Relationship of replication and transcription of Simian Virus 40 DNA.

RNA produced by the Simian Virus 40 (SV40) mutant tsA30 during lytic infection of kidney cells of African green monkeys was examined by RNA-DNA competition-hybridization. This mutant is temperature-sensitive in a function (gene A) that regulates synthesis of viral DNA. No detectable difference between mutant RNA synthesized at the permissive temperature (33 degrees ) and wild-type viral RNA was found. During continuous infection with the mutant at the restrictive temperature (41 degrees ) only early viral RNA was produced. When mutant DNA and late RNA synthesis were initiated at the permissive temperature, a shift to the restrictive temperature rapidly terminated synthesis of viral DNA but not that of late viral RNA. The data indicate that the function of gene A is required before synthesis of late viral RNA and that after initiation, the production of late RNA continues without further expression of gene A or concomittant viral DNA synthesis.