title: A 61,000-dalton truncated large T-antigen is uniformly expressed in hamster cells transformed by polyomavirus.
abstract: Various polyomavirus-transformed hamster cell lines derived from tumors or from infected hamster cell cultures synthesized polyoma middle and small tumor (T)-antigens but no full-size large T-antigen. Instead, all cell lines produced the same or similar polyoma T-antigen-related proteins of ca. 61 kilodaltons (kDal). Like large T-antigen synthesized in lytically infected mouse cells, the 61-kDal proteins were phosphoproteins showing electrophoretic and charge heterogeneities. Chromatographic analysis of the methionine-containing tryptic peptides indicated that the 61-kDal proteins were truncated forms of large T-antigen comprising amino acid residues 1 to 485 (+/- 25). Analysis of viral DNA present in hamster chromosomal DNA of three independently isolated cell lines confirmed that synthesis of the 61-kDal proteins was due to a discontinuity in the large T-antigen coding sequence, most likely located between 7 and 8.9 map units on the polyoma DNA map. The three cell lines yielded essentially the same patterns of viral DNA-containing restriction enzyme fragments, suggesting that insertion of viral DNA into the hamster chromosomes took place at closely similar sites.
mesh_terms: D000818:Animals; D000952:Antigens, Polyomavirus Transforming; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D006224:Cricetinae; D004247:DNA / Q000302:isolation & purification; D004262:DNA Restriction Enzymes; D007668:Kidney / Q000201:enzymology; D008647:Mesocricetus; D051379:Mice; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D011120:Polyomavirus / Q000201:enzymology / Q000235:genetics*; D011494:Protein Kinases / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D000952:Antigens, Polyomavirus Transforming; D010446:Peptide Fragments; D014764:Viral Proteins; D004247:DNA; D011494:Protein Kinases; D004262:DNA Restriction Enzymes