Phenotypic complementation of the SV40 tsA mutant defect in viral DNA synthesis following microinjection of SV40 T antigen.
African green monkey cells (CV-1P) were microinjected with highly purified SV40 T antigen using protein-loaded red cell ghosts and polyethylene glycol as fusagen. The microinjected cells were infected  with a temperature-sensitive mutant of SV40 (tsA209) which is defective in the initiation of viral DNA synthesis. Using in situ hybridization as an assay method, we found that PEG-microinjection of both partially and highly purified T antigen resulted in an increase in the amount of viral DNA sequences in the monolayer. Moreover, 3H-thymidine-labeled and unlabeled Hirt supernatant from microinjected, tsA209-injected cells contained significantly more SV40 DNA than comparable extracts from sham-injected, tsA209-infected or uninfected cells, which were tested in parallel. Thus the introduction of highly purified, "large" SV40 T antigen led to phenotypic complementation of the tsA defect in viral DNA synthesis.
D000956:Antigens, Viral; D002460:Cell Line; D004279:DNA, Viral / Q000096:biosynthesis*; D008845:Microinjections; D009154:Mutation; D009693:Nucleic Acid Hybridization; D013539:Simian virus 40 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D013696:Temperature
D000956:Antigens, Viral; D004279:DNA, Viral