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Boston AM, Dwead AM, Al-Mathkour MM, Khazaw K, Zou J, Zhang Q, Wang G, Cinar B. Discordant interactions between YAP1 and polycomb group protein SCML2 determine cell fate. iScience 2023; 26:107964. [PMID: 37810219 PMCID: PMC10558808 DOI: 10.1016/j.isci.2023.107964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 05/25/2023] [Accepted: 09/15/2023] [Indexed: 10/10/2023] Open
Abstract
The Polycomb group protein SCML2 and the transcriptional cofactor YAP1 regulate diverse cellular biology, including stem cell maintenance, developmental processes, and gene regulation in mammals and flies. However, their molecular and functional interactions are unknown. Here, we show that SCML2 interacts with YAP1, as revealed by immunological assays and mass spectroscopy. We have demonstrated that the steroid hormone androgen regulates the interaction of SCML2 with YAP1 in human tumor cell models. Our proximity ligation assay and GST pulldown showed that SCML2 and YAP1 physically interacted with each other. Silencing SCML2 by RNAi changed the growth behaviors of cells in response to androgen signaling. Mechanistically, this phenomenon is attributed to the interplay between distinct chromatin modifications and transcriptional programs, likely coordinated by the opposing SCML2 and YAP1 activity. These findings suggest that YAP1 and SCML2 cooperate to regulate cell growth, cell survival, and tumor biology downstream of steroid hormones.
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Affiliation(s)
- Ava M Boston
- Department of Biological Sciences, Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA, USA
| | - Abdulrahman M Dwead
- Department of Biological Sciences, Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA, USA
| | - Marwah M Al-Mathkour
- Department of Biological Sciences, Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA, USA
| | - Kezhan Khazaw
- Department of Biological Sciences, Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA, USA
| | - Jin Zou
- Department of Biological Sciences, Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA, USA
| | - Qiang Zhang
- Department of Chemistry, Xavier University of Louisiana, New Orleans, LA, USA
| | - Guangdi Wang
- Department of Chemistry, Xavier University of Louisiana, New Orleans, LA, USA
| | - Bekir Cinar
- Department of Biological Sciences, Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA, USA
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2
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Sehrawat P, Shobhawat R, Kumar A. Catching Nucleosome by Its Decorated Tails Determines Its Functional States. Front Genet 2022; 13:903923. [PMID: 35910215 PMCID: PMC9329655 DOI: 10.3389/fgene.2022.903923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 06/07/2022] [Indexed: 11/13/2022] Open
Abstract
The fundamental packaging unit of chromatin, i.e., nucleosome, consists of ∼147 bp of DNA wrapped around a histone octamer composed of the core histones, H2A, H2B, H3, and H4, in two copies each. DNA packaged in nucleosomes must be accessible to various machineries, including replication, transcription, and DNA damage repair, implicating the dynamic nature of chromatin even in its compact state. As the tails protrude out of the nucleosome, they are easily accessible to various chromatin-modifying machineries and undergo post-translational modifications (PTMs), thus playing a critical role in epigenetic regulation. PTMs can regulate chromatin states via charge modulation on histones, affecting interaction with various chromatin-associated proteins (CAPs) and DNA. With technological advancement, the list of PTMs is ever-growing along with their writers, readers, and erasers, expanding the complexity of an already intricate epigenetic field. In this review, we discuss how some of the specific PTMs on flexible histone tails affect the nucleosomal structure and regulate the accessibility of chromatin from a mechanistic standpoint and provide structural insights into some newly identified PTM–reader interaction.
