134 diluted 1 400 and mouse MAb Ch IBV 26


id: cord-283132-rfw8njpo
type: DISEASE
entity:
  encephalomyelitis virus HIV human immunodeficiency virus HRSV human respiratory syncytial virus IBV infectious bronchitis


id: cord-292178-bd8u8udl
type: DISEASE
entity:
  LCMV lymphocytic choriomeningitis virus VSV vesicular stomatitis virus HIV human immunodeficiency virus and HTLV 1 human T cell leukemia virus and 2 its multifunctional immunoregulatory


id: cord-292178-bd8u8udl
type: CHEMICAL
entity:
  N 4 lt Stl l iftelcntial nlodttlation of Mt class J arLltgen e q rc sion on lllOUqC brain cndolhehal cell I y MHV 4 infection


id: cord-289045-vft163v0
type: DNA
entity:
  MHV JHM X04797 MHV 1 D83333 MHV 2 D83334 MHV 3 D83335 MHV S D83337 MHV U D83336 MHV BHK AY497331 RCoV AAF97738 BCoV strain L9 P25191 and HCoV


id: cord-289045-vft163v0
type: PROTEIN
entity:
  murine coronaviruses Purified soluble recombinant mouse hepatitis virus receptor bgp1 b and bgp2 murine coronavirus receptors


id: cord-289045-vft163v0
type: ORG
entity:
  Susan Weiss Department of Microbiology University of Pennsylvania School of Medicine Philadelphia PA S


id: cord-285869-jwflooop
type: DNA
entity:
  murine coronavirus MHV A59 Analysis of murine hepatitis virus strain A59 temperature sensitive mutant TS LA6


id: cord-290877-dap0zo2m
type: ORG
entity:
  the Institutional Animal Ethical Committeee and Committee for the Purpose of Control and Supervision on Experiments on Animals CPCSEA


id: cord-293913-frkb8iso
type: CHEMICAL
entity:
  N terminal ORF la proteins of the coronavirus MHV A59 requires multiple proteolytic events Expression of virusencoded proteinases functional and structural similarities with cellular enzymes Determinants of the p28 cleavage site recognized by the first papain like cysteine


id: cord-301942-ppa7gb95
type: CHEMICAL
entity:
  N terminal Gag domain Structural organization of authentic mature HIV 1 virions and cores Cryo electron microscopy reveals ordered domains in the immature HIV 1 particle Projection structures of human Further evidence of icosahedral symmetry in human and simian immunodeficiency virus Organization of immature human immunodeficiency virus type 1 Supramolecular organization of immature and mature murine leukemia


id: cord-267671-ys43n672
type: PROTEIN
entity:
  S2 I1 I2 I3 I4 I5 I6 C1 C2 L1 L2 L3 E1 S1 S2 I1 I2 I3 I4 I5 I6 C1 C2 L1 L2 L3 E1 S1 S2 I1 I2 I3 I4 I5 I6 C1 C2 L1 L2 L3 E1 S1 S2 I1 I2 I3 I4 I5 I6 C1 C2 L1 L2


id: cord-267671-ys43n672
type: CELL_TYPE
entity:
  lung skeletal muscle myocardium kidneys nerves and adrenal glands The histologic hallmark is perivascular granulomatosis


id: cord-267671-ys43n672
type: CELL_TYPE
entity:
  glycogen positive intracytoplasmic inclusions elementary bodies C trachomatis causes ocular and urogenital disease


id: cord-267671-ys43n672
type: CELL_LINE
entity:
  transmissible murine colonic hyperplasia Mouse hepatitis virus infection intestine mouse Mouse hepatitis virus infection liver mouse Murine rotavirus infection intestine mouse


id: cord-267671-ys43n672
type: GGP
entity:
  I1 I2 I3 I4 I5 I6 C1 C2 L1 L2 L3 E1 S1 S2 I1 I2 I3 I4 I5 I6 C1 C2 L1 L2 L3 E1 S1 S2 I1 I2 I3 I4 I5 I6 C1 C2 L1 L2 L3 E1 S1 S2 I1 I2 I3 I4 I5 I6 C1 C2 L1


id: cord-267671-ys43n672
type: CL
entity:
  lymphopoietic and hematopoietic neoplasia belong to the family Retroviridae type C oncornaviruses and contain RNA


id: cord-267671-ys43n672
type: DISEASE
entity:
  Komarek 2007 fallopian tube 3 uterine horn 4 endometrium 5 cervix 6 vagina 7 vaginal vestibulum 8 clitoris 9 clitoral gland 10 urethra 11 bladder 12 medial ligament


id: cord-299756-m0va36er
type: PROTEIN
entity:
  interferon regulatory factor 7 Irf7 signal transducer and activator of transcription 1 Stat1 and 2 5 oligoadenylate synthetase


id: cord-330266-uypjqif7
type: CELL_LINE
entity:
  NL63 5 TGT CAA CGA GGT TTT GCA TTA AAT 3 F and 5 ACT GGC CTA CCA TTG TGT GTA AGA 3 R MHV 5 ATC CTC AAG AAG ACC ACT TGG GCT GAC 3 F and 5 GAG TAA TGG GGA ACC ACA CTC CCG 3 R


id: cord-330266-uypjqif7
type: WORK_OF_ART
entity:
  the Treatment of Human African Trypanosomiasis Efficacy and Toxicity of Eflornithine for Treatment of Trypanosoma Brucei Gambiense Sleeping Sickness Vaniqa Eflornithine 13


id: cord-330266-uypjqif7
type: WORK_OF_ART
entity:
  the Treatment of Women with Facial Hair Distinct Roles for Sialoside and Protein Receptors in Coronavirus Infection Hypusine a Polyamine Derived Amino Acid Critical for Eukaryotic Translation Differential Mechanisms for the Involvement of Polyamines and Hypusinated EIF5A


id: cord-295781-b831y105
type: WORK_OF_ART
entity:
  Controlling the False Discovery Rate a Practical and Powerful Approach to Multiple Testing Interferome


id: cord-295781-b831y105
type: DISEASE
entity:
  cord 295781 b831y105 authors VanLeuven James T Ridenhour Benjamin J Gonzalez Andres J Miller Craig R Miura Tanya A title Lung epithelial


id: cord-295781-b831y105
type: CHEMICAL
entity:
  coronavirus replication Ribose 2 O methylation provides a molecular signature for the distinction of self and non self mRNA dependent on the RNA sensor Mda5 Protective and pathologic roles of the immune response to mouse hepatitis virus type 1 implications


id: cord-303153-z7bdiuvx
type: PROTEIN
entity:
  lysosomes ER endoplasmic reticulum L lysosome M mitochondria N nucleus PM plasma membrane White bar 500 nm black bar 200


id: cord-317169-qlqavi4t
type: TAXON
entity:
  mengovirus herpes simplex parainfluenza type 3 pseudorabies respiratory syncytial and Sindbis viruses


id: cord-304421-xpj6c0vx
type: CHEMICAL
entity:
  N terminal ORF 1a proteins of the coronavirus MHV A59 requires multiple proteolytic events Identification of polypeptides encoded in open reading frame 1b of the putative polymerase gene of the murine


id: cord-337976-c2auspti
type: RNA
entity:
  intracellular RNA 5 0 0 5 and 0 05 g were used and in the case of purified genome RNA 0 1 0 01 and 0 001 ug were used The filter was hybridized with 106 cpm 10 s cpm g of 229E 32P cDNA


id: cord-325624-6anybxnk
type: CL
entity:
  stem and spinal cord grey matter were identified as Iba 1 positive microglia or infiltrating monocytes


id: cord-325624-6anybxnk
type: CL
entity:
  stem and spinal cord The enhanced demyelination phenotype is thus distinct from demyelination attributed to enhanced white matter infection by recombinant neuronotropic MHV variants


id: cord-329036-4bf8eiix
type: DNA
entity:
  rat monoclonal anti mouse IFN 3 antibody hybridoma R4 6A2 ATCC HB 170 or rabbit polyclonal anti mouse IFN a 3 Lee Biomolecular


id: cord-313263-epylkxdx
type: DNA
entity:
  b c d e f g h i j Interdisciplinary Perspectives on Infectious Diseases MHV A59 viral antigen d5 MHV 2 H and E d5 MHV 2 viral antigen d5


id: cord-313263-epylkxdx
type: GGP
entity:
  Spike glycoprotein S transmembrane glycoprotein M envelope protein E and hemagglutinin esterase protein


id: cord-338307-vfutmwxq
type: DNA
entity:
  murine coronavirus JHM and A59 Antigenic relationships amongst coronaviruses The propagation of coronaviruses


id: cord-338307-vfutmwxq
type: CHEMICAL
entity:
  Sindbis virus glycoproteins Immunogenicity and antigenicity of human coronaviruses 2293 and OC43 Polypeptides


id: cord-352379-q5inrxcm
type: DNA
entity:
  human coronavirus 229E HCoV 229E porcine transmissible gastroentefitis virus TGEV porcine respiratory coronavirus PRCV feline infectious peritonitis virus


id: cord-345630-bam3pa70
type: PROTEIN
entity:
  I I I I I I I I I I I I 1 2000 2500 3000 3500 3 ORF la lb 0 ORF lb I I I I I I I I I I I I I 1000 1500 2000 2500 FIG 2 Hydropathy


id: cord-334499-fz7vrnb1
type: DNA
entity:
  CD4 T cell response 19 42 43 44 Future studies will be aimed at further characterizing the roles of these specific epitopes


id: cord-356115-vblgotjn
type: PROTEIN
entity:
  cysteine proteinase ExoN exonuclease HEL superfamily 1 helicase MT S adenosylmethioninedependent 29 O methyl transferase NeU endoribonuclease PL1 papain


id: cord-356115-vblgotjn
type: DISEASE
entity:
  infectious cycle the MHV A59 replicase transcriptase complex amplifies the genomic RNA and synthesizes subgenomic mRNAs Amplification of the genomic RNA involves full length negative strand templates and the synthesis of subgenomic mRNA involves subgenomelength negative strand templates 24 25 The structures engaged in the replication


id: cord-353190-7qcoxl81
type: DNA
entity:
  b or d haplotype 24 Subclinical or latent infections can be activated by immunosuppression e g with cyclophosphamide or cortisone or critical illness such as sepsis 30 Reactivation of MCMV 1


id: cord-353190-7qcoxl81
type: PROTEIN
entity:
  mouse adrenal gland I Light microscopic observations Electron microscope study of experimental enteric adenovirus infection in mice Experimental infection with mouse adenovirus in adult mice Intestinal resistance


id: cord-353190-7qcoxl81
type: TAXON
entity:
  viruses herpesviruses mousepox virus murine adenoviruses polyomaviruses parvoviruses lactate dehydrogenase


id: cord-353190-7qcoxl81
type: DISEASE
entity:
  pathogen Lymphocytic choriomeningitis virus reemerging central nervous system pathogen Lymphocytic choriomeningitis virus


id: cord-343221-e29of29o
type: GGP
entity:
  MHV A59 6 0 MHV H277A 5 6 p 0 024 left panel peak MHV A59 6 6 MHV H277A 6 0 p 0 016 right panel and significance


id: cord-343221-e29of29o
type: ORG
entity:
  Myeloid Cells Is Dependent on Basal Oas Gene Expression and Independent of Virus Induced Interferon Activation


id: cord-343221-e29of29o
type: ORG
entity:
  ORF1a Virology R Development Core Team A Language and Environment for Statistical Computing R Foundation for Statistical Computing Nonlinear


# url

id: cord-330266-uypjqif7
domain: www.who.int
url:
  http://www.who.int/docs/default-source/coronaviruse/realtime-rt-pcr-assays-for-the-detection-of-sars-cov-2-institutpasteur-paris.pdf?sfvrsn=3662fcb6_2


# bib

id: cord-000396-egy1d90x
author: Shindler, Kenneth S.
date: 2011-06-01
txt: ./txt/cord-000396-egy1d90x.txt
cache: ./cache/cord-000396-egy1d90x.txt
extension: .txt
mime: text/plain
url: https://academic.oup.com/jnen/article-pdf/70/6/470/9561356/70-6-470.pdf
doi: 10.1097/nen.0b013e31821da499
summary:
  Prior studies using recombinant MHV strains that differ only in the spike gene, which encodes a glycoprotein involved in virus-host cell attachment, demonstrated that spike mediates anterograde axonal transport of virus to the spinal cord. A demyelinating MHV strain induces optic neuritis, but whether this is due to retrograde axonal transport of viral particles to the retina, or if it is due to traumatic disruption of retinal ganglion cell axons during intracranial inoculation is not known. The optic nerve inflammation, demyelination, and axonal loss observed after RSA59 infection, but not after RSMHV2 infection, demonstrate that the MHV-A59 spike protein is required for the induction of optic neuritis. This differential ability of MHV strains to induce optic neuritis and axonal injury is dependent on spike glycoprotein mediated retrograde transport of viral antigen along RGC axons.

title:
  Macrophage-Mediated Optic Neuritis Induced by Retrograde Axonal Transport of Spike Gene Recombinant Mouse Hepatitis Virus

abstract:
  Following intracranial inoculation, neurovirulent mouse hepatitis virus (MHV) strains induce acute inflammation, demyelination and axonal loss in the CNS. Prior studies using recombinant MHV strains that differ only in the spike gene, which encodes a glycoprotein involved in virus-host cell attachment, demonstrated that spike mediates anterograde axonal transport of virus to the spinal cord. A demyelinating MHV strain induces optic neuritis, but whether this is due to retrograde axonal transport of viral particles to the retina, or if it is due to traumatic disruption of retinal ganglion cell axons during intracranial inoculation is not known. Using recombinant isogenic MHV strains, we examined the ability of recombinant MHV to induce optic neuritis by retrograde spread from the brain through the optic nerve into the eye following intracranial inoculation. Recombinant demyelinating MHV induced macrophage infiltration of optic nerves, demyelination and axonal loss whereas optic neuritis and axonal injury were minimal in mice infected with the non-demyelinating MHV strain that differs in the spike gene. Thus, optic neuritis was dependent on a spike glycoprotein-mediated mechanism of viral antigen transport along retinal ganglion cell axons. These data indicate that MHV spreads by retrograde axonal transport to the eye and that targeting spike protein interactions with axonal transport machinery is a potential therapeutic strategy for CNS viral infections and associated diseases.


id: cord-000409-lpf9lpky
author: Chen, Yongwen
date: 2011-07-07
txt: ./txt/cord-000409-lpf9lpky.txt
cache: ./cache/cord-000409-lpf9lpky.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3131267/
doi: 10.1371/journal.ppat.1001347
summary:
  Fluorescence double-staining revealed that FGL2 and PD-1 were not co-expressed on the same cells, while quantitative RT-PCR demonstrated that higher levels of IFN-γ and TNF-α mRNA transcription occurred in PD-1-deficient mice in response to MHV-3 infection. In all, these results demonstrated that PD-1 deficiency led to enhanced pathological damage by MHV-3 in the liver, spleen, lymph node and thymus, where higher levels of PD-1-positive cells were found after infection. Results showed that the expression of FGL2 was principally associated with CD31-positive endothelial cells, CD68-positive macrophages and CD11c-positive DCs. Surprisingly, significantly higher levels of FGL2 were observed after infection in all of PD-1-deficient organs, including the liver, thymus, spleen, lymph nodes, and serum than that in those from WT littermates. However, the number of Foxp3-positive cells in the liver, spleen, lymph node or thymus was not significantly different between PD-1-deficient mice and their WT littermates after 72 h of MHV-3 infection (Fig. S3) .

title:
  Programmed Death (PD)-1-Deficient Mice Are Extremely Sensitive to Murine Hepatitis Virus Strain-3 (MHV-3) Infection

abstract:
  The inhibitory receptor programmed death-1 (PD-1) has the capacity to maintain peripheral tolerance and limit immunopathological damage; however, its precise role in fulminant viral hepatitis (FH) has yet to be described. Here, we investigated the functional mechanisms of PD-1 as related to FH pathogenesis induced by the murine hepatitis virus strain-3 (MHV-3). High levels of PD-1-positive CD4(+), CD8(+) T cells, NK cells and macrophages were observed in liver, spleen, lymph node and thymus tissues following MHV-3 infection. PD-1-deficient mice exhibited significantly higher expression of the effector molecule which initiates fibrinogen deposition, fibrinogen-like protein 2 (FGL2), than did their wild-type (WT) littermates. As a result, more severe tissue damage was produced and mortality rates were higher. Fluorescence double-staining revealed that FGL2 and PD-1 were not co-expressed on the same cells, while quantitative RT-PCR demonstrated that higher levels of IFN-γ and TNF-α mRNA transcription occurred in PD-1-deficient mice in response to MHV-3 infection. Conversely, in vivo blockade of IFN-γ and TNF-α led to efficient inhibition of FGL2 expression, greatly attenuated the development of tissue lesions, and ultimately reduced mortality. Thus, the up-regulation of FGL2 in PD-1-deficient mice was determined to be mediated by IFN-γ and TNF-α. Taken together, our results suggest that PD-1 signaling plays an essential role in decreasing the immunopathological damage induced by MHV-3 and that manipulation of this signal might be a useful strategy for FH immunotherapy.


id: cord-001017-4qfhltg4
title: Microglia Play a Major Role in Direct Viral-Induced Demyelination
author: Chatterjee, Dhriti
date: 2013-06-20
txt: ./txt/cord-001017-4qfhltg4.txt
cache: ./cache/cord-001017-4qfhltg4.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3705805/
doi: 10.1155/2013/510396
summary:
  Previous studies demonstrated that microglia can be persistently infected by neurotropic mouse hepatitis virus (MHV) which causes meningoencephalitis, myelitis with subsequent axonal loss, and demyelination and serve as a virus-induced model of human neurological disease multiple sclerosis (MS). In our current studies, we have used RSA59 infection in vivo, in vitro, and ex vivo as a model to understand whether MHV can directly infect CNS resident microglia and the mechanism of microglial activation in the induction of chronic demyelination. To confirm the RSA59-induced CNS inflammation, brain and spinal cord sections from day 7 (peak of inflammation) and day 30 (peak of demyelination) postinfected mice were stained with H&E or LFB and examined. While Iba1 immunofluorescence was observed in both gray and white matter, double fluorescence/immunofluorescence demonstrated dual labelling of EGFP (viral antigen) positive Iba1 positive microglia/macrophages were present only in the white matter of RSA59 infected mice (Figure 1 ).

abstract:
  Microglia are the resident macrophage-like populations in the central nervous system (CNS). Microglia remain quiescent, unable to perform effector and antigen presentation (APC) functions until activated by injury or infection, and have been suggested to represent the first line of defence for the CNS. Previous studies demonstrated that microglia can be persistently infected by neurotropic mouse hepatitis virus (MHV) which causes meningoencephalitis, myelitis with subsequent axonal loss, and demyelination and serve as a virus-induced model of human neurological disease multiple sclerosis (MS). Current studies revealed that MHV infection is associated with the pronounced activation of microglia during acute inflammation, as evidenced by characteristic changes in cellular morphology and increased expression of microglia-specific proteins, Iba1 (ionized calcium-binding adaptor molecule 1), which is a macrophage/microglia-specific novel calcium-binding protein and involved in membrane ruffling and phagocytosis. During chronic inflammation (day 30 postinfection), microglia were still present within areas of demyelination. Experiments performed in ex vivo spinal cord slice culture and in vitro neonatal microglial culture confirmed direct microglial infection. Our results suggest that MHV can directly infect and activate microglia during acute inflammation, which in turn during chronic inflammation stage causes phagocytosis of myelin sheath leading to chronic inflammatory demyelination.


id: cord-001769-2sdg5ll7
author: Guo, Sheng
date: 2015-09-14
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4569300/
doi: 10.1371/journal.ppat.1005155
title:
  The NLRP3 Inflammasome and IL-1β Accelerate Immunologically Mediated Pathology in Experimental Viral Fulminant Hepatitis

abstract:
  Viral fulminant hepatitis (FH) is a severe disease with high mortality resulting from excessive inflammation in the infected liver. Clinical interventions have been inefficient due to the lack of knowledge for inflammatory pathogenesis in the virus-infected liver. We show that wild-type mice infected with murine hepatitis virus strain-3 (MHV-3), a model for viral FH, manifest with severe disease and high mortality in association with a significant elevation in IL-1β expression in the serum and liver. Whereas, the viral infection in IL-1β receptor-I deficient (IL-1R1 (-/-)) or IL-1R antagonist (IL-1Ra) treated mice, show reductions in virus replication, disease progress and mortality. IL-1R1 deficiency appears to debilitate the virus-induced fibrinogen-like protein-2 (FGL2) production in macrophages and CD45(+)Gr-1(high) neutrophil infiltration in the liver. The quick release of reactive oxygen species (ROS) by the infected macrophages suggests a plausible viral initiation of NLRP3 inflammasome activation. Further experiments show that mice deficient of p47 (phox), a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit that controls acute ROS production, present with reductions in NLRP3 inflammasome activation and subsequent IL-1β secretion during viral infection, which appears to be responsible for acquiring resilience to viral FH. Moreover, viral infected animals in deficiencies of NLRP3 and Caspase-1, two essential components of the inflammasome complex, also have reduced IL-1β induction along with ameliorated hepatitis. Our results demonstrate that the ROS/NLRP3/IL-1β axis institutes an essential signaling pathway, which is over activated and directly causes the severe liver disease during viral infection, which sheds light on development of efficient treatments for human viral FH and other severe inflammatory diseases.


id: cord-003199-03c9rx3o
author: Singh, Manmeet
date: 2018-09-04
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6132074/
doi: 10.3389/fcimb.2018.00311
title:
  Intracranial Inoculation Is More Potent Than Intranasal Inoculation for Inducing Optic Neuritis in the Mouse Hepatitis Virus-Induced Model of Multiple Sclerosis

abstract:
  Neurotropic strains of mouse hepatitis virus (MHV) induce acute inflammation and chronic demyelination in the spinal cord and optic nerves mediated by axonal spread following intracranial inoculation in mice, with pathologic features similar to the human demyelinating disease multiple sclerosis. Spinal cord demyelination is also induced following intranasal inoculation with neurotropic MHV strains, however much higher viral doses are required as compared to intracranial inoculation. Recently, it was shown that intranasal administration of low concentrations of proteins leads to significant, rapid accumulation of protein in the optic nerve and in the eye, with only low levels reaching spinal cord and other brain regions. Thus, we examined whether intranasal inoculation with MHV at doses equivalent to those given intracranially could induce optic neuritis—inflammation, demyelination and loss of retinal ganglion cells (RGCs) in the optic nerve with or without inducing spinal cord demyelination. Four week old male C57BL/6J mice were inoculated intracranially with the recombinant demyelinating strain RSA59, or intranasally with RSA59 or the non-demyelinating strain RSMHV2 as control. One month post-inoculation, mice inoculated intracranially with RSA59 had significant myelin loss in both spinal cord and optic nerves, with significant loss of RGCs as well, consistent with prior studies. As expected, intranasal inoculation with RSA59 failed to induce demyelination in spinal cord; however, it also did not induce optic nerve demyelination. No acute inflammation was found, and no viral antigen was detected, in the optic nerve or retina 1 day after inoculation. Results confirm the neurotropic effects of RSA59 following intracranial inoculation, and suggest that direct infection with axonal transport of virus from brain to spinal cord and optic nerve is required to induce demyelinating disease. These studies suggest that MHV does not selectively concentrate in optic nerve and retina to sufficient levels to induce demyelination following intranasal inoculation. Intracranial inoculation should continue to be considered a preferred method for studies of MHV-induced optic neuritis and central nervous system (CNS) demyelinating disease.


id: cord-003378-0ozhye9q
author: Yu, Haijing
date: 2018-12-13
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6300492/
doi: 10.3389/fimmu.2018.02935
title:
  Clara Cell 10 kDa Protein Alleviates Murine Hepatitis Virus Strain 3-Induced Fulminant Hepatitis by Inhibiting Fibrinogen-Like Protein 2 Expression

abstract:
  Background: Fulminant hepatitis (FH) is a serious threat to human life, accompanied by massive and rapid necroinflammation. Kupffer cells, the major immune cell population involved in innate immune responses, are considered to be central for FH. Fibrinogen-like protein 2 (Fgl2) is a pro-coagulant protein that is substantially induced in macrophages upon viral infection, and Fgl2 depletion represses murine hepatitis virus strain 3 (MHV-3) infection. Clara cell 10 kDa (CC10) protein is a secretory protein with anti-inflammatory properties in allergic rhinitis and asthma. However, its mechanisms of action and pathogenic roles in other disease are still unclear. In this study, we aimed to determine the role of CC10 in FH and the regulation of Fgl2 by CC10. Methods: A mouse FH model was established by peritoneal injection of MHV-3. The mice received CC10 protein through tail vein injection before viral infection. Survival rate, liver function, liver histology, fibrin deposition, and necrosis were examined. The regulatory effect of CC10 on Fgl2 expression was investigated using THP-1 cells and mouse peritoneal macrophages in vitro. Results: In the mouse FH model induced by MHV-3, the survival rate increased from 0 to 12.5% in the CC10 group compared to that in the saline-only control group. Meanwhile, the levels of ALT and AST in serum were significantly decreased and liver damage was reduced. Furthermore, hepatic Fgl2, TNF-α, and IL-1β expression was obviously downregulated together with fibrin deposition, and hepatocyte apoptosis was reduced after administration of CC10 protein. In vitro, CC10 was found to significantly inhibit the expression of Fgl2 in IFN-γ-treated THP-1 cells and MHV-3-infected mouse peritoneal macrophages by western blot and real-time PCR. However, there was no direct interaction between CC10 and Fgl2 as shown by co-immunoprecipitation. Microarray investigations suggested that HMG-box transcription factor 1 (HBP1) was significantly low in CC10-treated and IFN-γ-primed THP-1 cells. HBP1-siRNA treatment abrogated the inhibitory effect of CC10 on Fgl2 expression in Human Umbilical Vein Endothelial cells (HUVECs). Conclusion:CC10 protects against MHV-3-induced FH via suppression of Fgl2 expression in macrophages. Such effects may be mediated by the transcription factor HBP1.


id: cord-004663-a47pkh8q
author: Tardieu, M.
date: 1982
txt: ./txt/cord-004663-a47pkh8q.txt
cache: ./cache/cord-004663-a47pkh8q.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7086528/
doi: 10.1007/bf00690797
summary:
  title: Ependymitis, leukoencephalitis, hydrocephalus, and thrombotic vasculitis following chronic infection by mouse hepatitis virus 3 (MHV 3) In semisusceptible mice, infection led first to a transient meningitis, ependymitis, and leukoencephalitis, followed by a permanent communicating hydrocephalus and, later on, to a chronic thrombotic vasculitis affecting meningeal and parenchymal vessels at the brain stem level. Identical lesions occurred in fully susceptible mice infected with a low dose of virus, but no neurologic disorder could be induced in genetically resistant mice even following immunosuppression or intracranial inoculation. When six susceptible BALB/c mice were injected i.p. with MHV 3 (103LD50), they died of an acute hepatic necrosis 5 -8 d a y s after M H V 3 infection, and no neuropatholigic lesion was observed except a slight degree of meningeal infiltration.

title:
  Ependymitis, leukoencephalitis, hydrocephalus, and thrombotic vasculitis following chronic infection by mouse hepatitis virus 3 (MHV 3)

abstract:
  Mouse hepatitis virus 3 (MHV 3) is either avirulent (resistant mice), hepatotropic (susceptible mice). or neurotropic (semisusceptible mice), depending on the strain of mice infected. In semisusceptible mice, infection led first to a transient meningitis, ependymitis, and leukoencephalitis, followed by a permanent communicating hydrocephalus and, later on, to a chronic thrombotic vasculitis affecting meningeal and parenchymal vessels at the brain stem level. Small foci of ischemic necrosis related to vascular occlusions were seen in the dorsal brain stem. Cyclophosphamide treatment of semisusceptible mice significantly reduced the meningeal infiltrates but did not prevent the development of hydrocephalus and other neuropathologic changes. Identical lesions occurred in fully susceptible mice infected with a low dose of virus, but no neurologic disorder could be induced in genetically resistant mice even following immunosuppression or intracranial inoculation. The leukoencephalitis differed from the demyelinating lesions observed with MHV4. Vascular lesions were of particular interest. More attention should be given to the possibifity of virus induced chronic cerebral vasculitis in man.


id: cord-004670-k1om7prn
title: Olfactory neural pathway in mouse hepatitis virus nasoencephalitis
author: Barthold, S. W.
date: 1988
txt: ./txt/cord-004670-k1om7prn.txt
cache: ./cache/cord-004670-k1om7prn.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7086557/
doi: 10.1007/bf00686390
summary:
  The mechanism of brain infection with mouse hepatitis virus-JHM was studied in BALB/cByJ mice following intranasal inoculation, and found to be a consequence of direct viral spread along olfactory nerves into olfactory bulbs of the brain. Lesions, antigen and virus were observed in the olfactory bulb and anterior brain as early as 2 days and posterior brain by 4 days after inoculation. The purpose of this study was to determine the route of virus entry into brain by examination of the sequential progression of infection with neurotropic MHV-JHM following i.n. inoculation of mice. To confirm that brain infection resulted from direct extension of virus along olfactory nerves and not due to viremia, groups of five mice were inoculated either i.n. or p.o. with MHV-JHM. Sequential studies of lesion, antigen and virus distribution in nose and brain indicated anterior to posterior progression of infection.

abstract:
  The mechanism of brain infection with mouse hepatitis virus-JHM was studied in BALB/cByJ mice following intranasal inoculation, and found to be a consequence of direct viral spread along olfactory nerves into olfactory bulbs of the brain. Infection was followed sequentially from nose to brain, using microscopy, immunohistochemistry and virus quantification. Lesions, antigen and virus were observed in the olfactory bulb and anterior brain as early as 2 days and posterior brain by 4 days after inoculation. Viral antigen extended through nasal mucosa into submucosa, then coursed along the olfactory nerve perineurium and fibers, through the cribriform plate into the olfactory bulbs. On days 4 and 7, viral antigen was found in the antero-ventral brain, along ventral meninges, olfactory tracts and anterior ramifications of the lateral ventricles. Virus was cleared from nose by 10 days and anterior brain by 20 days, but persisted in posterior brain for 20 days after inoculation. Mice also developed disseminated infection, with viremia and hepatitis. Infection of brain did not correlate with presence of viremia. In contrast to intranasally inoculated mice, orally-inoculated mice did not develop encephalitis, despite evidence of disseminated infection.


id: cord-004690-q38ogrem
title: Viremic dissemination of mouse hepatitis virus-JHM following intranasal inoculation of mice
author: Barthold, S. W.
date: 1992
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7086624/
doi: 10.1007/bf01321116
abstract:
  Using a sensitive infant mouse bioassay to detect infectious virus, the pattern of mouse hepatitis virus (MHV) JHM dissemination in blood and other tissues was examined during the first 5 days following intranasal inoculation. MHV replicated in nasal turbinates of both susceptible BALB and resistant SJL mice from days 1 through 5, but BALB mice had higher titers on days 1 and 2. Viremia was detectable on days 1 through 5 in BALB mice, but only on days 3 and 5 in SJL mice. Transient virus replication occurred in the lungs of both mouse genotypes at 1 and 2 days, then ceased. This correlated with more consistently demonstrable virus in blood collected from the left atrium of the heart, compared to jugular vein, portal vein and right atrial blood. Virus was associated equally with the plasma and cellular fractions of blood on day 3, but was primarily in the buffy coat of the cellular fraction on day 5. Interferon-α/β was detected in serum and spleen, but not liver or brain of BALB mice or in any tissue of SJL mice. BALB serum and spleen interferon was first detected at 36h, peaked between 48 and 72h, and was undetectable by 108h. The distribution of virus in nose, cervical, axillary and mesenteric lymph nodes, spleen, Peyer's patch, thymus, bone marrow and liver was examined at 1, 2, and 3 days. The resulting pattern suggested lymphatic spread of virus to cervical lymph node and mesenteric lymph node as pathways of dissemination in addition to viremia.


