Further studies on the inhibition of cellular protein synthesis by vesicular stomatitis virus

After infection of L cells by vesicular stomatitis virus, the rate of protein synthesis steadily declines. Simultaneously, polysomes disaggregate and 80 S ribosomes accumulate. Transit time studies indicate that the average rate of polypeptide chain elongation is virtually identical for infected and uninfected cells. Cellular mRNAs remain intact and potentially functional in infected cells, as determined by their ability to be translated into cellular proteins in nuclease-treated reticulocyte lysates. More template activity is present in infected cells than in uninfected cells as a result of the presence of viral mRNAs in infected cells. Extracts from infected L cells translate their endogenous mRNAs less efficiently than do comparable extracts from uninfected cells. Nuclease-treated extracts from infected cells also show a lesser ability to translate given amounts of exogenous L cell or vesicular stomatitis virus mRNAs than do comparable extracts from uninfected cells. This observation suggests that the translation of both cellular and viral mRNAs is affected equally by the lesion induced in the cell by virus infection. The lesion appears to act at the level of initiation of protein synthesis and results in an underutilization of the total template activity present in infected cells.