Adenovirus VAI RNA antagonizes the antiviral action of interferon by preventing activation of the interferon-induced eIF-2 alpha kinase.

The VAI RNA of adenovirus is a small, RNA polymerase III-transcribed species required for efficient translation of host cell and viral mRNAs late after infection. The growth of a viral mutant that is unable to produce the RNA is inhibited by interferon, while wild-type virus is not affected. VAI RNA prevents activation of the interferon-induced P1/eIF-2 alpha kinase. This inhibition can be reproduced in extracts of interferon-treated cells where purified VAI RNA prevents activation of latent kinase by double-stranded RNA.