[Differences in the biosynthesis of 2 types of viral transcript in cells infected with influenza virus]

An analysis of poly A(+)-and poly A(--)-transcripts in influenza A/WSN (H0N1) virus-infected cells done by the method of Hay and coworkers demonstrated three stages of transcription: (1) primary transcription during which mRNA of all the genes is synthesized, (2) early secondary transcription during which mRNA of NS gene is amplified, and (3) late secondary transcription in which mRNA of all the genes is amplified. Poly A(--) transcripts are synthesized at the stage of secondary transcription. The effect of three concentrations of actinomycin D at various stages of transcription was studied. The experimental results suggest differences in inhibition by actinomycin D of synthesis of transcripts of both types at the early and late stages of secondary transcription. The effect on the infected cells of alpha-amanitine specifically inhibiting synthesis of primary mRNA showed the synthesis of cellular RNAs to be much more necessary for the synthesis of polyA(+)-transcripts than for that of polyA(--)-transcripts.