id: cord-004728-rjl35dpa
title: Asymptomatic infection of mouse hepatitis virus in the rat
author: Taguchi, F.
date: 1979
txt: ./txt/cord-004728-rjl35dpa.txt
cache: ./cache/cord-004728-rjl35dpa.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7086774/
doi: 10.1007/bf01317424
summary:
  After intranasal inoculation of suckling rats mouse hepatitis virus multiplied mostly in the nasal epithelium; though there were no symptoms, antibodies were produced. Bar represents 0.1 mm Two-, 4-, 6-and t0-week-old rats were also inoculated i.n. with t05 PFU of MHV-S and infectious viruses were assayed in the lung, brain, salivary glands and liver. So far only mice have been considered to be natural hosts of MHV and rat; has been excluded because highly virulent MHV inoculated by various routes did not cause any sy~lptomatic infection like that produced in the mouse (7, 13) . B~tATT and his eoworkers showed that SDAV multiplied in mice producing some histopathological changes in the respiratory system after i.n. inoculation (3) and we demonstrated in the w e s e n t paper that 3{HV infected rats of any ages. Pathogenicity of mouse hepatitis virus for mice depending upon host age and route of infection

abstract:
  After intranasal inoculation of suckling rats mouse hepatitis virus multiplied mostly in the nasal epithelium; though there were no symptoms, antibodies were produced. Antibodies were also demonstrated in adult rats. These findings suggest that the rat may be a natural host for the virus.


id: cord-004765-7e4yu2do
title: Maternally-derived passive immunity to enterotropic mouse hepatitis virus
author: Homberger, F. R.
date: 1992
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7086897/
doi: 10.1007/bf01321123
abstract:
  Maternally-derived antibody to enterotropic mouse hepatitis virus (MHV) strain Y was transferred to pups by both intrauterine (IgG) and lactogenic (IgA and IgG) routes. Antibody present in the gastric whey of pups suckling immune dams dropped to undetectable levels by weaning age (21 days post partum). MHV-specific IgG was found in the serum of passively immune pups up to 10 weeks of age. Immune dams transferred equal levels of antibody to 3 consecutive litters of pups, without evidence of decline. Immunoblots showed that IgA and IgG in whey and serum were directed against nucleoprotein N and glycoprotein S. MHV-specific IgM was not detected in any sample.


id: cord-007637-o2cijp5a
author: Knobler, R.L.
date: 2005-06-03
txt: ./txt/cord-007637-o2cijp5a.txt
cache: ./cache/cord-007637-o2cijp5a.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7119749/
doi: 10.1016/s0165-5728(85)80044-8
summary:
  In the present report we provide the strain distribution patterns of susceptibility to acute mouse hepatitis virus type-4 (MHV-4) encephalomyelitis, acute experimental allergic encephalomyelitis (EAE) and vasoactive amine sensitivity (VAAS) for 9 (CXJ) recombinant-inbred strains between BALB/cKe (C) and SJL/J (J) mice. Susceptibility to acute experimental autoimmune encephalomyelitis (EAE), an acute perivascular inflammatory demyelinating disease, is controlled by at least two genes, one, H-2 linked [responder haplotype (H-2 S, H-2 q or H-2d)]; the other associated with natural vasoactive amine sensitivity (VAAS) or that induced by Bordetella pertussis (Linthicum and Frelinger 1982) . Nine RI strains between BALB/cKe and SJL/J (CXJ) have been tested to provide the SDP of susceptibility to acute MHV-4 encephalomyelitis, acute EAE and VAAS. Finally, although some (CXJ) RI strains are susceptible to acute EAE, induced VAAS and acute M H V -4 encephalomyelitis EAE-like histopathological disease does not occur in these animals following MHV-4 intracerebral infection.

title:
  Host genetic regulation of acute MHV-4 viral encephalomyelitis and acute experimental autoimmune encephalomyelitis in (BALB/cKe × SJL/J) recombinant-inbred mice()

abstract:
  In the present report we provide the strain distribution patterns of susceptibility to acute mouse hepatitis virus type-4 (MHV-4) encephalomyelitis, acute experimental allergic encephalomyelitis (EAE) and vasoactive amine sensitivity (VAAS) for 9 (CXJ) recombinant-inbred strains between BALB/cKe (C) and SJL/J (J) mice. We confirm that susceptibility to MHV-4 is not linked to the H-2 complex, and that all strains susceptible to acute EAE have both a responder H-2 haplotype (H-2(s) or H-2(d)) and induced (B. pertussis) VAAS. In addition, we provide evidence that susceptibility to acute EAE induction is controlled by an additional presently unmapped locus and that an EAE-like histopathological disease does not usually follow MHV-4 infection intracerebrally in animals susceptible to MHV-4, acute EAE and induced VAAS.


id: cord-009504-sn00p8iw
author: Taguchi, Fumihiro
date: 2013-11-14
txt: ./txt/cord-009504-sn00p8iw.txt
cache: ./cache/cord-009504-sn00p8iw.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7159379/
doi: 10.1111/j.1348-0421.1979.tb00461.x
summary:
  The pathogenesis of mouse hepatitis virus (MHV‐S) infection in suckling and weanling mice was comparatively studied after intranasal inoculation. In the posterior part of the brain and spinal cord, virus was detected on days 3 to 4 postinoculation when viral growth was clearly demonstrable in the liver, spleen and intestines. In weanling mice, however, neither infectious virus nor viral antigen was detected in the liver or other visceral organs, while serum neutralizing antibody became detectable on day 5 postinoculation, increasing in titer thereafter. 2A and 2B , significant viral growth was observed in the brain, spinal cord ( Fig. 2A) and head without brain (Fig. 2B) , whereas no virus was demonstrated in the spleen or liver of the infected mice with a few exceptions (not included in the figures). In 4-week-old mice, however, no or little infectious virus was detected in the liver or other visceral organs, although high titered virus demonstrable in the brain was probably disseminated from the nasal mucosa as was observed in suckling mice.

title:
  Pathogenesis of Mouse Hepatitis Virus Infection: The Role of Nasal Epithelial Cells as a Primary Target of Low‐Virulence Virus, MHV‐S

abstract:
  The pathogenesis of mouse hepatitis virus (MHV‐S) infection in suckling and weanling mice was comparatively studied after intranasal inoculation. In sucklings, infectious virus as well as specific antigen was first detected in the nasal mucosa at 12 hr, then in the nerve cells of the olfactory bulbs. At this stage viral particles were demonstrated both in the supporting cells and olfactory cells of the nasal mucosa. In the posterior part of the brain and spinal cord, virus was detected on days 3 to 4 postinoculation when viral growth was clearly demonstrable in the liver, spleen and intestines. In weanlings too, infection was first established in the nasal mucosa, shedding infectious virus in the nasal washing until day 6 postinoculation, and later infection spread to the brain and spinal cord. In weanling mice, however, neither infectious virus nor viral antigen was detected in the liver or other visceral organs, while serum neutralizing antibody became detectable on day 5 postinoculation, increasing in titer thereafter. Histopathologically degenerative and necrotic changes were observed in the nasal mucosa and central nervous system of both age groups of animals coincidentally with the presence of viral specific antigen, while inflammatory response was much less prominent in sucklings. In the liver, spleen and intestines, however, some lesions were observed only in sucklings.


id: cord-009793-t5bz4kmk
author: Macphee, Peggy J.
date: 2005-12-05
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7165583/
doi: 10.1002/hep.1840050422
title:
  Acute and chronic changes in the microcirculation of the liver in inbred strains of mice following infection with mouse hepatitis virus type 3

abstract:
  The acute and chronic effects of mouse hepatitis virus type 3 on the microcirculation of the liver in both semisusceptible C3HeB/FeJ and fully resistant A/J mice were studied. In the C3HeB/FeJ mice, abnormalities of microcirculatory flow were noted as early as 12 hr after infection and by 24 hr, localized avascular foci appeared. Disturbances were characterized by granular blood flow, sinusoidal microthrombi, distortion of sinusoids by edematous hepatocytes and necrotic lesions. Following the acute infection, Day 10, two patterns of chronic disease were observed. Eighty percent of the mice developed chronic granulomatous hepatitis whereas in the remaining 20% a more severe chronic aggressive hepatitis was observed which was characterized by ongoing hepatocellular necrosis and a marked mononuclear cell infiltrate. In both cases, in vivo microcirculatory abnormalities were found predominantly around visible lesions. Onset of the microcirculatory abnormalities was found to be concomitant with a rise in monocyte related procoagulant activity. Procoagulant activity rose acutely and remained elevated throughout the chronic phase but was higher in animals with severe disease. In contrast to the above, normal blood flow and histology were seen in the resistant A/J mice at all times following infection, and procoagulant activity remained at basal levels despite active viral replication as demonstrated by immunofluorescence studies and recovery of infectious virus. These observations suggest a role for monocyte procoagulant activity in the development of microcirculatory abnormalities following mouse hepatitis virus type 3 infection which may be important in the pathogenesis of the disease.


id: cord-009821-19dxy56e
author: van Berlo, M.F.
date: 2004-10-12
txt: ./txt/cord-009821-19dxy56e.txt
cache: ./cache/cord-009821-19dxy56e.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7165824/
doi: 10.1002/glia.440020204
summary:
  The present study examined the effects of MHV-JHM on cultured brain cells derived from Balb/c mice and from Wistar and from Lewis rats. To study the infection of astrocytes with MHV-JHM in vitro, cultures of brain cells derived from either newborn mice or rats were prepared and infected with virus. Infection of these oligodendrocyte-enriched cultures with MHV-JHM showed that 1 day after infection only a few GalC-positive (Fig. 4A,B) and no A2B5-positive cells (results not shown) contained viral proteins. When MHV-JHM infection caused an acute encephalitis in young rat pups, antigen could be found throughout the brain, mainly in astrocytes (Fig. 1A,B) . This susceptibility to MHV-JHM infection is found also in cultures of mouse astrocytes and Lewis rats (Massa et al., 1986) . Analysis of murine hepatitis virus (JHM strain) tropism toward Lewis rat glia cells in vitro: Type 1 astrocytes and brain macrophages (microglia) a s primary glial cell targets

title:
  Vulnerability of rat and mouse brain cells to murine hepatitis virus (JHM‐strain): Studies in vivo and in vitro

abstract:
  The pathogenicity and cell tropism of mouse hepatitis virus (MHV‐JHM‐strain) in the developing mouse (Balb/c) and rat (Wistar and Lewis) brain were analysed. Intracranial infection of Balb/c mice at postnatal day 5 induced a lethal encephalitis in all animals. Of Wistar rats infected at day 2 or 5 after birth, 30 to 70%, respectively, survived. The distribution of viral antigen was studied in frozen brain sections of animals that died after infection; astrocytes were found to be the major virus‐infected cell type throughout the central nervous system. More than 75% of the surviving rat pups developed paralysis, but viral antigen was detected in only few brain cells and not in astrocytes. The cell tropism of MHV‐JHM was examined further in virus‐infected glial cell cultures derived from brains of rats or mice. In the glial cultures derived from Wistar rats, only oligodendrocytes were infected, whereas in cultures derived from mouse or Lewis rat brain viral antigen was detected in both astrocytes and oligodendrocytes. Infection of astrocytes led to the formation of syncytia and degradation of the cytoskeleton. Infected rat oligodendrocytes gradually disappeared from the cultures because of cell death. These phenomena indicate that, besides an indirect autoimmune response triggered by infected astrocytes, direct virus‐induced injury to astrocytes or to oligodendrocytes can have a dominant role in the neuropathogenicity of mouse hepatitis virus. The present results underscore the importance of species and developmental stage of experimental animals in the neurotropism and pathogenicity of MHV‐JHM.


id: cord-010252-go8cmgpo
title: Muramyl peptides confer hepatoprotection against murine viral hepatitis
author: Masihi, K.Noel
date: 2006-03-15
txt: ./txt/cord-010252-go8cmgpo.txt
cache: ./cache/cord-010252-go8cmgpo.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7173131/
doi: 10.1016/0192-0561(89)90109-4
summary:
  The hepatoprotection induced by synthetic muramyl peptides was investigated using a model of lethal murine mouse hepatitis MHV-3 virus infection. MDP and a nonpyrogenic analog, Murametide, inhibited the steep elevation of serum transaminases induced by MHV-3 irrespective of whether the immunomodulators were administered before or after the infection. In the present study, the effect of MDP and a nonpyrogenic analog, Murametide, on biochemical and other parameters was investigated using a model of lethal routine MHV-3 virus infection. In contrast, the MHV-3 infection induced increased GOT and GPT activities on day 3 and the enzyme levels were elevated even further on day 4, a time period when many of the animals were dying. Protective effect of muramyl dipeptide analogs in combination with trehalose dimycolate against aerogenic influenza and Mycobacterium tuberculosis infections in mice

abstract:
  The hepatoprotection induced by synthetic muramyl peptides was investigated using a model of lethal murine mouse hepatitis MHV-3 virus infection. MDP and a nonpyrogenic analog, Murametide, inhibited the steep elevation of serum transaminases induced by MHV-3 irrespective of whether the immunomodulators were administered before or after the infection. A significant proportion of MDP or Murametide-treated animals, in contrast to controls, survived the MHV-3 infection. The histopathological examination of the liver revealed marked necrosis of the hepatic parenchymal cells and infiltration of the inflammatory cells in controls but not in MDP-treated animals.


id: cord-017613-va4ft5we
title: Coronavirus Receptors
author: Taguchi, Fumihiro
date: 2005
txt: ./txt/cord-017613-va4ft5we.txt
cache: ./cache/cord-017613-va4ft5we.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7122215/
doi: 10.1007/0-387-25518-4_46
summary:
  The major receptor for murine coronavirus, mouse hepatitis virus (MHV), is identified as a protein, cell-adhesion molecule 1 in the carcinoembryonic antigen family (CEACAM1), which is classified in the immunoglobulin superfamily. This domain is also responsible for binding to the MHV spike (S) protein; the CC'' face protruding in this domain interacts with an N terminal region of the S protein composed of 330 amino acids (called S1N330). found that the plasma membranes isolated from MHV-susceptible BALB/c mouse hepatocytes or enterocytes contained a 110 to 120-kDa protein that binds to MHV particles, but those derived from MHV-resistant SJL mice lacked such a protein (2). Although CEACAM1 consisting of N domain alone bound MHV, it did not work as a functional receptor when expressed on CEACAMl-negative cells (18) . Communication between S1N330 and a region in $2 of murine coronavirus spike protein is important for virus entry into cells expressing CEACAM I b receptor

abstract:
  The major receptor for murine coronavirus, mouse hepatitis virus (MHV), is identified as a protein, cell-adhesion molecule 1 in the carcinoembryonic antigen family (CEACAM1), which is classified in the immunoglobulin superfamily. There are four CEACAM1 isoforms, with either four or two ectodomains, resulting from an alternative splicing mechanism. CEACAM1 is expressed on the epithelium and in endothelial cells of a variety of tissues and hemopoietic cells, and functions as a homophilic and heterophilic adhesion molecule. It is used as a receptor for some bacteria as well. The N terminal domain participates in mediating homophilic adhesion. This domain is also responsible for binding to the MHV spike (S) protein; the CC’ face protruding in this domain interacts with an N terminal region of the S protein composed of 330 amino acids (called S1N330). The binding of CEACAM1 with MHV S protein induces S protein conformational changes and converts fusion-negative S protein to a fusion-positive form. The allelic forms of CEACAM1 found among mouse strains are thought to be an important determinant for mouse susceptibility to MHV.


id: cord-019076-4qu9j953
title: Expression and Functions of SARS Coronavirus Replicative Proteins
author: Ulferts, Rachel
date: 2009-07-22
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7124140/
doi: 10.1007/978-3-642-03683-5_6
abstract:
  The discovery of a previously unknown coronavirus as the causative agent of the SARS epidemic in 2002/2003 stimulated a large number of studies into the molecular biology of SARS coronavirus (SARS-CoV) and related viruses. This research has provided significant new insight into the functions and activities of the coronavirus replicase–transcriptase complex, a multiprotein complex that directs coordinated processes of both continuous and discontinuous RNA synthesis to replicate and transcribe the large coronavirus genome, a single-stranded, positive-sense RNA of ~30 kb. In this chapter, we review our current understanding of the expression and functions of key replicative enzymes, such as RNA polymerases, helicase, ribonucleases, ribose-2′-O-methyltransferase and other replicase gene-encoded proteins involved in genome expression, virus–host interactions and other processes. Collectively, these recent studies reveal fascinating details of an enzymatic machinery that, in the RNA virus world, is unparalleled in terms of the number and nature of virally encoded activities involved in virus replication and host interactions.


id: cord-021413-1ht1xm88
title: Viral Diseases of the Digestive System
author: Kraft, Lisbeth M.
date: 2013-10-21
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7149642/
doi: 10.1016/b978-0-12-262502-2.50016-x
abstract:
  This chapter discusses three virus infections affecting the digestive system of mice and their properties: (1) epizootic diarrhea of infant mice (EDIM), (2) reovirus 3 infection, and (3) murine hepatitis virus infection (MHV). All three infections may cause serious, debilitating, and sometimes fatal diarrheal disease in nursling and weanling mice. Mice of all ages can be infected by the EDIM virus but overt disease is restricted to animals up to about 12–13 days of age at the time of first exposure. The EDIM virus is worldwide in distribution. Its prevalence is difficult to estimate because serologic tests have not been readily available, and it is not customary to sacrifice animals for the purpose of examining the appearance of their intestinal tract or for electron microscopic visualization of fecal contents. The acute disease of reovirus 3 infection affects mainly sucklings and weanlings, whereas the chronic disease is encountered in animals over 28 days of age. The MHV virus, on the other hand, has been found to affect cotton rats, rats, and hamsters.


id: cord-048204-6lvn10f4
title: Heterogeneous nuclear ribonucleoprotein A1 regulates RNA synthesis of a cytoplasmic virus
author: Shi, Stephanie T.
date: 2000-09-01
url: http://europepmc.org/articles/pmc302072?pdf=render
doi: 10.1093/emboj/19.17.4701
abstract:
  Heterogeneous nuclear ribonucleoprotein (hnRNP A1) is involved in pre-mRNA splicing in the nucleus and translational regulation in the cytoplasm. In the present study, we demonstrate that hnRNP A1 also participates in the transcription and replication of a cytoplasmic RNA virus, mouse hepatitis virus (MHV). Overexpression of hnRNP A1 accelerated the kinetics of viral RNA synthesis, whereas the expression in the cytoplasm of a dominant-negative hnRNP A1 mutant that lacks the nuclear transport domain significantly delayed it. The hnRNP A1 mutant caused a global inhibition of viral mRNA transcription and genomic replication, and also a preferential inhibition of the replication of defective-interfering RNAs. Similar to the wild-type hnRNP A1, the hnRNP A1 mutant complexed with an MHV polymerase gene product, the nucleocapsid protein and the viral RNA. However, in contrast to the wild-type hnRNP A1, the mutant protein failed to bind a 250 kDa cellular protein, suggesting that the recruitment of cellular proteins by hnRNP A1 is important for MHV RNA synthesis. Our findings establish the importance of cellular factors in viral RNA-dependent RNA synthesis.


id: cord-103306-1wc3f1rl
author: Sengupta, Sourodip
date: 2020-09-18
txt: ./txt/cord-103306-1wc3f1rl.txt
cache: ./cache/cord-103306-1wc3f1rl.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1101/2020.09.17.302877
doi: 10.1101/2020.09.17.302877
summary:
  Elevated mRNA and protein levels of tissue inhibitors of metalloproteinases 1 (TIMP-1) in MHV-A59 infection are suggestive of a TIMP-1 mediated host antiviral response. Total RNA was isolated from mock and virus-infected brain tissues 238 for expression analysis of viral nucleocapsid and Mmp genes through RT-qPCR. MMPs. To understand the regulation of MMPs upon MHV-A59 infection, we also 254 considered the gene expression of TIMPs. As described above, total RNA from brain samples 255 of mock and MHV-A59 infected mice were subjected to RT-qPCR using specific primers 256 12 (Table 1) to determine the transcript levels of Timp1, Timp2, Timp3, and Timp4. While Timp1 mRNA 260 followed a similar expression pattern as the Mmps following MHV-A59 infection-induced 261 inflammation, its protein levels remained high throughout post-infection, as shown in the 262 representative figure (Fig. 2, B) . Transcript levels of Parkinson''s disease 7 312 (Park7) gene were significantly upregulated following RSA59 infection and remained 313 elevated p.i compared to mock-infected samples (Fig. 7, A; p<0.05).

title:
  Matrix metalloproteinases and tissue inhibitors of metalloproteinases in murine coronavirus-induced neuroinflammation

abstract:
  Mouse hepatitis virus (MHV) belongs to the same beta-coronavirus family as SARS-CoV-2, MERS-CoV, and SARS-CoV. Studies have shown the requirement of host cellular proteases for priming the surface spike protein during viral entry and transmission in coronaviruses. The metzincin family of metal-dependent endopeptidases called matrix metalloproteinases (MMPs) is involved in virus encephalitis, enhanced blood-brain barrier permeability, or cell-to-cell fusion upon viral infection. Here we show the role of MMPs as mediators of virus-induced host neuroinflammatory response in the MHV model. Infection of mice with wild-type MHV-A59 or its isogenic recombinant strains, RSA59 or RSMHV2 significantly upregulated MMP-3, MMP-8, and MMP-14 transcript levels. Functional network assessment with Ingenuity Pathway Analysis revealed a direct involvement of these MMPs in disrupting junctional assembly between endothelial cells via interaction with junctional adhesion molecules and thereby facilitating transmigration of peripheral lymphocytes. Our findings also suggest mRNA upregulation of Park7, which is involved in NADPH oxidase-dependent ROS production, following RSA59 infection. RSA59 infection resulted in elevated mRNA levels of RelA, a subunit of NF-κB. Infection with MHV-A59 is known to generate ROS, and oxidative stress can activate NF-κB. Thus, our findings indicate the existence of a possible nexus between ROS, NF-κB, and MMPs in RSA59-induced neuroinflammation. We also assessed the expression of endogenously produced regulators of MMP activities. Elevated mRNA and protein levels of tissue inhibitors of metalloproteinases 1 (TIMP-1) in MHV-A59 infection are suggestive of a TIMP-1 mediated host antiviral response. Importance The newly emergent coronavirus has brought the world to a near standstill. In the past, studies have focused on the function of host proteases in virus attachment and entry. Our research indicates the involvement of a group of metal-dependent host proteases in inflammation associated with coronavirus infection. Inflammation is the first response of the host to virus infection. While it helps in restricting the spread and clearance of viral particles, uncontrolled inflammation results in several inflammatory consequences. Therefore, it becomes vital to limit unchecked host immune response. The inhibition of specific metalloproteases represents a potential new therapeutic approach in coronavirus infection and disease outcome.


id: cord-104226-bb4lyvhy
author: nan
date: 1992-09-01
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2119354/
doi: nan
title:
  Monoclonal antiprothrombinase (3D4.3) prevents mortality from murine hepatitis virus (MHV-3) infection

abstract:
  The induction of monocyte/macrophage procoagulant activity (PCA) has been implicated in the pathogenesis of murine hepatitis virus strain 3 (MHV-3) infection and disease. Previously, we have shown that induction of PCA by MHV-3 correlated with resistance/susceptibility to infection in different mouse strains. In this study, all BALB/cJ mice that were infected with 10(3) plaque-forming units of MHV-3 developed severe liver disease and died within 96-120 h. Examination of the livers of these animals showed marked hepatic necrosis, deposition of fibrin, and cellular expression of PCA by direct immunofluorescence staining in areas of necrosis as well as in hepatic sinusoids. Splenic mononuclear cells recovered from these mice expressed high concentrations of PCA with time after infection. Infusion into mice of a high-titered monoclonal antibody that neutralized PCA (3D4.3) attenuated the development of hepatic necrosis and enhanced survival in a dose- dependent manner. All of the animals receiving 100 micrograms, and 44% and 22% of the animals that received 50 and 25 micrograms per day, respectively, survived for 10 d and made a full recovery. Administration of the antibody resulted in a dose-dependent reduction in fibrin deposition, PCA expression as detected by direct immunofluorescence staining and by a functional assay. In animals treated with high concentrations of antibody, titers of antibody to PCA fell from 87 +/- 15 micrograms/ml to 100 +/- 7 ng/ml during the active phase of the disease, consistent with sequestration due to binding of the immunoglobulin to cells expressing PCA. Surviving animals, when rechallenged with MHV-3, had a 40% mortality, consistent with the known rates of metabolism of immunoglobulin. This further suggested that protection was by a passive mechanism. The results reported here demonstrate that a neutralizing antibody to PCA protects animals from fulminant hepatitis and death associated with MHV-3 infection, and supports the notion that PCA is a potent inflammatory mediator that plays a pivotal role in the pathogenesis of liver injury resulting from MHV-3 infection.


id: cord-104253-v1r0idg0
author: nan
date: 1981-10-01
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2186492/
doi: nan
title:
  Induction of monocyte procoagulant activity by murine hepatitis virus type 3 parallels disease susceptibility in mice

abstract:
  The in vitro induction of procoagulant activity (PCA) in murine peripheral blood mononuclear cells (PBM) by murine hepatitis virus type 3 (MHV-3) correlates with the disease susceptibility in three strains of mice. PBM from BALB/c mice, a strain in which MHV-3 infection results in fatal acute fulminant hepatitis, responds to the virus with a robust PCA response, whereas PBM from C3H/St mice, a strain which develops mild acute hepatitis followed by chronic hepatitis, only exhibit a modest PCA response. In contrast, PBM from A/J mice, a strain fully resistant to MHV-3, generate no increase in PCA above control levels. The induction phase of MHV-3 PCA is rapid, with an increase within 1-1.5 h, with maximum activity at 18h, and it precedes MHV-3 replication in either 17 CL1 cells, a fully permissive cell line, or in monocytes from these strains of mice. The PCA response of BALB/c PBM exceeds the response to any other known stimulus. No induction occurs upon direct stimulation of monocytes by MHV-3, but in the presence of lymphocyte collaboration, the PCA response is observed first at a lymphocyte:monocyte ratio of 2:1 and reaches a maximum as the lymphocyte:monocyte ratio approaches 4:1. This response appears to provide a functional marker for susceptibility to MHV-3 infection in inbred strains of mice and could be important in the pathogenesis of MHV-3-induced disease.


id: cord-252882-2qhoqa88
author: Hingley, Susan T.
date: 2002
txt: ./txt/cord-252882-2qhoqa88.txt
cache: ./cache/cord-252882-2qhoqa88.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/12402166/
doi: 10.1080/13550280260422703
summary:
  Targeted recombination was used to introduce amino acid substitutions into the cleavage signal of the fusion glycoprotein (spike or S protein) of MHV strain A59. The mutant cleavage and fusion phenotypes were seen only when the H716D substitution was present (Hingley et al, 1995; Leparc-Goffart et al, 1997 ; however, none of the glial cell mutants had the H716D mutation alone, so it was necessary to isolate recombinant viruses expressing the H716D mutation alone in order to assess the potential affect of this particular mutation on cleavage of S, fusogenicity, and virulence. Previous studies from this laboratory using mutants isolated from persistently infected glial cells (Gombold et al, 1993) have suggested that an H716D mutation, which changes the RRAHR cleavage signal to an RRADR sequence, is associated with an uncleaved S protein, but did not directly assess the affect of that mutation on virulence.

title:
  The virulence of mouse hepatitis virus strain A59 is not dependent on efficient spike protein cleavage and cell-to-cell fusion

abstract:
  The cleavage and fusion properties of recombinant murine hepatitis viruses (MHV) were examined to assess the role of the cleavage signal in determining the extent of S protein cleavage, and the correlation between cleavage and induction of cell-to-cell fusion. Targeted recombination was used to introduce amino acid substitutions into the cleavage signal of the fusion glycoprotein (spike or S protein) of MHV strain A59. The recombinants were then used to address the question of the importance of S protein cleavage and viral-mediated cell-to-cell fusion on pathogenicity. Our data indicate that cleavage of spike is not solely determined by the amino acid sequence at the cleavage site, but may also depend on sequences removed from the cleavage site. In addition, efficient cell-to-cell fusion is not necessary for virulence.


id: cord-253024-b393ea2u
title: Evidence for variable rates of recombination in the MHV genome
author: Fu, Kaisong
date: 1992-07-31
url: https://www.sciencedirect.com/science/article/pii/004268229290684H
doi: 10.1016/0042-6822(92)90684-h
abstract:
  Abstract Mouse hepatitis virus has been shown to undergo RNA recombination at high frequency during mixed infection. Temperature-sensitive mutants were isolated using 5-fluorouracil and 5-azacytidine as mutagen. Six RNA+ mutants that reside within a single complementation group mapping within the S glycoprotein gene of MHV-A59 were isolated which did not cause syncytium at the restrictive temperature. Using standard genetic techniques, a recombination map was established that indicated that these mutants mapped into two distinct domains designated F1 and F2. These genetic domains may correspond to mutations mapping within the S1 and S2 glycoproteins, respectively, and suggest that both the S1 and S2 domains are important in eliciting the fusogenic activity of the S glycoprotein gene. In addition, assuming that most distal is alleles map roughly 4.0 kb apart, a recombination frequency of 1 % per 575–676 by was predicted through the S glycoprotein gene. Interestingly, this represents a threefold increase in the recombination frequency as compared to rates predicted through the polymerase region. The increase in the recombination rate was probably not due to recombination events resulting in large deletions or insertions (>50 bp), but rather was probably due to a combination of homologous and nonhomologous recombination. A variety of explanations could account for the increased rates of recombination in the S gene.


id: cord-254871-qmx74umk
author: Barthold, Stephen W.
date: 1987-05-31
txt: ./txt/cord-254871-qmx74umk.txt
cache: ./cache/cord-254871-qmx74umk.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/3037819/
doi: 10.1016/0168-1702(87)90030-x
summary:
  Abstract Mouse hepatitis virus (MHV)-JHM infection was studied in genetically susceptible (BALB/cByJ) and resistant (SJL/J) mice following intranasal inoculation at 1, 3, 6 or 12 wk of age. Mouse hepatitis virus (MH~-JH~ infection was studied in genetically susceptible (BALB/cBy~ and resistant (SJL/J) mice follo~ng intranasal inoculation at 1, 3, 6 or 12 wk of age. The following tissues were specifically examined for MHV antigen and lesions in mice of both genotypes, all ages and all intervals: nose, eye, brain, spinal cord, lung, liver, spleen, submaxillary and mesenteric lymph nodes, salivary glands, bone and bone marrow, small intestine, cecum, colon, kidney, urinary bladder and gonad. Lesions and antigen of 1-wk-old SJL mice resembled BALB mice, and were found in nose, olfactory bulb, brain, liver, spleen, lymph nodes, bone marrow and gut associated lymphoid tissue (Fig. 1 ). Titers of MHV-JHM were determined in brain, liver, spleen and intestine at 0, 3, 5,10,20 and 30 days after inoculation of Gwk-old BALB and SJL mice (Fig. 8) .

title:
  Response of genetically susceptible and resistant mice to intranasal inoculation with mouse hepatitis virus JHM

abstract:
  Abstract Mouse hepatitis virus (MHV)-JHM infection was studied in genetically susceptible (BALB/cByJ) and resistant (SJL/J) mice following intranasal inoculation at 1, 3, 6 or 12 wk of age. Markers of infection included histology, immunohistochemistry, virus quantification and virus serology. All BALE mice developed severe disseminated disease with high mortality due to encephalitis and hepatitis. Peak MHV titers appeared in brain, liver, spleen and intestine on days 3 or 5. Age at inoculation did not influence virus titers in brain, spleen or intestine, but virus titers in liver were inversely proportional to age at inoculation. In 6-wk-old BALE mice, virus was cleared from spleen, intestine and liver by day 30 and from brain by day 60. In intestine, MHV was localized to lymphoid tissue, without fecal excretion. SJL mice of all ages developed remarkably milder disease with low mortality occurring only among mice inoculated at 1 wk of age. SJL mice inoculated at 1 wk had disseminated infection at day 3, but lesions and antigen were cleared from most organs by day 5. Mice inoculated at 3 and 6 wk of age had minimal or no involvement of peripheral organs, and mice inoculated at 12 wk of age had infections restricted to the nose. At day 5, MHV titers in brain, liver, spleen and intestine were significantly lower or undetectable in SJL mice of all ages compared to age-matched BALB mice. In 6-wk-old mice, MHV was cleared from all organs by day 10. Serum antibody titers to MHV were many-fold higher in BALB mice, compared to SJL mice, which mounted only a modest response.


