Ultraviolet-irradiated simian virus 40 activates a mutator function in rat cells under conditions preventing viral DNA replication.
The UV-irradiated temperature-sensitive early SV40 mutant tsA209 is able to activate at the nonpermissive temperature the expression of mutator and recovery functions in rat cells. Unirradiated SV40 activates these functions only to a low extent. The expression of these mutator and recovery functions in SV40-infected cells was detected using the single-stranded DNA parvovirus H-1 as a probe. Because early SV40 mutants are defective in the initiation of viral DNA synthesis at the nonpermissive temperature, these results suggest that replication of UV-damaged DNA is not a prerequisite for the activation of mutator and recovery functions in mammalian cells. The expression of the mutator function is dose-dependent, i.e., the absolute number of UV-irradiated SV40 virions introduced per cell determines its level. Implications for the interpretation of mutation induction curves in the progeny of UV-irradiated SV40 in permissive host cells are discussed.
D000818:Animals; D002460:Cell Line; D002472:Cell Transformation, Viral; D004261:DNA Replication; D008099:Liver; D009154:Mutation; D010641:Phenotype; D051381:Rats; D013539:Simian virus 40 / Q000235:genetics*; D014466:Ultraviolet Rays; D014779:Virus Replication