Transcription of adenovirus RNA in permissive and nonpermissive infections

The mechanism of blocked replication of human adenoviruses in monkey cells was examined. Previous experiments have placed the replicative block at the level of transcription or translation of adenovirus mRNA. Coinfection of the monkey cells with simian virus 40 enhances adenovirus replication in these cells. We compared the adenovirus mRNA transcribed during infection of permissive human cells and enhanced and unenhanced monkey cells. Adenovirus mRNA from enhanced monkey cells appeared to be identical to adenovirus mRNA from human cells. This indicated that simian virus 40 coinfection did not overcome the blocked replication by substituting for a missing adenovirus transcript. Comparison of adenovirus mRNA from enhanced and unenhanced monkey cell infection revealed two types of transcriptional discrepancies. There was a decrease in both the complexity and the relative abundance of several regions of the enhanced adenovirus mRNA. However, neither of these transcriptional defects was sufficient to totally explain the difference in yield of infectious virus and viral protein seen in these two types of infection.