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SWI/SNF subunit BAF155 N-terminus structure informs the impact of cancer-associated mutations and reveals a potential drug binding site. Commun Biol 2021; 4:528. [PMID: 33953332 PMCID: PMC8099880 DOI: 10.1038/s42003-021-02050-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 03/26/2021] [Indexed: 01/13/2023] Open
Abstract
SWI/SNF (BAF) chromatin remodelling complexes are key regulators of gene expression programs, and attractive drug targets for cancer therapies. Here we show that the N-terminus of the BAF155/SMARCC1 subunit contains a putative DNA-binding MarR-like domain, a chromodomain and a BRCT domain that are interconnected to each other to form a distinct module. In this structure the chromodomain makes interdomain interactions and has lost its canonical function to bind to methylated lysines. The structure provides new insights into the missense mutations that target this module in cancer. This study also reveals two adjacent, highly-conserved pockets in a cleft between the domains that form a potential binding site, which can be targeted with small molecules, offering a new strategy to target SWI/SNF complexes. Allen et al. determine crystal structure of the N-terminus of SWI/SNF chromatin remodelling factor subunit BAF155. They identify an interconnected structure of MarR-like, BRCT and chromodomains, visualise the potential effect of cancer-associated missense mutations and suggest a binding site and target for small molecule inhibitors.
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Stützer A, Welp LM, Raabe M, Sachsenberg T, Kappert C, Wulf A, Lau AM, David SS, Chernev A, Kramer K, Politis A, Kohlbacher O, Fischle W, Urlaub H. Analysis of protein-DNA interactions in chromatin by UV induced cross-linking and mass spectrometry. Nat Commun 2020; 11:5250. [PMID: 33067435 PMCID: PMC7567871 DOI: 10.1038/s41467-020-19047-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 09/24/2020] [Indexed: 02/08/2023] Open
Abstract
Protein–DNA interactions are key to the functionality and stability of the genome. Identification and mapping of protein–DNA interaction interfaces and sites is crucial for understanding DNA-dependent processes. Here, we present a workflow that allows mass spectrometric (MS) identification of proteins in direct contact with DNA in reconstituted and native chromatin after cross-linking by ultraviolet (UV) light. Our approach enables the determination of contact interfaces at amino-acid level. With the example of chromatin-associated protein SCML2 we show that our technique allows differentiation of nucleosome-binding interfaces in distinct states. By UV cross-linking of isolated nuclei we determined the cross-linking sites of several factors including chromatin-modifying enzymes, demonstrating that our workflow is not restricted to reconstituted materials. As our approach can distinguish between protein–RNA and DNA interactions in one single experiment, we project that it will be possible to obtain insights into chromatin and its regulation in the future. Cross-linking mass spectrometry (XLMS) allows mapping of protein-protein and protein-RNA interactions, but the analysis of protein-DNA complexes remains challenging. Here, the authors develop a UV light-based XLMS workflow to determine protein-DNA interfaces in reconstituted chromatin and isolated nuclei.
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Affiliation(s)
- Alexandra Stützer
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Luisa M Welp
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Monika Raabe
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Timo Sachsenberg
- Institute for Bioinformatics and Medical Informatics, University of Tübingen, 72076, Tübingen, Germany.,Applied Bioinformatics, Department for Computer Science, University of Tübingen, 72076, Tübingen, Germany
| | - Christin Kappert
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany.,Somatosensory Signaling and Systems Biology Group, Max Planck Institute of Experimental Medicine, 37075, Göttingen, Germany
| | - Alexander Wulf
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Andy M Lau
- Department of Chemistry, King's College London, London, SE1 1DB, UK
| | - Stefan-Sebastian David
- Laboratory of Chromatin Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany.,King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division, Laboratory of Chromatin Biochemistry, 23955, Thuwal, Saudi Arabia
| | - Aleksandar Chernev
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | | | - Argyris Politis
- Department of Chemistry, King's College London, London, SE1 1DB, UK
| | - Oliver Kohlbacher
- Institute for Bioinformatics and Medical Informatics, University of Tübingen, 72076, Tübingen, Germany.,Applied Bioinformatics, Department for Computer Science, University of Tübingen, 72076, Tübingen, Germany.,Institute for Translational Bioinformatics, University Hospital Tübingen, 72076, Tübingen, Germany.,Biomolecular Interactions, Max Planck Institute for Developmental Biology, 72076, Tübingen, Germany
| | - Wolfgang Fischle
- Laboratory of Chromatin Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany.,King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division, Laboratory of Chromatin Biochemistry, 23955, Thuwal, Saudi Arabia
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany. .,Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center Göttingen, 37075, Göttingen, Germany.
