Altered Patterns of Protein Synthesis in Infection by SV40 Mutants

SV40 may cause either productive infection of permissive cells or transforming infection of restrictive cells. The viral gene(s) expressed early in productive infection are the only gene(s) expressed in transforming infection (Khoury et al. 1972; Sambrook et al. 1972). Although several virus-induced early antigens have been identified in infected cells (Black et al. 1963; Lewis and Rowe 1971), only one early gene (gene A) has been detected by genetic techniques (Tegtmeyer and Ozer 1971; Chou and Martin 1974). That gene may be directly or indirectly responsible for the induction of each of the early antigens. Gene A codes for a diffusible gene product to be referred to as the A protein. Its function is directly and continuously required to initiate, but not to propagate or complete, each round of viral DNA replication (Tegtmeyer 1972). Expression of the same gene is only transiently required to initiate the continuous transcription of late...