Expression of early genes of origin-defective mutants of simian virus 40.

Abstract
The nucleotide sequences of 8 origin-defective mutants of SV40 were determined. All of the mutants suffered deletions, which range in size from 4-241 nucleotides. Some of the mutants induce the synthesis of tumor (T) antigen, others do not. Viral mRNA extracted from rat cells transformed by 2 of the T[tumor]-antigen-positive mutants was analyzed by the S1 nuclease technique of Berk and Sharp. Irrespective of the size or the location of the deletions, the 5'' ends of viral mRNA are located approximately the same distance from the A + T-rich region (A-T-T-T-A-T) rather than at a specific site in the viral genome.