title: Multiple forms of polyoma virus tumor antigens from infected and transformed cells.
abstract: At least three distinct forms of polyoma virus tumor antigens were isolated from productively infected and transformed hamster cells by immunoprecipitation with anti-T serum. These proteins had approximate molecular weights of 105,000 (large T antigen), 63,000 (middle T antigen), and 20,000 (small T antigen) as estimated by acrylamide gel electrophoresis. An examination of the appearance of these antigens in polyoma-infected mouse cells showed that all three polypeptides were synthesized maximally at approximately the same time after infection. Analysis of the methionine-containing tryptic peptides of these proteins indicated that the large, middle, and small forms of polyoma T antigens contained five similar or identical peptides. In addition, the 63,000- and 20,000-dalton antigens contained two other methionine peptides absent from the large T-antigen species. Other methionine peptides were found only in the large or middle T-antigen forms. These results and results obtained previously suggested that the three T-antigen species have the same NH2-terminal end regions but different COOH termini. A model is presented describing the synthesis of these polypeptides from different regions of the polyoma virus genome.
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000032:analysis*; D000956:Antigens, Viral / Q000032:analysis*; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D002472:Cell Transformation, Viral; D006224:Cricetinae; D008715:Methionine / Q000032:analysis; D051379:Mice; D008970:Molecular Weight; D010455:Peptides / Q000032:analysis; D011120:Polyomavirus / Q000276:immunology*; D014764:Viral Proteins / Q000032:analysis / Q000276:immunology
chemical_list: D000951:Antigens, Neoplasm; D000956:Antigens, Viral; D010455:Peptides; D014764:Viral Proteins; D008715:Methionine