Transcription by Infectious Subviral Particles of Reovirus

AUTOR(ES)
RESUMO

Digestion of purified reovirus with chymotrypsin in the presence of 0.15 M NaCl converts virions to infectious subviral particles (SVPi). The SVPi have an active ribonucleic acid (RNA) polymerase and are similar in composition to the partially uncoated virions which have been isolated from infected L cells. SVPi have a buoyant density of 1.40 g/ml in CsCl and sediment at 420S as compared to 1.37 g/ml and 630S for virions. They consist of 30% less protein and include the polypeptides of the inner structural layer, λ1, λ2, and σ3, and a polypeptide derived by cleavage of μ2, a constituent of the outer shell. The genome RNA is retained within SVPi, but more than 60% of the “adenine-rich,” single-stranded RNA is released by the proteolytic treatment. Infection of L cells with SVPi or virions results in the transcription of all 10 genome segments. In cycloheximide-treated SVPi-infected cells, transcription occurs predominantly from one medium and two small genome segments, the same pattern of early messenger RNA (mRNA) observed in virion-infected cells. In contrast, SVPi incubated in vitro synthesize mRNA corresponding to all genome segments.

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