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Molecular basis of PRC1 targeting to Polycomb response elements by PhoRC. Genes Dev 2017; 30:1116-27. [PMID: 27151979 PMCID: PMC4863741 DOI: 10.1101/gad.279141.116] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 04/13/2016] [Indexed: 12/11/2022]
Abstract
Here, Frey et al. report the structural basis by which the Drosophila Pho-repressive complex (PhoRC), the only Polycomb group protein complex with sequence-specific DNA-binding activity, binds to Polycomb-repressive complex 1 (PRC1) and thereby recruits it to Polycomb response elements in target genes. Polycomb group (PcG) protein complexes repress transcription by modifying target gene chromatin. In Drosophila, this repression requires association of PcG protein complexes with cis-regulatory Polycomb response elements (PREs), but the interactions permitting formation of these assemblies are poorly understood. We show that the Sfmbt subunit of the DNA-binding Pho-repressive complex (PhoRC) and the Scm subunit of the canonical Polycomb-repressive complex 1 (PRC1) directly bind each other through their SAM domains. The 1.9 Å crystal structure of the Scm-SAM:Sfmbt-SAM complex reveals the recognition mechanism and shows that Sfmbt-SAM lacks the polymerization capacity of the SAM domains of Scm and its PRC1 partner subunit, Ph. Functional analyses in Drosophila demonstrate that Sfmbt-SAM and Scm-SAM are essential for repression and that PhoRC DNA binding is critical to initiate PRC1 association with PREs. Together, this suggests that PRE-tethered Sfmbt-SAM nucleates PRC1 recruitment and that Scm-SAM/Ph-SAM-mediated polymerization then results in the formation of PRC1-compacted chromatin.
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Structural aspects of small-molecule inhibition of methyllysine reader proteins. Future Med Chem 2016; 8:1681-702. [PMID: 27577975 DOI: 10.4155/fmc-2016-0082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Methyl reader proteins recognize and bind to post-translationally methylated residues. They execute the commands issued by protein methyltransferases and play functional roles in diverse cellular processes including gene regulation, development and oncogenesis. Efforts to inhibit these proteins are relatively new. Only a small number of methyl reader proteins belonging to the chromodomain, malignant brain tumor domain, plant homeodomain finger and Tudor domain families have been targeted by chemical inhibitors. This review summarizes inhibitors that have been reported to date, and provides a perspective for future progress. Structural determinants for methyl reader inhibition will be presented, along with an analysis of the molecular interactions that control potency and selectivity for inhibitors of each family.
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Guo J, Jin D. A genetic screen in Drosophila implicates Sex comb on midleg (Scm) in tissue overgrowth and mechanisms of Scm degradation by Wds. Mech Dev 2015; 136:1-7. [PMID: 25772304 DOI: 10.1016/j.mod.2015.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 03/04/2015] [Accepted: 03/05/2015] [Indexed: 11/30/2022]
Abstract
The sex comb on midleg (scm) gene encodes a transcriptional repressor and belongs to the Polycomb group (PcG) of genes, which regulates growth in Drosophila. Scm interacts with Polyhomeotic (a PcG protein) in vitro by recognizing its SPM domain. The homologous human protein, Sex comb on midleg-like 2 (Scml2), has been implicated in malignant brain tumors. Will die slowly (Wds) is another factor that regulates Drosophila development, and its homologous human protein, WD repeat domain 5(Wdr5), is part of the mixed lineage leukemia 1(MLL1) complex that promotes histone H3Lys4 methylation. Like Scml2, Wdr5 has been implicated in certain cancers; this protein plays an important role in leukemogenesis. In this study, we find that loss-of-function mutations in Scm result in non-autonomous tissue overgrowth in Drosophila, and determine that Scm is essential for ommatidium development and important for cell survival in Drosophila. Furthermore, our research suggests a relationship between Wds and Scm; Wds promotes Scm degradation through ubiquitination in vitro in Drosophila.