id: cord-256149-btjq84q7
title: The peptide specificities of the autoantibodies elicited by mouse hepatitis virus A59
author: Duhalde-Vega, Maite
date: 2006-10-31
txt: ./txt/cord-256149-btjq84q7.txt
cache: ./cache/cord-256149-btjq84q7.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S0896841106000783
doi: 10.1016/j.jaut.2006.09.003
summary:
  Synthetic decapeptides (N = 206) covering the entire sequence of mouse liver fumarylacetoacetate hydrolase (FAH) were used to analyze the specificities of the autoantibodies (autoAb) elicited towards this enzyme in mice infected with mouse hepatitis virus (MHV). Results indicated that the induction of the autoAb is not only related to molecular or structural mimicry, but rather supports the Danger model, in which any aggression, in this case the MHV infection, is susceptible to trigger the production of autoAb. Mouse hepatitis virus strain A59 (MHV-A59) is a coronavirus that triggers various pathologies in susceptible mice, including hepatitis and thymus involution, IgG2a-restricted hypergammaglobulinaemia and transient demyelination [1, 2] . Overlapping decapeptides corresponding to the entire mouse FAH sequence were prepared using the PEPSCAN method and their reactivities with sera from MHV-infected mice at different times was determined by ELISA. Results indicated that various regions of the enzyme, including sequence 1e20, are recognized as soon as 15 days after infection and that the autoimmune response is not restricted to peptides homologous to viral proteins.

abstract:
  Synthetic decapeptides (N = 206) covering the entire sequence of mouse liver fumarylacetoacetate hydrolase (FAH) were used to analyze the specificities of the autoantibodies (autoAb) elicited towards this enzyme in mice infected with mouse hepatitis virus (MHV). These autoAb bound mainly to N- and C-terminal FAH peptides, the most reactive sequences being 1–50 and 390–420, respectively. Surprisingly, although FAH sequence 1–50 shares a high degree of homology with various MHV proteins, the C-terminal portion does not. Moreover, whereas the autoAb reacted with homologous peptides surrounding residues 70, 160 and 360, non-similar sequences around residues 130, 210, 240, 250, and 300 were also recognized, indicating that autoAb were not restricted to epitopes with sequence homologies. There was also a lack of correlation between the amount of anti-MHV or anti-FAH antibodies produced and the reactivity towards the peptides. Moreover, the spectrum of peptides recognized by the autoAb of a given mouse did not change significantly with time, which suggests that the MHV-elicited autoimmune response does not induce an epitope recognition spreading. Finally, anti-FAH Ab produced after immunization with rat liver FAH recognized essentially the same mouse FAH regions than autoAb from MHV-infected mice. Results indicated that the induction of the autoAb is not only related to molecular or structural mimicry, but rather supports the Danger model, in which any aggression, in this case the MHV infection, is susceptible to trigger the production of autoAb.


id: cord-256444-grw5s2pf
title: The Molecular Biology of Coronaviruses
author: Lai, Michael M.C.
date: 1997-12-31
txt: ./txt/cord-256444-grw5s2pf.txt
cache: ./cache/cord-256444-grw5s2pf.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S0065352708602869
doi: 10.1016/s0065-3527(08)60286-9
summary:
  Publisher Summary This chapter discusses the manipulation of clones of coronavirus and of complementary DNAs (cDNAs) of defective-interfering (DI) RNAs to study coronavirus RNA replication, transcription, recombination, processing and transport of proteins, virion assembly, identification of cell receptors for coronaviruses, and processing of the polymerase. This decade has seen the manipulation of these clones, and of complementary DNAs (cDNAs) of defective-interfering (DI) RNAs, to study coronavirus RNA replication, transcription, recombination, processing and transport of proteins, virion assembly, identification of cell receptors for coronaviruses, and processing of the polymerase. The species and tissue specificity of a coronavirus infection is a t least partially dictated by the nature and distribution of cellular receptors and other related molecules that regulate virus entry, as evidenced by the viral replication that results when viral RNA is directly introduced into cell types of other animal species.

abstract:
  Publisher Summary This chapter discusses the manipulation of clones of coronavirus and of complementary DNAs (cDNAs) of defective-interfering (DI) RNAs to study coronavirus RNA replication, transcription, recombination, processing and transport of proteins, virion assembly, identification of cell receptors for coronaviruses, and processing of the polymerase. The nature of the coronavirus genome is nonsegmented, single-stranded, and positive-sense RNA. Its size ranges from 27 to 32 kb, which is significantly larger when compared with other RNA viruses. The gene encoding the large surface glycoprotein is up to 4.4 kb, encoding an imposing trimeric, highly glycosylated protein. This soars some 20 nm above the virion envelope, giving the virus the appearance-with a little imagination-of a crown or coronet. Coronavirus research has contributed to the understanding of many aspects of molecular biology in general, such as the mechanism of RNA synthesis, translational control, and protein transport and processing. It remains a treasure capable of generating unexpected insights.


id: cord-258286-lodjcj8c
author: Zhang, Xuming
date: 1997-07-07
txt: ./txt/cord-258286-lodjcj8c.txt
cache: ./cache/cord-258286-lodjcj8c.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S0042682297985986
doi: 10.1006/viro.1997.8598
summary:
  Previous studies have shown that immunocoma large plaque variant derived from the parental JHM petent mice infected with MHV exhibited increased exstrain (Stohlman et al., 1982) ; the small plaque variant pression of a number of cytokines, including IL-1, IL-6, DS (Stohlman et al., 1982) ; the neutralization-escape mu-TNF-a, and IFN-g, in the CNS at the time of viral cleartant 2.2-V-1 (Fleming et al., 1987; Wang et al., 1992) , and ance (Pearce et al., 1994) . The expressed IFNg exhibited antiviral activity, prevented virus spread in layers of DBT cells grown at approximately 70% confluence in 60-mm petri dishes were infected with MHV at vitro, and altered viral pathogenesis in mice. Expression of IFN-g using an MHV DI RNA vector cell metabolism prior to infection or it may be that interferon acts at an early stage of viral replication.

title:
  Expression of Interferon-γ by a Coronavirus Defective-Interfering RNA Vector and Its Effect on Viral Replication, Spread, and Pathogenicity

abstract:
  Abstract A defective-interfering (DI) RNA of the murine coronavirus mouse hepatitis virus (MHV) was developed as a vector for expressing interferon-γ (IFN-γ). The murine IFN-γ gene was cloned into the DI vector under the control of an MHV transcriptional promoter and transfected into MHV-infected cells. IFN-γ was secreted into culture medium as early as 6 hr posttransfection and reached a peak level (up to 180 U/ml) at 12 hr posttransfection. The DI-expressed IFN-γ (DE-IFN-γ) exhibited an antiviral activity comparable to that of recombinant IFN-γ and was blocked by a neutralizing monoclonal antibody against IFN-γ. Treatment of macrophages with DE-IFN-γ selectively induced the expression of the cellular inducible nitric oxide synthase and the IFN-γ-inducing factor (IGIF) but did not affect the amounts of the MHV receptor mRNA. Antiviral activity was detected only when cells were pretreated with IFN-γ for 24 hr prior to infection; no inhibition of virus replication was detected when cells were treated with IFN-γ during or after infection. Furthermore, addition of IFN-γ together with MHV did not prevent infection, but appeared to prevent subsequent viral spread. MHV variants with different degrees of neurovirulence in mice had correspondingly different levels of sensitivities to IFN-γ treatmentin vitro,with the most virulent strain being most resistant to IFN-γ treatment. Infection of susceptible mice with DE-IFN-γ-containing virus caused significantly milder disease, accompanied by more pronounced mononuclear cell infiltrates into the CNS and less virus replication, than that caused by virus containing a control DI vector. This study thus demonstrates the feasibility and usefulness of this MHV DI vector for expressing cytokines and may provide a model for studying the role of cytokines in MHV pathogenesis.


id: cord-259095-mfptcw8t
title: Determinants of Mouse Hepatitis Virus 3C-like Proteinase Activity
author: Lu, Yiqi
date: 1997-04-14
url: https://www.ncbi.nlm.nih.gov/pubmed/9143289/
doi: 10.1006/viro.1997.8479
abstract:
  Abstract The coronavirus, mouse hepatitis virus strain A59 (MHV), expresses a chymotrypsin-like cysteine proteinase (3CLpro) within the gene 1 polyprotein. The MHV 3CLpro is similar to the picornavirus 3C proteinases in the relative location of confirmed catalytic histidine and cysteine residues and in the predicted use of Q/(S, A, G) dipeptide cleavage sites. However, less is known concerning the participation of aspartic acid or glutamic acid residues in catalysis by the coronavirus 3C-like proteinases or of the precise coding sequence of 3CLpro within the gene 1 polyprotein. In this study, aspartic acid residues in MHV 3CLpro were mutated and the mutant proteinases were tested for activity in anin vitro transcleavage assay. MHV 3CLpro was not inactivated by substitutions at Asp3386(D53) or Asp3398(D65), demonstrating that they were not catalytic residues. MHV 3CLpro was able to cleave at a glutamine–glycine (QG3607-8) dipeptide within the 3CLpro domain upstream from the predicted carboxy-terminal QS3635-6cleavage site of 3CLpro. The predicted full-length 3CLpro (S3334to Q3635) had an apparent mass of 27 kDa, identical to the p27 3CLpro in cells, whereas the truncated proteinase (S3334to Q3607) had an apparent mass of 24 kDa. This 28-amino-acid carboxy-terminal truncation of 3CLpro rendered it inactive in atranscleavage assay. Thus, MHV 3CLpro was able to cleave at a site within the putative full-length proteinase, but the entire predicted 3CLpro domain was required for activity. These studies suggest that the coronavirus 3CL-proteinases may have a substantially different structure and catalytic mechanism than other 3C-like proteinases.


id: cord-259374-m7q1roay
author: Agostini, Maria L.
date: 2019-11-26
url: https://doi.org/10.1128/jvi.01348-19
doi: 10.1128/jvi.01348-19
title:
  Small-Molecule Antiviral β-d-N(4)-Hydroxycytidine Inhibits a Proofreading-Intact Coronavirus with a High Genetic Barrier to Resistance

abstract:
  Coronaviruses (CoVs) have emerged from animal reservoirs to cause severe and lethal disease in humans, but there are currently no FDA-approved antivirals to treat the infections. One class of antiviral compounds, nucleoside analogues, mimics naturally occurring nucleosides to inhibit viral replication. While these compounds have been successful therapeutics for several viral infections, mutagenic nucleoside analogues, such as ribavirin and 5-fluorouracil, have been ineffective at inhibiting CoVs. This has been attributed to the proofreading activity of the viral 3′-5′ exoribonuclease (ExoN). β-d-N(4)-Hydroxycytidine (NHC) (EIDD-1931; Emory Institute for Drug Development) has recently been reported to inhibit multiple viruses. Here, we demonstrate that NHC inhibits both murine hepatitis virus (MHV) (50% effective concentration [EC(50)] = 0.17 μM) and Middle East respiratory syndrome CoV (MERS-CoV) (EC(50) = 0.56 μM) with minimal cytotoxicity. NHC inhibited MHV lacking ExoN proofreading activity similarly to wild-type (WT) MHV, suggesting an ability to evade or overcome ExoN activity. NHC inhibited MHV only when added early during infection, decreased viral specific infectivity, and increased the number and proportion of G:A and C:U transition mutations present after a single infection. Low-level NHC resistance was difficult to achieve and was associated with multiple transition mutations across the genome in both MHV and MERS-CoV. These results point to a virus-mutagenic mechanism of NHC inhibition in CoVs and indicate a high genetic barrier to NHC resistance. Together, the data support further development of NHC for treatment of CoVs and suggest a novel mechanism of NHC interaction with the CoV replication complex that may shed light on critical aspects of replication. IMPORTANCE The emergence of coronaviruses (CoVs) into human populations from animal reservoirs has demonstrated their epidemic capability, pandemic potential, and ability to cause severe disease. However, no antivirals have been approved to treat these infections. Here, we demonstrate the potent antiviral activity of a broad-spectrum ribonucleoside analogue, β-d-N(4)-hydroxycytidine (NHC), against two divergent CoVs. Viral proofreading activity does not markedly impact sensitivity to NHC inhibition, suggesting a novel interaction between a nucleoside analogue inhibitor and the CoV replicase. Further, passage in the presence of NHC generates only low-level resistance, likely due to the accumulation of multiple potentially deleterious transition mutations. Together, these data support a mutagenic mechanism of inhibition by NHC and further support the development of NHC for treatment of CoV infections.


id: cord-259580-fn5pkec9
author: Shi, Xiaodong
date: 2020-05-08
url: https://doi.org/10.1016/j.intimp.2020.106578
doi: 10.1016/j.intimp.2020.106578
title:
  Glycyrrhetinic acid alleviates hepatic inflammation injury in viral hepatitis disease via a HMGB1-TLR4 signaling pathway

abstract:
  Various human disorders are cured by the use of licorice, a key ingredient of herbal remedies. Glycyrrhizic acid (GL), a triterpenoid glycoside, is the aqueous extract from licorice root. Glycyrrhetinic acid (GA) has been reported to be a major bioactive hydrolysis product of GL and has been regarded as an anti-inflammatory agent for the treatment of a variety of inflammatory diseases, including hepatitis. However, the mechanism by which GA inhibits viral hepatic inflammatory injury is not completely understood. In this study, we found that, by consecutively treating mice with a traditional herbal recipe, licorice plays an important role in the detoxification of mice. We also employed a murine hepatitis virus (MHV) infection model to illustrate that GA treatment inhibited activation of hepatic inflammatory responses by blocking high-mobility group box 1 (HMGB1) cytokine activity. Furthermore, decreased HMGB1 levels and downstream signaling triggered by injection of a neutralizing HMGB1 antibody or TLR4 gene deficiency, also significantly protected against MHV-induced severe hepatic injury. Thus, our findings characterize GA as a hepatoprotective therapy agent in hepatic infectious disease not only by suppressing HMGB1 release and blocking HMGB1 cytokine activity, but also via an underlying viral-induced HMGB1-TLR4 immunological regulation axis that occurs during the cytokine storm. The present study provides a new therapy strategy for the treatment of acute viral hepatitis in the clinical setting.


id: cord-259603-bh198xgl
title: The Nonstructural Proteins Directing Coronavirus RNA Synthesis and Processing
author: Snijder, E.J.
date: 2016-09-14
url: https://api.elsevier.com/content/article/pii/S0065352716300471
doi: 10.1016/bs.aivir.2016.08.008
abstract:
  Coronaviruses are animal and human pathogens that can cause lethal zoonotic infections like SARS and MERS. They have polycistronic plus-stranded RNA genomes and belong to the order Nidovirales, a diverse group of viruses for which common ancestry was inferred from the common principles underlying their genome organization and expression, and from the conservation of an array of core replicase domains, including key RNA-synthesizing enzymes. Coronavirus genomes (~ 26–32 kilobases) are the largest RNA genomes known to date and their expansion was likely enabled by acquiring enzyme functions that counter the commonly high error frequency of viral RNA polymerases. The primary functions that direct coronavirus RNA synthesis and processing reside in nonstructural protein (nsp) 7 to nsp16, which are cleavage products of two large replicase polyproteins translated from the coronavirus genome. Significant progress has now been made regarding their structural and functional characterization, stimulated by technical advances like improved methods for bioinformatics and structural biology, in vitro enzyme characterization, and site-directed mutagenesis of coronavirus genomes. Coronavirus replicase functions include more or less universal activities of plus-stranded RNA viruses, like an RNA polymerase (nsp12) and helicase (nsp13), but also a number of rare or even unique domains involved in mRNA capping (nsp14, nsp16) and fidelity control (nsp14). Several smaller subunits (nsp7–nsp10) act as crucial cofactors of these enzymes and contribute to the emerging “nsp interactome.” Understanding the structure, function, and interactions of the RNA-synthesizing machinery of coronaviruses will be key to rationalizing their evolutionary success and the development of improved control strategies.


id: cord-259671-7de21oaq
title: RNA structure analysis of alphacoronavirus terminal genome regions
author: Madhugiri, Ramakanth
date: 2014-12-19
txt: ./txt/cord-259671-7de21oaq.txt
cache: ./cache/cord-259671-7de21oaq.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S0168170214004055
doi: 10.1016/j.virusres.2014.10.001
summary:
  Overall, the conservation pattern identified for 5′ and 3′-terminal RNA structural elements in the genomes of alphaand betacoronaviruses is in agreement with the widely used replicase polyprotein-based classification of the Coronavirinae, suggesting co-evolution of the coronavirus replication machinery with cognate cis-acting RNA elements. Other internal cis-acting elements include specific RNA signals required for genome packing, which have been characterized in a small number of coronaviruses Escors et al., 2003; Morales et al., 2013; Penzes et al., 1994) , and a complex RNA pseudoknot structure located in the ORF1a-ORF1b overlap region that mediates a (−1) ribosomal frameshift event and thus controls the expression of the second large ORF on the coronavirus genome RNA (ORF1b) (Brierley et al., 1987 (Brierley et al., , 1989 de Haan et al., 2002; Namy et al., 2006) .

abstract:
  Coronavirus genome replication is mediated by a multi-subunit protein complex that is comprised of more than a dozen virally encoded and several cellular proteins. Interactions of the viral replicase complex with cis-acting RNA elements located in the 5′ and 3′-terminal genome regions ensure the specific replication of viral RNA. Over the past years, boundaries and structures of cis-acting RNA elements required for coronavirus genome replication have been extensively characterized in betacoronaviruses and, to a lesser extent, other coronavirus genera. Here, we review our current understanding of coronavirus cis-acting elements located in the terminal genome regions and use a combination of bioinformatic and RNA structure probing studies to identify and characterize putative cis-acting RNA elements in alphacoronaviruses. The study suggests significant RNA structure conservation among members of the genus Alphacoronavirus but also across genus boundaries. Overall, the conservation pattern identified for 5′ and 3′-terminal RNA structural elements in the genomes of alpha- and betacoronaviruses is in agreement with the widely used replicase polyprotein-based classification of the Coronavirinae, suggesting co-evolution of the coronavirus replication machinery with cognate cis-acting RNA elements.


id: cord-260177-xu0elmak
author: Collins, Arlene R.
date: 1982-06-30
url: https://api.elsevier.com/content/article/pii/0042682282900952
doi: 10.1016/0042-6822(82)90095-2
title:
  Monoclonal antibodies to murine hepatitis virus-4 (strain JHM) define the viral glycoprotein responsible for attachment and cell-cell fusion

abstract:
  Abstract Hybridoma cell lines producing monoclonal antibodies to the JHM strain of mouse hepatitis virus-4 (MHV-4) were established. By indirect immunofluorescence and immune precipitation, monoclonal antibodies of three viral polypeptide specificities were characterized. Monoclonal antibodies to nucleocapsid reacted in the cytoplasm of infected cells and precipitated the 60,000d nucleocapsid polypeptide (VP-4) of MHV-4. Other monoclonal antibodies reacted both in the cytoplasm and on the surface of infected cells and were found to precipitate the 170,000d viral glycoprotein (GP-1). A third set of monoclonal antibodies reacted both in the cytoplasm and on the surface of infected cells and precipitated the 25,000d viral glycoprotein (GP-5) and its precursor VP-6 (23,000d). AntiGP-1 alone had direct neutralizing activity for MHV-4 virus, while in the presence of complement both anti-GP-1 and anti-GP-5 neutralized virus. Only anti-GP-1 had the ability to inhibit the spread of infection due to fusion in L241 cells. Thus, the viral glycoprotein GP-1 likely contains both the attachment and fusion activities of MHV-4.


id: cord-261291-0lntii22
author: Talbot, Pierre J.
date: 1985-06-30
txt: ./txt/cord-261291-0lntii22.txt
cache: ./cache/cord-261291-0lntii22.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/2412363/
doi: 10.1016/0168-1702(85)90028-0
summary:
  Abstract A panel of 28 monoclonal antibodies (MAb) against the structural proteins of murine hepatitis virus-4, strain JHM (MHV-4) was used in three antigen binding assays to determine the extent of antigenic homology among six strains of murine coronaviruses. Antigenic preparations for dot immunoblotting and enzyme immunoassays (EIA) consisted of microsomal fractions from MHV infected or uninfected control cells, as described previously (Talbot et al., 1984a) . (1983) , extensive conservation of the El glycoprotein was evident and similar levels of antibody binding were seen on each MHV strain, with the exception of the ts8 mutant of MHV-4. 28 monoclonal antibodies against the JHM strain of murine hepatitis virus (MHV-4) were used in three different antigen binding assays to delineate antigenic relationships among the structural proteins of six MHV strains.

title:
  Antigenic variation among murine coronaviruses: Evidence for polymorphism on the peplomer glycoprotein, E2

abstract:
  Abstract A panel of 28 monoclonal antibodies (MAb) against the structural proteins of murine hepatitis virus-4, strain JHM (MHV-4) was used in three antigen binding assays to determine the extent of antigenic homology among six strains of murine coronaviruses. The antigenic determinants studied were highly conserved on the E1 glycoproteins and nucleocapsid (N) proteins of all strains tested. In contrast, antigenic polymorphism was observed among the E2 glycoproteins. Of three previously described antigenic determinants against which neutralizing antibodies are directed, only one, termed A(E2), was conserved on all strains. Antigenic site B(E2) was found only on the strongly neurotropic MHV-4 and site C(E2) was present on the virulent MHV-4 and MHV-3 (hepatotropic) strains, but absent on the weakly pathogenic MHV-A59, MHV-1 and MHV-S strains. Four non-neutralizing antibodies against at least one topographically distinct antigenic determinant, which we previously designated D(E2), gave binding patterns consistent with two distinct sites. One of these was present on all MHV strains tested and the other was present on all strains except MHV-S. These non-neutralizing antigenic sites were redesignated E(E2) and D(E2) respectively.


id: cord-262505-1ufgwxxg
title: Genetic heterogeneity of murine coronaviruses
author: Lai, M. M. C.
date: 1983
url: https://www.ncbi.nlm.nih.gov/pubmed/6318691/
doi: 10.1007/bf01311312
abstract:
  Several mouse hepatitis viruses (MHV) with different pathogenicity were studied by oligonucleotide fingerprinting. Two strains, MHV-K and MHV-D, which were isolated in Japan and, which cause anaplasia and necrosis of bone marrow and diarrhea, respectively, were found to be closely related to MHV-A59, the prototype MHV. Two other MHV strains, isolated from nude mice, were found to have diverged extensively from the known MHV strains. The MHVs isolated from separate cloned neuroblastoma cell lines persistently infected with JHM strain were also found to have diverged more markedly than the corresponding virus maintained under the conditions of lytic infection. Genetic divergence during persistent infection may be one of the mechanisms by which the MHV diverges.


id: cord-263658-dlmzcl9g
title: SEROEPIDEMIOLOGIC STUDIES OF CORONAVIRUS INFECTION IN ADULTS AND CHILDREN(1)
author: MCINTOSH, KENNETH
date: 1970-06-17
txt: ./txt/cord-263658-dlmzcl9g.txt
cache: ./cache/cord-263658-dlmzcl9g.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/4315625/
doi: 10.1093/oxfordjournals.aje.a121171
summary:
  authors: MCINTOSH, KENNETH; KAPIKIAN, ALBERT Z.; TURNER, HORACE C.; HARTLEY, JANET W.; PARROTT, ROBERT H.; CHANOCK, ROBERT M. Table 1 shows the proportion of infants and children with and without LRTD showing fourfold or greater antibody responses to the three related coronavirus antigens OC38, OC43, and MHV, strain A-59. It is evident from the studies of hospitalized children that infection with coronaviruses was not significantly associated in this survey with pediatric lower respiratory tract disease. It is of interest that in the seroepidemiologic studies of Hartley and others, where several strains of MHV were tested with sera from military recruits, no epidemiologic association of MHV or MHV-like virus infection with respiratory tract disease was made (11) . Antigenic studies of human coronaviruses have shown that those members of the group which were originally recovered in tissue culture are all closely related to the prototype virus strain 229E (2, 5) .

abstract:
  McIntosh, K. A. Z. Kapikian, H. C Turner, J. W. Hartley, R. H. Parrott and R. M. Chanock. (Lab. of Infectious Diseases, NIAID, NIH, Bethesda, Md. 20014) Sero-epidemiologic studies of coronavirus infection in adults and children. Amer. J. Epid., 1970, 97: 585–592-A seroepidemiologic study of infection by coronavirus strains 229E, OC38, OC43, and mouse hepatitis virus (MHV) strain A-59, is described. In adults with upper respiratory disease, two “outbreaks” of coronavirus infection occurred, one during the winter of 1965–1966 associated with complement fixing (CF) antibody responses to OC38, OC43 and MHV, and the other during the following winter associated with CF antibody responses to 229E. In hospitalized children, infection with 229E was rare; infection with OC38, OC43, and MHV occurred less often in hospitalized children with lower respiratory tract disease (3.5%) than in a control group with non-respiratory tract disease (8.2%). The limitations of the CF test using available coronavirus antigens are discussed.


id: cord-263678-z94utwbk
author: Fu, Li
date: 2004
txt: ./txt/cord-263678-z94utwbk.txt
cache: ./cache/cord-263678-z94utwbk.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/14982727/
doi: 10.1080/13550280490262229
summary:
  The authors have previously shown that the spike (S) glycoprotein gene of MHV contains determinants of virulence, hepatitis, and demyelination. In the present study, the authors produced new recombinant viruses with each one of these S gene mutations by site-directed mutagenesis and targeted recombination and studied the effect of each individual mutation on the pathogenesis of the virus. The use of the virus with feline spike protein (fMHV) also provided a Coronavirus S gene demyelination determinants L Fu et al 43 useful method to select recombinant viruses against the background of parental viruses. Viral RNA persistence of all recombinant and parental viruses in mouse organs (brain, spinal cord and liver) was analyzed by reverse transcriptase L Fu et al Figure 3 Pathologic analysis of recombinant viruses during acute infection. Targeted recombination within the spike gene of murine coronavirus mouse hepatitis virus-A59: Q159 is a determinant of hepatotropism

title:
  A combination of mutations in the S1 part of the spike glycoprotein gene of coronavirus MHV-A59 abolishes demyelination

abstract:
  The A59 strain of coronavirus, mouse hepatitis virus (MHV), produces acute hepatitis, meningoencephalitis, and chronic demyelination. The authors have previously shown that the spike (S) glycoprotein gene of MHV contains determinants of virulence, hepatitis, and demyelination. They then identified viruses containing mutations in the S gene that exhibit alterations in viral pathogenesis. In the present study, the authors produced new recombinant viruses with each one of these S gene mutations by site-directed mutagenesis and targeted recombination and studied the effect of each individual mutation on the pathogenesis of the virus. They identified a combination of mutations in the S1 gene (I375M and L652I) that abolishes demyelination. Individual mutation and other combinations of mutations in the S gene only interfere with virulence and hepatitis and only reduce demyelination (I375M), but do not abolish demyelination completely. Thus, demyelination determinants exist within genomic regions on both sides of the hypervariable region, downstream from the receptor-binding domain in the S1 part of the MHV spike glycoprotein gene. The structure and precise function of these regions awaits further investigation.


id: cord-264848-wl29jk16
author: Totoiu, Minodora O.
date: 2004-03-21
txt: ./txt/cord-264848-wl29jk16.txt
cache: ./cache/cord-264848-wl29jk16.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S001448860400041X
doi: 10.1016/j.expneurol.2004.01.028
summary:
  Transplantation of glial-committed progenitor cells into the T8 spinal cord of MHV-infected mice demonstrating complete hindlimb paralysis resulted in migration of cells up to 12 mm from the implantation site and remyelination of up to 67% of axons. Counts of the total number of axons (normally myelinated, demyelinated, and remyelinated) within the region extending 8 mm cranial and 6 mm caudal to the transplantation site (the extent of spinal cord examined) suggest that transplanted animals had significantly more axons ( P < 0.01) within the ventral and lateral columns as compared to non-transplanted animals (Figs. Multipotential PSA-NCAM + neural precursors isolated from the postnatal rat brain have been shown to differentiate into oligodendrocytes, Schwann cells, and astrocytes following transplantation, to completely remyelinate regions of acute demyelination in the adult rat induced by ethidium bromide injection into x-irradiated dorsal column white matter .

title:
  Remyelination, axonal sparing, and locomotor recovery following transplantation of glial-committed progenitor cells into the MHV model of multiple sclerosis

abstract:
  The behavior and myelinogenic properties of glial cells have been well documented following transplantation into regions of focal experimental demyelination in animal models. However, the ability of glial cell preparations to remyelinate in such models does not necessarily indicate that their transplantation into demyelinated lesions in clinical disease will be successful. One of the precluding factors in this regard is a greater understanding of the environmental conditions that will support transplant-mediated remyelination. In this study, we determined whether the complex and reactive CNS environment of the mouse hepatitis virus (MHV) model of multiple sclerosis (MS) could support transplant-mediated remyelination. Striatal neural precursors derived from postnatal day 1 mice were committed to a glial cell lineage and labeled. Immunohistochemical staining indicated that this population generated >93% glial cells following differentiation in vitro. Transplantation of glial-committed progenitor cells into the T8 spinal cord of MHV-infected mice demonstrating complete hindlimb paralysis resulted in migration of cells up to 12 mm from the implantation site and remyelination of up to 67% of axons. Transplanted-remyelinated animals contained approximately 2× the number of axons within sampled regions of the ventral and lateral columns as compared to non-transplanted animals, suggesting that remyelination is associated with axonal sparing. Furthermore, transplantation resulted in behavioral improvement. This study demonstrates for the first time that transplant-mediated remyelination is possible in the pathogenic environment of the MHV demyelination model and that it is associated with locomotor improvement.


id: cord-264884-ydkigome
title: The Widespread Evolutionary Significance of Viruses
author: Villarreal, Luis P.
date: 2008-07-05
url: https://api.elsevier.com/content/article/pii/B9780123741530000217
doi: 10.1016/b978-0-12-374153-0.00021-7
abstract:
  In the last 30 years, the study of virus evolution has undergone a transformation. Originally concerned with disease and its emergence, virus evolution had not been well integrated into the general study of evolution. This chapter reviews the developments that have brought us to this new appreciation for the general significance of virus evolution to all life. We now know that viruses numerically dominate all habitats of life, especially the oceans. Theoretical developments in the 1970s regarding quasispecies, error rates, and error thresholds have yielded many practical insights into virus–host dynamics. The human diseases of HIV-1 and hepatitis C virus cannot be understood without this evolutionary framework. Yet recent developments with poliovirus demonstrate that viral fitness can be the result of a consortia, not one fittest type, a basic Darwinian concept in evolutionary biology. Darwinian principles do apply to viruses, such as with Fisher population genetics, but other features, such as reticulated and quasispecies-based evolution distinguish virus evolution from classical studies. The available phylogenetic tools have greatly aided our analysis of virus evolution, but these methods struggle to characterize the role of virus populations. Missing from many of these considerations has been the major role played by persisting viruses in stable virus evolution and disease emergence. In many cases, extreme stability is seen with persisting RNA viruses. Indeed, examples are known in which it is the persistently infected host that has better survival. We have also recently come to appreciate the vast diversity of phage (DNA viruses) of prokaryotes as a system that evolves by genetic exchanges across vast populations (Chapter 10). This has been proposed to be the “big bang” of biological evolution. In the large DNA viruses of aquatic microbes we see surprisingly large, complex and diverse viruses. With both prokaryotic and eukaryotic DNA viruses, recombination is the main engine of virus evolution, and virus host co-evolution is common, although not uniform. Viral emergence appears to be an unending phenomenon and we can currently witness a selective sweep by retroviruses that infect and become endogenized in koala bears.


