Cerulenin inhibits production of mature virion particles in chick embryo fibroblasts infected by influenza A viruses.

We investigated acylation of haemagglutinin (HA) of type A influenza viruses during infection of permissive chick embryo fibroblasts (CEF) treated with cerulenin. Fatty acid binding was monitored using a maintenance medium containing 3H-palmitic acid. Our results suggest that fatty acid acylation of viral haemagglutinin may be essential for production of mature viral particles. Indeed, palmitoylation was found in infected CEF cells, but was lacking during the infectious cycle when cells were treated with a dose of 30 micrograms/ml of cerulenin. We discuss the possibility that acylation of virus-induced HA is a posttranslational modification regulating correct insertion of virus haemagglutinin into the cellular membrane and, as a consequence, controlling the maturation of budding influenza virus.