we have examined the discrete species of simian virus 40 ( sv40 ) rna present very early in infection of monkey cells with wild-type virus , with mutant tsa58 virus , and with the corresponding dnas to distinguish between two classes of models for control of late transcription : ( i ) positive control mediated by large-t antigen and ( ii ) negative control mediated by a repressor protein associated with viral dna in the virion .
C0012854
dnas
C0012939
viral dna