Control of Transcription Initiation In Vitro Requires Binding of a Transcription Factor to the Distal Promoter of the Ovalbumin Gene

Abstract

We used a cell-free HeLa cell transcription system to identify and characterize transcription factors and the promoter elements that they recognize in RNA polymerase II-transcribed genes. Deletion of the region (-71 to -83) containing the GTCAAA direct repeat resulted in a marked decrease of specific transcription of the ovalbumin gene; transcription could be competed with DNA fragments containing this sequence. Furthermore, DNase I footprinting identified a protein-binding site including this direct repeat with crude extracts and one of the partially purified protein fractions required for transcription. We propose that a soluble factor activates transcription through binding to the direct repeat of GTCAAA sequence upstream from the ovalbumin gene.