Stable T-p53 complexes are not required for replication of simian virus 40 in culture or for enhanced phosphorylation of T antigen and p53.

We generated a number of simian virus 40 (SV40) mutants with single amino acid substitutions in T antigen between residues 388 and 411. All but one mutant (398LV) replicated like wild-type SV40 and gave rise to normal-size plaques. Three different mutations at residue 402 (Asp to Glu, Asn, or His) totally prevented the formation of stable complexes with the cellular protein p53 in monkey cells but had no effect on virus replication. Only one other mutation in this region, involving residue 401 (Met to Thr), slightly inhibited the formation of T-monkey p53 complexes. The three mutant T antigens with substitutions at residue 402 also formed no stable complexes with human p53 but generated low levels of complexes with mouse p53. These results indicate that residue 402 is critical for binding to monkey and human p53 proteins and is important for binding to mouse p53. We suggest that it is one of several points of contact. In cells infected with any one of the three residue 402 mutant viruses. T antigen and p53 became increasingly phosphorylated, as they were in cells infected with wild-type virus. Our data therefore show that stable T-p53 complexes are not required for replication of SV40 in culture or for enhanced phosphorylation of either protein.