Temperature-Sensitive Mutants and DI Particles Restricted in Transcription

Temperature-Sensitive Mutants and DI Particles Restricted in Transcription 

The purpose of these experiments was to determine whether primary transcription from the 3 end of the VSV genome was essential to express its capacity to inhibit cellular RNA synthesis. Quite obviously, such studies could not distinguish between viral RNAs and proteins as the potential inhibitors. The use of protein synthesis inhibitors, such as cycloheximide, puromycin, and amino acid analogues, always resulted in inhibition of cellular RNA synthesis as well (Week and Wagner, unpublished data), thus, precluding this approach to the problem of identifying the viral inhibitor. 

Week and Wagner (1979a) analyzed RNA metabolism in MPC-11 cells infected with various temperature-sensitive (ts) mutants and 5 -defective-interfering particles which cannot synthesize mRNA. A group I mutant, /sG114, restricted in transcriptional activities (Hunt et al., 1976), failed to shut-off host cell RNA metabolism in MPC-11 cells incubated at the restrictive temperature of 39°C for 4 hr. At the permissive temperature (3rC), all mutants (including /5G114) were as effective as the wild-type virus in the shut-off of RNA synthesis. Because tjG 114(1) did not inhibit cell RNA metabolism at the non-permissive temperature, it was used to test for a virion structural 

These experiments strongly indicate that VSV transcript(s) can inhibit cellular nucleic acid synthesis directly or by means of their translated products. 

Use of UV Irradiation to Identify VSV Genetic Information Responsible for Shutting Off Cellular RNA Synthesis 

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