The promoter-specific transcription factor Sp1 binds to upstream sequences in the SV40 early promoter
1983; Cell Press; Volume: 35; Issue: 1 Linguagem: Inglês
10.1016/0092-8674(83)90210-6
ISSN1097-4172
AutoresWilliam S. Dynan, Robert Tjian,
Tópico(s)RNA Interference and Gene Delivery
ResumoFractionation 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.
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