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Affiliation(s)
- Jiwei Guo
- College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Dan Jin
- College of Life Sciences, Nankai University, Tianjin 300071, China
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Polycomb protein SCML2 associates with USP7 and counteracts histone H2A ubiquitination in the XY chromatin during male meiosis. PLoS Genet 2015; 11:e1004954. [PMID: 25634095 PMCID: PMC4310598 DOI: 10.1371/journal.pgen.1004954] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 12/12/2014] [Indexed: 11/19/2022] Open
Abstract
Polycomb group proteins mediate transcriptional silencing in diverse developmental processes. Sex chromosomes undergo chromosome-wide transcription silencing during male meiosis. Here we report that mouse SCML2 (Sex comb on midleg-like 2), an X chromosome-encoded polycomb protein, is specifically expressed in germ cells, including spermatogonia, spermatocytes, and round spermatids. SCML2 associates with phosphorylated H2AX and localizes to the XY body in spermatocytes. Loss of SCML2 in mice causes defective spermatogenesis, resulting in sharply reduced sperm production. SCML2 interacts with and recruits a deubiquitinase, USP7, to the XY body in spermatocytes. In the absence of SCML2, USP7 fails to accumulate on the XY body, whereas H2A monoubiquitination is dramatically augmented in the XY chromatin. Our results demonstrate that the SCML2/USP7 complex constitutes a novel molecular pathway in modulating the epigenetic state of sex chromosomes during male meiosis.
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Meier K, Brehm A. Chromatin regulation: how complex does it get? Epigenetics 2014; 9:1485-95. [PMID: 25482055 PMCID: PMC4622878 DOI: 10.4161/15592294.2014.971580] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 08/18/2014] [Accepted: 09/29/2014] [Indexed: 12/16/2022] Open
Abstract
Gene transcription is tightly regulated at different levels to ensure that the transcriptome of the cell is appropriate for developmental stage and cell type. The chromatin state in which a gene is embedded determines its expression level to a large extent. Activation or repression of transcription is typically accomplished by the recruitment of chromatin-associated multisubunit protein complexes that combine several molecular tools, such as histone-binding and chromatin-modifying activities. Recent biochemical purifications of such complexes have revealed a substantial diversity. On the one hand, complexes that were thought to be unique have been revealed to be part of large complex families. On the other hand, protein subunits that were thought to only exist in separate complexes have been shown to coexist in novel assemblies. In this review we discuss our current knowledge of repressor complexes that contain MBT domain proteins and/or the CoREST co-repressor and use them as a paradigm to illustrate the unexpected heterogeneity and tool sharing of chromatin regulating protein complexes. These recent insights also challenge the ways we define and think about protein complexes in general.
