Simian virus 40-transformed cells express new species of proteins precipitable by anti-simian virus 40 tumor serum

Abstract

In addition to the virus-coded large-T and small-t antigens, two new classes of proteins were immunoprecipitated by anti-simian virus 40 (SV40) tumor serum from extracts of various SV40-transformed cell lines. These were as follows: (i) proteins (termed "super-T proteins") with an Mr higher than that of large-T antigen (86,000), which were found in many SV40-transformed cell lines derived from mouse and rat cells (super-T proteins and large-T antigen appeared to have closely related structures as judged by the Chromobead elution patterns of their methionine-labeled tryptic peptides); (ii) proteins (termed "55K proteins") with an Mr ranging from 50,000 to 60,000, which were present in all SV40-transformed cell lines examined so far, including those obtained by chromosome-mediated gene transfer. The 55K proteins were not structurally related to large-T antigen, as judged by the Chromobead elution patterns of their methionine-labeled tryptic peptides. Our data are compatible with the assumption that the 55K proteins are largely or totally cell coded. with 25 to 50 ,uCi of L-[35S]methionine per ml (750 to 930 Ci/mmol; The Radiochemical Centre, Amersham, England) or with 100 JCi of 32PO4 per ml (C.E.A., France) in methionine (or phosphate)-free medium. SV40-infected BMK and SV40-infected CV1 cells were labeled 24 h and 72 h, respectively, after infection, with the same radioactive molecules, specific activities, length of time, and media as described for trans-472

TP53 Mutations in Human Cancer: Database Reassessment and Prospects for the Next Decade

“…The third factor that strongly modulates TP53 mutation frequency is exogenous features such as viral or bacterial infection [Levine, 2009;Moody and Laimins, 2010;Schetter and Harris, 2012]. Most human viruses impair TP53 activity, thus constraining the cell to proficient viral DNA replication, a mechanism that was, on another note, at the root of the discovery of TP53 [Kress et al, 1979;Lane and Crawford, 1979;Linzer and Levine, 1979]. In cervical cancer, the human papillomavirus E6 protein targets the TP53 protein to the proteasomal degradation pathway [Scheffner et al, 1990].…”

Subcellular distribution of simian virus 40 T antigen species in various cell lines: The 56K protein

“…Immunoprecipitates from simian virus 40 (SV40) transformed cells, obtained following treatment with hamster SV40 anti-T serum, generally contain three polypeptides: the tumor antigens (T Ag), large T Ag (Crawford et a[., 1978;Prives et al, 1977;Carroll and Smith, 1976;Tegtmeyer, 1974) and small t Ag (Crawford et al, 1978;Sleigh et al, 1978;Prives et al, 1977;Tabuchi et al, 1976) and the intermediate size, 56,000 molecular weight protein (56K protein) (Chang et al, 19796;Edwards et al, 1979;Kress et al, 1979;Lane and Crawford, 1979;Melero et al, 1979;Gaudray et al, 1978). Such immunoprecipitates, commonly analyzed by sodium dodecylsulfatepolyacrylamide gel electrophoresis (SDS-PAGE), contain antigens of molecular weights near 94K and 19K, for the large T Ag and the small t Ag, respectively.…”

Detection of simian virus 40 surface‐associated large tumor antigen by enzyme‐catalyzed radioiodination

“…A possible explanation could be based upon the association of T-ag with preexisting cellular proteins. The association of nuclear and membrane-associated T-ag with a 53,000 mol.wt cellular protein (nonviral T-ag; nvT-ag) (Chang et al, 1979;Kress et al, 1979;Lane and Crawford, 1979;Linzer and Levine, 1979;Melero et al, 1979;Smith et al, 1979;McCormick and Harlow, 1980) has been described (Soule and Butel, 1979;Luborsky and Chandrasekaran, 1980; M. Santos and J.S. Butel, submitted).…”