Open AccessStimulation of RNA synthesis in isolated nuclei by partially purified preparations of simian virus 40 T-antigen.
Author(s) -
Toshinori Ide,
Sandra Whelly,
Renato Baserga
Publication year - 1977
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.74.8.3189
Subject(s) - antigen , hamster , antiserum , biology , rna , microbiology and biotechnology , stimulation , in vitro , virus , mutant , virology , biochemistry , immunology , gene , neuroscience
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.