UHRF1 binds G9a and participates in p21 transcriptional regulation in mammalian cells

New England Biolabs, Ipswich, MA 01938-2723, USA.
Nucleic Acids Research (Impact Factor: 9.11). 02/2009; 37(2):493-505. DOI: 10.1093/nar/gkn961
Source: PubMed


UHRF1 (ubiquitin-like, containing PHD and RING finger domains 1) is a multi-domain protein associated with cellular proliferation
and epigenetic regulation. The UHRF1 binds to methylated CpG dinucleotides and recruits transcriptional repressors DNA methyltransferase
1 (DNMT1) and histone deacetylase 1 (HDAC1) through its distinct domains. However, the molecular basis of UHRF1-mediated transcriptional
regulation via chromatin modifications is yet to be fully understood. Here we show that UHRF1 binds histone lysine methyltransferase
G9a, and both are co-localized in the nucleus in a cell-cycle-dependent manner. Concurrent with the cell-cycle progression,
gradual deposition of UHRF1 and G9a was observed, which mirrored H3K9me2 accumulation on chromatin. Murine Uhrf1-null embryonic stem (ES) cells displayed a reduced amount of G9a and H3K9me2 on chromatin. UHRF1 recruited and cooperated
with G9a to inhibit the p21 promoter activity, which correlated with the elevated p21 protein level in both human UHRF1 siRNA-transfected
HeLa cells and murine Uhrf1-null ES cells. Furthermore, endogenous p21 promoter remained bound to UHRF1, G9a, DNMT1 and HDAC1, and knockdown of UHRF1
impaired the association of all three chromatin modifiers with the promoter. Thus, our results suggest that UHRF1 may serve
as a focal point of transcriptional regulation mediated by G9a and other chromatin modification enzymes.

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Available from: Pierre-Olivier Estève, Jan 13, 2014
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    • "Loss of Uhrf1 causes global DNA hypomethylation in human, mouse and zebrafish cells (Bostick et al., 2007; Feng et al., 2010; Hervouet et al., 2010; Sharif et al., 2007; Tittle et al., 2011). In addition, UHRF1 has been implicated in histone deacetylation (Achour et al., 2009; Papait et al., 2008; Unoki et al., 2004) and histone H3 trimethylation [H3K9me3 (Cheng et al., 2013; Kim et al., 2009; Rottach et al., 2010; Fig. 4 "

    Full-text · Article · Jan 2015 · Development
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    • "H3K4 and H3K27 methylation appear to be maintained on newly-synthesised DNA by association of the respective methyltransferases (TrxG and PcG complexes) with DNA through the replication fork [169] [170]. By contrast, it seems that Uhrf1 and Dnmt1 contribute to the maintenance of H3K9 methylation through interactions with H3K9 methyltransferases [108] [109] [110]. There is thus emerging evidence for complex interactions between histone and DNA methylation in the maintenance of heterochromatin during DNA replication. "
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    ABSTRACT: DNA methylation acts as an epigenetic modification in vertebrate DNA. Recently it has become clear that the DNA and histone lysine methylation systems are highly interrelated and rely mechanistically on each other for normal chromatin function in vivo. Here we examine some of the functional links between these systems, with a particular focus on several recent discoveries suggesting how lysine methylation may help to target DNA methylation during development, and vice versa. In addition, the emerging role of non-methylated DNA found in CpG islands in defining histone lysine methylation profiles at gene regulatory elements will be discussed in the context of gene regulation. This article is part of a Special Issue entitled: Methylation: A Multifaceted Modification looking at transcription and beyond. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license
    Full-text · Article · Dec 2014 · Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanisms
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    • "Similarly to H3K27 methylation, NuRD activity seems important for deacetylation of H3K9 that promotes methylation and the formation of silent chromatin containing H3K9me3 (51,52). Our finding of a H3K9 methylation associated to DNA replication is consistent with the identification of G9a/EHMT2, which associates with UHRF1 (34,53), and SETDB1 methyltransferases at the replication fork in our and other studies (54,55). The failure of H3K9 methylation during replication after VPA treatment suggests that licensing by deacetylation precedes and is required for methylation and the formation of silenced chromatin. "
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    ABSTRACT: Pluripotency of embryonic stem cells (ESCs) is maintained by transcriptional activities and chromatin modifying complexes highly organized within the chromatin. Although much effort has been focused on identifying genome-binding sites, little is known on their dynamic association with chromatin across cell divisions. Here, we used a modified version of the iPOND (isolation of proteins at nascent DNA) technology to identify a large protein network enriched at nascent DNA in ESCs. This comprehensive and unbiased proteomic characterization in ESCs reveals that, in addition to the core replication machinery, proteins relevant for pluripotency of ESCs are present at DNA replication sites. In particular, we show that the chromatin remodeller HDAC1–NuRD complex is enriched at nascent DNA. Interestingly, an acute block of HDAC1 in ESCs leads to increased acetylation of histone H3 lysine 9 at nascent DNA together with a concomitant loss of methylation. Consistently, in contrast to what has been described in tumour cell lines, these chromatin marks were found to be stable during cell cycle progression of ESCs. Our results are therefore compatible with a rapid deacetylation-coupled methylation mechanism during the replication of DNA in ESCs that may participate in the preservation of pluripotency of ESCs during replication.
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