id: cord-265895-ck7eto16
author: Baric, Ralph S.
date: 1987-02-28
txt: ./txt/cord-265895-ck7eto16.txt
cache: ./cache/cord-265895-ck7eto16.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/0042682287904144
doi: 10.1016/0042-6822(87)90414-4
summary:
  These data, coupled with the high frequency of RNA recombination during MHV infection, suggest that the viral polymerase may pause in or around regions of secondary structure, thereby generating pools of free leader-containing RNA intermediates which can reassociate with the template, acting as primers for the synthesis of full-length or recombinant RNAs. These data suggest that MHV transcription uses a discontinuous and nonprocessive mechanism in which RNA polymerase allows the partial RNA products to be dissociated from the template temporarily during the process of transcription. These data, coupled with the presence of discrete large leader-containing RNAs which range from 84 to 1000 nucleotides in length in MHV-infected cells (Baric et a/., 1985) suggest that discontinuous RNA intermediates may be dissociated and reassert between viral RNA templates to generate recombinant viruses by a copy-choice mechanism (Makino eta/., 1986a). The leader-containing RNAs larger than 1 10 nucleotides in length detected by the leader-specific cDNA probe were more heterogeneous (Fig. 2) (Baric et al., 1985) suggesting that multiple RNA species in this size range were present.

title:
  Analysis of intracellular small RNAs of mouse hepatitis virus: evidence for discontinuous transcription

abstract:
  Abstract We have previously shown the presence of multiple small leader-containing RNA species in mouse hepatitis virus (MHV)-infected cells. In this paper, we have analyzed the origin, structure, and mechanism of synthesis of these small RNAs. Using cDNA probes specific for leader RNA and genes A, D, and F, we demonstrate that subsets of these small RNAs were derived from the various viral genes. These subsets have discrete and reproducible sizes, varying with the gene from which they are derived. The size of each subset correlates with regions of secondary structure, whose free energy ranges from −1.6 to −77.1 kcal/mol, in each of the mRNAs examined. In addition, identical subsets were detected on the replicative intermediate (RI) RNA, suggesting that they represent functional transcriptional intermediates. The biological significance of these small RNAs is further supported by the detection of leader-containing RNAs of 47, 50, and 57 nucleotides in length, which correspond to the crossover sites in two MHV recombinant viruses. These data, coupled with the high frequency of RNA recombination during MHV infection, suggest that the viral polymerase may pause in or around regions of secondary structure, thereby generating pools of free leader-containing RNA intermediates which can reassociate with the template, acting as primers for the synthesis of full-length or recombinant RNAs. These data suggest that MHV transcription uses a discontinuous and nonprocessive mechanism in which RNA polymerase allows the partial RNA products to be dissociated from the template temporarily during the process of transcription.


id: cord-266018-8bhnlsgy
author: Trifilo, Matthew J.
date: 2004-09-15
url: https://www.sciencedirect.com/science/article/pii/S004268220400409X
doi: 10.1016/j.virol.2004.06.027
title:
  The CC chemokine ligand 3 regulates CD11c(+)CD11b(+)CD8α(−) dendritic cell maturation and activation following viral infection of the central nervous system: implications for a role in T cell activation

abstract:
  The role of CC chemokine ligand 3 (CCL3) in activation of dendritic cells (DCs) following mouse hepatitis virus (MHV) infection of the central nervous system (CNS) was examined. The results indicate that CCL3 participates in an effective host response to MHV infection by contributing to CD11c(+)CD11b(+)CD8α(−) DC maturation, activation, and migration to cervical lymph nodes (CLN). Diminished CD8α(−) DC activation correlated with reduced IFN-γ expression by virus-specific T cells accompanied by increased IL-10 production suggesting that CCL3 contributes to an effective host response to viral infection by enhancing the T cell activation potential of DC.


id: cord-266138-yibbiiij
title: Immunopathological aspects of coronavirus infections
author: Wege, Helmut
date: 1995
txt: ./txt/cord-266138-yibbiiij.txt
cache: ./cache/cord-266138-yibbiiij.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/8571165/
doi: 10.1007/bf00196162
abstract: nan
summary:
  Murine coronaviruses (mouse hepatitis virus, MHV) can spread inapparently or may hide as persistent infections that modulate the immune response [38, 100] . Suppression of immune response induction in Peyer''s patch lymphoid cells from mice infected with mouse hepatitis virus Infection of BALB/cByJ mice with the JHM strain of mouse hepatitis virus alters in vitro splenic T cell proliferation and cytokine production Interaction of immune and central nervous systems: contribution of anti-viral Thy-1 + cells to demyelination induced by coronavirus JHM Impaired T and B cell subpopulations involved in a chronic disease induced by mouse hepatitis virus type 3 Identification of antigenic sites mediating antibody-dependent enhancement of feline infectious peritonitis virus infectivity The pathogenic role of virus-specific antibody-secreting cells in the central nervous system of rats with different susceptibility to coronavirus-induced demyelinating encephalitis Demyelination induced by murine hepatitis virus JHM strain (MHV-4) is immunologically mediated


id: cord-267671-ys43n672
title: Biology and Diseases of Mice
author: Whary, Mark T.
date: 2015-07-10
txt: ./txt/cord-267671-ys43n672.txt
cache: ./cache/cord-267671-ys43n672.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/B9780124095274000031
doi: 10.1016/b978-0-12-409527-4.00003-1
summary:
  Clinical Signs MCMV causes subclinical infection in adult immunocompetent mice, but experimental inoculation of neonates can cause lethal disease due to multisystemic necrosis and inflammation. Diagnosis Because infected mice do not manifest signs or lesions and the virus is very difficult to propagate in cell culture, detection and diagnosis rely on serology and molecular methods. Differential Diagnosis Reovirus infection must be differentiated from other diarrheal diseases of infant mice, including those caused by mouse coronaviruses, EDIM virus, Salmonella spp., or Clostridium piliforme. Epizootiology EDIM virus appears to be infectious only for mice and occurs episodically in mouse colonies, and infection is probably widespread geographically (Livingston and Riley, 2003; Pritchett-Corning LABORATORY ANIMAL MEDICINE et al., 2009) . Sentinel mouse surveillance, using soiled bedding, is an effective strategy for detecting MNV (Manuel et al., 2008) Differential Diagnosis The mild change in fecal consistency associated with MNV in adult mice may mimic rotavirus, coronavirus, Helicobacter spp., Citrobacter rodentium, or other enteric diseases.

abstract:
  Today’s laboratory mouse, Mus musculus, has its origins as the ‘house mouse’ of North America and Europe. Beginning with mice bred by mouse fanciers, laboratory stocks (outbred) derived from M. musculus musculus from eastern Europe and M. m. domesticus from western Europe were developed into inbred strains. Since the mid-1980s, additional strains have been developed from Asian mice (M. m. castaneus from Thailand and M. m. molossinus from Japan) and from M. spretus which originated from the western Mediterranean region.


id: cord-268139-tgpsu4qz
author: Brockway, Sarah M.
date: 2005-09-30
txt: ./txt/cord-268139-tgpsu4qz.txt
cache: ./cache/cord-268139-tgpsu4qz.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S0042682205003776
doi: 10.1016/j.virol.2005.06.035
summary:
  title: Mutagenesis of the murine hepatitis virus nsp1-coding region identifies residues important for protein processing, viral RNA synthesis, and viral replication In the current study, a reverse genetic approach was used to define the role of the 28-kDa amino-terminal product (nsp1) of the gene 1 polyprotein during replication of the coronavirus murine hepatitis virus (MHV) in cell culture. To determine whether nsp1 is required for MHV replication and to identify residues critical for protein function, mutant viruses that contained deletions or point mutations within the nsp1-coding region were generated and assayed for defects in viral replication, viral protein expression, protein localization, and RNA synthesis. Mutagenesis of the murine hepatitis virus nsp1-coding region identifies residues important for protein processing, viral RNA synthesis, and viral replication Experiments were next performed to determine if viral gene expression occurred in cells electroporated with RNA for mutants that did not produce infectious virus (VUSB5, VUSB6, nsp1DFL, and nsp1DMid).

title:
  Mutagenesis of the murine hepatitis virus nsp1-coding region identifies residues important for protein processing, viral RNA synthesis, and viral replication

abstract:
  Despite ongoing research investigating mechanisms of coronavirus replication, functions of many viral nonstructural proteins (nsps) remain unknown. In the current study, a reverse genetic approach was used to define the role of the 28-kDa amino-terminal product (nsp1) of the gene 1 polyprotein during replication of the coronavirus murine hepatitis virus (MHV) in cell culture. To determine whether nsp1 is required for MHV replication and to identify residues critical for protein function, mutant viruses that contained deletions or point mutations within the nsp1-coding region were generated and assayed for defects in viral replication, viral protein expression, protein localization, and RNA synthesis. The results demonstrated that the carboxy-terminal half of nsp1 (residues K(124) through L(241)) was dispensable for virus replication in culture but was required for efficient proteolytic cleavage of nsp1 from the gene 1 polyprotein and for optimal viral replication. Furthermore, whereas deletion of nsp1 residues amino-terminal to K(124) failed to produce infectious virus, point mutagenesis of the nsp1 amino-terminus allowed recovery of several mutants with altered replication and RNA synthesis. This study identifies nsp1 residues important for protein processing, viral RNA synthesis, and viral replication.


id: cord-268238-ipfs7hcb
author: Mathieu, Patricia A.
date: 2004-07-17
url: https://api.elsevier.com/content/article/pii/S0896841104000575
doi: 10.1016/j.jaut.2004.05.006
title:
  Sequence similarity and structural homologies are involved in the autoimmune response elicited by mouse hepatitis virus A59

abstract:
  The features of autoantibodies (autoAb) to liver fumarylacetoacetate hydrolase (FAH) elicited in mice infected with mouse hepatitis virus (MHV) were studied by ELISA and western-blot competition assays. All sera tested contained Ab to cryptic FAH epitopes according with results from western-blot tests, whereas ELISA data indicated that some of these same sera did recognize native epitopes of the autoantigen (autoAg). Such differences were detected in individual sera from various mouse strains, and were ascribed to the fact that proteins insolubilized on solid supports expose a variety of conformational and cryptic antigenic determinants. On the other hand, whereas results from both experimental protocols showed that anti-MHV Ab did not cross-react with the soluble autoAg, the opposite situation did not show analogous results. Thus, binding of autoAb to insolubilized FAH could be inhibited by MHV depending on the mouse serum or the experimental protocol used. Additionally, a set of synthetic homologous peptides from mouse FAH and various viral proteins was employed to analyze the Ab repertoire of MHV-infected mice. Results indicated that two homologous peptides were recognized by most Ab: the N-terminal sequences (1–10) from FAH and the nucleocapside, both sharing 50% of identity, and sequence 2317–2326 of the RNA polymerase, a peptide showing 30% of identity with FAH 11–20. Results indicated that MHV-infection triggers at least three distinct Ab populations: anti-MHV, anti-FAH and cross-reacting Ab. This cross-reaction implies either sequential or conformational epitopes from both the viral proteins and the autoAg and may differ between individuals.


id: cord-268416-8hw80qx8
title: The coronavirus nucleocapsid protein is ADP-ribosylated
author: Grunewald, Matthew E.
date: 2018-04-01
txt: ./txt/cord-268416-8hw80qx8.txt
cache: ./cache/cord-268416-8hw80qx8.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1016/j.virol.2017.11.020
doi: 10.1016/j.virol.2017.11.020
summary:
  While screening for ADP-ribosylated proteins during coronavirus (CoV) infection, we detected a ~55 kDa ADP-ribosylated protein in mouse hepatitis virus (MHV)-infected cells and in virions, which we identified as the viral nucleocapsid (N) protein. To identify potential targets of the CoV macrodomain, we analyzed infected cells for changes in ADP-ribosylation patterns utilizing antibodies specific for ADPr. We focused on cells infected with a murine CoV, mouse hepatitis virus (MHV). If the macrodomain was indeed removing the ADPr from the N protein, we would expect to see increased N protein ADP-ribosylation in cells infected with mutant virus compared to wild-type infected cells. To determine if N protein expressed in the absence of CoV infection could be ADP-ribosylated in cell culture, we transduced Vero cells with VEEV replicon particles (VRPs) encoding the MERS-CoV N protein or control GFP at different MOIs .

abstract:
  ADP-ribosylation is a common post-translational modification, although how it modulates RNA virus infection is not well understood. While screening for ADP-ribosylated proteins during coronavirus (CoV) infection, we detected a ~55 kDa ADP-ribosylated protein in mouse hepatitis virus (MHV)-infected cells and in virions, which we identified as the viral nucleocapsid (N) protein. The N proteins of porcine epidemic diarrhea virus (PEDV), severe acute respiratory syndrome (SARS)-CoV and Middle East respiratory syndrome (MERS)-CoV were also ADP-ribosylated. ADP-ribosylation of N protein was also observed in cells exogenously expressing N protein by transduction using Venezuelan equine encephalitis virus replicon particles (VRPs). However, plasmid-derived N protein was not ADP-ribosylated following transient transfection but was ADP-ribosylated after MHV infection, indicating that this modification requires virus infection. In conclusion, we have identified a novel post-translation modification of the CoV N protein that may play a regulatory role for this important structural protein.


id: cord-269011-230p8rsf
title: Molecular Interactions in the Assembly of Coronaviruses
author: de Haan, Cornelis A.M.
date: 2005-08-31
txt: ./txt/cord-269011-230p8rsf.txt
cache: ./cache/cord-269011-230p8rsf.txt
extension: .txt
mime: text/plain
url: https://www.sciencedirect.com/science/article/pii/S0065352705640067
doi: 10.1016/s0065-3527(05)64006-7
summary:
  Biochemical and theoretical studies led to a topological model for the MHV M protein Rottier et al., 1984 Rottier et al., , 1986 , in which the polypeptide spans the lipid bilayer three times, leaving a small amino-terminal domain (15-35 residues) in the lumen of intracellular organelles (or outside the virus), whereas the carboxyterminal half of the protein is located on the cytoplasmic side of the membrane (or inside the virion). Using a mutational approach including deletions, insertions, and substitutions, both the transmembrane domain and the cysteine-rich region immediately downstream thereof, but not the carboxy-terminal part of the cytoplasmic tail, were shown to be important for MHV S protein-induced cell-cell fusion (Bos et al., 1995; Chang and Gombold, 2001; Chang et al., 2000) The cleavage requirements of the S proteins for the biological activities of the coronavirus spike remain enigmatic.

abstract:
  This chapter describes the interactions between the different structural components of the viruses and discusses their relevance for the process of virion formation. Two key factors determine the efficiency of the assembly process: intracellular transport and molecular interactions. Many viruses have evolved elaborate strategies to ensure the swift and accurate delivery of the virion components to the cellular compartment(s) where they must meet and form (sub) structures. Assembly of viruses starts in the nucleus by the encapsidation of viral DNA, using cytoplasmically synthesized capsid proteins; nucleocapsids then migrate to the cytosol, by budding at the inner nuclear membrane followed by deenvelopment, to pick up the tegument proteins.


id: cord-270473-5tok4mqk
author: Nanda, S. K.
date: 2003-09-19
txt: ./txt/cord-270473-5tok4mqk.txt
cache: ./cache/cord-270473-5tok4mqk.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/14689278/
doi: 10.1007/s00705-003-0196-4
summary:
  We have previously shown that mitochondrial-aconitase binds specifically to the 3′ terminal 42 nucleotides of the Murine hepatitis virus (MHV) RNA along with three additional proteins of 70, 58 and 40 kDa to form a stable RNA-protein complex. The assays were done essentially as previously described [22] except that the partially purified post-mitochondrial lysates (approximately 3 µg total protein) were incubated at 22 • C with purified m-apo-aconitase (8-10 µg, graciously supplied by M.C. Kennedy, Gannon University, Erie, PA) and MHV-JHM 3 UTR RNA in ATPase buffer (20 mM Hepes, pH 7.4, 100 mM KCl, 5 mM MgCl 2 , 0.1% NP-40, 1 mM DTT, 1 mM ATP containing 2 µCi [γ-32 P]ATP plus cocktails of protease and phosphatase inhibitors). Gel supershift assays with anti-phosphotyrosine antibodies (Fig. 2B ) demonstrate that at least one of the proteins in the complex formed with MHV 3 (+)42 containing RNAs and m-aconitase, mtHSP70, HSP60, and HSP40 is tyrosine phosphorylated.

title:
  Mitochondrial HSP70, HSP40, and HSP60 bind to the 3′ untranslated region of the Murine hepatitis virus genome

abstract:
  We have previously shown that mitochondrial-aconitase binds specifically to the 3′ terminal 42 nucleotides of the Murine hepatitis virus (MHV) RNA along with three additional proteins of 70, 58 and 40 kDa to form a stable RNA-protein complex. Supershift and western blot assays have identified these three proteins as mitochondrial HSP70 (mtHSP70), HSP60, and HSP40. A series of co-immunoprecipitation assays have established that these four MHV RNA binding proteins are associated, even in the absence of MHV RNA. However, the presence of a synthetic RNA containing the sequence bound by these four proteins does increase the amount of co-precipitated protein, in particular the amount of HSP60 which is brought down with antibodies directed against HSP40 and mtHSP70. We have provided evidence for the interaction of these four proteins with the 3′ end region of MHV RNA in infected cells by a series of immunoprecipitation RT-PCR assays. We believe it is likely that MHV RNA interacts with m-aconitase prior to its import into mitochondria in cooperation with extra-mitochondrial mtHSP70, HSP60, and HSP40.


id: cord-270814-krw8zmr5
author: Rao, Pasupuleti V.
date: 1997-03-17
url: https://api.elsevier.com/content/article/pii/S0042682297984464
doi: 10.1006/viro.1997.8446
title:
  Identification of a Contiguous 6-Residue Determinant in the MHV Receptor That Controls the Level of Virion Binding to Cells

abstract:
  Abstract Murine carcinoembryonic antigens serve as receptors for the binding and entry of the enveloped coronavirus mouse hepatitis virus (MHV) into cells. Numerous receptor isoforms are now known, and each has extensive differences in its amino terminal immunoglobulin-like domain (NTD) to which MHV binds via its protruding spike proteins. Some of these receptor alterations may affect the ability to bind viral spikes. To identify individual residues controlling virus binding differences, we have used plasmid and vaccinia virus vectors to express two forms of MHV receptor differing only in their NTD. The two receptors, designated biliary glycoproteins (Bgp) 1aand 1b NTD, varied by 29 residues in the 107 amino acid NTD. When expressed from cDNAs in receptor-negative HeLa cells, these two Bgp molecules were displayed on cell surfaces to equivalent levels, as both were equally modified by a membrane-impermeant biotinylation reagent. Infectious center assays revealed that the 1aisoform was 10 to 100 times more effective than 1b NTDin its ability to confer sensitivity to MHV (strain A59) infection. Bgp1awas also more effective than Bgp1b NTDin comparative virus adsorption assays, binding 6 times more MHV (strain A59) and 2.5 times more MHV (strain JHMX). Bgp1awas similarly more effective in promoting the capacity of viral spikes to mediate intercellular membrane fusion as judged by quantitation of syncytia following cocultivation of spike and receptor-bearing cells. To identify residues influencing these differences, we inserted varying numbers of 1bresidues into the Bgp1abackground via restriction fragment exchange and site-directed mutagenesis. Analysis of the resulting chimeric receptors showed that residues 38 to 43 of the NTD were key determinants of the binding and fusion differences between the two receptors. These residues map to an exposed loop (C-C′ loop) in a structural model of the closely related human carcinoembryonic antigen.


id: cord-271526-14nfqusv
author: Molenkamp, Richard
date: 1997-12-08
url: https://api.elsevier.com/content/article/pii/S004268229798867X
doi: 10.1006/viro.1997.8867
title:
  Identification of a Specific Interaction between the Coronavirus Mouse Hepatitis Virus A59 Nucleocapsid Protein and Packaging Signal

abstract:
  Abstract The coronavirus mouse hepatitis virus (MHV) is an enveloped positive stranded RNA virus. In infected cells MHV produces a 3′ coterminal nested set of subgenomic messenger RNAs. Only the genomic RNA, however, is encapsidated by the nucleocapsid protein and incorporated in infectious MHV virions. It is believed that an RNA packaging signal (Ps), present only in the genomic RNA, is responsible for this selectivity. Earlier studies mapped this signal to a 69-nt stem–loop structure positioned in the 3′ end of ORF1b. The selective encapsidation mechanism probably initiates by specific interaction of the packaging signal with the nucleocapsid protein. In this study we demonstrate thein vitrointeraction of the MHV-A59 nucleocapsid protein with the packaging signal of MHV using gel retardation and UV cross-linking assays. This interaction was observed not only with the nucleocapsid protein from infected cells but also with that from purified virions and from cells expressing a recombinant nucleocapsid protein. The specificity of the interaction was demonstrated by competition experiments with nonlabeled Ps containing RNAs, tRNA, and total cytoplasmic RNA. The results indicated that no virus specific modification of the N-protein or the presence of other viral proteins are required for thisin vitrointeraction. The assays described in this report provide us with a powerful tool for studying encapsidation (initiation) in more detail.


id: cord-271763-cual2qv4
author: Abraham, Sushma
date: 1990-05-31
txt: ./txt/cord-271763-cual2qv4.txt
cache: ./cache/cord-271763-cual2qv4.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/2184576/
doi: 10.1016/0042-6822(90)90257-r
summary:
  Abstract The sequence of the spike (also called peplomer or E2) protein gene of the Mebus strain of bovine coronavirus (BCV) was obtained from cDNA clones of genomic RNA. Amino terminal amino acid sequencing of the virion-derived gp100 spike subunit confirmed the location of the predicted cleavage site, and established that gp120 and gp100 are the glycosylated virion forms of the S1 and S2 subunits, respectively. The deduced amino acid sequence of the extended ORF demonstrated high sequence similarity to the C-terminal end of the antigenically related MHV-A59 (22) and MHV-JHM (32) S proteins, both antigenic homologs of the BCV S protein (13). The N-terminal sequence of the lOO-kDa subunit could be obtained, however, and was determined to be X-l-T-T-G-Y-X-F-, identifying the first amino acids downstream from the predicted internal cleavage site.

title:
  Deduced sequence of the bovine coronavirus spike protein and identification of the internal proteolytic cleavage site

abstract:
  Abstract The sequence of the spike (also called peplomer or E2) protein gene of the Mebus strain of bovine coronavirus (BCV) was obtained from cDNA clones of genomic RNA. The gene sequence predicts a 150,825 mol wt apoprotein of 1363 amino acids having an N-terminal hydrophobic signal sequence of 17 amino acids, 19 potential N-linked glycosylation sites, a hydrophobic anchor sequence of approximately 17 amino acids near the C terminus, and a hydrophilic cysteinerich C terminus of 35 amino acids. An internal LysArgArgSerArgArg sequence predicts a protease cleavage site between amino acids 768 and 769 that would separate the S apoprotein into S1 and S2 segments of 85690 and 65153 mol wt, respectively. Amino terminal amino acid sequencing of the virion-derived gp100 spike subunit confirmed the location of the predicted cleavage site, and established that gp120 and gp100 are the glycosylated virion forms of the S1 and S2 subunits, respectively. Sequence comparisons between BCV and the antigenically related mouse hepatitis coronavirus revealed more sequence divergence in the putative knob region of the spike protein (S1) than in the stem region (S2).


id: cord-271815-yr1dq258
title: Inactivation of surrogate coronaviruses on hard surfaces by health care germicides
author: Hulkower, Rachel L.
date: 2011-06-30
url: https://www.ncbi.nlm.nih.gov/pubmed/21256627/
doi: 10.1016/j.ajic.2010.08.011
abstract:
  Background In the 2003 severe acute respiratory syndrome outbreak, finding viral nucleic acids on hospital surfaces suggested surfaces could play a role in spread in health care environments. Surface disinfection may interrupt transmission, but few data exist on the effectiveness of health care germicides against coronaviruses on surfaces. Methods The efficacy of health care germicides against 2 surrogate coronaviruses, mouse hepatitis virus (MHV) and transmissible gastroenteritis virus (TGEV), was tested using the quantitative carrier method on stainless steel surfaces. Germicides were o-phenylphenol/p-tertiary amylphenol) (a phenolic), 70% ethanol, 1:100 sodium hypochlorite, ortho-phthalaldehyde (OPA), instant hand sanitizer (62% ethanol), and hand sanitizing spray (71% ethanol). Results After 1-minute contact time, for TGEV, there was a log10 reduction factor of 3.2 for 70% ethanol, 2.0 for phenolic, 2.3 for OPA, 0.35 for 1:100 hypochlorite, 4.0 for 62% ethanol, and 3.5 for 71% ethanol. For MHV, log10 reduction factors were 3.9 for 70% ethanol, 1.3 for phenolic, 1.7 for OPA, 0.62 for 1:100 hypochlorite, 2.7 for 62% ethanol, and 2.0 for 71% ethanol. Conclusion Only ethanol reduced infectivity of the 2 coronaviruses by >3-log10 after 1 minute. Germicides must be chosen carefully to ensure they are effective against viruses such as severe acute respiratory syndrome coronavirus.


id: cord-274247-5qiwui6u
author: Torrecilhas, A C T
date: 1999-03-01
txt: ./txt/cord-274247-5qiwui6u.txt
cache: ./cache/cord-274247-5qiwui6u.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/10233719/
doi: 10.1046/j.1365-2567.1999.00719.x
summary:
  We have investigated the effects of a natural acute outbreak of MHV in our otherwise specific-pathogen-free (SPF) inbred mouse colonies, and of enzootic chronic MHV infection on cytokine production and resistance to the intracellular pathogen Trypanosoma cruzi. IL-10 that were serologically MHV+ or MHV− production, on day 11 after infection, in BALB/c (but not in C57BL/6) mice was CD4-activation dependent as treatment Our preliminary observation, suggestive of an infection with GK1.5 mAb suppressed most of its synthesis outbreak in the mouse colonies, was increased susceptibility (63 units/ml in untreated versus 6 units/ml in GK1.5 treated to T. cruzi determined by the situation of acute MHV+ C57BL/6 and BALB/c mice cells to Con A stimulation simultaneous infection with blood parasites derived from was not significantly higher than in spleen cell cultures from acutely infected MHV+ donors as described above, no statis-MHV− animals (Fig. 2) .

title:
  Interference of natural mouse hepatitis virus infection with cytokine production and susceptibility to Trypanosoma cruzi

abstract:
  Mouse hepatitis virus (MHV) infection can have a pronounced impact on several investigation areas. Reports on natural MHV outbreaks are rare and most studies have been conducted by deliberately infecting mice with MHV laboratory strains that cause moderate to severe disturbances to the immune system. We have investigated the effects of a natural acute outbreak of MHV in our otherwise specific-pathogen-free (SPF) inbred mouse colonies, and of enzootic chronic MHV infection on cytokine production and resistance to the intracellular pathogen Trypanosoma cruzi. We found that BALB/c and/or C57BL/6 SPF mice that had been injected with T. cruzi blood trypomastigotes from recently MHV-contaminated (MHV(+)) mice developed significantly higher parasite blood counts, accelerated death, and showed higher IL-10 production by spleen cells than their counterparts whose T. cruzi inoculum was derived from MHV-negative (MHV(−)) donors. Interferon-γ (IFN-γ) production by MHV(+) and MHV(−) mice was not significantly different. In contrast, T. cruzi infection of chronically MHV-infected mice did not result in major changes in the course of infection when compared with that observed in mice from MHV(−) colonies, although a trend to higher parasitaemia levels was observed in BALB/c MHV(+) mice. Nevertheless, both BALB/c and C57BL/6 T. cruzi-infected MHV(+) mice had diminished IFN-γ production to parasite-antigen stimulation in comparison with similarly infected MHV(−) mice. Interleukin-10 (IL-10) production levels by spleen cells did not differ between chronic MHV(+) and MHV(−) mice, but IFN-γ neutralization by monoclonal antibody treatment of anti-CD3-stimulated spleen cell cultures showed higher levels of IL-10 synthesis in MHV(+) BALB/c mice.


id: cord-276198-psjua913
title: New insights on the role of paired membrane structures in coronavirus replication
author: V’kovski, Philip
date: 2015-04-16
txt: ./txt/cord-276198-psjua913.txt
cache: ./cache/cord-276198-psjua913.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S0168170214005358
doi: 10.1016/j.virusres.2014.12.021
summary:
  Many nidovirus and all coronavirus TM1 proteins contain one or more ubiquitin-like domains which may help to anchor the viral RNA to the membranes where replication takes place (Hurst et al., 2013) . The maze-like paired-membrane structures that resulted from coexpression of SARS-CoV TM1 and TM2 have not ever been reported in coronavirus-infected cells, suggesting that this should be interpreted as a conditional, or perhaps partial phenotype, that is not observed when the full viral replicase polyprotein is expressed. Since DMVs are reminiscent of the double-membranes of autophagosomes, several lines of controversial evidence hypothesized a diversion of Atg (autophagyrelated) proteins and autophagosome function during coronavirus replication, as it is the case for other +RNA viruses (Prentice et al., 2004; Snijder et al., 2006; Zhao et al., 2007; Maier and Britton, 2012; Richards and Jackson, 2013) . Expression of hepatitis C virus proteins induces distinct membrane alterations including a candidate viral replication complex

abstract:
  The replication of coronaviruses, as in other positive-strand RNA viruses, is closely tied to the formation of membrane-bound replicative organelles inside infected cells. The proteins responsible for rearranging cellular membranes to form the organelles are conserved not just among the Coronaviridae family members, but across the order Nidovirales. Taken together, these observations suggest that the coronavirus replicative organelle plays an important role in viral replication, perhaps facilitating the production or protection of viral RNA. However, the exact nature of this role, and the specific contexts under which it is important have not been fully elucidated. Here, we collect and interpret the recent experimental evidence about the role and importance of membrane-bound organelles in coronavirus replication.


id: cord-277566-j3ehiwn9
title: Mouse Hepatitis Coronavirus RNA Replication Depends on GBF1-Mediated ARF1 Activation
author: Verheije, Monique H.
date: 2008-06-13
url: https://doi.org/10.1371/journal.ppat.1000088
doi: 10.1371/journal.ppat.1000088
abstract:
  Coronaviruses induce in infected cells the formation of double membrane vesicles, which are the sites of RNA replication. Not much is known about the formation of these vesicles, although recent observations indicate an important role for the endoplasmic reticulum in the formation of the mouse hepatitis coronavirus (MHV) replication complexes (RCs). We now show that MHV replication is sensitive to brefeldin A (BFA). Consistently, expression of a dominant-negative mutant of ARF1, known to mimic the action of the drug, inhibited MHV infection profoundly. Immunofluorescence analysis and quantitative electron microscopy demonstrated that BFA did not block the formation of RCs per se, but rather reduced their number. MHV RNA replication was not sensitive to BFA in MDCK cells, which are known to express the BFA-resistant guanine nucleotide exchange factor GBF1. Accordingly, individual knockdown of the Golgi-resident targets of BFA by transfection of small interfering RNAs (siRNAs) showed that GBF1, but not BIG1 or BIG2, was critically involved in MHV RNA replication. ARF1, the cellular effector of GBF1, also appeared to be involved in MHV replication, as siRNAs targeting this small GTPase inhibited MHV infection significantly. Collectively, our results demonstrate that GBF1-mediated ARF1 activation is required for efficient MHV RNA replication and reveal that the early secretory pathway and MHV replication complex formation are closely connected.


id: cord-281552-zfjy3m3i
title: Identification of a Membrane Binding Peptide in the Envelope Protein of MHV Coronavirus
author: Alsaadi, Entedar A. J.
date: 2020-09-22
txt: ./txt/cord-281552-zfjy3m3i.txt
cache: ./cache/cord-281552-zfjy3m3i.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/32971895/
doi: 10.3390/v12091054
summary:
  Here, we test E-derived peptides for membrane binding activity in vitro and confirm those identified as positive in the context of the full length protein expressed in two different cell types. Relative densitometry of the HSP and LSP bands revealed significant differences among the mutants with regard to their localisation to the different membrane fractions of E expressing insect cells ( Figure 5B ) and confirmed a role for the amphipathic MHV CoV E 50-64 peptide in membrane interaction. An amphipathic helix, EPTM, detected in the post-TM region of E, was suggested by bioinformatics analysis and assessed for direct membrane interaction in vitro by binding to GUVs. For comparison, the predicted E protein TM domain, ETM, and an established membrane active peptide from the influenza M2 protein were also included. Following expression of the complete E protein with mutations in the same identified peptide, altered membrane binding in two distinct cell types, mammalian and insect, was apparent.

