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Transcription initiation patterns indicate divergent strategies for gene regulation at the chromatin level

Item Type:Article
Title:Transcription initiation patterns indicate divergent strategies for gene regulation at the chromatin level
Creators Name:Rach, E.A. and Winter, D.R. and Benjamin, A.M. and Corcoran, D.L. and Ni, T. and Zhu, J. and Ohler, U.
Abstract:The application of deep sequencing to map 5' capped transcripts has confirmed the existence of at least two distinct promoter classes in metazoans: "focused" promoters with transcription start sites (TSSs) that occur in a narrowly defined genomic span and "dispersed" promoters with TSSs that are spread over a larger window. Previous studies have explored the presence of genomic features, such as CpG islands and sequence motifs, in these promoter classes, but virtually no studies have directly investigated the relationship with chromatin features. Here, we show that promoter classes are significantly differentiated by nucleosome organization and chromatin structure. Dispersed promoters display higher associations with well-positioned nucleosomes downstream of the TSS and a more clearly defined nucleosome free region upstream, while focused promoters have a less organized nucleosome structure, yet higher presence of RNA polymerase II. These differences extend to histone variants (H2A.Z) and marks (H3K4 methylation), as well as insulator binding (such as CTCF), independent of the expression levels of affected genes. Notably, differences are conserved across mammals and flies, and they provide for a clearer separation of promoter architectures than the presence and absence of CpG islands or the occurrence of stalled RNA polymerase. Computational models support the stronger contribution of chromatin features to the definition of dispersed promoters compared to focused start sites. Our results show that promoter classes defined from 5' capped transcripts not only reflect differences in the initiation process at the core promoter but also are indicative of divergent transcriptional programs established within gene-proximal nucleosome organization.
Keywords:Chromatin, CpG Islands, Gene Expression Regulation, Genetic Promoter Regions, Genetic Transcription, Animals, Drosophila melanogaster
Source:PLoS Genetics
Publisher:Public Library of Science
Page Range:e1001274
Date:13 January 2011
Official Publication:https://doi.org/10.1371/journal.pgen.1001274
PubMed:View item in PubMed

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