title: Viral DNA synthesis in cells infected by temperature-sensitive mutants of simian virus 40.
abstract: Temperature-sensitive mutants of simian virus 40 (SV40) have been classified as those that are blocked prior to viral DNA synthesis at the restrictive temperature, "early" mutants, and those harboring a defect later in the replication cycle, "late" mutants. Mutants of the A and D complementation groups are early, those of the B, C, and BC groups are late. Our results confirm earlier reports that A mutants are defective in a function required for the initiation of each round of viral DNA synthesis. D mutants, on the other hand, continue viral DNA replication at the restrictive temperature after preincubation at the permissive temperature. The length of time required for D function to be expressed at the permissive temperature-after which infection proceeds unabated on shifting of the cultures to the restrictive temperature-is 10 to 20 h. The viral DNA synthesized in D mutants under these conditions progresses in normal fashion through replicative intermediate molecules to mature component I and II DNA molecules.
mesh_terms: D000818:Animals; D002250:Carbon Radioisotopes; D002460:Cell Line; D004247:DNA / Q000096:biosynthesis; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis*; D066298:In Vitro Techniques; D007668:Kidney; D009154:Mutation; D013539:Simian virus 40 / Q000254:growth & development*; D013696:Temperature; D013936:Thymidine; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D004279:DNA, Viral; D014316:Tritium; D004247:DNA; D013936:Thymidine