Nucleosomal elements that control the topography of the barrier to transcription.

ABSTRACT: The nucleosome represents a mechanical barrier to transcription that operates as a general regulator of gene expression. We investigate how each nucleosomal component-the histone tails, the specific histone-DNA contacts, and the DNA sequence-contributes to the strength of the barrier. Removal of the tails favors progression of RNA polymerase II into the entry region of the nucleosome by locally increasing the wrapping-unwrapping rates of the DNA around histones. In contrast, point mutations that affect histone-DNA contacts at the dyad abolish the barrier to transcription in the central region by decreasing the local wrapping rate. Moreover, we show that the nucleosome amplifies sequence-dependent transcriptional pausing, an effect mediated through the structure of the nascent RNA. Each of

SUBMITTER: Bintu L 

PROVIDER: S-EPMC3508686 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature