Mechanisms of Groucho-mediated repression revealed by genome-wide analysis of Groucho binding and activity

BMC Genomics

Research Article

Michael Chambers¹  Min Woo Kim¹  Kenny Chen¹  Sean D. Gallaher²  Wiam Turki-Judeh³  Albert J. Courey³ 

[1] Department of Chemistry and Biochemistry, University of California, 90095, Los Angeles, CA, USA;Department of Chemistry and Biochemistry, University of California, 90095, Los Angeles, CA, USA;Department of Energy, Institute of Genomics and Proteomics, University of California, 90095, Los Angeles, CA, USA;Department of Chemistry and Biochemistry, University of California, 90095, Los Angeles, CA, USA;Molecular Biology Institute, University of California, 90095, Los Angeles, CA, USA;

关键词: Groucho;    Transcriptional repression;    Drosophila embryogenesis;    ChIP-seq;    RNA-seq;    Chromatin-associated RNA-seq, RNA polymerase II pausing;   

DOI  :  10.1186/s12864-017-3589-6

 received in 2016-10-22, accepted in 2017-02-13,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundThe transcriptional corepressor Groucho (Gro) is required for the function of many developmentally regulated DNA binding repressors, thus helping to define the gene expression profile of each cell during development. The ability of Gro to repress transcription at a distance together with its ability to oligomerize and bind to histones has led to the suggestion that Gro may spread along chromatin. However, much is unknown about the mechanism of Gro-mediated repression and about the dynamics of Gro targeting.ResultsOur chromatin immunoprecipitation sequencing analysis of temporally staged Drosophila embryos shows that Gro binds in a highly dynamic manner primarily to clusters of discrete (<1 kb) segments. Consistent with the idea that Gro may facilitate communication between silencers and promoters, Gro binding is enriched at both cis-regulatory modules, as well as within the promotors of potential target genes. While this Gro-recruitment is required for repression, our data show that it is not sufficient for repression. Integration of Gro binding data with transcriptomic analysis suggests that, contrary to what has been observed for another Gro family member, Drosophila Gro is probably a dedicated repressor. This analysis also allows us to define a set of high confidence Gro repression targets. Using publically available data regarding the physical and genetic interactions between these targets, we are able to place them in the regulatory network controlling development. Through analysis of chromatin associated pre-mRNA levels at these targets, we find that genes regulated by Gro in the embryo are enriched for characteristics of promoter proximal paused RNA polymerase II.ConclusionsOur findings are inconsistent with a one-dimensional spreading model for long-range repression and suggest that Gro-mediated repression must be regulated at a post-recruitment step. They also show that Gro is likely a dedicated repressor that sits at a prominent highly interconnected regulatory hub in the developmental network. Furthermore, our findings suggest a role for RNA polymerase II pausing in Gro-mediated repression.

【 授权许可】

CC BY   
© The Author(s). 2017