Simian virus 40 mutant with transposed T-antigen and VP1 genes.

A simian virus 40 mutant with the T-antigen gene transposed to the late region of the viral genome has been constructed. This transposed molecule directed the synthesis of a full-sized, 92,000-dalton large T antigen in both permissive and nonpermissive cells. This large T antigen functioned in the initiation of viral DNA replication and in the transformation of nonpermissive cells. T-antigen synthesis by this transposed genome had the characteristics of late transcription, thus indicating that functional large T antigen of simian virus 40 is not required for the initiation of late transcription.