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Key Words
- ATP, adenosine triphosphate
- BAP, brahma associated protein
- BHC80, BRAF-histone deacetylase complex 80
- BRG1, brahma Related Gene 1
- CHD, chromo domain helicase DNA binding
- CoREST
- CoREST REST, corepressor
- DNA, deoxyribonucleic acid
- DNMT, DNA methyltransferase
- DP-1, dimerization partner 1
- E2F, E2 transcription Factor
- ELM2, EGL-27 and MTA1 homology 2
- ES cell, embryonic stem cells
- H, histone
- HDAC, histone deacetylas
- HMTase, histone methylase
- HP1, heterochromatin protein 1
- K, lysine
- L3MBTL, lethal 3 malignant brain tumor-like
- LINT, l(3)mbt interacting
- LSD1, lysine-specific demethylase 1
- Lint-1, l(3)mbt interacting 1
- MBT protein
- MBT, malignant brain tumor
- MBTS, malignant brain tumor signature
- NPA1, nucleosome assembly protein
- NRSF, neural-restrictive silencing factor
- NuRD, nucleosome remodeling and deacetylase
- PBAP, polybromo-associated BAP
- PHD, plant homeo domain
- PRC1, polycomb repressive complex 1
- PRE, polycomb responsive element
- Pc, polycomb
- PcG, polycomb group
- Ph, polyhomeotic
- Pho, pleiohomeotic
- PhoRC, Pho repressive complex
- Psc, posterior sex combs
- RB, retinoblastoma
- REST, repressor element 1 silencing transcription factor
- RNA, ribonucleic acid
- Rpd3, reduced potassium dependency 3
- SANT, SWI/ADA2/N-CoR/TFIIIB
- SCML, sex combs on midleg-like
- SLC, SFMBT1, LSD1, CoREST
- SWH, Salvador-Warts-Hippo
- SWI/SNF, switching defective/sucrose non-fermenting
- Sce, sex combs extra
- Scm, sex combs on midleg
- Sfmbt, Scm-related gene containing 4 mbt domains
- TSS, transcription start site
- YY1, ying-yang 1
- ZNF, zinc finger
- complex family
- dL(3)mbt, Drosophila Lethal 3 malignant brain tumor
- hBRM, human Brahma
- l(3)mbt, lethal 3 malignant brain tumor
- protein complex
- transcriptional regulation
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Affiliation(s)
- Karin Meier
- Institut für Molekularbiologie und Tumorforschung; Philipps-Universität Marburg; Marburg, Germany
- Instituto de Fisiología Celular; Departamento de Genética Molecular; Universidad Nacional Autónoma de México; México City, México
| | - Alexander Brehm
- Institut für Molekularbiologie und Tumorforschung; Philipps-Universität Marburg; Marburg, Germany
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Bonasio R, Lecona E, Narendra V, Voigt P, Parisi F, Kluger Y, Reinberg D. Interactions with RNA direct the Polycomb group protein SCML2 to chromatin where it represses target genes. eLife 2014; 3:e02637. [PMID: 24986859 PMCID: PMC4074974 DOI: 10.7554/elife.02637] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Polycomb repressive complex-1 (PRC1) is essential for the epigenetic regulation of gene expression. SCML2 is a mammalian homolog of Drosophila SCM, a Polycomb-group protein that associates with PRC1. In this study, we show that SCML2A, an SCML2 isoform tightly associated to chromatin, contributes to PRC1 localization and also directly enforces repression of certain Polycomb target genes. SCML2A binds to PRC1 via its SPM domain and interacts with ncRNAs through a novel RNA-binding region (RBR). Targeting of SCML2A to chromatin involves the coordinated action of the MBT domains, RNA binding, and interaction with PRC1 through the SPM domain. Deletion of the RBR reduces the occupancy of SCML2A at target genes and overexpression of a mutant SCML2A lacking the RBR causes defects in PRC1 recruitment. These observations point to a role for ncRNAs in regulating SCML2 function and suggest that SCML2 participates in the epigenetic control of transcription directly and in cooperation with PRC1.DOI: http://dx.doi.org/10.7554/eLife.02637.001.
