Expression of p53 after sv40 virus-infection of quiescent cells

SV40 infection of quiescent mouse cells leads to a re-entry of the cells into the cell cycle and to cellular DNA synthesis. At about 2 hours after virus infection the p53 protein becomes detectable. By using the p53 specific monoclonal antibody PAb246 we were able to demonstrate that p53 is expressed in wild-type conformation. At late time after virus infection wild-type p53 is complexed to the SV40 large T antigen. SV40 infection of quiescent cells in the presence of an elevated level of cAMP does not result in cellular DNA synthesis and not in expression of elevated levels of p53 suggesting that p53 is implicated in stimulation of cellular DNA synthesis. Phosphorylation of p53 increases with time after SV40 infection of quiescent cells indicating that phosphorylation of p53 varies during cell cycle progression.