abstract:
  Coronaviruses (CoVs) are enveloped, positive sense, single strand RNA viruses that cause respiratory, intestinal and neurological diseases in mammals and birds. Following replication, CoVs assemble on intracellular membranes including the endoplasmic reticulum Golgi intermediate compartment (ERGIC) where the envelope protein (E) functions in virus assembly and release. In consequence, E potentially contains membrane-modifying peptides. To search for such peptides, the E coding sequence of Mouse Hepatitis Virus (MHV) was inspected for its amino acid conservation, proximity to the membrane and/or predicted amphipathic helices. Peptides identified in silico were synthesized and tested for membrane-modifying activity in the presence of giant unilamellar vesicles (GUVs) consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), sphingomyelin and cholesterol. To confirm the presence of membrane binding peptides identified in the context of a full-length E protein, the wild type and a number of mutants in the putative membrane binding peptide were expressed in Lenti-X-293T mammalian and insect cells, and the distribution of E antigen within the expressing cell was assessed. Our data identify a role for the post-transmembrane region of MHV E in membrane binding.


id: cord-283132-rfw8njpo
author: Olsen, Christopher W.
date: 1993-07-31
url: https://www.sciencedirect.com/science/article/pii/037811359390126R
doi: 10.1016/0378-1135(93)90126-r
title:
  A review of feline infectious peritonitis virus: molecular biology, immunopathogenesis, clinical aspects, and vaccination

abstract:
  Abstract Feline infectious peritontis (FIP) has been an elusive and frustrating problem for veterinary practitioners and cat breeders for many years. Over the last several years, reports have begun to elucidate aspects of the molecular biology of the causal virus (FIPV). These papers complement a rapidly growing base of knowledge concerning the molecular organization and replication of coronaviruses in general. The fascinating immunopathogenesis of FIPV infection and the virus' interaction with macrophages has also been the subject of several recent papers. It is now clear that FIPV may be of interest to scientists other than veterinary virologists since its pathogenesis may provide a useful model system for other viruses whose infectivity is enhanced in the presence of virus-specific antibody. With these advances and the recent release of the first commercially-available FIPV vaccine, it is appropriate to review what is known about the organization and replication of coronaviruses and the pathogenesis of FIPV infection.


id: cord-284707-72vx11aq
title: Synthesis of virus-specific RNA in permeabilized murine coronavirus-infected cells
author: Leibowitz, Julian L.
date: 1988-09-30
txt: ./txt/cord-284707-72vx11aq.txt
cache: ./cache/cord-284707-72vx11aq.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/004268228890147X
doi: 10.1016/0042-6822(88)90147-x
summary:
  For mouse hepatitis virus (MHV), one of the most extensively studied coronaviruses, there are seven species of MHV-specific mRNA present in infected cells, the largest of which is indistinguishable from virion RNA (Leibowitz et a/., 1981; Lai et a/., 1981; Spaan et a/., 1981) . In this paper we report the characteristics of a permeabilized cell system and demonstrate that it incorporates ribonucle-otide triphosphates into RNA molecules which appear identical to the virus-specific mRNAs synthesized in MHV-infected cells. Protease inhibitors and RNase inhibitors have both been reported to increase the RNA-dependent RNA polymerase activity present in extracts of West Nile virus-infected cells (Grun and Brinton, 1986) . The kinetics of the development of the MHV-specific RNA polymerase activity over the course of infection was determined in permeabilized cells. In this work we report the development and characterization of a permeabilized cell system for assaying MHV-specific RNA polymerase activity.

abstract:
  Abstract We have developed a permeabilized cell system for assaying mouse hepatitis virus-specific RNA polymerase activity. This activity was characterized as to its requirements for mono- and divalent cations, requirements for an exogenous energy source, and pH optimum. This system faithfully reflects MHV-specific RNA synthesis in the intact cell, with regard to both its time of appearance during the course of infection and the products synthesized. The system is efficient and the RNA products were identical to those observed in intact MHV-infected cells as judged by agarose gel electrophoresis and hybridization. Permeabilized cells appear to be an ideal system for studying coronavirus RNA synthesis since they closely mimic in vivo conditions while allowing much of the experimental flexibility of truly cell-free systems.


id: cord-285676-4kgy20o9
author: de Vries, Antoine A.F.
date: 1997-02-28
txt: ./txt/cord-285676-4kgy20o9.txt
cache: ./cache/cord-285676-4kgy20o9.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S1044577397901049
doi: 10.1006/smvy.1997.0104
summary:
  The overlapping ORFs 1a and b found at the 58 end of the nidoviral genome are frequently referred to as the ''''polymerase gene.'''' However, there is little doubt that the processing of the encoded polyproteins yields proteins required for RNA synthesis as well as a number of products involved in other aspects of virus replication. The sequence conservation between the more closely related corona-and toroviruses is clustered in six domains, four of which are also found in the arterivirus POL1b: the ''''classical'''' RNA-dependent RNA polymerase (RdRp) and helicase (H) domains, which are also present in the polymerases of most other viruses, a zinc finger motif (zf), and a short region of 80-100 residues, which has not yet been identified in other viral polymerases and was called the ''''coronavirus-like'''' (CVL) domain (3) (motif 2 in Fig. 1b) .

title:
  The Genome Organization of the Nidovirales: Similarities and Differences between Arteri-, Toro-, and Coronaviruses

abstract:
  Abstract Viruses in the families Arteriviridae and Coronaviridae have enveloped virions which contain nonsegmented, positive-stranded RNA, but the constituent genera differ markedly in genetic complexity and virion structure. Nevertheless, there are striking resemblances among the viruses in the organization and expression of their genomes, and sequence conservation among the polymerase polyproteins strongly suggests that they have a common ancestry. On this basis, the International Committee on Taxonomy of Viruses recently established a new order, Nidovirales, to contain the two families. Here, the common traits and distinguishing features of the Nidovirales are reviewed.


id: cord-285869-jwflooop
title: Mutation in murine coronavirus replication protein nsp4 alters assembly of double membrane vesicles
author: Clementz, Mark A.
date: 2008-05-01
url: https://api.elsevier.com/content/article/pii/S0042682208000378
doi: 10.1016/j.virol.2008.01.018
abstract:
  Coronaviruses are positive-strand RNA viruses that replicate in the cytoplasm of infected cells by generating a membrane-associated replicase complex. The replicase complex assembles on double membrane vesicles (DMVs). Here, we studied the role of a putative replicase anchor, nonstructural protein 4 (nsp4), in the assembly of murine coronavirus DMVs. We used reverse genetics to generate infectious clone viruses (icv) with an alanine substitution at nsp4 glycosylation site N176 or N237, or an asparagine to threonine substitution (nsp4-N258T), which is proposed to confer a temperature sensitive phenotype. We found that nsp4-N237A is lethal and nsp4-N258T generated a virus (designated Alb ts6 icv) that is temperature sensitive for viral replication. Analysis of Alb ts6 icv-infected cells revealed that there was a dramatic reduction in DMVs and that both nsp4 and nsp3 partially localized to mitochondria when cells were incubated at the non-permissive temperature. These results reveal a critical role of nsp4 in directing coronavirus DMV assembly.


id: cord-286250-bq1u3d4z
title: Multiple regions of the murine coronavirus spike glycoprotein influence neurovirulence
author: Phillips, Joanna J.
date: 2001
url: https://www.ncbi.nlm.nih.gov/pubmed/11582514/
doi: 10.1080/135502801753170273
abstract:
  The spike (S) glycoprotein of mouse hepatitis virus (MHV) is a major determinant of neurovirulence. Using targeted recombination we previously demonstrated that the S gene of the highly neurovirulent MHV-4 conferred a dramatic increase in neurovirulence to the mildly neurovirulent MHV-A59. To identify the genetic determinants of neurovirulence within the MHV-4 spike, we generated isogenic recombinant viruses containing various MHV-4/MHV-A59 chimeric spike genes, and studied their phenotypes in vivo. The MHV-4/MHV-A59 chimeric spike genes consisted of either reciprocal exchanges between the S1 and S2 spike subunits, or smaller exchanges specifically in the hyper-variable region (HVR) of S1. The chimeric spike gene containing recombinants all exhibited efficient replication in vitro, yet many were severely attenuated for virulence in vivo. Furthermore, these attenuated recombinants exhibited decreased titers of infectious virus in the brain relative to the parental recombinant viruses containing the full-length MHV-4 or MHV-A59 spike genes. This is the first report that compares the neurovirulence and pathogenesis of isogenic viruses with defined alterations in the MHV spike protein. From these studies, it appears that the interactions of multiple regions of the MHV spike, including the HVR, act in concert to allow for efficient infection of and virulence in the murine central nervous system.


id: cord-286332-cdg4im5h
author: van Beurden, Steven J.
date: 2017-06-12
url: https://www.ncbi.nlm.nih.gov/pubmed/28606144/
doi: 10.1186/s12985-017-0775-8
title:
  A reverse genetics system for avian coronavirus infectious bronchitis virus based on targeted RNA recombination

abstract:
  BACKGROUND: Avian coronavirus infectious bronchitis virus (IBV) is a respiratory pathogen of chickens that causes severe economic losses in the poultry industry worldwide. Major advances in the study of the molecular biology of IBV have resulted from the development of reverse genetics systems for the highly attenuated, cell culture-adapted, IBV strain Beaudette. However, most IBV strains, amongst them virulent field isolates, can only be propagated in embryonated chicken eggs, and not in continuous cell lines. METHODS: We established a reverse genetics system for the IBV strain H52, based on targeted RNA recombination in a two-step process. First, a genomic and a chimeric synthetic, modified IBV RNA were co-transfected into non-susceptible cells to generate a recombinant chimeric murinized (m) IBV intermediate (mIBV). Herein, the genomic part coding for the spike glycoprotein ectodomain was replaced by that of the coronavirus mouse hepatitis virus (MHV), allowing for the selection and propagation of recombinant mIBV in murine cells. In the second step, mIBV was used as the recipient. To this end a recombination with synthetic RNA comprising the 3′-end of the IBV genome was performed by introducing the complete IBV spike gene, allowing for the rescue and selection of candidate recombinants in embryonated chicken eggs. RESULTS: Targeted RNA recombination allowed for the modification of the 3′-end of the IBV genome, encoding all structural and accessory genes. A wild-type recombinant IBV was constructed, containing several synonymous marker mutations. The in ovo growth kinetics and in vivo characteristics of the recombinant virus were similar to those of the parental IBV strain H52. CONCLUSIONS: Targeted RNA recombination allows for the generation of recombinant IBV strains that are not able to infect and propagate in continuous cell lines. The ability to introduce specific mutations holds promise for the development of rationally designed live-attenuated IBV vaccines and for studies into the biology of IBV in general. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12985-017-0775-8) contains supplementary material, which is available to authorized users.


id: cord-287487-qeltdch7
author: Graepel, Kevin W.
date: 2017-11-07
url: https://www.ncbi.nlm.nih.gov/pubmed/29114026/
doi: 10.1128/mbio.01503-17
title:
  Proofreading-Deficient Coronaviruses Adapt for Increased Fitness over Long-Term Passage without Reversion of Exoribonuclease-Inactivating Mutations

abstract:
  The coronavirus (CoV) RNA genome is the largest among the single-stranded positive-sense RNA viruses. CoVs encode a proofreading 3′-to-5′ exoribonuclease within nonstructural protein 14 (nsp14-ExoN) that is responsible for CoV high-fidelity replication. Alanine substitution of ExoN catalytic residues [ExoN(-)] in severe acute respiratory syndrome-associated coronavirus (SARS-CoV) and murine hepatitis virus (MHV) disrupts ExoN activity, yielding viable mutant viruses with defective replication, up to 20-fold-decreased fidelity, and increased susceptibility to nucleoside analogues. To test the stability of the ExoN(-) genotype and phenotype, we passaged MHV-ExoN(-) 250 times in cultured cells (P250), in parallel with wild-type MHV (WT-MHV). Compared to MHV-ExoN(-) P3, MHV-ExoN(-) P250 demonstrated enhanced replication and increased competitive fitness without reversion at the ExoN(-) active site. Furthermore, MHV-ExoN(-) P250 was less susceptible than MHV-ExoN(-) P3 to multiple nucleoside analogues, suggesting that MHV-ExoN(-) was under selection for increased replication fidelity. We subsequently identified novel amino acid changes within the RNA-dependent RNA polymerase and nsp14 of MHV-ExoN(-) P250 that partially accounted for the reduced susceptibility to nucleoside analogues. Our results suggest that increased replication fidelity is selected in ExoN(-) CoVs and that there may be a significant barrier to ExoN(-) reversion. These results also support the hypothesis that high-fidelity replication is linked to CoV fitness and indicate that multiple replicase proteins could compensate for ExoN functions during replication.


id: cord-289045-vft163v0
author: Thackray, Larissa B.
date: 2005-03-30
url: https://www.ncbi.nlm.nih.gov/pubmed/15749126/
doi: 10.1016/j.virol.2005.01.016
title:
  Substitutions of conserved amino acids in the receptor-binding domain of the spike glycoprotein affect utilization of murine CEACAM1a by the murine coronavirus MHV-A59

abstract:
  The host range of the murine coronavirus (MHV) is limited to susceptible mice and murine cell lines by interactions of the spike glycoprotein (S) with its receptor, mCEACAM1a. We identified five residues in S (S33, L79, T82, Y162 and K183) that are conserved in the receptor-binding domain of MHV strains, but not in related coronaviruses. We used targeted RNA recombination to generate isogenic viruses that differ from MHV-A59 by amino acid substitutions in S. Viruses with S33R and K183R substitutions had wild type growth, while L79A/T82A viruses formed small plaques. Viruses with S33G, L79M/T82M or K183G substitutions could only be recovered from cells that over-expressed a mutant mCEACAM1a. Viruses with Y162H or Y162Q substitutions were never recovered, while Y162A viruses formed minute plaques. However, viruses with Y162F substitutions had wild type growth, suggesting that Y162 may comprise part of a hydrophobic domain that contacts the MHV-binding site of mCEACAM1a.


id: cord-290877-dap0zo2m
author: Bose, Abhishek
date: 2018-01-11
url: https://www.ncbi.nlm.nih.gov/pubmed/29327203/
doi: 10.1007/s12035-017-0861-3
title:
  Loss of Cx43-Mediated Functional Gap Junction Communication in Meningeal Fibroblasts Following Mouse Hepatitis Virus Infection

abstract:
  Mouse hepatitis virus (MHV) infection causes meningoencephalitis by disrupting the neuro-glial and glial-pial homeostasis. Recent studies suggest that MHV infection alters gap junction protein connexin 43 (Cx43)-mediated intercellular communication in brain and primary cultured astrocytes. In addition to astrocytes, meningeal fibroblasts also express high levels of Cx43. Fibroblasts in the meninges together with the basal lamina and the astrocyte endfeet forms the glial limitans superficialis as part of the blood–brain barrier (BBB). Alteration of glial-pial gap junction intercellular communication (GJIC) in MHV infection has the potential to affect the integrity of BBB. Till date, it is not known if viral infection can modulate Cx43 expression and function in cells of the brain meninges and thus affect BBB permeability. In the present study, we have investigated the effect of MHV infection on Cx43 localization and function in mouse brain meningeal cells and primary meningeal fibroblasts. Our results show that MHV infection reduces total Cx43 levels and causes its intracellular retention in the perinuclear compartments reducing its surface expression. Reduced trafficking of Cx43 to the cell surface in MHV-infected cells is associated with loss functional GJIC. Together, these data suggest that MHV infection can directly affect expression and cellular distribution of Cx43 resulting in loss of Cx43-mediated GJIC in meningeal fibroblasts, which may be associated with altered BBB function observed in acute infection.


id: cord-292178-bd8u8udl
author: Joseph, Jeymohan
date: 1993-01-31
txt: ./txt/cord-292178-bd8u8udl.txt
cache: ./cache/cord-292178-bd8u8udl.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/8380807/
doi: 10.1016/0165-5728(93)90211-g
summary:
  title: Interleukin-6 induction in vitro in mouse brain endothelial cells and astrocytes by exposure to mouse hepatitis virus (MHV-4, JHM) Abstract Interleukin-6 (IL-6) induction, as detected by bioassay and Northern analysis, was examined in vitro in endothelial cells or astrocytes derived from BALB/c (susceptible) or SJL (resistant) mice following exposure to mouse hepatitis virus (MHV-4) or UV inactivated MHV-4 (UV-MHV-4). BALB/c (MHV-4 susceptible) derived endothelial cells can produce up to 16-fold higher levels of IL-6, and release this earlier than SJL (MHV-4 resistant), as determined both by bioassay and Northern analysis. Tables 1 and 2 demonstrate that IL-6 is induced in both BALB/c and SJL derived endothelial ceils following exposure to MHV-4 as determined by bioassays, albeit at very different levels. We report on the induction of IL-6 in cultures of cerebral endothelial cells or astrocytes following infection with MHV-4.

title:
  Interleukin-6 induction in vitro in mouse brain endothelial cells and astrocytes by exposure to mouse hepatitis virus (MHV-4, JHM)

abstract:
  Abstract Interleukin-6 (IL-6) induction, as detected by bioassay and Northern analysis, was examined in vitro in endothelial cells or astrocytes derived from BALB/c (susceptible) or SJL (resistant) mice following exposure to mouse hepatitis virus (MHV-4) or UV inactivated MHV-4 (UV-MHV-4). In BALB/c endothelial cells, up to 16-fold more IL-6 (> 640 U/ml) was induced, compared to SJL cells which showed a minimal response (40 U/ml), relative to basal levels (< 20 U/ml). In contrast, both BALB/c and SJL astrocytes showed a substantial IL-6 response to MHV-4 and UV-MHV-4 exposure, although a strain difference persisted. Despite strain and cell specific differences in released IL-6, equivalent levels of IL-6 mRNA were induced in all cell types following exposure to MHV-4 or UV-MHV-4.


id: cord-292424-daj4zcm1
author: Shang, Jian
date: 2020-03-09
txt: ./txt/cord-292424-daj4zcm1.txt
cache: ./cache/cord-292424-daj4zcm1.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/32150576/
doi: 10.1371/journal.ppat.1008392
summary:
  Together these results reveal a new role of receptor binding in MHV entry: in addition to its well-characterized role in viral attachment to host cells, receptor binding also induces the conformational change of the spike and hence the fusion of viral and host membranes. In this study, we determined the cryo-electron microscopic (cryo-EM) structure of pre-fusion MHV spike in complex with CEACAM1a (D1-D4), which reveals the structural change of MHV spike associated with receptor binding. Using proteolysis and negative-stain EM assays, we further investigated the impact of receptor binding on proteases sensitivity and the final structural transitions of MHV spike. The result showed that receptor treatment of the trypsin-cleaved MHV S-e led to a protease K-resistant S2'' fragment, suggesting that CEACAM1a binding facilitated the already cleaved MHV S-e to transition from pre-fusion to post-fusion conformation.

title:
  Structure of mouse coronavirus spike protein complexed with receptor reveals mechanism for viral entry

abstract:
  Coronaviruses recognize a variety of receptors using different domains of their envelope-anchored spike protein. How these diverse receptor recognition patterns affect viral entry is unknown. Mouse hepatitis coronavirus (MHV) is the only known coronavirus that uses the N-terminal domain (NTD) of its spike to recognize a protein receptor, CEACAM1a. Here we determined the cryo-EM structure of MHV spike complexed with mouse CEACAM1a. The trimeric spike contains three receptor-binding S1 heads sitting on top of a trimeric membrane-fusion S2 stalk. Three receptor molecules bind to the sides of the spike trimer, where three NTDs are located. Receptor binding induces structural changes in the spike, weakening the interactions between S1 and S2. Using protease sensitivity and negative-stain EM analyses, we further showed that after protease treatment of the spike, receptor binding facilitated the dissociation of S1 from S2, allowing S2 to transition from pre-fusion to post-fusion conformation. Together these results reveal a new role of receptor binding in MHV entry: in addition to its well-characterized role in viral attachment to host cells, receptor binding also induces the conformational change of the spike and hence the fusion of viral and host membranes. Our study provides new mechanistic insight into coronavirus entry and highlights the diverse entry mechanisms used by different viruses.


id: cord-293417-oqusfhei
author: Ma, Yanlin
date: 2010-07-01
txt: ./txt/cord-293417-oqusfhei.txt
cache: ./cache/cord-293417-oqusfhei.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/21203940/
doi: 10.1007/s13238-010-0079-x
summary:
  The higher resolution provides more detailed structural information than previous reports, showing that the NTD structure from MHV shares a similar overall and topology structure with that of SARS-CoV and IBV, but varies in its potential surface, which indicates a possible difference in RNA-binding module. To gain insight into the precise mechanism of N protein, several crystallographic or NMR structural results were reported, including MHV N-terminal RNA binding domain (residues 60-195) (Grossoehme et al., 2009) , two proteaseresistant domains of the N protein from SARS-CoV (Huang et al., 2004; Luo et al., 2006; Yu et al., 2006; Chen et al., 2007; Saikatendu et al., 2007; Takeda et al., 2008) , and IBV (Beaudette strain and Gray strain) (Fan et al., 2005; Jayaram et al., 2006) . In overall ribbon posture, the high resolution structure of MHV-NTD determined using two forms of crystals with different packing modes is similar to previously reported SARS-CoV and IBV structures, with a remarkable difference in surface electrostatic distribution.

title:
  Structures of the N- and C-terminal domains of MHV-A59 nucleocapsid protein corroborate a conserved RNA-protein binding mechanism in coronavirus

abstract:
  Coronaviruses are the causative agent of respiratory and enteric diseases in animals and humans. One example is SARS, which caused a worldwide health threat in 2003. In coronaviruses, the structural protein N (nucleocapsid protein) associates with the viral RNA to form the filamentous nucleocapsid and plays a crucial role in genome replication and transcription. The structure of Nterminal domain of MHV N protein also implicated its specific affinity with transcriptional regulatory sequence (TRS) RNA. Here we report the crystal structures of the two proteolytically resistant N- (NTD) and C-terminal (CTD) domains of the N protein from murine hepatitis virus (MHV). The structure of NTD in two different crystal forms was solved to 1.5 Å. The higher resolution provides more detailed structural information than previous reports, showing that the NTD structure from MHV shares a similar overall and topology structure with that of SARS-CoV and IBV, but varies in its potential surface, which indicates a possible difference in RNA-binding module. The structure of CTD was solved to 2.0-Å resolution and revealed a tightly intertwined dimer. This is consistent with analytical ultracentrifugation experiments, suggesting a dimeric assembly of the N protein. The similarity between the structures of these two domains from SARS-CoV, IBV and MHV corroborates a conserved mechanism of nucleocapsid formation for coronaviruses.


id: cord-293913-frkb8iso
title: Identification of the polymerase polyprotein products p72 and p65 of the murine coronavirus MHV-JHM
author: Gao, Hong-Qiang
date: 1996-12-31
url: https://www.sciencedirect.com/science/article/pii/S0168170296013688
doi: 10.1016/s0168-1702(96)01368-8
abstract:
  Abstract The RNA polymerase gene of murine coronavirus MHV-JHM encodes a polyprotein of greater than 750 kDa. This polyprotein is proposed to be processed by two papain-like cysteine proteinases, PCP-1 and PCP-2, and a poliovirus 3C-like proteinase domain, 3C-pro, to generate protein products. The amino-terminal product of the MHV polymerase polyprotein, p28, is generated by cleavage of the polyprotein by PCP-1. To identify the viral products downstream of p28, we generated a fusion-protein specific antiserum directed against the region adjacent to p28 and used the antiserum to detect virus-specific proteins from MHV-JHM infected cells. When this antiserum was used to immunoprecipitate radiolabeled proteins from MHV-JHM infected cell lysates, virus-specific proteins of 72 and 65 kDa were detected. Furthermore, pulse and chase experiments demonstrated that p72 is likely a precursor to the mature protein product, p65. To investigate which viral proteinase may be responsible for generating p72 and p65, we expressed the 5′-region of the MHV-JHM RNA polymerase gene including the two papain-like cysteine proteinase domains in an in vitro transcription/translation system and analyzed the translation products for proteolytic processing. We also cloned and expressed the 72 kDa region immediately downstream from p28, and tested the ability of in vitro translated PCP-1 and PCP-2 to cleave p72 to p65 in trans. Our results indicate that neither viral proteinase domain PCP-1 nor PCP-2 is capable of cleavage of p72 to produce p65 in vitro. The role of MHV proteinases in the processing of p72 and p65 is discussed.


id: cord-293975-np9xdag5
author: Barnett, E. M.
date: 1993-12-31
txt: ./txt/cord-293975-np9xdag5.txt
cache: ./cache/cord-293975-np9xdag5.txt
extension: .txt
mime: text/plain
url: https://www.sciencedirect.com/science/article/pii/030645229390045H
doi: 10.1016/0306-4522(93)90045-h
summary:
  The data also demonstrate that two viruses can enter the brain via the olfactory system and localize to different structures, suggesting that neurological diseases involving disparate regions of the brain could be caused by different viruses, even if entry occurred at a common A number of viruses have been shown to spread transneuronally into and throughout the rodent CNS following intranasal inoculation, including herpes simplex virus type 1 (HSV-I)," vesicular stomatitis virus,43 Borna disease virus," mouse hepatitis virus (MHV),-pseudorabies viru? Abbreviafions: HSV-1, hernes simplex virus, type 1; LC, locus coeruleus; MHV''-JHM, -mouse hepatitis virus, strain JHM; MOB, main olfactorv bulb; PFU, plaque forming unit; p.i. post-inoculation; TH, tyrosine hydroxylase; TH + , tyrosine hydroxylase immunoreactive; TH -, tyrosine hydroxylase immunonegative; VTA, ventral tegmental area; WGA-HRP, wheatgerm agglutinin-horseradish peroxidase.

title:
  Two neurotropic viruses, herpes simplex virus type 1 and mouse hepatitis virus, spread along different neural pathways from the main olfactory bulb

abstract:
  Abstract Several neurotropic viruses enter the brain after peripheral inoculation and spread transneuronally along pathways known to be connected to the initial site of entry. In this study, the pathways utilized by two such viruses, herpes simplex virus type 1 and mouse hepatitis virus strain JHM, were compared using in situ hybridization following inoculation into either the nasal cavity or the main olfactory bulb of the mouse. The results indicate that both viruses spread to infect a unique and only partially overlapping set of connections of the main olfactory bulb. Both quantitative and qualitative differences were observed in the patterns of infection of known primary and secondary main olfactory bulb connections. Using immunohistochemistry for tyrosine hydroxylase combined with in situ hybridization, it was shown that only herpes simplex virus infected noradrenergic neurons in the locus coeruleus. In contrast, both viruses infected dopaminergic neurons in the ventral tegmental area, although mouse hepatitis virus produced a more widespread infection in the A10 group, as well as infecting A8 and A9. The results suggest that differential virus uptake in specific neurotransmitter systems contributes to the pattern of viral spread, although other factors, such as differences in access to particular synapses on infected cells and differences in the distribution of the cellular receptor for the two viruses, are also likely to be important. The data show that neural tracing with different viruses may define unique neural pathways from a site of inoculation. The data also demonstrate that two viruses can enter the brain via the olfactory system and localize to different structures, suggesting that neurological diseases involving disparate regions of the brain could be caused by different viruses, even if entry occurred at a common site.


id: cord-294467-kq5wmavt
author: Kasai, H.
date: 2014-04-08
txt: ./txt/cord-294467-kq5wmavt.txt
cache: ./cache/cord-294467-kq5wmavt.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/9856082/
doi: 10.1007/s007050050431
summary:
  title: Characterization of haemagglutinin-esterase protein (HE) of murine corona virus DVIM by monoclonal antibodies We analyzed the characteristics of seven monoclonal antibodies (mAbs) raised against purified HE (hemagglutinin-esterase) glycoprotein of the murine coronavirus DVIM (diarrhea virus of infant mice). Neutralizing activity was shown in group A mAbs exclusively, suggesting that the ratio of HA and/or AE activities may play important roles in the cell fusion activity of DVIM-infected cells. As described in a previous report [8] , by treatment of DVIM with the non-ionic detergent NP-40 we isolated the HE protein, which carries the functional sites for both acetylesterase (AE) and the haemagglutination (HA) activities. We examined the cytopathic effect of mAbs with respect to the formation of syncytia in DVIM-infected cells. The antibodies that had low titers to both activities did not delay the fusion of infected cells.

title:
  Characterization of haemagglutinin-esterase protein (HE) of murine corona virus DVIM by monoclonal antibodies

abstract:
  We analyzed the characteristics of seven monoclonal antibodies (mAbs) raised against purified HE (hemagglutinin-esterase) glycoprotein of the murine coronavirus DVIM (diarrhea virus of infant mice). Immunocrossreaction of these mAbs with JHM and/or MHV-S suggest that antigenic epitopes of HE of DVIM are similar to those of JHM and/or MHV-S. Four mAbs (1b4, 3Aff28, 4c19, 10b7), designated as group A mAbs, strongly inhibited both HA and AE activities. On the other hand, three mAbs (5Aff3, 6Aff6, 13Aff4), referred to as group B, had a comparatively weak HA inhibition activity. These results indicate that the antigenic epitopes of this glycoprotein can be classified into at least two groups and that the functional sites of HA and AE activities are similar but not identical. Neutralizing activity was shown in group A mAbs exclusively, suggesting that the ratio of HA and/or AE activities may play important roles in the cell fusion activity of DVIM-infected cells.


id: cord-295307-zrtixzgu
author: Delgado-Chaves, Fernando M.
date: 2020-07-21
txt: ./txt/cord-295307-zrtixzgu.txt
cache: ./cache/cord-295307-zrtixzgu.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/32708319/
doi: 10.3390/genes11070831
summary:
  Through the integration of differential expression analyses and reconstructed networks exploration, significant differences in the immune response to virus were observed in Ly6E [Formula: see text] compared to wild type animals. Among the different types of GNs, gene co-expression networks (GCNs) are widely used in the literature due to their computational simplicity and good performance in order to study biological processes or diseases [8] [9] [10] . In the present work mice samples were compared organ-wise depending on whether these corresponded to control, 3 d p.i. and 5 d p.i. The identification of DEG was performed using the Limma [63] R package, which provides non-parametric robust estimation of the gene expression variance. In this work four gene networks were reconstructed to model the genetic response MHV infection in two tissues, liver and spleen, and in two different genetic backgrounds, wild type and Ly6E ∆HSC .

title:
  Computational Analysis of the Global Effects of Ly6E in the Immune Response to Coronavirus Infection Using Gene Networks

abstract:
  Gene networks have arisen as a promising tool in the comprehensive modeling and analysis of complex diseases. Particularly in viral infections, the understanding of the host-pathogen mechanisms, and the immune response to these, is considered a major goal for the rational design of appropriate therapies. For this reason, the use of gene networks may well encourage therapy-associated research in the context of the coronavirus pandemic, orchestrating experimental scrutiny and reducing costs. In this work, gene co-expression networks were reconstructed from RNA-Seq expression data with the aim of analyzing the time-resolved effects of gene Ly6E in the immune response against the coronavirus responsible for murine hepatitis (MHV). Through the integration of differential expression analyses and reconstructed networks exploration, significant differences in the immune response to virus were observed in Ly6E [Formula: see text] compared to wild type animals. Results show that Ly6E ablation at hematopoietic stem cells (HSCs) leads to a progressive impaired immune response in both liver and spleen. Specifically, depletion of the normal leukocyte mediated immunity and chemokine signaling is observed in the liver of Ly6E [Formula: see text] mice. On the other hand, the immune response in the spleen, which seemed to be mediated by an intense chromatin activity in the normal situation, is replaced by ECM remodeling in Ly6E [Formula: see text] mice. These findings, which require further experimental characterization, could be extrapolated to other coronaviruses and motivate the efforts towards novel antiviral approaches.