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Affiliation(s)
- Roberto Bonasio
- Department of Biochemistry and Molecular Pharmacology, Howard Hughes Medical Institute, New York University School of Medicine, New York, United States
| | - Emilio Lecona
- Department of Biochemistry and Molecular Pharmacology, Howard Hughes Medical Institute, New York University School of Medicine, New York, United States
| | - Varun Narendra
- Department of Biochemistry and Molecular Pharmacology, Howard Hughes Medical Institute, New York University School of Medicine, New York, United States
| | - Philipp Voigt
- Department of Biochemistry and Molecular Pharmacology, Howard Hughes Medical Institute, New York University School of Medicine, New York, United States
| | - Fabio Parisi
- Department of Pathology, Yale University School of Medicine, New Haven, United States Yale Cancer Center, Yale University School of Medicine, New Haven, United States
| | - Yuval Kluger
- Department of Pathology, Yale University School of Medicine, New Haven, United States Yale Cancer Center, Yale University School of Medicine, New Haven, United States
| | - Danny Reinberg
- Department of Biochemistry and Molecular Pharmacology, Howard Hughes Medical Institute, New York University School of Medicine, New York, United States
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Bezsonova I. Solution NMR structure of the DNA-binding domain from Scml2 (sex comb on midleg-like 2). J Biol Chem 2014; 289:15739-49. [PMID: 24727478 DOI: 10.1074/jbc.m113.524009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Scml2 is a member of the Polycomb group of proteins involved in epigenetic gene silencing. Human Scml2 is a part of a multisubunit protein complex, PRC1 (Polycomb repressive complex 1), which is responsible for maintenance of gene repression, prevention of chromatin remodeling, preservation of the "stemness" of the cell, and cell differentiation. Although the majority of PRC1 subunits have been recently characterized, the structure of Scml2 and its role in PRC1-mediated gene silencing remain unknown. In this work a conserved protein domain within human Scml2 has been identified, and its structure was determined by solution NMR spectroscopy. This module was named Scm-like embedded domain, or SLED. Evolutionarily, the SLED domain emerges in the first multicellular organisms, consistent with the role of Scml2 in cell differentiation. Furthermore, it is exclusively found within the Scm-like family of proteins, often accompanied by malignant brain tumor domain (MBT) and sterile α motif (SAM) domains. The domain adopts a novel α/β fold with no structural analogues found in the Protein Data Bank (PDB). The ability of the SLED to bind double-stranded DNA was also examined, and the isolated domain was shown to interact with DNA in a sequence-specific manner. Because PRC1 complexes localize to the promoters of a specific subset of developmental genes in vivo, the SLED domain of Scml2 may provide an important link connecting the PRC1 complexes to their target genes.
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Affiliation(s)
- Irina Bezsonova
- From the Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, 06032-3305
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12
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Rapp C, Goldberger E, Tishbi N, Kirshenbaum R. Cation-π interactions of methylated ammonium ions: a quantum mechanical study. Proteins 2014; 82:1494-502. [PMID: 24464782 DOI: 10.1002/prot.24519] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 01/12/2014] [Accepted: 01/16/2014] [Indexed: 11/05/2022]
Abstract
Cation-π interactions of methylated ammonium ions play a key role in a broad range of biochemical systems. These include methyl-lysine binding proteins which bind to methylated sites on histone proteins, lysine demethylase enzymes which demethylate these sites, and neurotransmitter receptor complexes which bind choline-derived ligands. Recognition in these systems is achieved through an 'aromatic cage' motif in the binding site. Here we use high-level quantum mechanical calculations to address how cation-π interactions of methylated ammonium ions are modulated by a change in methylation state and interaction geometry. We survey methyl-lysine and choline-derived complexes in the Protein Databank to validate our results against available structural data. A quantitative description of cation-π interactions of methylated ammonium systems is critical to structure-based efforts to target methyl-lysine binding proteins and demethylase enzymes in the treatment of unregulated transcriptional control, and neurotransmitter receptors in the treatment of neurological disease. It is our hope that our work will serve as a benchmark for the development of physical chemistry based force fields that can accurately model the contribution of cation-π interactions to binding and specificity in these systems.
