Interferon Action III. The Rate of Primary Transcription of Vesicular Stomatitis Virus is Inhibited by Interferon Action

Abstract

Transcription of vesicular stomatitis virus (VSV) in Vero cells was confined to the synthesis of parentally-derived mRNA (primary transcription) by the use of cycloheximide and/or a ts mutant, G41(IV), at a non-permissive temperature (40 °C). More transcripts accumulated in the presence of cycloheximide than in its absence. This so-called ‘cycloheximide effect’ results from higher rates of virus transcription sustained for longer periods of time. The rate of VSV transcription initially increases linearly for 1 to 2 h after infection. Interferon reduces this rate (≃ fourfold with 50 units/ml interferon) irrespective of the presence or absence of cycloheximide. The VSV mRNA transcripts synthesized in mock- or interferon-treated cells were equal in size and had an equivalent half-life of 17 h at 40 °C. It seems likely that once transcription is initiated in interferon-treated cells, it is completed successfully.