id: cord-295781-b831y105
author: VanLeuven, James T.
date: 2017-06-02
txt: ./txt/cord-295781-b831y105.txt
cache: ./cache/cord-295781-b831y105.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/28575086/
doi: 10.1371/journal.pone.0178408
summary:
  title: Lung epithelial cells have virus-specific and shared gene expression responses to infection by diverse respiratory viruses We used microarray analysis to compare changes in gene expression of murine lung epithelial cells infected individually by three respiratory viruses causing mild (rhinovirus, RV1B), moderate (coronavirus, MHV-1), and severe (influenza A virus, PR8) disease in mice. While these models are invaluable for evaluating pathology and host responses to infection, parallel in vitro studies can be used to identify gene expression and signaling pathway changes that occur in infected cells to mediate pathogenesis. In this study, we compare the gene expression response of murine lung epithelial cells to infection by three respiratory viruses used in murine models: rhinovirus (serotype RV1B) in the family Picornaviridae, mouse hepatitis virus (MHV strain 1) in the family Coronaviridae, and influenza A virus (strain PR8) in the family Orthomyxoviridae.

title:
  Lung epithelial cells have virus-specific and shared gene expression responses to infection by diverse respiratory viruses

abstract:
  The severity of respiratory viral infections is partially determined by the cellular response mounted by infected lung epithelial cells. Disease prevention and treatment is dependent on our understanding of the shared and unique responses elicited by diverse viruses, yet few studies compare host responses to viruses from different families while controlling other experimental parameters. Murine models are commonly used to study the pathogenesis of respiratory viral infections, and in vitro studies using murine cells provide mechanistic insight into the pathogenesis observed in vivo. We used microarray analysis to compare changes in gene expression of murine lung epithelial cells infected individually by three respiratory viruses causing mild (rhinovirus, RV1B), moderate (coronavirus, MHV-1), and severe (influenza A virus, PR8) disease in mice. RV1B infection caused numerous gene expression changes, but the differential effect peaked at 12 hours post-infection. PR8 altered an intermediate number of genes whose expression continued to change through 24 hours. MHV-1 had comparatively few effects on host gene expression. The viruses elicited highly overlapping responses in antiviral genes, though MHV-1 induced a lower type I interferon response than the other two viruses. Signature genes were identified for each virus and included host defense genes for PR8, tissue remodeling genes for RV1B, and transcription factors for MHV-1. Our comparative approach identified universal and specific transcriptional signatures of virus infection that can be used to distinguish shared and virus-specific mechanisms of pathogenesis in the respiratory tract.


id: cord-296416-q0rsfzgw
author: LAVI, EHUD
date: 1996-07-15
url: https://www.ncbi.nlm.nih.gov/pubmed/8661443/
doi: 10.1006/viro.1996.0382
title:
  Syncytia Formation Induced by Coronavirus Infection Is Associated with Fragmentation and Rearrangement of the Golgi Apparatus

abstract:
  Abstract Coronavirus mouse hepatitis virus (MHV) possesses a membrane glycoprotein (M) which is targeted to the Golgi apparatus (GA). We used immunocytochemistry with an organelle-specific antiserum to investigate the morphologic changes of the GA during infection of L2 murine fibroblasts with MHV-A59. Twenty-four hours after infection the GA was fragmented and translocated in the center of syncytia, while the microtubular network was also rearranged displaying radiating elements toward the center of syncytia. Two fusion-defective mutants, which contain an identical amino acid substitution in the cleavage signal sequence of the spike glycoprotein (S), induced fragmentation of the GA. However, the GA migrated only partially to the centers of syncytia during infection with these mutants. Revertant viruses, in which the above mutation was corrected, had fusion properties and GA staining similar to wtMHV-A59. Experiments with brefeldin A (BFA), which induces redistribution of the GA into the rough endoplasmic reticulum (RER), revealed that an intact GA for a period of 4–16 hr postinfection, is required for coronavirus replication and syncytia formation. Thus, during MHV infection, syncytia formation is associated with fragmentation of the GA, followed by a previously undescribed phenomenon of migration of the organelle into the centers of syncytia. The fragmentation of the GA, however, may occur without the formation of syncytia. Therefore, two distinct mechanisms may be responsible for the fragmentation of the GA and its subsequent migration to the center of syncytia.


id: cord-298326-f5q7j3iu
author: Nick, Benjamin C.
date: 2020-06-19
txt: ./txt/cord-298326-f5q7j3iu.txt
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extension: .txt
mime: text/plain
url: https://doi.org/10.1101/2020.06.18.160671
doi: 10.1101/2020.06.18.160671
summary:
  In this study, we describe the identification of an essential, conserved horseshoe-shaped region in the nsp5 interdomain loop (IDL) of mouse hepatitis virus (MHV), a common coronavirus replication model. Structural modeling and sequence analysis of these sites in other coronaviruses, including all 7 human coronaviruses, suggests that the identified structure and sequence of this horseshoe regions is highly conserved and may represent a new, non-active-site regulatory region of the nsp5 (3CLpro) protease to target with coronavirus inhibitors. To evaluate whether any of 207 the recovered MHV nsp5 IDL mutants may exhibit a temperature-sensitive phenotype, we 208 performed an efficiency of plating (EOP) analysis by comparing the titers of each IDL virus by 209 plaque assay determined at a physiologic (37°C) and elevated temperature (40°C) (Fig. 3A) .

title:
  Identification of a critical horseshoe-shaped region in the nsp5 (Mpro, 3CLpro) protease interdomain loop (IDL) of coronavirus mouse hepatitis virus (MHV)

abstract:
  Human coronaviruses are enveloped, positive-strand RNA viruses which cause respiratory diseases ranging in severity from the seasonal common cold to SARS and COVID-19. Of the 7 human coronaviruses discovered to date, 3 emergent and severe human coronavirus strains (SARS-CoV, MERS-CoV, and SARS-CoV-2) have recently jumped to humans in the last 20 years. The COVID-19 pandemic spawned by the emergence of SARS-CoV-2 in late 2019 has highlighted the importance for development of effective therapeutics to target emerging coronaviruses. Upon entry, the replicase genes of coronaviruses are translated and subsequently proteolytically processed by virus-encoded proteases. Of these proteases, nonstructural protein 5 (nsp5, Mpro, or 3CLpro), mediates the majority of these cleavages and remains a key drug target for therapeutic inhibitors. Efforts to develop nsp5 active-site inhibitors for human coronaviruses have thus far been unsuccessful, establishing the need for identification of other critical and conserved non-active-site regions of the protease. In this study, we describe the identification of an essential, conserved horseshoe-shaped region in the nsp5 interdomain loop (IDL) of mouse hepatitis virus (MHV), a common coronavirus replication model. Using site-directed mutagenesis and replication studies, we show that several residues comprising this horseshoe-shaped region either fail to tolerate mutagenesis or were associated with viral temperature-sensitivity. Structural modeling and sequence analysis of these sites in other coronaviruses, including all 7 human coronaviruses, suggests that the identified structure and sequence of this horseshoe regions is highly conserved and may represent a new, non-active-site regulatory region of the nsp5 (3CLpro) protease to target with coronavirus inhibitors. Importance In December 2019, a novel coronavirus (SARS-CoV-2) emerged in humans and triggered a pandemic which has to date resulted in over 8 million confirmed cases of COVID-19 across more than 180 countries and territories (June 2020). SARS-CoV-2 represents the third emergent coronavirus in the past 20 years and the future emergence of new coronaviruses in humans remains certain. Critically, there remains no vaccine nor established therapeutics to treat cases of COVID-19. The coronavirus nsp5 protease is a conserved and indispensable virus-encoded enzyme which remains a key target for therapeutic design. However, past attempts to target the active site of nsp5 with inhibitors have failed stressing the need to identify new conserved non-active-site targets for therapeutic development. This study describes the discovery of a novel conserved structural region of the nsp5 protease of coronavirus mouse hepatitis virus (MHV) which may provide a new target for coronavirus drug development.


id: cord-298847-szezd2vb
title: Vacuolating encephalitis in mice infected by human coronavirus OC43
author: Jacomy, Hélène
date: 2003-10-10
url: https://www.ncbi.nlm.nih.gov/pubmed/14592756/
doi: 10.1016/s0042-6822(03)00323-4
abstract:
  Involvement of viruses in human neurodegenerative diseases and the underlying pathologic mechanisms remain generally unclear. Human respiratory coronaviruses (HCoV) can infect neural cells, persist in human brain, and activate myelin-reactive T cells. As a means of understanding the human infection, we characterized in vivo the neurotropic and neuroinvasive properties of HCoV-OC43 through the development of an experimental animal model. Virus inoculation of 21-day postnatal C57BL/6 and BALB/c mice led to a generalized infection of the whole CNS, demonstrating HCoV-OC43 neuroinvasiveness and neurovirulence. This acute infection targeted neurons, which underwent vacuolation and degeneration while infected regions presented strong microglial reactivity and inflammatory reactions. Damage to the CNS was not immunologically mediated and microglial reactivity was instead a consequence of direct virus-mediated neuronal injury. Although this acute encephalitis appears generally similar to that induced by murine coronaviruses, an important difference rests in the prominent spongiform-like degeneration that could trigger neuropathology in surviving animals.


id: cord-298934-vtrfqozl
title: Primary structure and translation of a defective interfering rna of murine coronavirus
author: Makino, Shinji
date: 1988-10-31
url: https://api.elsevier.com/content/article/pii/0042682288905260
doi: 10.1016/0042-6822(88)90526-0
abstract:
  Abstract An intracellular defective-interfering (DI) RNA, DIssE, of mouse hepatitis virus (MHV) obtained after serial high multiplicity passage of the virus was cloned and sequenced. DIssE RNA is composed of three noncontiguous genomic regions, representing the first 864 nucleotides of the Fend, an internal 748 nucleotides of the polymerase gene, and 601 nucleotides from the 3′ end of the parental MHV genome. The DIssE sequence contains one large continuous open reading frame. Two protein products from this open reading frame were identified both by in vitro translation and in DI-infected cells. Sequence comparison of DIssE and the corresponding parts of the parental virus genome revealed that DIssE had three base substitutions within the leader sequence and also a deletion of nine nucleotides located at the junction of the leader and the remaining genomic sequence. The 5′ end of DIssE RNA was heterogeneous with respect to the number of UCUAA repeats within the leader sequence. The parental MHV genomic RNA appears to have extensive and stable secondary structures at the regions where DI RNA rearrangements occurred. These data suggest that MHV DI RNA may have been generated as a result of the discontinuous and nonprocessive manner of MHV RNA synthesis.


id: cord-299756-m0va36er
author: Raaben, Matthijs
date: 2009-08-03
url: https://www.ncbi.nlm.nih.gov/pubmed/19650917/
doi: 10.1186/1471-2164-10-350
title:
  Type I interferon receptor-independent and -dependent host transcriptional responses to mouse hepatitis coronavirus infection in vivo

abstract:
  BACKGROUND: The role of type I IFNs in protecting against coronavirus (CoV) infections is not fully understood. While CoVs are poor inducers of type I IFNs in tissue culture, several studies have demonstrated the importance of the type I IFN response in controlling MHV infection in animals. The protective effectors against MHV infection are, however, still unknown. RESULTS: In order to get more insight into the antiviral gene expression induced in the brains of MHV-infected mice, we performed whole-genome expression profiling. Three different mouse strains, differing in their susceptibility to infection with MHV, were used. In BALB/c mice, which display high viral loads but are able to control the infection, 57 and 121 genes were significantly differentially expressed (≥ 1.5 fold change) upon infection at 2 and 5 days post infection, respectively. Functional association network analyses demonstrated a strong type I IFN response, with Irf1 and Irf7 as the central players. At 5 days post infection, a type II IFN response also becomes apparent. Both the type I and II IFN response, which were more pronounced in mice with a higher viral load, were not observed in 129SvEv mice, which are much less susceptible to infection with MHV. 129SvEv mice lacking the type I interferon receptor (IFNAR-/-), however, were not able to control the infection. Gene expression profiling of these mice identified type I IFN-independent responses to infection, with IFN-γ as the central player. As the BALB/c and the IFNAR-/- 129SvEv mice demonstrated very similar viral loads in their brains, we also compared their gene expression profiles upon infection with MHV in order to identify type I IFN-dependent transcriptional responses. Many known IFN-inducible genes were detected, several of which have previously been shown to play an important protective role against virus infections. We speculate that the additional type I IFN-dependent genes that we discovered may also be important for protection against MHV infection. CONCLUSION: Transcriptional profiling of mice infected with MHV demonstrated the induction of a robust IFN response, which correlated with the viral load. Profiling of IFNAR-/- mice allowed us to identify type I IFN-independent and -dependent responses. Overall, this study broadens our present knowledge of the type I and II IFN-mediated effector responses during CoV infection in vivo.


id: cord-301942-ppa7gb95
title: Ultrastructure of SARS-CoV, FIPV, and MHV Revealed by Electron Cryomicroscopy
author: Neuman, Benjamin W.
date: 2006
txt: ./txt/cord-301942-ppa7gb95.txt
cache: ./cache/cord-301942-ppa7gb95.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/17037527/
doi: 10.1007/978-0-387-33012-9_31
abstract: nan
summary:
  The current understanding of coronavirus ultrastructure relies heavily on transmission electron microscopy of negatively stained images. Each virus appeared approximately round in cryo-EM images, with a fringe of spikes protruding from the viral membrane and a region of lower density near the virion center ( Fig. 1A-B) . Spike-depleted SARS-CoV particles appeared similar to spike-depleted MHV particles in negative stain, but were produced in lower yield, not suitable for effective cryo-EM imaging. The arrangement of spike densities near the center of some particles approximates a rhombus, which would not be inconsistent with a paracrystalline organization of spikes as observed in the virions of pleomorphic arenavirus particles, 17 or a local hexagonal close-packing of structural proteins as observed in retroviral particles. Fine structure of influenza A virus observed by electron cryo-microscopy Cryo-electron microscopy reveals ordered domains in the immature HIV-1 particle Supramolecular organization of immature and mature murine leukemia virus revealed by electron cryo-microscopy: implications for retroviral assembly mechanisms


id: cord-303153-z7bdiuvx
author: Ulasli, Mustafa
date: 2010-01-20
txt: ./txt/cord-303153-z7bdiuvx.txt
cache: ./cache/cord-303153-z7bdiuvx.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1111/j.1462-5822.2010.01437.x
doi: 10.1111/j.1462-5822.2010.01437.x
summary:
  This approach has allowed us to establish that MHV induces the formation of six membranous rearrangements in the following order: DMVs, CMs, virions, LVCVs, TBs and CMSs. Importantly, we were able to show that most membrane rearrangements (LVCVs, TBs, CMSs and possibly CMs) observed in addition to the key structures in the infection (DMVs and virions) actually appear to be the consequence of a massive synthesis of viral proteins. In order to be able to correlate our EM and IEM analyses with the progression of a CoV infection inside the host cells, we first measured important known parameters that reflect the CoV life cycle: viral RNA replication/transcription, viral protein synthesis and secretion of progeny virus. In the centre of the DMV clusters, we frequently observed a small network of membranes with a diameter varying from 200 to 600 nm, which have recently been described in SARS-CoV-infected cells and called CMs [ Fig. 2A and B, arrowheads; (Knoops et al., 2008) .

title:
  Qualitative and quantitative ultrastructural analysis of the membrane rearrangements induced by coronavirus

abstract:
  Coronaviruses (CoV) are enveloped positive‐strand RNA viruses that induce different membrane rearrangements in infected cells in order to efficiently replicate and assemble. The origin, the protein composition and the function of these structures are not well established. To shed further light on these structures, we have performed a time‐course experiment in which the mouse hepatitis virus (MHV)‐induced membrane rearrangements were examined qualitatively and quantitatively by (immuno)‐electron microscopy. With our approach we were able to confirm the appearance of 6, previously reported, membranous structures during the course of a complete infection cycle. These structures include the well‐characterized double‐membrane vesicles (DMVs), convoluted membranes (CMs) and virions but also the more enigmatic large virion‐containing vacuoles (LVCVs), tubular bodies (TBs) and cubic membrane structures (CMSs). We have characterized the LVCVs, TBs and CMSs, and found that the CoV‐induced structures appear in a strict order. By combining these data with quantitative analyses on viral RNA, protein synthesis and virion release, this study generates an integrated molecular and ultrastructural overview of CoV infection. In particular, it provides insights in the role of each CoV‐induced structure and reveals that LVCVs are ERGIC/Golgi compartments that expand to accommodate an increasing production of viral particles.


id: cord-303238-us3dybue
title: Membrane Topology of Murine Coronavirus Replicase Nonstructural Protein 3
author: Kanjanahaluethai, Amornrat
date: 2007-05-01
txt: ./txt/cord-303238-us3dybue.txt
cache: ./cache/cord-303238-us3dybue.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/17222884/
doi: 10.1016/j.virol.2006.12.009
summary:
  The papain-like protease (PLpro) encoded by the coronavirus that causes severe acute respiratory syndrome (SARS-CoV) processes three sites in the replicase polyprotein (Harcourt et al., 2004) , and has recently been shown to have de-ubiquitinating activity (Barretto et al., 2005; Lindner et al., 2005) . To extend these studies of membrane association of coronavirus replicase products, we analyzed the amino acid sequence of MHV-JHM nsp3 (from glycine-833 to glycine-2840) for probability of transmembrane helices using the five different programs designed to search for putative membrane-spanning sequences: Phobius, TMHMM, HMMTOP, SOSUI and TMpred (Fig. 2) . In contrast, when CMMs were added to the mixture, protein products that included all or part of nsp3-TM (PLP2-2485, -2390 and -2258) were detected predominantly in the pelleted fraction, consistent with membrane association (Fig. 3B ).

abstract:
  Mouse hepatitis virus (MHV) is a member of the family Coronaviridae. These positive strand RNA viruses encode a replicase polyprotein that is processed into 16 nonstructural proteins (nsps). The nsps assemble with membranes to generate double membrane vesicles, which are the sites of viral RNA synthesis. MHV nsp3 contains multiple domains including two papain-like protease domains, PLP1 and PLP2, and a predicted transmembrane (TM) domain. In this study, we determined the membrane topology of nsp3-TM and showed that TM-mediated tethering of PLP2 is important for processing at cleavage site 3. Biochemical analysis revealed that nsp3 is an integral membrane protein that is inserted into endoplasmic reticulum (ER) membranes co-translationally and glycosylated at asparagine-2357. Proteinase K digestion experiments indicate that the TM domain of nsp3 has 4 membrane-spanning helices. We show that nsp3-TM is sufficient to mediate ER membrane association of a cytosolic protein. This study is the first detailed analysis of the topology and function of the coronavirus nsp3 TM domain.


id: cord-304421-xpj6c0vx
author: Piñón, Josefina D.
date: 1999-10-25
url: https://www.sciencedirect.com/science/article/pii/S0042682299999543
doi: 10.1006/viro.1999.9954
title:
  Further Requirements for Cleavage by the Murine Coronavirus 3C-like Proteinase: Identification of a Cleavage Site within ORF1b

abstract:
  Abstract The coronavirus mouse hepatitis virus strain A59 (MHV-A59) encodes a 3C-like proteinase (3CLpro) that is proposed to be responsible for the majority of the processing events that take place within the replicase polyproteins pp1a and pp1ab. In this study we demonstrate that the Q939↓S940 peptide bond, located between the polymerase and Zn-finger regions of pp1ab (the POL↓Zn site), is processed by the 3CLpro, albeit inefficiently. Mutagenesis of the POL↓Zn site, as well as the previously identified HD1↓3C site in the 1a region of pp1a and pp1ab, demonstrated that the amino acid residues at the P2 and P1 positions of the cleavage site, occupied by L and Q, respectively, were important determinants of 3CLpro substrate specificity. Finally, a direct comparison of the 3CLpro-mediated cleavages at the HD1↓3C and POL↓Zn sites was made by determining the rate constants using synthetic peptides. The results show that while a larger polypeptide substrate carrying the HD1↓3C site was processed more efficiently than a polypeptide substrate carrying the POL↓Zn site, cleavage of the synthetic peptide substrates containing these two cleavage sites occurred at similar efficiencies. This indicates that the overall conformation of a large polyprotein substrate is important in the accessibility of the cleavage site to the proteinase.


id: cord-304855-7v0cncid
author: Raaben, Matthijs
date: 2009-02-10
url: https://doi.org/10.1111/j.1462-5822.2009.01298.x
doi: 10.1111/j.1462-5822.2009.01298.x
title:
  Non‐invasive imaging of mouse hepatitis coronavirus infection reveals determinants of viral replication and spread in vivo

abstract:
  Bioluminescence imaging (BLI) is a powerful new method to study virus dissemination in the live animal. Here we used this method to monitor the spatial and temporal progression of mouse hepatitis coronavirus (MHV) infection in mice using luciferase‐expressing viruses. Upon intranasal inoculation, virus replication could initially be observed in the nasal cavity and the cervical lymph nodes, after which the infection spread to the brain and frequently to the eyes. The kinetics of virus spread to and clearance from the brain appeared to depend on the inoculation dose. After intraperitoneal inoculation, virus replication was predominantly observed in the liver and occasionally in the intestines, but interestingly also in the tail and paws. BLI thus elucidated new anatomic locations of virus replication. Furthermore, MHV dissemination was shown to be critically depended on the viral spike protein, but also on the mouse strain used. Widespread dissemination was observed in mice lacking a functional type I interferon response. The importance of the type I interferon system in limiting viral spread was also demonstrated by the administration of type I interferons to mice. Our results provide new insights in coronavirus pathogenesis and demonstrate the potential of BLI to study coronavirus–host interactions in vivo.


id: cord-304954-5b4yji8n
author: Yamaguchi, Kenjiro
date: 1991-04-30
txt: ./txt/cord-304954-5b4yji8n.txt
cache: ./cache/cord-304954-5b4yji8n.txt
extension: .txt
mime: text/plain
url: https://www.sciencedirect.com/science/article/pii/016557289190065F
doi: 10.1016/0165-5728(91)90065-f
summary:
  title: Production of mice from a lethal coronavirus infection in the central nervous system by adoptive transfer of virus-specific T cell clones Abstract The protective effect of a mouse hepatitis virus type-4 (MHV-4)-specific CD8+ cytotoxic T cell clone and a CD4+ helper T cell clone was examined by the adoptive transfer into brains of mice lethally infected with MHV-4. Although the adoptive transfer of both types of the T cell clones suppressed viral growth and viral antigen-positive cells in the brains, a significant inhibition of virus replication by the cytotoxic T cell clone was detected prior to that induced by the helper T cell clone. In the present study we demonstrate that the adoptive transfer of virus-specific CD8 ÷ CTL clones also protects mice from a lethal MHV-4 infection. In this study we have confirmed that the adoptive transfer of virus-specific CD4 + Th cells protects mice from a MHV-4 lethal infection.

title:
  Production of mice from a lethal coronavirus infection in the central nervous system by adoptive transfer of virus-specific T cell clones

abstract:
  Abstract The protective effect of a mouse hepatitis virus type-4 (MHV-4)-specific CD8+ cytotoxic T cell clone and a CD4+ helper T cell clone was examined by the adoptive transfer into brains of mice lethally infected with MHV-4. Mice survived acute encephalitis if more than 5 × 105 cells of either type of the virus-specific T cell clones had been transfered into H-2-matched recipients by 1 day post-infection. Although the adoptive transfer of both types of the T cell clones suppressed viral growth and viral antigen-positive cells in the brains, a significant inhibition of virus replication by the cytotoxic T cell clone was detected prior to that induced by the helper T cell clone. Histologically, cell destruction was prominent in the brains of mice which received the cytotoxic T cell clone. These results demonstrate that both the CD8+ cytotoxic T cell and the CD4+ helper T cell can protect mice from a lethal MHV-4 infection in the central nervous system.


id: cord-307098-oq7zrnuv
title: Difference in Bgp-independent fusion activity among mouse hepatitis viruses
author: Taguchi, F.
date: 2014-05-20
txt: ./txt/cord-307098-oq7zrnuv.txt
cache: ./cache/cord-307098-oq7zrnuv.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/10550676/
doi: 10.1007/s007050050725
summary:
  Co-cultivation of MHV-nonpermissive hamster BHK cells devoid of mouse Bgp with mouse DBT cells infected with MHV-A59 or JHMV induces syncytia formation on BHK cells (Bgp-independent fusion). Under a phase contrast microscopy, JHMV (cl-2, sp-4) induced the Bgp-independent syncytia on BHK cells similar to those observed on DBT cells, while such syncytia were not seen with the infection of other MHV strains (MHV-1, MHV-3, MHV-A59, MHV-S, srr7, srr11 and srr18). Interestingly, no syncytia formation was demonstrated on BHK cells with other strains or srr mutants under the phase contrast microscopy, though all of them produced syncytia on Bgp-positive DBT cells [10] . The cl-2 S protein could have a very strong Bgp-independent fusion activity, but its replication in BHK cells could be less efficient than the other MHV strains. Present study showed that JHMV (cl-2 and sp-4) could induce syncytia on BHK cells detectable by microscopy, whereas the other MHVs and srr mutants failed.

abstract:
  Mouse hepatitis virus (MHV) utilizes a mouse biliary glycoprotein (Bgp) as a receptor. Co-cultivation of MHV-nonpermissive hamster BHK cells devoid of mouse Bgp with mouse DBT cells infected with MHV-A59 or JHMV induces syncytia formation on BHK cells (Bgp-independent fusion). This study shows the difference in Bgp-independent fusion activity among various MHV strains. Under a phase contrast microscopy, JHMV (cl-2, sp-4) induced the Bgp-independent syncytia on BHK cells similar to those observed on DBT cells, while such syncytia were not seen with the infection of other MHV strains (MHV-1, MHV-3, MHV-A59, MHV-S, srr7, srr11 and srr18). Tiny syncytia detectable only by immunofluorescence were produced with the latter MHV strains except for srr7 which failed to produce syncytia. MHVs except for srr7 grew in BHK cells after Bgp-independent infection. The Bgp-independent fusion by JHMV was inhibited either by anti-S1 or anti-S2 antibodies. These results showed that the JHMV spike protein had a remarkably high Bgp-independent fusion activity.


id: cord-309109-c5hajb6k
title: Murine hepatitis virus—A model for virus-induced CNS demyelination
author: Matthews, A. E.
date: 2002
txt: ./txt/cord-309109-c5hajb6k.txt
cache: ./cache/cord-309109-c5hajb6k.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/11935460/
doi: 10.1080/13550280290049534
summary:
  Although activated , MHV-speci c, CD8 C T cells transferred to infected mice can control viral replication, they are not suf cient to clear infectious virus from oligodendrocytes (Stohlman et al, 1998b) . Clearance of an MHV strain that primarily infects neurons is delayed in the absence of IFN-gamma, suggesting that it may affect viral control in other cell types as well without being absolutely required for clearance (Lane et al, 1997) . The contribution of humoral immunity to viral clearance and persistent infection in the CNS has been investigated using mice de cient in secreted antibodies or B cells Bergmann et al, 2001; Matthews et al, 2001) . These data suggest that T cells play a role in controlling viral titers, even before 5 d.p.i. Beta2-microglobulinde cient mice, which lack CD8 C T cells, have delayed clearance of virus from the liver .

abstract:
  Most murine hepatitis virus (MHV) strains, as their name suggests, infect the liver. However, several murine strains are tropic for the central nervous system (CNS) and cause encephalitis with subsequent CNS demyelination. The CNS demyelination shares pathological similarities with human CNS demyelinating diseases such as multiple sclerosis (MS). These viruses are, therefore, used to study the role of the immune system in viral clearance from the CNS, in CNS demyelination, and in remyelination. Nevertheless, it is still unclear exactly how MHV induces demyelination and to what extent the immune system plays a role in this pathology. Here we review this field in the context of the immune response to MHV in the liver and the CNS focusing on studies that have been published in the past 5 years.


id: cord-312294-c9e18rai
author: Daniel, Claude
date: 1994-12-31
txt: ./txt/cord-312294-c9e18rai.txt
cache: ./cache/cord-312294-c9e18rai.txt
extension: .txt
mime: text/plain
url: https://www.sciencedirect.com/science/article/pii/0166093494901805
doi: 10.1016/0166-0934(94)90180-5
summary:
  title: Increased viral titers and enhanced reactivity of antibodies to the spike glycoprotein of murine coronavirus produced by infection at pH 6 Abstract Infection of cell monolayers by murine coronavirus A59 at pH 6 rather than 7 yielded a ten-fold increase in the infectious titer and a remarkable enhancement of the reactivities of monoclonal and polyclonal antibodies against the spike glycoprotein in immunoblotting, immuno-precipitation and enzyme-linked immunosorbent assays. In this study, we show that infection by MHV-A59 in culture medium at pH 6, instead of the usual pH 7, not only increased infectious viral titers, but also greatly enhanced the reactivity of the spike glycoprotein to antibodies. Metabolically labeled virus-infected cell lysates were immunoprecipitated with MHV-specific antibodies ((Y-AS9: hyperimmune serum; 7-10A: anti-S MAb; 653: control ascites fluid) and resolved by SDS-PAGE on a 7-15% gel. Monoclonal antibodies to murine hepatitis virus-4 (strain JHM) define the viral glycoprotein responsible for attachment and cell-cell fusion

title:
  Increased viral titers and enhanced reactivity of antibodies to the spike glycoprotein of murine coronavirus produced by infection at pH 6

abstract:
  Abstract Infection of cell monolayers by murine coronavirus A59 at pH 6 rather than 7 yielded a ten-fold increase in the infectious titer and a remarkable enhancement of the reactivities of monoclonal and polyclonal antibodies against the spike glycoprotein in immunoblotting, immuno-precipitation and enzyme-linked immunosorbent assays. These observations are very useful for detecting antibodies against the S glycoprotein of coronaviruses and enhancing infectious titers.


id: cord-313263-epylkxdx
title: A Mechanism of Virus-Induced Demyelination
author: Das Sarma, Jayasri
date: 2010-06-21
url: https://doi.org/10.1155/2010/109239
doi: 10.1155/2010/109239
abstract:
  Myelin forms an insulating sheath surrounding axons in the central and peripheral nervous systems and is essential for rapid propagation of neuronal action potentials. Demyelination is an acquired disorder in which normally formed myelin degenerates, exposing axons to the extracellular environment. The result is dysfunction of normal neuron-to-neuron communication and in many cases, varying degrees of axonal degeneration. Numerous central nervous system demyelinating disorders exist, including multiple sclerosis. Although demyelination is the major manifestation of most of the demyelinating diseases, recent studies have clearly documented concomitant axonal loss to varying degrees resulting in long-term disability. Axonal injury may occur secondary to myelin damage (outside-in model) or myelin damage may occur secondary to axonal injury (inside-out model). Viral induced demyelination models, has provided unique imminent into the cellular mechanisms of myelin destruction. They illustrate mechanisms of viral persistence, including latent infections, virus reactivation and viral-induced tissue damage. These studies have also provided excellent paradigms to study the interactions between the immune system and the central nervous system (CNS). In this review we will discuss potential cellular and molecular mechanism of central nervous system axonal loss and demyelination in a viral induced mouse model of multiple sclerosis.


