Inhibition of ribonucleic acid accumulation in mouse L cells infected with vesicular stomatitis virus requires viral ribonucleic acid transcription

The accumulation of ribonucleic acid (RNA) in mouse L-929 cells infected with temperature-sensitive mutants of vesicular stomatitis virus or ultraviolet- (UV-) irradiated virus was studied. At the permissive temperature (30 degrees C infection by all mutants resulted in an inhibition of cellular RNA accumulation. At the nonpermissive temperature (40 degrees C) mutants G114 (I) and G22 (II) failed to inhibit RNA accumulation, but mutants G11 (I), O52 (II), G31 (III), G33 (III), G41 (IV), W10 (IV), O45 (V), and O110 (V) were still active in this respect. In most cases the accumulation of 28S and 18S mature rRNA was inhibited to a greater extent than the synthesis of the 45S rRNA precursor. UV irradiation of wild type virus considerably reduced its capacity to inhibit cellular RNA synthesis. The target size for inactivation of this capacity of the virus was approximately 17% of the viral genome or that corresponding to the N gene. These results indicate that the virion proteins themselves are incapable of inhibiting cellular RNA synthesis and that transcription of approximately 17% of the genome is required. Expression of RNA synthesis inhibition also requires some function of virion NS protein in addition to its transcriptase activity.