1991 Articles

Excess Wild-Type p53 Blocks Initiation and Maintenance of Simian Virus 40 Transformation

Fukasawa, Kenji; Sakoulas, George; Pollack, Robert; Chen, Suzie

Wild-type (wt) murine p53 has been tested for its ability to block and reverse the transforming effects of simian virus 40 (SV40) large T antigen. Established and precrisis mouse cells overexpressing exogenously introduced wt p53 became resistant to SV40 transformation. The introduction of excess wt p53 into SV40-transformed precrisis cells reverted their transformed phenotype. However, the phenotype of SV40transformed established cells was not reverted by excess wt p53. We conclude that an antioncogenic action of wt^53 is exerted during SV40 transformation and that in precrisis cells, the antitransforming action of wt p53 can be exerted both at initiation and during the maintenance of transformation.