Nucleotide sequence analysis of viable deletion mutants lacking segments of the Simian virus 40 genome coding for small t antigen

The deletions in nine viable simian virus 40 mutants have been mapped by direct DNA sequence analysis. The mutant DNAs lack small segments of the early region of the viral chromosome (between 0.535 and 0.600 map unit). The deletions are all located in the region which is removed from the large T antigen transcript by splicing. No one deletion removes this entire region, but no part of this segment is conserved in all of the mutants except for several nucleotides near the splice points of the transcript. Although the deletions do not alter the region coding for the large T polypeptide, they do delete portions of the segment coding for the C terminal half of the small t polypeptide.