IHF-binding sites inhibit DNA loop formation and transcription initiation.

ABSTRACT: Transcriptional activation of enhancer and sigma(54)-dependent promoters requires efficient interactions between enhancer-binding proteins (EBP) and promoter bound sigma(54)-RNA polymerase (E sigma(54)) achieved by DNA looping, which is usually facilitated by the integration host factor (IHF). Since the lengths of the intervening region supporting DNA-loop formation are similar among IHF-dependent and IHF-independent promoters, the precise reason(s) why IHF is selectively important for the frequency of transcription initiation remain unclear. Here, using kinetic cyclization and in vitro transcription assays we show that, in the absence of IHF protein, the DNA fragments containing an IHF-binding site have much less looping-formation ability than those that lack an IHF-binding site. Furtherm

SUBMITTER: Huo YX 

PROVIDER: S-EPMC2709558 | biostudies-literature | 2009 Jul

REPOSITORIES: biostudies-literature