The promoter-specific transcription factor Sp1 binds to upstream sequences in the SV40 early promoter.
Fractionation of HeLa cell extracts reveals the presence of a promoter-specific transcription factor, Sp 1, which activates a class of promoters that includes the SV40 early promoter but not several others that have been tested. We analyzed SV40 early-promoter deletion mutants and determined that transcriptional activation by Sp 1 requires sequences within tandem 21 bp repeats located 70-110 bp upstream of the transcription initiation sites. In a DNAase footprinting assay, Sp 1 protected sequences in this same 21 bp repeat region, thus indicating the presence of a specific site for Sp 1 binding. During purification of Sp 1, there was a correlation between transcription-stimulatory activity and promoter-binding activity. These results suggest that direct binding of Sp 1 to sequences in the upstream promoter element is the mechanism by which this factor activates transcription by RNA polymerase II at the SV40 early promoter.
D001665:Binding Sites; D004279:DNA, Viral / Q000378:metabolism*; D005814:Genes, Viral; D006367:HeLa Cells; D006801:Humans; D009154:Mutation; D009876:Operon; D012091:Repetitive Sequences, Nucleic Acid; D013539:Simian virus 40 / Q000235:genetics*; D014157:Transcription Factors / Q000302:isolation & purification / Q000378:metabolism*; D014158:Transcription, Genetic
D004279:DNA, Viral; D014157:Transcription Factors