Stimulation of RNA synthesis in isolated nuclei by partially purified preparations of simian virus 40 T-antigen.
T-Antigen was partially purified from nuclei of cells transformed by simian virus 40 (SV 40). When nuclei isolated from either rat liver or quiescent hamster cells were preincubated with T-antigen preparations, there was a marked stimulation of RNA synthesis in an in vitro assay, up to 150% above control levels. The stimulation of RNA synthesis was inhibited by hamster antiserum against T-antigen but not by normal hamster serum. When the T-antigen preparations were fractionated on glycerol gradients, the fractions containing complement-fixing activity with antiserum to T-antigen also had the highest stimulatory activity on nuclear RNA synthesis. T-Antigen was also partially purified from nuclei of cells transformed by a temperature-sensitive A mutant of SV40. When preincubated up to 2 hr at 50 degrees, the T-antigen preparation from these temperature-sensitive A mutants was rapidly inactivated, in terms of both complement-fixing activity and ability to stimulate RNA synthesis in isolated rat liver nuclei. Under the same conditions of preincubation, T-antigen preparations from cells transformed by wild-type SV40 maintained their complement-fixing activity and ability to stimulate RNA synthesis. These results suggest that the biological action of T-antigen may be exerted at the level of transcription.
D000818:Animals; D000956:Antigens, Viral; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D002472:Cell Transformation, Viral; D003168:Complement Fixation Tests; D006358:Hot Temperature; D007106:Immune Sera; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008970:Molecular Weight; D009154:Mutation; D014176:Protein Biosynthesis; D012313:RNA / Q000096:biosynthesis*; D051381:Rats; D013539:Simian virus 40; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000096:biosynthesis
D000956:Antigens, Viral; D007106:Immune Sera; D014764:Viral Proteins; D012313:RNA