Antigenic structure of simian virus 40 large tumor antigen and association with cellular protein p53 on the surfaces of simian virus 40-infected and -transformed cells.
The antigenic structure of simian virus 40 (SV40) large tumor antigen (T-ag) in the plasma membranes of SV40-transformed mouse cells and SV40-infected monkey cells was characterized as a step toward defining possible biological function(s). Wild-type SV40, as well as a deletion mutant of SV40 (dl1263) which codes for a truncated T-ag with an altered carboxy terminus, was used to infect permissive cells. Members of a series of monoclonal antibodies directed against antigenic determinants on either the amino or the carboxy terminus of the T-ag polypeptide were able to precipitate surface T-ag (as well as nuclear T-ag) from both SV40-transformed and SV40-infected cells. Cellular protein p53 was coprecipitated with T-ag by all T-ag-reactive reagents from the surface and nucleus of SV40-transformed cells. In contrast, T-ag, but not T-ag-p53 complex, was recovered from the surface of SV40-infected cells. These results confirm that nuclear T-ag and surface T-ag are highly related molecules and that a complex of SV40 T-ag and p53 is present at the surface of SV40-transformed cells. Detectable levels of such a complex do not appear to be present on SV40-infected cells. Both the carboxy and amino termini of T-ag are exposed on the surfaces of SV40-transformed and -infected cells. The possible relevance of the presence of a T-ag-p53 complex on the surface of SV40-transformed cells and its absence from SV40-infected cells is considered.
D000818:Animals; D000952:Antigens, Polyomavirus Transforming; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology; D002471:Cell Transformation, Neoplastic; D002522:Chlorocebus aethiops; D000939:Epitopes / Q000032:analysis*; D007668:Kidney; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000032:analysis*; D010750:Phosphoproteins / Q000032:analysis*; D013539:Simian virus 40 / Q000235:genetics* / Q000276:immunology; D016159:Tumor Suppressor Protein p53; D014764:Viral Proteins / Q000032:analysis*
D000952:Antigens, Polyomavirus Transforming; D000939:Epitopes; D009363:Neoplasm Proteins; D010750:Phosphoproteins; D016159:Tumor Suppressor Protein p53; D014764:Viral Proteins