On the structure and replication of influenza virus

Abstract

Influenza virus PR8 has been purified from the allantoic fluid of infected chick embryos and from tissue culture medium. Preliminary characterization indicates that the virus contains at least two major proteins and several RNA components with sedimentation coefficients ( S 20, w ) ranging from about 9 to 18 s. Synthesis of virus-specific RNA in influenza virus-infected chick embryo cells has been demonstrated under conditions where cell RNA synthesis is suppressed by actinomycin D. In addition to the single-stranded viral RNA components, a smaller fraction of virus-specific double-stranded RNA is labeled with [ 3H]-uridine in the presence of actinomycin D. This RNA has been purified after incubation of the RNA from infected cells with RNase. It has an approximate sedimentation coefficient of 8 to 10 s, shows a sharp thermal transition and has a lower buoyant density in cesium sulfate than single-stranded influenza virus RNA. Preliminary evidence indicates that the double-stranded RNA may be an intermediate in viral RNA synthesis.