Characterization of a Murine Cellular SV40 T Antigen in SV40-transformed Cells and Uninfected Embryonal Carcinoma Cells

Excerpt

SV40 contains the genetic information to code for two gene products expressed at early times after productive infection or in transformed cells. The gene-A product, or large tumor (T) antigen, has an apparent molecular weight of 94,000 in SDS-polyacrylamide gels (Tegtmeyer 1975a), whereas the second protein, small T antigen, has an estimated molecular weight of 17,000 (Prives et al. 1977; Crawford et al. 1978). These two proteins share common N-terminal amino acid sequences (Paucha et al. 1978) and antigenic determinants (Lane and Robbins 1978; Carroll et al. 1978). Animals bearing SV40-induced tumors produce antibody to both the large T and small T antigens (Black et al. 1963; Tegtmeyer 1975a; Prives et al. 1977; Crawford et al. 1978). Employing these antisera, it has been possible to immunoprecipitate [³⁵S]methionine-labeled large T and small T antigens from virus-infected or -transformed cells (Tegtmeyer et al. 1975; Crawford et al. 1978). In these experiments it...