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Affiliation(s)
- Chaya Rapp
- Department of Chemistry and Biochemistry, Stern College for Women, Yeshiva University, New York, New York
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13
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Stielow C, Stielow B, Finkernagel F, Scharfe M, Jarek M, Suske G. SUMOylation of the polycomb group protein L3MBTL2 facilitates repression of its target genes. Nucleic Acids Res 2013; 42:3044-58. [PMID: 24369422 PMCID: PMC3950706 DOI: 10.1093/nar/gkt1317] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Lethal(3) malignant brain tumour like 2 (L3MBTL2) is an integral component of the polycomb repressive complex 1.6 (PRC1.6) and has been implicated in transcriptional repression and chromatin compaction. Here, we show that L3MBTL2 is modified by SUMO2/3 at lysine residues 675 and 700 close to the C-terminus. SUMOylation of L3MBTL2 neither affected its repressive activity in reporter gene assays nor it’s binding to histone tails in vitro. In order to analyse whether SUMOylation affects binding of L3MBTL2 to chromatin, we performed ChIP-Seq analysis with chromatin of wild-type HEK293 cells and with chromatin of HEK293 cells stably expressing either FLAG-tagged SUMOylation-competent or SUMOylation-defective L3MBTL2. Wild-type FLAG-L3MBTL2 and the SUMOylation-defective FLAG-L3MBTL2 K675/700R mutant essentially occupied the same sites as endogenous L3MBTL2 suggesting that SUMOylation of L3MBTL2 does not affect chromatin binding. However, a subset of L3MBTL2-target genes, particularly those with low L3MBTL2 occupancy including pro-inflammatory genes, was de-repressed in cells expressing the FLAG-L3MBTL2 K675/700R mutant. Finally, we provide evidence that SUMOylation of L3MBTL2 facilitates repression of these PRC1.6-target genes by balancing the local H2Aub1 levels established by the ubiquitinating enzyme RING2 and the de-ubiquitinating PR–DUB complex.
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Affiliation(s)
- Christina Stielow
- Institute of Molecular Biology and Tumor Research, Philipps-University, Emil-Mannkopff-Str. 2, D-35032 Marburg and Helmholtz Centre for Infection Research (HZI), Inhoffenstraße 7, D-38124 Braunschweig, Germany
| | - Bastian Stielow
- Institute of Molecular Biology and Tumor Research, Philipps-University, Emil-Mannkopff-Str. 2, D-35032 Marburg and Helmholtz Centre for Infection Research (HZI), Inhoffenstraße 7, D-38124 Braunschweig, Germany
| | - Florian Finkernagel
- Institute of Molecular Biology and Tumor Research, Philipps-University, Emil-Mannkopff-Str. 2, D-35032 Marburg and Helmholtz Centre for Infection Research (HZI), Inhoffenstraße 7, D-38124 Braunschweig, Germany
| | - Maren Scharfe
- Institute of Molecular Biology and Tumor Research, Philipps-University, Emil-Mannkopff-Str. 2, D-35032 Marburg and Helmholtz Centre for Infection Research (HZI), Inhoffenstraße 7, D-38124 Braunschweig, Germany
| | - Michael Jarek
- Institute of Molecular Biology and Tumor Research, Philipps-University, Emil-Mannkopff-Str. 2, D-35032 Marburg and Helmholtz Centre for Infection Research (HZI), Inhoffenstraße 7, D-38124 Braunschweig, Germany
| | - Guntram Suske
- Institute of Molecular Biology and Tumor Research, Philipps-University, Emil-Mannkopff-Str. 2, D-35032 Marburg and Helmholtz Centre for Infection Research (HZI), Inhoffenstraße 7, D-38124 Braunschweig, Germany
- *To whom correspondence should be addressed. Tel: +49 6421 2866697; Fax +49 6421 2865959;
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14
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Astakhova IK, Hansen LH, Vester B, Wengel J. Peptide-LNA oligonucleotide conjugates. Org Biomol Chem 2013; 11:4240-9. [PMID: 23681061 DOI: 10.1039/c3ob40786a] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Although peptide-oligonucleotide conjugates (POCs) are well-known for nucleic acids delivery and therapy, reports on internal attachment of peptides to oligonucleotides are limited in number. To develop a convenient route for preparation of internally labeled POCs with improved biomedical properties, peptides were introduced into oligonucleotides via a 2'-alkyne-2'-amino-LNA scaffold. Derivatives of methionine- and leucine-enkephalins were chosen as model peptides of mixed amino acid content, which were singly and doubly incorporated into LNA/DNA strands using highly efficient copper(i)-catalyzed azide-alkyne cycloaddition (CuAAC) "click" chemistry. DNA/RNA target binding affinity and selectivity of the resulting POCs were improved in comparison to LNA/DNA mixmers and unmodified DNA controls. This clearly demonstrates that internal attachment of peptides to oligonucleotides can significantly improve biomolecular recognition by synthetic nucleic acid analogues. Circular dichroism (CD) measurements showed no distortion of the duplex structure by the incorporated peptide chains while studies in human serum indicated superior stability of the POCs compared to LNA/DNA mixmers and unmodified DNA references. Molecular modeling suggests strong interactions between positively charged regions of the peptides and the negative oligonucleotide backbones which leads to clamping of the peptides in a fixed orientation along the duplexes.
