Characterization of a surrogate TATA box promoter that regulates in vitro transcription of the simian virus 40 major late gene.

The presence of a surrogate TATA box sequence located ca. 30 nucleotides upstream of the major late RNA start site at nucleotide position (np) 325 (Brady et al., Cell 31:625-633, 1982) has been confirmed, and its structural specificity has been determined by the generation of additional base substitution mutations at the KpnI restriction site (np 294) in cloned simian virus 40 DNA. Two mutants generated new RNA initiation sites upstream of the np 325 start site and continued to utilize the authentic start site, but with decreased efficiency. The replacement of either one or both cytosines by thymines at np 298 and np 299 specifically enhanced in vitro transcription from the np 325 start site by 430 and 800%, respectively. This enhancement was due to conversion of the simian virus 40 late promoter present in the wild-type virus to a sequence that is similar to the TATA box present in the simian virus 40 early promoter.