| Structural highlights
Function
[SUZ12_DROME] Polycomb group (PcG) protein. While PcG proteins are generally required to maintain the transcriptionally repressive state of homeotic genes throughout development, this protein is specifically required during the first 6 hours of embryogenesis to establish the repressed state. Component of the Esc/E(z) complex, which methylates 'Lys-9' (H3K9me) and 'Lys-27' (H3K27me) of histone H3, leading to transcriptional repression of the affected target gene. The Esc/E(z) complex is necessary but not sufficient for the repression of homeotic target genes, suggesting that the recruitment of the distinct PRC1 complex is also required. [CAF1_DROME] Core histone-binding subunit that may target chromatin assembly factors, chromatin remodeling factors and histone deacetylases to their histone substrates in a manner that is regulated by nucleosomal DNA. Component of several complexes which regulate chromatin metabolism. These include the chromatin assembly factor 1 (CAF-1) complex, which is required for chromatin assembly following DNA replication and DNA repair; the nucleosome remodeling and deacetylase complex (the NuRD complex), which promotes transcriptional repression by histone deacetylation and nucleosome remodeling; the nucleosome remodeling factor (NURF) complex, which catalyzes ATP-dependent nucleosome sliding and facilitates transcription of chromatin; and the polycomb group (PcG) repressor complex ESC-E(Z), which promotes repression of homeotic genes during development. Also required for transcriptional repression of E2F target genes by E2f2 and Rbf or Rbf2.[1] [2] [3] [4] [5]
Publication Abstract from PubMed
The Polycomb repressive complex 2 (PRC2) confers transcriptional repression through histone H3 lysine 27 trimethylation (H3K27me3). Here, we examined how PRC2 is modulated by histone modifications associated with transcriptionally active chromatin. We provide the molecular basis of histone H3 N terminus recognition by the PRC2 Nurf55-Su(z)12 submodule. Binding of H3 is lost if lysine 4 in H3 is trimethylated. We find that H3K4me3 inhibits PRC2 activity in an allosteric fashion assisted by the Su(z)12 C terminus. In addition to H3K4me3, PRC2 is inhibited by H3K36me2/3 (i.e., both H3K36me2 and H3K36me3). Direct PRC2 inhibition by H3K4me3 and H3K36me2/3 active marks is conserved in humans, mouse, and fly, rendering transcriptionally active chromatin refractory to PRC2 H3K27 trimethylation. While inhibition is present in plant PRC2, it can be modulated through exchange of the Su(z)12 subunit. Inhibition by active chromatin marks, coupled to stimulation by transcriptionally repressive H3K27me3, enables PRC2 to autonomously template repressive H3K27me3 without overwriting active chromatin domains.
Histone Methylation by PRC2 Is Inhibited by Active Chromatin Marks.,Schmitges FW, Prusty AB, Faty M, Stutzer A, Lingaraju GM, Aiwazian J, Sack R, Hess D, Li L, Zhou S, Bunker RD, Wirth U, Bouwmeester T, Bauer A, Ly-Hartig N, Zhao K, Chan H, Gu J, Gut H, Fischle W, Muller J, Thoma NH Mol Cell. 2011 May 6;42(3):330-41. PMID:21549310[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Tyler JK, Bulger M, Kamakaka RT, Kobayashi R, Kadonaga JT. The p55 subunit of Drosophila chromatin assembly factor 1 is homologous to a histone deacetylase-associated protein. Mol Cell Biol. 1996 Nov;16(11):6149-59. PMID:8887645
- ↑ Martinez-Balbas MA, Tsukiyama T, Gdula D, Wu C. Drosophila NURF-55, a WD repeat protein involved in histone metabolism. Proc Natl Acad Sci U S A. 1998 Jan 6;95(1):132-7. PMID:9419341
- ↑ Gdula DA, Sandaltzopoulos R, Tsukiyama T, Ossipow V, Wu C. Inorganic pyrophosphatase is a component of the Drosophila nucleosome remodeling factor complex. Genes Dev. 1998 Oct 15;12(20):3206-16. PMID:9784495
- ↑ Beall EL, Manak JR, Zhou S, Bell M, Lipsick JS, Botchan MR. Role for a Drosophila Myb-containing protein complex in site-specific DNA replication. Nature. 2002 Dec 19-26;420(6917):833-7. PMID:12490953 doi:10.1038/nature01228
- ↑ Taylor-Harding B, Binne UK, Korenjak M, Brehm A, Dyson NJ. p55, the Drosophila ortholog of RbAp46/RbAp48, is required for the repression of dE2F2/RBF-regulated genes. Mol Cell Biol. 2004 Oct;24(20):9124-36. PMID:15456884 doi:10.1128/MCB.24.20.9124-9136.2004
- ↑ Schmitges FW, Prusty AB, Faty M, Stutzer A, Lingaraju GM, Aiwazian J, Sack R, Hess D, Li L, Zhou S, Bunker RD, Wirth U, Bouwmeester T, Bauer A, Ly-Hartig N, Zhao K, Chan H, Gu J, Gut H, Fischle W, Muller J, Thoma NH. Histone Methylation by PRC2 Is Inhibited by Active Chromatin Marks. Mol Cell. 2011 May 6;42(3):330-41. PMID:21549310 doi:10.1016/j.molcel.2011.03.025
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