MAPPING OF RNA INITIATION SITES BY HIGH-DOSES OF UV IRRADIATION - EVIDENCE FOR 3 INDEPENDENT PROMOTERS WITHIN THE LEFT 11-PERCENT OF THE AD-2 GENOME

Cells infected with Ad-2 virus were irradiated so that uv-induced lesions were introduced every 500-1000 nucleotides in the genome, consequently leading to the premature termination of RNA transcription. Such cells when labeled with [3H]uridine accumulate labeled promoter proximal RNA. Hybridization of this RNA after size fractionation to restriction fragments of the Ad-2 genome allowed the identification of DNA sequences containing active RNA initiation sites. Early during the infectious cycle two active RNA initiation sites were found within the left 11% of the Ad-2 genome within the 0-3.0 and 4.4-8.0 restriction fragments. During late infection (15 hr) an additional uv resistant transcript was detected indicating that a newly activated RNA initiation site, presumably for protein IX, resides within the fragment 8.0-11.,2. © 1979.