MUTATIONAL ANALYSIS OF INFLUENZA-B VIRUS-RNA TRANSCRIPTION IN-VITRO

The roles of the 3'- and 5'-terminal nucleotides and the panhandle str ucture of influenza B virus virion RNA were analyzed in vitro by trans cription of model RNA templates with influenza B virus RNA polymerase. The results suggest that the stability of the panhandle and breathing of the extreme ends of the panhandle are important factors for effici ent transcription. Influenza B virus polymerase appears to be more tol erant of mutations in the panhandle structure than influenza A virus p olymerase. This is consistent with the greater degree of heterogeneity observed naturally in the 3'-terminal nucleotides of the virion RNA o f influenza B virus than in influenza A virus.