SV40 T Antigen: Partial Purification and Properties

A large body of evidence has led to the hypothesis that papova virus nonvirion proteins may play an active role in initiating and maintaining virus-induced malignant transformation (Butel et al. 1972). In the case of SV40, three operationally distinct antigens-T (Black et al. 1963; Rapp et al. 1964a,b; Gilden et al. 1965), U (Lewis and Rowe 1971) and S (Koch and Sabin 1963; Girardi 1965)-fall into the category of virus-specific nonvirion proteins. Our interest is in their functions, especially as they may relate to the control of viral gene expression and to the initiation and maintenance of the transformed phenotype. In this communication we shall report the results of initial work on the attempted purification and structural characterization of the SV40 T antigen. This protein is a nuclear constituent of virus-transformed cells and is also synthesized prior to viral DNA synthesis by infected permissive cells (Hoggan et al. 1965; Rapp...