id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-330315-upcf15q5	Oudshoorn, Diede	Expression and Cleavage of Middle East Respiratory Syndrome Coronavirus nsp3-4 Polyprotein Induce the Formation of Double-Membrane Vesicles That Mimic Those Associated with Coronaviral RNA Replication	2017-11-21		.txt	text/plain	7718	349	50	Using electron tomography, we demonstrate that for both MERS-CoV and SARS-CoV coexpression of nsp3 and nsp4 is required and sufficient to induce DMVs. Coexpression of MERS-CoV nsp3 and nsp4 either as individual proteins or as a self-cleaving nsp3-4 precursor resulted in very similar DMVs, and in both setups we observed proliferation of zippered ER that appeared to wrap into nascent DMVs. Moreover, when inactivating nsp3-4 polyprotein cleavage by mutagenesis, we established that cleavage of the nsp3/nsp4 junction is essential for MERS-CoV DMV formation. To study whether the transmembrane nsp's of MERS-CoV are able to induce DMV formation, we expressed nsp3 and nsp4 from a CAG promoter (43) either by cotransfection of cells with plasmids encoding individual proteins or by transfection with a single plasmid encoding a self-cleaving nsp3-4 polyprotein fragment ( Fig. 1A ; Table S1 ). The observation of maze-like bodies and circular double-membrane profiles, which were interpreted to represent tubular structures, led these authors to conclude that coexpression of SARS-CoV nsp3 and nsp4 was not sufficient for DMV formation.	./cache/cord-330315-upcf15q5.txt	./txt/cord-330315-upcf15q5.txt