id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-258232-br4z3na6	Maeda, Junko	Release of Coronavirus E Protein in Membrane Vesicles from Virus-Infected Cells and E Protein-Expressing Cells	1999-10-25		.txt	text/plain	4132	189	51	The present study demonstrated that mouse hepatitis virus (MHV) E protein was released as an integral membrane protein in lipid vesicles from E-protein-expressing mammalian cells, in the absence of other MHV proteins. Complementation studies using two defective interfering (DI) RNAs of a prototypic coronavirus, mouse hepatitis virus (MHV), showed that E and M proteins are both required for the production of MHV particles containing the viral nucleocapsid (5) . To establish the buoyant density of released E protein, culture fluids from E-protein-expressing cells were applied onto a discontinuous sucrose gradient and centrifuged as described above. The release of E-protein-containing membrane vesicles from MHV-infected cells and E-protein-expressing cells further emphasized the pivotal role of E protein in coronavirus assembly. Furthermore, sucrose gradient centrifugation of MHV particles showed two E protein radioactive peaks, whereas N protein had only one peak corresponding to the MHV buoyant density (Fig. 3) , indicating that membrane vesicles containing only E protein do not include nucleocapsid.	./cache/cord-258232-br4z3na6.txt	./txt/cord-258232-br4z3na6.txt