id: cord-317169-qlqavi4t
author: Chiow, K.H.
date: 2015-12-19
txt: ./txt/cord-317169-qlqavi4t.txt
cache: ./cache/cord-317169-qlqavi4t.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/26851778/
doi: 10.1016/j.apjtm.2015.12.002
summary:
  (Saururaceae) and three of its constituent flavonoids (quercetin, quercitrin and rutin) against murine coronavirus and dengue virus (DENV). cordata and flavonoids were assessed using virus neutralization tests against mouse hepatitis virus (MHV) and DENV type 2 (DENV-2). Certain flavonoids exhibited comparatively weaker antiviral activity, notably quercetin which could inhibit both MHV and DENV-2. This was followed by quercitrin which could inhibit DENV-2 but not MHV, whereas rutin did not exert any inhibitory effect on either virus. cordata contribute to the superior antiviral efficacy of the EA fraction which lacked cytotoxicity in vitro and acute toxicity in vivo. cordata exhibited anti-MHV activity at a MIC of 0.98 mg/mL without any apparent cytotoxic effects on CCL9.1 cells. cordata and its flavonoid component, quercetin, could inhibit both MHV and DENV-2 in vitro. Houttuynia cordata extracts and constituents inhibit the infectivity of dengue virus type 2 in vitro

title:
  Evaluation of antiviral activities of Houttuynia cordata Thunb. extract, quercetin, quercetrin and cinanserin on murine coronavirus and dengue virus infection

abstract:
  OBJECTIVE: To evaluate the in vitro activities of the ethyl acetate (EA) fraction of Houttuynia cordata (H. cordata) Thunb. (Saururaceae) and three of its constituent flavonoids (quercetin, quercitrin and rutin) against murine coronavirus and dengue virus (DENV). METHODS: The antiviral activities of various concentrations of the EA fraction of H. cordata and flavonoids were assessed using virus neutralization tests against mouse hepatitis virus (MHV) and DENV type 2 (DENV-2). Cinanserin hydrochloride was also tested against MHV. The EA fraction of H. cordata was tested for acute oral toxicity in C57BL/6 mice. RESULTS: The EA fraction of H. cordata inhibited viral infectivity up to 6 d. Cinanserin hydrochloride was able to inhibit MHV for only 2 d. The 50% inhibitory concentrations (IC(50)) of the EA fraction of H. cordata added before the viral adsorption stage were 0.98 μg/mL for MHV and 7.50 μg/mL for DENV-2 with absence of cytotoxicity. The mice fed with the EA fraction up to 2 000 mg/kg did not induce any signs of acute toxicity, with normal histological features of major organs. Certain flavonoids exhibited comparatively weaker antiviral activity, notably quercetin which could inhibit both MHV and DENV-2. This was followed by quercitrin which could inhibit DENV-2 but not MHV, whereas rutin did not exert any inhibitory effect on either virus. When quercetin was combined with quercitrin, enhancement of anti-DENV-2 activity and reduced cytotoxicity were observed. However, the synergistic efficacy of the flavonoid combination was still less than that of the EA fraction. CONCLUSIONS: The compounds in H. cordata contribute to the superior antiviral efficacy of the EA fraction which lacked cytotoxicity in vitro and acute toxicity in vivo. H. cordata has much potential for the development of antiviral agents against coronavirus and dengue infections.


id: cord-317635-jal2tkra
author: Cervin, Marguerite
date: 2005-12-09
url: https://www.ncbi.nlm.nih.gov/pubmed/1662706/
doi: 10.1002/jmv.1890350213
title:
  Modulation of coronavirus‐mediated cell fusion by homeostatic control of cholesterol and fatty acid metabolism

abstract:
  Cellular susceptibility to fusion mediated by murine coronavirus (mouse hepatitis virus, MHV strain A59) was separated into lipid‐dependent and lipid‐independent mechanisms with the use of subclones and selected mutants of mouse L‐2 fibroblasts. Fusion‐resistant L‐2 cell mutants had similar cholesterol and fatty acid composition as did their fusion‐susceptible parent subclone, and were presumably deficient in a genetically mutable non‐lipid, host cell factor (e.g., fusion protein receptor). On the other hand, cellular sensitivity to virus fusion, which is known to be influenced by cell cholesterol content [Daya et al., 1988], was shown further to be modulated by homeostatic alterations in fatty acid metabolism. Cholesterol supplementation of mouse L‐2 fibroblasts or of peritoneal macrophages from MHV‐susceptible mice elevated susceptibility to viral fusion. Increased fusion susceptibility occurred in cholesterol‐supplemented L‐2 cells in the absence of any detectable alterations i n host cell fatty acid composition, thus demonstrating fusion enhancement by cholesterol alone. L‐2 cells cloned by limiting dilution in normal (not cholesterol‐supplemented) medium were found to be heterogeneous i n cholesterol content. Interestingly, high cholesterol‐containing subclones had increased levels of C‐18:0, C‐18:2, C‐20:4, and C‐22:6 and markedly reduced levels of C‐18:l fatty acids when compared to low cholesterol‐containing subclones. High cholesterol‐containing subclones did not show enhanced susceptibility to viral fusion, suggesting that homeostatic alteration of fatty acid metabolism compensated for the increased cholesterol levels and countered the normally fusion‐enhancing effect of cholesterol alone. Since these observations have potentially important consequences regarding the effects of dietary cholesterol on the severity of virus infection, we examined liver titres and pathology of normal and hypercholesterolemic mice infected with MHV. Hypercholesterolemia had no significant effect on virus replication or on liver pathology in two MHV‐ sensitive strains (Balb/c and AIJ) or in one MHV‐resistant (SJLIJ) of mice. Lipid analyses of the livers from normal and hypercholesterolemic mice showed evidence of two homeostatic mechanisms (cholesterol esterification and alteration of fatty acid composition) which likely counteracted the normally exacerbating effect of cholesterol on MHV cytopathology.


id: cord-320165-1b6sycgv
author: Guo, Qirui
date: 2020-09-09
url: https://doi.org/10.1101/2020.09.09.288704
doi: 10.1101/2020.09.09.288704
title:
  Small molecules inhibit SARS-COV-2 induced aberrant inflammation and viral replication in mice by targeting S100A8/A9-TLR4 axis

abstract:
  The SARS-CoV-2 pandemic poses an unprecedented public health crisis. Accumulating evidences suggest that SARS-CoV-2 infection causes dysregulation of immune system. However, the unique signature of early immune responses remains elusive. We characterized the transcriptome of rhesus macaques and mice infected with SARS-CoV-2. Alarmin S100A8 was robustly induced by SARS-CoV-2 in animal models as well as in COVID-19 patients. Paquinimod, a specific inhibitor of S100A8/A9, could reduce inflammatory response and rescue the pneumonia with substantial reduction of viral titers in SASR-CoV-2 infected animals. Remarkably, Paquinimod treatment resulted in 100% survival of mice in a lethal model of mouse coronavirus (MHV) infection. A novel group of neutrophils that contributed to the uncontrolled inflammation and onset of COVID-19 were dramatically induced by coronavirus infections. Paquinimod treatment could reduce these neutrophils and regain antiviral responses, unveiling key roles of S100A8/A9 and noncanonical neutrophils in the pathogenesis of COVID-19, highlighting new opportunities for therapeutic intervention.


id: cord-324321-y96x8x3h
author: Cai, Yingyun
date: 2003-11-10
txt: ./txt/cord-324321-y96x8x3h.txt
cache: ./cache/cord-324321-y96x8x3h.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/14599795/
doi: 10.1016/j.virol.2003.07.007
summary:
  Furthermore, treatment of cells with chloroquine, which blocks the acidification of endosomes, significantly inhibited the repression of the BNip3 promoter activity induced by the acidic pH-dependent MHV mutant OBLV60, which enters cells via endocytosis, indicating that the down-regulation of BNip3 expression is mediated by fusion between viral envelope and cell membranes during entry. To establish further the specificity of the down-regulation of BNip3 gene expression, we used vesicular stomatitis virus (VSV) in a parallel experiment, because VSV is also an enveloped RNA virus whose infection has a broad host cell range and is mediated by the interaction between the envelope G protein and cell membranes (Riedel et al., 1984) . By extrapolating the data from the mutant virus, we can envision that fusion between viral envelope and plasma/endosomal membranes during wild-type MHV infection is involved in the down-regulation of BNip3 gene expression.

title:
  Down-regulation of transcription of the proapoptotic gene BNip3 in cultured astrocytes by murine coronavirus infection

abstract:
  Murine coronavirus mouse hepatitis virus (MHV) causes encephalitis and demyelination in the central nervous system of susceptible rodents. Astrocytes are the major target for MHV persistence. However, the mechanisms by which astrocytes survive MHV infection and permit viral persistence are not known. Here we performed DNA microarray analysis on differential gene expression in astrocyte DBT cells by MHV infection and found that the mRNA of the proapoptotic gene BNip3 was significantly decreased following MHV infection. This finding was further confirmed by quantitative reverse transcription–polymerase chain reaction, Western blot analysis, and BNip3-promoter-luciferase reporter system. Interestingly, infection with live and ultraviolet light-inactivated viruses equally repressed BNip3 expression, indicating that the down-regulation of BNip3 expression does not require virus replication and is mediated during cell entry. Furthermore, treatment of cells with chloroquine, which blocks the acidification of endosomes, significantly inhibited the repression of the BNip3 promoter activity induced by the acidic pH-dependent MHV mutant OBLV60, which enters cells via endocytosis, indicating that the down-regulation of BNip3 expression is mediated by fusion between viral envelope and cell membranes during entry. Deletion analysis showed that the sequence between nucleotides 262 and 550 of the 588-base-pair BNip3 promoter is necessary and sufficient for driving the BNip3 expression and that it contains signals that are responsible for MHV-induced down-regulation of BNip3 expression in DBT cells. These results may provide insights into the mechanisms by which MHV evades host antiviral defense and promotes cell survival, thereby allowing its persistence in the host astrocytes.


id: cord-325624-6anybxnk
title: RNase L Mediated Protection from Virus Induced Demyelination
author: Ireland, Derek D. C.
date: 2009-10-02
url: https://www.ncbi.nlm.nih.gov/pubmed/19798426/
doi: 10.1371/journal.ppat.1000602
abstract:
  IFN-α/β plays a critical role in limiting viral spread, restricting viral tropism and protecting mice from neurotropic coronavirus infection. However, the IFN-α/β dependent mechanisms underlying innate anti-viral functions within the CNS are poorly understood. The role of RNase L in viral encephalomyelitis was explored based on its functions in inhibiting translation, inducing apoptosis, and propagating the IFN-α/β pathway through RNA degradation intermediates. Infection of RNase L deficient (RL(−/−)) mice with a sub-lethal, demyelinating mouse hepatitis virus variant revealed that the majority of mice succumbed to infection by day 12 p.i. However, RNase L deficiency did not affect overall control of infectious virus, or diminish IFN-α/β expression in the CNS. Furthermore, increased morbidity and mortality could not be attributed to altered proinflammatory signals or composition of cells infiltrating the CNS. The unique phenotype of infected RL(−/−) mice was rather manifested in earlier onset and increased severity of demyelination and axonal damage in brain stem and spinal cord without evidence for enhanced neuronal infection. Increased tissue damage coincided with sustained brain stem infection, foci of microglia infection in grey matter, and increased apoptotic cells. These data demonstrate a novel protective role for RNase L in viral induced CNS encephalomyelitis, which is not reflected in overall viral control or propagation of IFN-α/β mediated signals. Protective function is rather associated with cell type specific and regional restriction of viral replication in grey matter and ameliorated neurodegeneration and demyelination.


id: cord-329036-4bf8eiix
author: nan
date: 1994-09-01
url: https://www.ncbi.nlm.nih.gov/pubmed/8064222/
doi: nan
title:
  Coronavirus induction of class I major histocompatibility complex expression in murine astrocytes is virus strain specific

abstract:
  Neurotropic strains of mouse hepatitis viruses (MHV) such as MHV-A59 (A59) and MHV-4 (JHMV) cause acute and chronic encephalomyelitis and demyelination in susceptible strains of mice and rats. They are widely used as models of human demyelinating diseases such as multiple sclerosis (MS), in which immune mechanisms are thought to participate in the development of lesions in the central nervous system (CNS). The effects of MHV infection on target cell functions in the CNS are not well understood, but A59 has been shown to induce the expression of MHC class I molecules in glial cells after in vivo and in vitro infection. Changes in class I expression in infected cells may contribute to the immunopathogenesis of MHV infection in the CNS. In this communication, a large panel of MHV strains was tested for their ability to stimulate class I expression in primary astrocytes in vitro. The data show that the more hepatotropic strains, such as MHV-A59, MHV-1, MHV-2, MHV-3, MHV-D, MHV-K, and MHV-NuU, were potent inducers of class I expression in astrocytes during acute infection, measured by radioimmunoassay. The Kb molecule was preferentially expressed over Db. By contrast, JHMV and several viral strains derived from it did not stimulate the expression of class I molecules. Assays of virus infectivity indicated that the class I-inducing activity did not correlate with the ability of the individual viral strain to replicate in astrocytes. However, exposure of the viruses or the supernatants from infected astrocytes to ultraviolet light abolished the class I-inducing activity, indicating that infectious virus is required for class I expression. These data also suggest that class I expression was induced directly by virus infection, and not by the secretion of a soluble substance into the medium by infected astrocytes. Finally, analyses of A59/JHMV recombinant viral strains suggest that class I-inducing activity resides in one of the A59 structural genes.


id: cord-330266-uypjqif7
title: Targeting Polyamines Inhibits Coronavirus Infection by Reducing Cellular Attachment and Entry
author: Firpo, Mason R.
date: 2020-09-23
url: https://doi.org/10.1021/acsinfecdis.0c00491
doi: 10.1021/acsinfecdis.0c00491
abstract:
  [Image: see text] Coronaviruses first garnered widespread attention in 2002 when the severe acute respiratory syndrome coronavirus (SARS-CoV) emerged from bats in China and rapidly spread in human populations. Since then, Middle East respiratory syndrome coronavirus (MERS-CoV) emerged and still actively infects humans. The recent SARS-CoV-2 outbreak and the resulting disease (coronavirus disease 2019, COVID19) have rapidly and catastrophically spread and highlighted significant limitations to our ability to control and treat infection. Thus, a basic understanding of entry and replication mechanisms of coronaviruses is necessary to rationally evaluate potential antivirals. Here, we show that polyamines, small metabolites synthesized in human cells, facilitate coronavirus replication and the depletion of polyamines with FDA-approved molecules significantly reduces coronavirus replication. We find that diverse coronaviruses, including endemic and epidemic coronaviruses, exhibit reduced attachment and entry into polyamine-depleted cells. We further demonstrate that several molecules targeting the polyamine biosynthetic pathway are antiviral in vitro. In sum, our data suggest that polyamines are critical to coronavirus replication and represent a highly promising drug target in the current and any future coronavirus outbreaks.


id: cord-330907-srb8ac7l
author: Leparc-Goffart, Isabelle
date: 1997-12-08
txt: ./txt/cord-330907-srb8ac7l.txt
cache: ./cache/cord-330907-srb8ac7l.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/9426441/
doi: 10.1006/viro.1997.8877
summary:
  We have previously shown that C12 has two amino acid substitutions relative to wild type virus in the spike protein, Q159L (within a region of S1 shown to bind to viral receptor in anin vitroassay) and H716D (in the proteolytic cleavage recognition site). for the altered pathogenic properties of the mutant viruses, we compared the sequence of the spike (S) genes The murine coronavirus, mouse hepatitis virus strain of wild type and mutant viruses isolated from persistently A59 (MHV-A59), produces both hepatitis and neurologiinfected glial cells cultures. We have shown previously that the spike (S) protein from the supernatant of either the ''''C'''' culture of persisencoded by the C12 mutant has two amino acid substitutently infected glial cells at 1 week (C3), 6 weeks (C5), tions as compared with the wild type S protein.

title:
  Altered Pathogenesis of a Mutant of the Murine Coronavirus MHV-A59 Is Associated with a Q159L Amino Acid Substitution in the Spike Protein

abstract:
  Abstract C12, an attenuated, fusion delayed, very weakly hepatotropic mutant of mouse hepatitis virus strain A59 (MHV-A59) has been further characterized. We have previously shown that C12 has two amino acid substitutions relative to wild type virus in the spike protein, Q159L (within a region of S1 shown to bind to viral receptor in anin vitroassay) and H716D (in the proteolytic cleavage recognition site). We have sequenced the rest of the 31-kb genome of C12 and compared it to wild type virus. Only three additional amino acids substitutions were found, all encoded within the replicase gene. Analysis of C12in vivoin C57Bl/6 mice has shown that despite the fact that this virus replicates in the brain to titers at least as high as wild type and causes acute encephalitis similar to wild type, this virus causes a minimal level of demyelination and only at very high levels of virus inoculation. Thus acute encephalitis is not sufficient for the induction of demyelination by MHV-A59. Analysis of mutants isolated at earlier times from the same persistently infected glial cell culture as C12, as well as mutants isolated from a second independent culture of persistently infected glial cells, suggests that both the weakly demyelinating and the weakly hepatotropic phenotypes of C12 are associated with the Q159L amino acid substitution.


id: cord-331267-j9ld7q70
author: Wu, Z. G.
date: 2010-03-03
txt: ./txt/cord-331267-j9ld7q70.txt
cache: ./cache/cord-331267-j9ld7q70.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/20586931/
doi: 10.1111/j.1365-2893.2010.01268.x
summary:
  The effects of telbivudine on virus replication and cytokine production were investigated in vitro using MHV‐3‐infected macrophages, and the effects on T‐cell response were investigated in vivo in an MHV‐3‐induced viral hepatitis model. The aims of the present study were to characterize the effects of telbivudine on cytokine profile and T-cell response in vitro and in vivo using a previously characterized mouse model of viral hepatitis induced by the coronavirus mouse hepatitis virus strain 3 (MHV-3) [18, 19] . Cytokine level measurement by PCR and enzyme-linked immunosorbent assay To determine the effect of telbivudine on tumour necrosis factor (TNF)-a and interleukin (IL)-12 cytokine production, one million macrophages from BALB/cJ mice were stimulated with MHV-3 (multiplicity of infection, 2.5) and telbivudine was added at indicated concentrations. In summary, the present study demonstrates that the beneficial effects of telbivudine in MHV-3-induced hepatitis may be mediated by its effect on the immune response rather than the inhibition of viral replication in this animal model.

title:
  Telbivudine preserves T‐helper 1 cytokine production and downregulates programmed death ligand 1 in a mouse model of viral hepatitis

abstract:
  Summary. Telbivudine is an orally bioavailable L‐nucleoside with potent and specific anti‐hepatitis B virus activity. The higher rate of hepatitis B e antigen (HBeAg) seroconversion during telbivudine treatment than other potent anti‐HBV agents suggests a potential immunomodulatory effect. We sought to determine the effects of telbivudine on the immune system, particularly on cytokine production and T‐cell response, using an animal model with mouse hepatitis virus strain 3 (MHV‐3)‐induced hepatitis. The effects of telbivudine on virus replication and cytokine production were investigated in vitro using MHV‐3‐infected macrophages, and the effects on T‐cell response were investigated in vivo in an MHV‐3‐induced viral hepatitis model. Telbivudine had no effect on MHV‐3 replication in macrophages. However, the production of tumour necrosis factor‐α and interleukin‐12 was increased significantly in MHV‐3‐induced macrophages treated with telbivudine. In vivo survival was enhanced in telbivudine‐treated mice, with marked normalization in clinical conditions and histological lesions. Serum levels of interferon‐γ were elevated significantly after telbivudine treatment in MHV‐3‐infected C3H mice. In contrast, serum interleukin‐4 levels were decreased significantly. Furthermore, telbivudine treatment enhanced the ability of T cells to undergo proliferation and secrete cytokines but did not affect cytotoxicity of infected hepatocytes. Of note, we found that telbivudine treatment suppressed programmed death ligand 1 expression on T cells. The results demonstrate the immunomodulatory properties of telbivudine, independent of its antiviral activity, in a mouse model of MHV‐3‐induced hepatitis.


id: cord-333473-c1lykari
title: High-Resolution Analysis of Coronavirus Gene Expression by RNA Sequencing and Ribosome Profiling
author: Irigoyen, Nerea
date: 2016-02-26
txt: ./txt/cord-333473-c1lykari.txt
cache: ./cache/cord-333473-c1lykari.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/26919232/
doi: 10.1371/journal.ppat.1005473
summary:
  Also, it has been employed in the study of the replication of large DNA viruses; namely, human cytomegalovirus [17] [18] , Kaposi''s sarcoma-associated herpesvirus [19] , herpes simplex virus 1 [20] , vaccinia virus [21] , and bacteriophage lambda [22] , providing insights into the temporal regulation of gene expression in these viruses and identifying numerous previously unrecognized translated ORFs, including novel protein-coding ORFs and short regulatory uORFs. In this paper, we describe the first analysis of RNA virus replication and gene expression by ribosome profiling (and parallel RNASeq), using MHV as a model system. The latter are calculated on a per gene (rather than per transcript) basis, using RNASeq and RiboSeq reads contained entirely within annotated CDS regions (i.e. excluding 5 0 and 3 0 UTRs and also RPFs accumulating at or near to initiation or termination sites), and, like the virus values, are expressed relative to the mean levels for the cell (due to normalization by library size).

abstract:
  Members of the family Coronaviridae have the largest genomes of all RNA viruses, typically in the region of 30 kilobases. Several coronaviruses, such as Severe acute respiratory syndrome-related coronavirus (SARS-CoV) and Middle East respiratory syndrome-related coronavirus (MERS-CoV), are of medical importance, with high mortality rates and, in the case of SARS-CoV, significant pandemic potential. Other coronaviruses, such as Porcine epidemic diarrhea virus and Avian coronavirus, are important livestock pathogens. Ribosome profiling is a technique which exploits the capacity of the translating ribosome to protect around 30 nucleotides of mRNA from ribonuclease digestion. Ribosome-protected mRNA fragments are purified, subjected to deep sequencing and mapped back to the transcriptome to give a global “snap-shot” of translation. Parallel RNA sequencing allows normalization by transcript abundance. Here we apply ribosome profiling to cells infected with Murine coronavirus, mouse hepatitis virus, strain A59 (MHV-A59), a model coronavirus in the same genus as SARS-CoV and MERS-CoV. The data obtained allowed us to study the kinetics of virus transcription and translation with exquisite precision. We studied the timecourse of positive and negative-sense genomic and subgenomic viral RNA production and the relative translation efficiencies of the different virus ORFs. Virus mRNAs were not found to be translated more efficiently than host mRNAs; rather, virus translation dominates host translation at later time points due to high levels of virus transcripts. Triplet phasing of the profiling data allowed precise determination of translated reading frames and revealed several translated short open reading frames upstream of, or embedded within, known virus protein-coding regions. Ribosome pause sites were identified in the virus replicase polyprotein pp1a ORF and investigated experimentally. Contrary to expectations, ribosomes were not found to pause at the ribosomal frameshift site. To our knowledge this is the first application of ribosome profiling to an RNA virus.


id: cord-333525-67bbmo4m
author: Yao, Qianqian
date: 2013-07-01
txt: ./txt/cord-333525-67bbmo4m.txt
cache: ./cache/cord-333525-67bbmo4m.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S0042682213001955
doi: 10.1016/j.virol.2013.04.001
summary:
  In the current study, we analyzed the effects of the Endo charge-rich motif on virion incorporation of MHV S protein through substitutions of the homologous regions from the alphacoronavirus porcine transmissible gastroenteritis virus (TGEV), the betacoronaviruses bovine coronavirus (BCoV) and SARS-CoV, or the gammacoronavirus avian infectious bronchitis virus (IBV). Although the S2 portions of coronavirus S proteins show some degree of conservation, the Tm and Endo domains are highly divergent, with the exception of a conserved cluster of seven hydrophobic residues (WPWYVWL) at the start of Tm. To evaluate the functionality of different C-terminal sequence motifs in the MHV S protein, we constructed two sets of mutants in which the ectodomain of either S protein or HK protein was fused to the Tm and Endo domains from TGEV (an alphacoronavirus), BCoV (a betacoronavirus), SARS-CoV (a betacoronavirus), or IBV (a gammacoronavirus) ( Fig. 2A) . Reverting mutations in TGEV chimeras improved S assembly by eliminating positively charged residues in the endodomain MHV S protein mutants containing the entire carboxy terminus or just the charge-rich motif of TGEV S (Mut-TGEV and Mut-MMT) produced irregular plaques (Figs.

title:
  Negatively charged residues in the endodomain are critical for specific assembly of spike protein into murine coronavirus

abstract:
  Coronavirus spike (S) protein assembles into virions via its carboxy-terminus, which is composed of a transmembrane domain and an endodomain. Here, the carboxy-terminal charge-rich motif in the endodomain was verified to be critical for the specificity of S assembly into mouse hepatitis virus (MHV). Recombinant MHVs exhibited a range of abilities to accommodate the homologous S endodomains from the betacoronaviruses bovine coronavirus and human SARS-associated coronavirus, the alphacoronavirus porcine transmissible gastroenteritis virus (TGEV), and the gammacoronavirus avian infectious bronchitis virus respectively. Interestingly, in TGEV endodomain chimeras the reverting mutations resulted in stronger S incorporation into virions, and a net gain of negatively charged residues in the charge-rich motif accounted for the improvement. Additionally, MHV S assembly could also be rescued by the acidic carboxy-terminal domain of the nucleocapsid protein. These results indicate an important role for negatively charged endodomain residues in the incorporation of MHV S protein into assembled virions.


id: cord-334134-fhie2m3u
author: Mazaleuskaya, Liudmila
date: 2012-05-24
url: https://doi.org/10.3390/v4050901
doi: 10.3390/v4050901
title:
  Protective Role of Toll-like Receptor 3-Induced Type I Interferon in Murine Coronavirus Infection of Macrophages

abstract:
  Toll-like Receptors (TLRs) sense viral infections and induce production of type I interferons (IFNs), other cytokines, and chemokines. Viral recognition by TLRs and other pattern recognition receptors (PRRs) has been proven to be cell-type specific. Triggering of TLRs with selected ligands can be beneficial against some viral infections. Macrophages are antigen-presenting cells that express TLRs and have a key role in the innate and adaptive immunity against viruses. Coronaviruses (CoVs) are single-stranded, positive-sense RNA viruses that cause acute and chronic infections and can productively infect macrophages. Investigation of the interplay between CoVs and PRRs is in its infancy. We assessed the effect of triggering TLR2, TLR3, TLR4, and TLR7 with selected ligands on the susceptibility of the J774A.1 macrophage cell line to infection with murine coronavirus (mouse hepatitis virus, [MHV]). Stimulation of TLR2, TLR4, or TLR7 did not affect MHV production. In contrast, pre-stimulation of TLR3 with polyinosinic-polycytidylic acid (poly I:C) hindered MHV infection through induction of IFN-β in macrophages. We demonstrate that activation of TLR3 with the synthetic ligand poly I:C mediates antiviral immunity that diminishes (MHV-A59) or suppresses (MHV-JHM, MHV-3) virus production in macrophages.


id: cord-334499-fz7vrnb1
author: Templeton, Steven P.
date: 2007-06-01
txt: ./txt/cord-334499-fz7vrnb1.txt
cache: ./cache/cord-334499-fz7vrnb1.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/17917063/
doi: 10.1007/s12026-007-0079-y
summary:
  Infection of mice with variants of mouse hepatitis virus, strain JHM (MHV-JHM), provide models of acute and chronic viral infection of the central nervous system (CNS). Partially protective anti-viral immune responses may result in persistent infection and chronic demyelinating disease characterized by myelin removal from axons of the CNS and associated with dense macrophage/microglial infiltration. Demyelinating disease during MHV-JHM infection is immune-mediated, as mice that lack T lymphocytes fail to develop disease despite succumbing to encephalitis with high levels of infectious virus in the CNS. Demyelinating disease induced during MHV-JHM infection is partly immune mediated, as mice lacking the ability to generate T cell responses fail to develop demyelination, despite high viral loads and widespread inflammation in the CNS of infected mice [19, 20] . Further studies involve introduction of other chemoattractants into recombinant MHV-JHM, to evaluate their role in demyelinating disease, cell recruitment, generation of immune responses, and clearance of infectious virus in MHV-JHM-infected mice.

title:
  Pathogenesis of acute and chronic central nervous system infection with variants of mouse hepatitis virus, strain JHM

abstract:
  Infection of mice with variants of mouse hepatitis virus, strain JHM (MHV-JHM), provide models of acute and chronic viral infection of the central nervous system (CNS). Through targeted recombination and reverse genetic manipulation, studies of infection with MHV-JHM variants have identified phenotypic differences and examined the effects of these differences on viral pathogenesis and anti-viral host immune responses. Studies employing recombinant viruses with a modified spike (S) glycoprotein of MHV-JHM have identified the S gene as a major determinant of neurovirulence. However, the association of S gene variation and neurovirulence with host ability to generate anti-viral CD8 T cell responses is not completely clear. Partially protective anti-viral immune responses may result in persistent infection and chronic demyelinating disease characterized by myelin removal from axons of the CNS and associated with dense macrophage/microglial infiltration. Demyelinating disease during MHV-JHM infection is immune-mediated, as mice that lack T lymphocytes fail to develop disease despite succumbing to encephalitis with high levels of infectious virus in the CNS. However, the presence of T lymphocytes or anti-viral antibody can induce disease in infected immunodeficient mice. The mechanisms by which these immune effectors induce demyelination share an ability to activate and recruit macrophages and microglia, thus increasing the putative role of these cells in myelin destruction.


id: cord-336416-vas0b6dt
author: Wege, H.
date: 1980-12-31
txt: ./txt/cord-336416-vas0b6dt.txt
cache: ./cache/cord-336416-vas0b6dt.txt
extension: .txt
mime: text/plain
url: https://www.sciencedirect.com/science/article/pii/B9780122558504500676
doi: 10.1016/b978-0-12-255850-4.50067-6
summary:
  ABSTRACT The murine coronavirus JHM induces in weanling rats different types of central nervous diseases ranging from an acute panencephalitis to a late demyelinating encephalomyelitis. Of particular interest are the central nervous system (CNS) diseases associated with this virus group, especially the mouse hepatitis virus strain JHM reveals a distinct neurovirulence for mice and rats (1, 2, 3, 4) . In the present communication the neurovirulence of four murine coronavirus strains (MHV 1, MHV 2, MHV 3 and MHV A59) for rats is compared to the JHM virus. The occurrence and rate of the different types of CNS disease induced by JHM virus is associated with the properties of the virus preparation used as inoculum as summarized in table 2. Reisolated mutants from diseased animals with LDE did not always maintain their temperature sensitivity but were different from revertants by the type of neurovirulence.

title:
  NEUROVIRULENCE AND PERSISTENCY OF MOUSE HEPATITIS VIRUSES IN RATS 1 1 Supported by the Deutsche Forschungsgemeinschaft and Hertie-Stiftung

abstract:
  ABSTRACT The murine coronavirus JHM induces in weanling rats different types of central nervous diseases ranging from an acute panencephalitis to a late demyelinating encephalomyelitis. The occurrence and rate of these different disease types is associated with the virus variant used for inoculation. Except for MHV 2, neurovirulence was not observed in four other murine coronavirus strains. The relationship of these coronaviruses to JHM was investigated by cross neutralization and oligonucleotide maps of their genomic RNA.


id: cord-337976-c2auspti
author: Weiss, Susan R.
date: 1983-04-30
txt: ./txt/cord-337976-c2auspti.txt
cache: ./cache/cord-337976-c2auspti.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S0042682283800221
doi: 10.1016/s0042-6822(83)80022-1
summary:
  A cDNA probe representing the genome of mouse hepatitis virus (MHV) strain A59 (MHV-A59) was used to measure nucleotide sequence homologies among murine and human coronaviruses and the SD and SK coronaviruses isolated by Burks et al. Since SD and SK were isolated by inoculation of multiple sclerosis (MS) central nervous system (CNS) tissue into mice or cultured mouse cells, it is important to determine their relationships to other murine and human coronavirus isolates. Some strains of HCV such as 0C43, are antigenically related to murine coronaviruses such as MHV strain JHM (McIntosh, 1974; Gerdes et al., 1981a, b) and may be grown in the brains of suckling mice (McIntosh et al., 1967) . We have further compared murine and human coronaviruses and SD and SK by using molecular hybridization of virus-specific RNA with cDNA probes. RNA extracted either from brain homogenates of OC43-infected suckling mice or from HRT cells infected with OC43 shows homology with A59 cDNA when assayed by blot hybridization.

title:
  Coronaviruses SD and SK share extensive nucleotide homology with murine coronavirus MHV-A59, more than that shared between human and murine coronaviruses

abstract:
  A cDNA probe representing the genome of mouse hepatitis virus (MHV) strain A59 (MHV-A59) was used to measure nucleotide sequence homologies among murine and human coronaviruses and the SD and SK coronaviruses isolated by Burks et al. Since SD and SK were isolated by inoculation of multiple sclerosis (MS) central nervous system (CNS) tissue into mice or cultured mouse cells, it is important to determine their relationships to other murine and human coronavirus isolates. Our results indicate that SD and SK share almost complete nucleotide homology (approximately 90%) with MHV-A59 and generate subgenomic RNAs of the same sizes as MHV-A59. The human coronavirus (HCV) strains tested show less homology with MHV-A59. The immunologically unrelated HCV-229 E shows no nucleotide homology with MHV-A59. The immunologically crossreactive HCV-OC43 shows nucleotide homology with MHV-A59 by blot hybridization but not when hybridized in solution and assayed by S1 nuclease digestion.


