Influenza A virus lacking the NS1 gene replicates in interferon-deficient systems

The NS1 protein is the only nonstructural protein encoded by influenza A vi rus. It has been proposed that the NS1 performs several regulatory function s during the viral replication cycle, including the regulation of synthesis , transport, splicing, and translation of mRNAs. Through the use of reverse genetics, a viable transfectant influenza A virus (delNS1) which lacks the NS1 gene has been generated. Our results indicate that the NS1 of influenz a A virus is an auxiliary (virulence) factor which plays a crucial role in inhibiting interferon-mediated antiviral responses of the host. (C) 1998 Ac ademic Press.