A positive role for polycomb in transcriptional regulation via H4K20me1

Abstract

The highly conserved polycomb group (PcG) proteins maintain heritable transcription repression of the genes essential for development from fly to mammals. However, sporadic reports imply a potential role of PcGs in positive regulation of gene transcription, although systematic investigation of such function and the underlying mechanism has rarely been reported. Here, we report a Pc-mediated, H3K27me3-dependent positive transcriptional regulation of Senseless (Sens), a key transcription factor required for development. Mechanistic studies show that Pc regulates Sens expression by promoting H4K20me1 at the Sens locus. Further bioinformatic analysis at genome-wide level indicates that the existence of H4K20me1 acts as a selective mark for positive transcriptional regulation by Pc/H3K27me3. Both the intensities and specific patterns of Pc and H3K27me3 are important for the fates of target gene transcription. Moreover, binding of transcription factor Broad (Br), which physically interacts with Pc and positively regulates the transcription of Sens, is observed in Pc+H3K27me3+H4K20me1+ genes, but not in Pc+H3K27me3+H4K20me1− genes. Taken together, our study reveals that, coupling with the transcription factor Br, Pc positively regulates transcription of Pc+H3K27me3+H4K20me1+ genes in developing Drosophila wing disc.

Histone methylation changes are required for life cycle progression in the human parasite Schistosoma mansoni

“…e . female cercariae to female adults, we also performed ChIP-seq on H4K20me1, a mark associated with the transcriptional activation state and that could be involved in bivalency with repressive H3K27me3 in early vertebrate embryos [ 39 ]. Knowing that each histone mark has a specific profile, two set of parameters were used to detect small peaks (< 10 kb), as well as differences over ranges (10–100 kb) between cercariae and adults (detailed in Tables 2 and 3 ) .…”

Repression of Abd-B by Polycomb is critical for cell identity maintenance in adult Drosophila testis

“…Their malfunction may lead to the failure of stem cell identity maintenance or cancers 23 – 29 . Among them, Pc is a key component of canonical PRC1, which can recognize the H3K27me3 deposited by PRC2 via its chromodomain 26 , 30 , 31 . Several previous studies have demonstrated that Pc functions in various tissues and developmental stages via repressive or positive manners 24 , 26 , 32 – 35 .…”

Identification of human silencers by correlating cross-tissue epigenetic profiles and gene expression

“…Transcriptional dynamics during development and disease initiation have been attributed to H3K27me3 (Simon and Kingston 2009;Sexton et al 2012;Jiang et al 2013;Pinello et al 2014;Laprell et al 2017). Notwithstanding the fact that H3K27me3 is well-known as a modification of silencers, the regulatory contribution of H3K27me3 has been asserted to be context-dependent (Young et al 2011;Lv et al 2016). H3K27me3 and H3K4me1, simultaneously recruited by Polycomb repressive complex 2 (PRC2), collaborate to precisely fine-tune the expression of targeting genes in pluripotent cells (Mikkelsen et al 2007;Schwartz and Pirrotta 2008).…”