id: cord-338165-mgrf1odm
author: Wang, Xiaojing
date: 2012-11-30
txt: ./txt/cord-338165-mgrf1odm.txt
cache: ./cache/cord-338165-mgrf1odm.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1016/j.cellimm.2012.11.010
doi: 10.1016/j.cellimm.2012.11.010
summary:
  Virus titers were determined in the liver tissue of MHV-3 infected C3H/HeJ mice at various time points by standard plaque assay as described before [32] . Cell suspensions of processed spleens from C3H/HeJ mice on days 4, 10, 15, 20, and 30 post MHV-3 infection were stained with PEcy5.5-anti-CD3, FITC-anti-CD4, FITC-anti-CD8, APC-anti-CD25, APC-anti-TCRb, PE-anti-TCRcd, PE-anti-CD28/PE-anti-CD30, PE-anti-CD44, PE-anti-CD95L, PEanti-CD95 monoclonal antibodies or isotype control Ab (eBioscience, San Diego, CA, USA). Adoptive transfer of DN T cells from MHV-3 infected C3H/HeJ mice increased the survival rate and improved liver histology of recipient mice infected by the same virus strain but had little impact on the virus titer of liver tissue Fig. 3A showed that no significant difference in virus titer of liver tissue was observed among DN T cells group, splenocytes group, DNT-depleted splenocytes group and PBS control group.

title:
  CD4–CD8-T cells contribute to the persistence of viral hepatitis by striking a delicate balance in immune modulation

abstract:
  Abstract Viral hepatitis remains the most common cause of liver disease and a major public health problem. Here, we focus on the role of CD4 CD8 double negative T (DN T) cells involved in the mechanisms of viral persistence in hepatitis. C3H/HeJ mice infected with murine hepatitis virus strain 3 (MHV-3) were used to display chronic viral hepatitis. DN T cells dramatically increased in MHV-3 infected mice. Adoptive transfer of DN T cells from MHV-3 infected mice led to a significant increase in mice survival. The DN T cells with production of IFN-γ and IL-2 are able to kill virus-specific CD8+ T cells via the Fas/FasL dependent pathway. The delicate balance of multiple effects of DN T cells may lead to viral persistence in MHV-3 induced hepatitis. In short, our study identified DN T cells contributing to viral persistence in MHV-3 induced hepatitis in C3H/HeJ mice, which provides a rationale for modulating DN T cells for the management of viral hepatitis.


id: cord-338307-vfutmwxq
title: The Molecular Biology of Coronaviruses
author: Sturman, Lawrence S.
date: 1983-12-31
txt: ./txt/cord-338307-vfutmwxq.txt
cache: ./cache/cord-338307-vfutmwxq.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/6362367/
doi: 10.1016/s0065-3527(08)60721-6
summary:
  The pattern of three major structural proteins and their organization in the virion as shown for MHV-A59 in Fig. 3 is generally applicable to most other species of coronaviruses (reviewed in detail by Siddell et al., 1982) . (1981b) , using a cDNA probe prepared against the mRNA of MHV-A59 which coded for the nucleocapsid protein, obtained evidence of 7 0 4 0 % homology by analysis of hybridization kinetics of viral RNA from cells infected with MHV-1, -3, -S, and -JHM. t 1980) demonstrated that different size classes of poly(A)containing intracellular MHV-JHM RNAs fractionated on sucroseformamide gradients directed the synthesis of different structural proteins in cell-free translation systems. The studies showed that, like avian coronaviruses, for the murine coronavirus MHV-A59, the oligonucleotides of each of the subgenomic RNAs were included within the next larger species, starting from the 3'' end of the genome.

abstract:
  Publisher Summary Coronaviruses have recently emerged as an important group of animal and human pathogens that share a distinctive replicative cycle. Some of the unique characteristics in the replication of coronaviruses include generation of a 3' coterminal-nested set of five or six subgenomic mRNAs, each of which appears to direct the synthesis of one protein. Two virus-specific RNA polymerase activities have been identified. Many of the distinctive features of coronavirus infection and coronavirus-induced diseases may result from the properties of the two coronavirus glycoproteins. The intracellular budding site, which may be important in the establishment and maintenance of persistent infections, appears to be due to the restricted intracytoplasmic migration of the E1 glycoprotein, which acts as a matrix-like transmembrane glycoprotein. E1 also exhibits distinctive behavior by self-aggregating on heating at 100°C in sodium dodecyl sulfate (SDS) and by its interaction with RNA in the viral nucleocapsid. The E1 of mouse hepatitis virus (MHV) is an O-linked glycoprotein, unlike most other viral glycoproteins. Thus, the coronavirus system may be a useful model for the study of synthesis, glycosylation, and transport of O-linked cellular glycoproteins.


id: cord-341278-klv9jdm8
title: The role of gamma interferon in infection of susceptible mice with murine coronavirus, MHV-JHM
author: Smith, Abigail L.
date: 1991
url: https://www.ncbi.nlm.nih.gov/pubmed/1662041/
doi: 10.1007/bf01316746
abstract:
  Infection of BALB/c mice with mouse hepatitis virus, strain JHM (MHV-JHM), at any of several intervals relative to ovalbumin (OVA) administration resulted in elevated OVA-specific IgG 2 a titers. Since gamma interferon (IFN) has been implicated as an up-regulator of IgG 2 a production, attempts were made to determine whether levels of this cytokine were modified in sera of infected mice. Serum IFN-γ was not detected, but treatment of MHV-JHM-infected mice with monoclonal anti-IFN-γ antibody resulted in high mortality with decreased survival times, enhanced virus titers in liver and spleen, and more severe virus-associated pathology, compared to mock-treated, infected mice. Immunotherapy with recombinant IFN-γ ameliorated disease as reflected by mortality rates and virus titers in target organs.


id: cord-341342-kyavg4vu
author: Masters, P. S.
date: 1992
txt: ./txt/cord-341342-kyavg4vu.txt
cache: ./cache/cord-341342-kyavg4vu.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/1322650/
doi: 10.1007/bf01309634
summary:
  The RNase sensitivity of the ability of N protein to migrate into nondenaturing gels was not due to possible contaminating protease activity in the RNase preparations, since the same RNase-treated samples of translated N 148 P.S. Masters protein showed no degradation when analyzed by SDS-PAGE (Fig. 3, lanes an, lower) . Since the N mRNAs synthesized from the transcription vectors shown in Fig. 1 contained this portion of the leader sequence, it seemed possible that the N-RNA complex observed in nondenaturing PAGE was that of translated N protein binding to its own mRNA. That the observed complex was not due to translated N protein binding to the leader portion of its own mRNA was also supported by the observation that full-length N protein translated from a construct in which the MHV leader sequence was entirely deleted was also able to migrate into nondenaturing gels (data not shown).

title:
  Localization of an RNA-binding domain in the nucleocapsid protein of the coronavirus mouse hepatitis virus

abstract:
  The interaction between the nucleocapsid (N) protein of mouse hepatitis virus (MHV) and RNA was studied in an effort to define portions of the N molecule that participate in binding to RNA. N mRNAs transcribed from SP6 and T7 vectors were translated in a rabbit reticulocyte lysate. Analysis of synthesized N protein in a nondenaturing gel system showed that it bound in vitro to an endogenous RNA in the reticulocyte lysate but not to its own mRNA. A set of deletion mutants was constructed in order to localize the RNA-binding activity of the N protein. It was found that removal of as much as 135 amino-terminal or 57 carboxy-terminal amino acids from the molecule had little or no effect on RNA binding. Moreover, deletion mutants lacking both termini still retained RNA-binding ability. By contrast, internal deletions or truncations extending beyond these two limits effectively abolished RNA binding by N protein. Thus, the RNA-binding region of N has been mapped to the second (central) of the three structural domains of the molecule.


id: cord-342151-1e6x589e
title: Hemagglutination by Murine Hepatitis Viruses
author: Talbot, Pierre J.
date: 2008-07-29
txt: ./txt/cord-342151-1e6x589e.txt
cache: ./cache/cord-342151-1e6x589e.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/2542182/
doi: 10.1159/000150083
summary:
  Erythrocytes from twelve mammalian and avian sources in ten different buffers at three incubation temperatures could not be hemagglutinated with murine hepatitis virus (MHV) strains 3, A59, or S grown on DBT cells. Viral antigen preparation in the absence of fetal calf serum, partial virus purification, or various concentrations of red blood cells still failed to yield detectable hemagglutinating activity. For use as antigen for hemag glutination assays, MHV-3 was grown in the absence of fetal calf serum (FCS) and har vested from clarified medium by precipita tion with 10% (w/v) polyethylene glycol in 0.5 M NaCl. After centrifugation at 10,000 g for 30 min, the pellet was resuspended and dialyzed against TMEN buffer: 50 mM Tris-HCi (pH 6.2), 0.1 M NaCl, 1 m M EDTA. Control hemagglutinating antigens were either rabbit enteric coronavirus (titer 1/64 with rabbit red blood cells ) or pneumonia virus of mice (titer 1/320 with CDI mouse erythrocytes).

abstract:
  Erythrocytes from twelve mammalian and avian sources in ten different buffers at three incubation temperatures could not be hemagglutinated with murine hepatitis virus (MHV) strains 3, A59, or S grown on DBT cells. Viral antigen preparation in the absence of fetal calf serum, partial virus purification, or various concentrations of red blood cells still failed to yield detectable hemagglutinating activity. Thus, the newly described MHV-DVIM remains the only hemagglutinating strain of murine coronavirus.


id: cord-343221-e29of29o
title: Early endonuclease-mediated evasion of RNA sensing ensures efficient coronavirus replication
author: Kindler, Eveline
date: 2017-02-03
txt: ./txt/cord-343221-e29of29o.txt
cache: ./cache/cord-343221-e29of29o.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/28158275/
doi: 10.1371/journal.ppat.1006195
summary:
  Specifically, we show that genetically engineered mutants of mouse hepatitis virus (MHV) and human coronavirus 229E (HCoV-229E), respectively, that encode an EndoU active-site substitution known to abolish nucleolytic activity, were severely attenuated and elicited an immediate and simultaneous activation of host cell dsRNA sensors. The severe attenuation of MHV H277A and HCoV-229E H250A replication in wild-type murine and human macrophages, respectively, precluded the use of primary macrophages to assess the sensitivity of EndoU-deficient coronaviruses to IFN-I pre-treatment. Our data suggest that direct restriction of replication of EndoU-deficient coronaviruses is mediated by RNase L-mediated RNA degradation and inhibition of host cell translation through activation of PKR. Notably, also in this case Xrn1 is required to further process the de-capped mRNAs. Our data show that early during coronavirus infection the EndoU activity conceptually fulfils the same task, namely the removal of dsRNA that would otherwise trigger host cell dsRNA responses, such as IFN-β expression and activation of PKR and OAS/RNase L.

abstract:
  Coronaviruses are of veterinary and medical importance and include highly pathogenic zoonotic viruses, such as SARS-CoV and MERS-CoV. They are known to efficiently evade early innate immune responses, manifesting in almost negligible expression of type-I interferons (IFN-I). This evasion strategy suggests an evolutionary conserved viral function that has evolved to prevent RNA-based sensing of infection in vertebrate hosts. Here we show that the coronavirus endonuclease (EndoU) activity is key to prevent early induction of double-stranded RNA (dsRNA) host cell responses. Replication of EndoU-deficient coronaviruses is greatly attenuated in vivo and severely restricted in primary cells even during the early phase of the infection. In macrophages we found immediate induction of IFN-I expression and RNase L-mediated breakdown of ribosomal RNA. Accordingly, EndoU-deficient viruses can retain replication only in cells that are deficient in IFN-I expression or sensing, and in cells lacking both RNase L and PKR. Collectively our results demonstrate that the coronavirus EndoU efficiently prevents simultaneous activation of host cell dsRNA sensors, such as Mda5, OAS and PKR. The localization of the EndoU activity at the site of viral RNA synthesis–within the replicase complex—suggests that coronaviruses have evolved a viral RNA decay pathway to evade early innate and intrinsic antiviral host cell responses.


id: cord-345630-bam3pa70
author: Lee, Han-Jung
date: 1991-02-28
txt: ./txt/cord-345630-bam3pa70.txt
cache: ./cache/cord-345630-bam3pa70.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/004268229190071I
doi: 10.1016/0042-6822(91)90071-i
summary:
  authors: Lee, Han-Jung; Shieh, Chien-Kou; Gorbalenya, Alexander E.; Koonin, Eugene V.; La Monica, Nicola; Tuler, Jeremy; Bagdzhadzhyan, Anush; Lai, Michael M.C. title: The complete sequence (22 kilobases) of murine coronavirus gene 1 encoding the putative proteases and RNA polymerase Third, the 3''-half of the gene 1 sequences of IBV and MHV-A59 contains the sequence motifs for RNA polymerase and helicase, which are the activities expected to be involved in RNA synthesis Gorbalenya et a/., 198913; Bredenbeek et a/., 1990) . The alignment of amino acids in ORF la of MHV-JHM and IBV showed that there are four possible stretches of moderate homology which are separated by highly diverged sequences (Fig. 8) . Although ORF la is highly diverged between MHV-JHM and IBV, common functional domains could be identified in this ORF of both viruses by detailed amino acid sequence analysis (see Materials and Methods) (Fig. 9 ).

title:
  The complete sequence (22 kilobases) of murine coronavirus gene 1 encoding the putative proteases and RNA polymerase

abstract:
  Abstract The 5′-most gene, gene 1, of the genome of murine coronavirus, mouse hepatitis virus (MHV), is presumed to encode the viral RNA-dependent RNA polymerase. We have determined the complete sequence of this gene of the JHM strain by cDNA cloning and sequencing. The total length of this gene is 21,798 nucleotides long, which includes two overlapping, large open reading frames. The first open reading frame, ORF 1 a, is 4488 amino acids long. The second open reading frame, ORF 1 b, overlaps ORF 1 a for 75 nucleotides, and is 2731 amino acids long. The overlapping region may fold into a pseudoknot RNA structure, similar to the corresponding region of the RNA of avian coronavirus, infectious bronchitis virus (IBV). The in vitro transcription and translation studies of this region indicated that these two ORFs were most likely translated into one polyprotein by a ribosomal frameshifting mechanism. Thus, the predicted molecular weight of the gene 1 product is more than 800,000 Da. The sequence of ORF 1 b is very similar to the corresponding ORF of IBV. In contrast, the ORF 1 a of these two viruses differ in size and have a high degree of divergence. The amino acid sequence analysis suggested that ORF 1 a contains several functional domains, including two hydrophobic, membrane-anchoring domains, and three cysteine-rich domains. It also contains a picornaviral 3C-like protease domain and two papain-like protease domains. The presence of these protease domains suggests that the polyprotein is most likely processed into multiple protein products. In contrast, the ORF 1b contains polymerase, helicase, and zinc-finger motifs. These sequence studies suggested that the MHV gene 1 product is involved in RNA synthesis, and that this product is processed autoproteolytically after translation. This study completes the sequence of the MHV genome, which is 31 kb long, and constitutes the largest viral RNA known.


id: cord-348746-yaf61cmx
title: A Review of Coronavirus Infection in the Central Nervous System of Cats and Mice
author: Foley, Janet E.
date: 2008-06-28
txt: ./txt/cord-348746-yaf61cmx.txt
cache: ./cache/cord-348746-yaf61cmx.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/11596730/
doi: 10.1111/j.1939-1676.2001.tb01572.x
summary:
  F eline infectious peritonitis (FIP) is a fatal, immune-mediated disease produced as a result of infection of macrophages by mutant feline coronavirus strains (FIPVs). In acute MHV-A59 infection in CD8ϩ T-cell deficient mice, periventricular encephalitis occurs with lymphocytic infiltration into the choroid plexus, ependyma, and subependymal brain tissue. Depending on mouse strain and immunological status, MHV-JHM produces meningeal inflammation associated with T-cells and macrophages and demyelination but relatively little disease in axons. If mice are pretreated with passive infusions of antibodies or T-cells or if they receive neuroattenuated MHV strains, they develop chronic, but not fatal, disease after MHV-JHM infection. 62, 63 Immunocompetent C57BL/6 mice clear MHV-JHM virus from the brain but develop severe immune-mediated demyelination and paralysis. Two related strains of feline infectious peritonitis virus isolated from immunocompromised cats infected with a feline enteric coronavirus

abstract:
  Feline infectious peritonitis (FIP) is a common cause of death in cats. Management of this disease has been hampered by difficulties identifying the infection and determining the immunological status of affected cats and by high variability in the clinical, pathological, and immunological characteristics of affected cats. Neurological FIP, which is much more homogeneous than systemic effusive or noneffusive FIP, appears to be a good model for establishing the basic features of FIP immunopathogenesis. Very little information is available about the immunopathogenesis of neurologic FIP, and it is reasonable to use research from the well‐characterized mouse hepatitis virus (MHV) immune‐mediated encephalitis system, as a template for FIP investigation, and to contrast findings from the MHV model with those of FIP. It is expected that the immunopathogenic mechanisms will have important similarities. Such comparative research may lead to better understanding of FIP immunopathogenesis and rational prospects for management of this frustrating disease.


id: cord-349135-it5ahzj3
author: Lane, T. E.
date: 2006
url: https://www.ncbi.nlm.nih.gov/pubmed/16570854/
doi: 10.1007/978-3-540-33397-5_1
title:
  Functional Diversity of Chemokines and Chemokine Receptors in Response to Viral Infection of the Central Nervous System

abstract:
  Encounters with neurotropic viruses result in varied outcomes ranging from encephalitis, paralytic poliomyelitis or other serious consequences to relatively benign infection. One of the principal factors that control the outcome of infection is the localized tissue response and subsequent immune response directed against the invading toxic agent. It is the role of the immune system to contain and control the spread of virus infection in the central nervous system (CNS), and paradoxically, this response may also be pathologic. Chemokines are potent proinflammatory molecules whose expression within virally infected tissues is often associated with protection and/or pathology which correlates with migration and accumulation of immune cells. Indeed, studies with a neurotropic murine coronavirus, mouse hepatitis virus (MHV), have provided important insight into the functional roles of chemokines and chemokine receptors in participating in various aspects of host defense as well as disease development within the CNS. This chapter will highlight recent discoveries that have provided insight into the diverse biologic roles of chemokines and their receptors in coordinating immune responses following viral infection of the CNS.


id: cord-351934-g7tgo5cn
title: MHV-A59 Orf1a Replicase Protein NSP7-NSP10 Processing in Replication
author: Deming, Damon J.
date: 2006
txt: ./txt/cord-351934-g7tgo5cn.txt
cache: ./cache/cord-351934-g7tgo5cn.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/17037513/
doi: 10.1007/978-0-387-33012-9_17
abstract: nan
summary:
  authors: Deming, Damon J.; Graham, Rachel L.; Denison, Mark R.; Baric, Ralph S. Through use of an efficient MHV-A59 reverse genetics system, 6 we ablated each of the M pro cleavage sites associated with the nsp7-nsp10 cassette, and evaluated whether the mutated genome was capable of supporting a viable virus, and if so, characterized the M pro processing of the mutated protein, transcription function, and in vitro growth fitness. Surprisingly, the recovered virus did not revert to wild-type sequence at the nsp9/nsp10 M pro cleavage site, indicating that an as of yet unidentified mutation(s) has compensated for the virus''s inability to properly process the nsp9-nsp10 precursor protein. Serial passage of this virus restored wild-type replication but did so without reverting the mutated cleavage site or the ability to process the nsp9-nsp10 protein. The data demonstrate that with the exception of cleavage between the nsp9 and nsp10 proteins, M pro processing of the nsp7-nsp10 cassette is essential in coronavirus RNA transcription and replication.


id: cord-351964-hduv0ur4
author: nan
date: 1987-09-01
url: https://www.ncbi.nlm.nih.gov/pubmed/2821011/
doi: nan
title:
  Sorting of progeny coronavirus from condensed secretory proteins at the exit from the trans-Golgi network of AtT20 cells

abstract:
  Murine hepatitis virus (strain A59), (MHV-A59) is a coronavirus that buds into pre-Golgi compartments and then exploits the exocytic pathway of the host cell to reach the exterior. The fibroblastic cells in which replication of this virus is usually studied have only a constitutive exocytic pathway that the virus uses. MHV-A59 also infects, albeit inefficiently, AtT20 cells, murine pituitary tumor cells with a regulated as well as a constitutive exocytic pathway. Here we examine AtT20 cells at early times after the infection, when the Golgi apparatus retains its morphological and biochemical integrity. We observe that progeny coronavirus and secretory protein destined for the secretory granules of the regulated exocytic pathway traverse the same Golgi stacks and accumulate in the trans-Golgi network. Their pathways diverge at this site, the condensed secretory proteins including the ACTH going to the secretory granules and the coronavirus to post-Golgi transport vesicles devoid of ACTH. On very rare occasions there is missorting such that aggregates of condensed secretory proteins and viruses occur together in post-Golgi vesicles. We conclude that the constitutive and regulated exocytic pathways, identified respectively by the progeny virions and the secretory protein ACTH, diverge at the exit from the trans-Golgi network.


id: cord-352379-q5inrxcm
title: SARS virus: The beginning of the unraveling of a new coronavirus
author: Lai, Michael M. C.
date: 2003-10-17
txt: ./txt/cord-352379-q5inrxcm.txt
cache: ./cache/cord-352379-q5inrxcm.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/14631105/
doi: 10.1007/bf02256318
summary:
  Nevertheless, the lack of a firm association of coronaviruses with any serious human illnesses had dampened the public''s interest in this virus family until the sudden emergence of the SARS coronavirus [24, 41, 62] , which caused the first new infectious disease of this millennium. In the SARS virus genome, the organization of gene la-lb, which accounts for more than two-thirds of the viral RNA, is very similar to that of the murine coronavirus MHV, except that it contains only one papain-like protease (PLpro-2) ( fig. Based on the predicted cleavage site specificity, the SARS virus gene la-lb is likely processed into thirteen final protein products. However, the published sequence analysis indicated that the entire SARS virus RNA resembled that of group II viruses; no evidence of recombination was noted [55, 66] . Comparative full-length genome sequence analysis of 14 SARS coronavirus isolates and common mutations associated with putative origins of infection

abstract:
  Severe acute respiratory syndrome (SARS) virus caused a severe outbreak in several regions of the world in 2003. The virus is a novel coronavirus, which may have an origin in wild animals such as civet cats in southern China. Its genome structure, gene expression pattern and protein profiles are similar to those of other coronaviruses. However, distinct patterns of several open reading frames in the SARS virus genome may contribute to its severe virulence. The potential mutability of the coronavirus genome may pose problems in the control of future SARS outbreaks. The mechanism of SARS pathogenesis may involve both direct viral cytocidal effects on the target cells and immune-mediated mechanisms. The life cycle of the SARS virus is largely unknown; however, based on the analogy with other coronaviruses, several potential targets for antiviral development are identified. Vaccines offer an important preventive measure for possible future recurrences of SARS, but the prospect for their development is still unknown because of the uncertainty regarding the role of immune responses in SARS virus pathogenesis. The comparative studies of other coronaviruses offer insights into the understanding of SARS virus.


id: cord-353190-7qcoxl81
title: Viral Infections of Laboratory Mice
author: Nicklas, Werner
date: 2012-05-17
txt: ./txt/cord-353190-7qcoxl81.txt
cache: ./cache/cord-353190-7qcoxl81.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/B9780123820082000192
doi: 10.1016/b978-0-12-382008-2.00019-2
summary:
  This chapter covers infections of mice with the following viruses: herpesviruses, mousepox virus, murine adenoviruses, polyomaviruses, parvoviruses, lactate dehydrogenase-elevating virus, lymphocytic choriomeningitis virus, mammalian orthoreovirus serotype 3, murine hepatitis virus, murine norovirus, murine pneumonia virus, murine rotavirus, Sendai virus, and Theiler''s murine encephalomyelitis virus. These results are very difficult to summarize because the outcome of experimental infection in laboratory mice depends on various factors such as mouse strain and age, virus strain and passage history [26] , virus dose and route of inoculation [24] . Experimental infection of laboratory mice with MHV-68 is a frequently used model system for the study of human gammaherpesvirus pathogenesis, e.g. of Kaposi''s sarcoma-associated herpesvirus or Epstein-Barr virus (EBV) [62, 63] which are members of the same subfamily. Early descriptions of naturally occurring disease may have been complicated by concurrent infections such as MHV (murine hepatitis virus) or murine rotavirus A (MuRV-A)/epizootic diarrhoea of infant mice (EDIM) virus that contributed to the severity of the lesions especially in liver, pancreas, CNS and intestine.

abstract:
  Viral infections of laboratory mice have considerable impact on research results, and prevention of such infections is therefore of crucial importance. This chapter covers infections of mice with the following viruses: herpesviruses, mousepox virus, murine adenoviruses, polyomaviruses, parvoviruses, lactate dehydrogenase-elevating virus, lymphocytic choriomeningitis virus, mammalian orthoreovirus serotype 3, murine hepatitis virus, murine norovirus, murine pneumonia virus, murine rotavirus, Sendai virus, and Theiler’s murine encephalomyelitis virus. For each virus, there is a description of the agent, epizootiology, clinical symptoms, pathology, methods of diagnosis and control, and its impact on research.


id: cord-354726-b9xvycyk
title: Envelope glycoprotein interactions in coronavirus assembly
author: nan
date: 1995-10-02
url: https://www.ncbi.nlm.nih.gov/pubmed/7593163/
doi: nan
abstract:
  Coronaviruses are assembled by budding into smooth membranes of the intermediate ER-to-Golgi compartment. We have studied the association of the viral membrane glycoproteins M and S in the formation of the virion envelope. Using coimmunoprecipitation analysis we demonstrated that the M and S proteins of mouse hepatitis virus (MHV) interact specifically forming heteromultimeric complexes in infected cells. These could be detected only when the detergents used for their solubilization from cells or virions were carefully chosen: a combination of nonionic (NP-40) and ionic (deoxycholic acid) detergents proved to be optimal. Pulse-chase experiments revealed that newly made M and S proteins engaged in complex formation with different kinetics. Whereas the M protein appeared in complexes immediately after its synthesis, newly synthesized S protein did so only after a lag phase of > 20 min. Newly made M was incorporated into virus particles faster than S, which suggests that it associates with preexisting S molecules. Using the vaccinia virus T7-driven coexpression of M and S we also demonstrate formation of M/S complexes in the absence of other coronaviral proteins. Pulse-chase labelings and coimmunoprecipitation analyses revealed that M and S associate in pre-Golgi membranes because the unglycosylated form of M appeared in M/S complexes rapidly. Since no association of M and S was detected when protein export from the ER was blocked by brefeldin A, stable complexes most likely arise in the ER-to-Golgi intermediate compartment. Sucrose velocity gradient analysis showed the M/S complexes to be heterogeneous and of higher order, suggesting that they are maintained by homo- and heterotypic interactions. M/S complexes colocalized with alpha-mannosidase II, a resident Golgi protein. They acquired Golgi-specific oligosaccharide modifications but were not detected at the cell surface. Thus, the S protein, which on itself was transported to the plasma membrane, was retained in the Golgi complex by its association with the M protein. Because coronaviruses bud at pre-Golgi membranes, this result implies that the envelope glycoprotein complexes do not determine the site of budding. Yet, the self-association of the MHV envelope glycoproteins into higher order complexes is indicative of its role in the sorting of the viral membrane proteins and in driving the formation of the viral lipoprotein coat in virus assembly.


id: cord-356013-pl3tmky8
title: Coronavirus Genome Structure and Replication
author: Brian, D. A.
date: 2005
url: https://www.ncbi.nlm.nih.gov/pubmed/15609507/
doi: 10.1007/3-540-26765-4_1
abstract:
  In addition to the SARS coronavirus (treated separately elsewhere in this volume), the complete genome sequences of six species in the coronavirus genus of the coronavirus family [avian infectious bronchitis virus-Beaudette strain (IBV-Beaudette), bovine coronavirus-ENT strain (BCoV-ENT), human coronavirus-229E strain (HCoV-229E), murine hepatitis virus-A59 strain (MHV-A59), porcine transmissible gastroenteritis-Purdue 115 strain (TGEV-Purdue 115), and porcine epidemic diarrhea virus-CV777 strain (PEDV-CV777)] have now been reported. Their lengths range from 27,317 nt for HCoV-229E to 31,357 nt for the murine hepatitis virus-A59, establishing the coronavirus genome as the largest known among RNA viruses. The basic organization of the coronavirus genome is shared with other members of the Nidovirus order (the torovirus genus, also in the family Coronaviridae, and members of the family Arteriviridae) in that the nonstructural proteins involved in proteolytic processing, genome replication, and subgenomic mRNA synthesis (transcription) (an estimated 14–16 end products for coronaviruses) are encoded within the 5′-proximal two-thirds of the genome on gene 1 and the (mostly) structural proteins are encoded within the 3′-proximal one-third of the genome (8–9 genes for coronaviruses). Genes for the major structural proteins in all coronaviruses occur in the 5′ to 3′ order as S, E, M, and N. The precise strategy used by coronaviruses for genome replication is not yet known, but many features have been established. This chapter focuses on some of the known features and presents some current questions regarding genome replication strategy, the cis-acting elements necessary for genome replication [as inferred from defective interfering (DI) RNA molecules], the minimum sequence requirements for autonomous replication of an RNA replicon, and the importance of gene order in genome replication.


id: cord-356115-vblgotjn
title: Functional and Genetic Analysis of Coronavirus Replicase-Transcriptase Proteins
author: Sawicki, Stanley G
date: 2005-12-09
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url: https://www.ncbi.nlm.nih.gov/pubmed/16341254/
doi: 10.1371/journal.ppat.0010039
summary:
  The coronavirus replicase-transcriptase complex is an assembly of viral and cellular proteins that mediate the synthesis of genome and subgenome-sized mRNAs in the virus-infected cell. Here, we report a genetic and functional analysis of 19 temperature-sensitive (ts) mutants of Murine hepatitis virus MHV-A59 that are unable to synthesize viral RNA when the infection is initiated and maintained at the non-permissive temperature. We focused our phenotypic analysis on the eight MHV-A59 ts mutants that had been genotyped and began by measuring ''''total'''' viral RNA synthesis in infected cells prior to and following shift from the permissive to the non-permissive temperature. This phenotype resembled that seen with MHV-A59-infected cells treated with CH, and we conclude that the complementation group I mutants are defective in their ability to form active replicase-transcriptase complexes at 40 8C but retain the positive-strand synthesis activity of the complexes formed at the permissive temperature.

abstract:
  The coronavirus replicase-transcriptase complex is an assembly of viral and cellular proteins that mediate the synthesis of genome and subgenome-sized mRNAs in the virus-infected cell. Here, we report a genetic and functional analysis of 19 temperature-sensitive (ts) mutants of Murine hepatitis virus MHV-A59 that are unable to synthesize viral RNA when the infection is initiated and maintained at the non-permissive temperature. Both classical and biochemical complementation analysis leads us to predict that the majority of MHV-A59 ORF1a replicase gene products (non-structural proteins nsp1–nsp11) form a single complementation group (cistron1) while the replicase gene products encoded in ORF1b (non-structural proteins nsp12–nsp16) are able to function in trans and comprise at least three, and possibly five, further complementation groups (cistrons II–VI). Also, we have identified mutations in the non-structural proteins nsp 4, nsp5, nsp10, nsp12, nsp14, and nsp16 that are responsible for the ts phenotype of eight MHV-A59 mutants, which allows us to conclude that these proteins are essential for the assembly of a functional replicase-transcriptase complex. Finally, our analysis of viral RNA synthesis in ts mutant virus-infected cells allows us to discriminate three phenotypes with regard to the inability of specific mutants to synthesize viral RNA at the non-permissive temperature. Mutant LA ts6 appeared to be defective in continuing negative-strand synthesis, mutant Alb ts16 appeared to form negative strands but these were not utilized for positive-strand RNA synthesis, and mutant Alb ts22 was defective in the elongation of both positive- and negative-strand RNA. On the basis of these results, we propose a model that describes a pathway for viral RNA synthesis in MHV-A59-infected cells. Further biochemical analysis of these mutants should allow us to identify intermediates in this pathway and elucidate the precise function(s) of the viral replicase proteins involved.


