Point mutations of the adenovirus major late promoter with different transcriptional efficiencies in vitro.

Synthetic oligodeoxyribonucleotides were used to introduce single base changes into the TATAA box of the adenovirus-2 major late promoter. The resultant mutant DNA templates that contained altered TATAA sequences (TATAA leads to TCTAA/TATCA) were tested for their relative transcriptional activity in vitro using HeLa whole cell extracts. The data indicate that the change TATAA leads to TCTAA results in a level of specific transcription reduced to 48.7% of that from the parental template, whereas the change TATAA leads to TATCA reduced transcription to 21%. Neither base change abolished promoter activity.