id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-010374-z9ygudv6	Siddell, S.G.	Coronaviridae1	2008-07-24		.txt	text/plain	1541	111	51	The main characteristics of the member viruses are: (i) Morphological: Enveloped pleomorphic particles typically 100 nm in diameter (range 60-220 nm), bearing about 20 nm long club-shaped surface projections, (ii) Structural: A single-stranded infectious molecule of genomic RNA of about (5-7) × 10(6) molecular weight. (iv) Antigenic: 3 major antigens, each corresponding to one class of virion protein, (v) Biological: Predominantly restricted to infection of natural vertebrate hosts by horizontal transmission via the fecal/oral route. Recently, there have been reports of virus-specific RNA poly merases in coronavirus-infected cells, but the components of the enzyme have not been iden tified. UV inactivation studies in dicate that coronavirus mRNAs are not pro duced by the processing of a larger RNA, although extensive sequence homologies have been detected at the 5' ends of ail murine hepatitis virus-specific subgenomic RNAs. For murine hepatitis virus, the mRNA function of each of the subgenomic viral RNAs has been demonstrated in vitro, and the mRNAs encod ing each of the virion proteins, or its precur sors, have been identified ( fig.	./cache/cord-010374-z9ygudv6.txt	./txt/cord-010374-z9ygudv6.txt