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Affiliation(s)
- I Kira Astakhova
- Nucleic Acid Center and the Biomolecular Nanoscale Engineering Center, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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15
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Santiveri CM, Sborgi L, de Alba E. Nuclear magnetic resonance study of protein-protein interactions involving apoptosis regulator Diva (Boo) and the BH3 domain of proapoptotic Bcl-2 members. J Mol Recognit 2013. [PMID: 23192964 DOI: 10.1002/jmr.2240] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
According to biochemical assays, the Bcl-2 protein Diva from mouse regulates programmed cell death by heterodimerizing with other members of the family and by interacting with the apoptotic protease-activating factor Apaf-1. In typical Bcl-2 heterodimers, peptide fragments comprising the Bcl-2 homology domain 3 (BH3 domain) of proapoptotic members are capable of forming functional complexes with prosurvival proteins. High-resolution structural studies have revealed that the BH3 peptide forms an α-helix positioned in a canonical hydrophobic cleft of the antiapoptotic protein. Because Diva shows mutations in conserved residues within this area, it has been proposed to have a different interacting surface. However, we showed previously that Diva binds through the canonical groove the BH3 peptide of the human Bcl-2 killing member Harakiri. To further test Diva's binding capabilities, here we show Nuclear Magnetic Resonance (NMR) data, indicating that Diva binds peptides derived from the BH3 domain of several other proapoptotic Bcl-2 proteins, including mouse Harakiri, Bid, Bak and Bmf. We have measured the binding affinities of the heterodimers, which show significant variability. Structural models of the protein-peptide complexes based on NMR chemical shift perturbation data indicate that the binding surface is analogous. These models do not rely on NMR NOE (Nuclear Overhauser Effect) data, and thus our results can only suggest that the complexes share similar intermolecular interactions. However, the observed affinity differences correlate with the α-helical population of the BH3-peptides obtained from circular dichroism experiments, which highlights a role of conformational selection in the binding mechanism. Altogether, our results shed light on important factors governing Diva-BH3 peptide molecular recognition mode.
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Affiliation(s)
- Clara M Santiveri
- Chemical and Physical Biology Department, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, Madrid, 28040, Spain
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16
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Nady N, Krichevsky L, Zhong N, Duan S, Tempel W, Amaya MF, Ravichandran M, Arrowsmith CH. Histone recognition by human malignant brain tumor domains. J Mol Biol 2012; 423:702-18. [PMID: 22954662 DOI: 10.1016/j.jmb.2012.08.022] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 08/27/2012] [Accepted: 08/27/2012] [Indexed: 10/27/2022]
Abstract
Histone methylation has emerged as an important covalent modification involved in a variety of biological processes, especially regulation of transcription and chromatin dynamics. Lysine methylation is found in three distinct states (monomethylation, dimethylation and trimethylation), which are recognized by specific protein domains. The malignant brain tumor (MBT) domain is one such module found in several chromatin regulatory complexes including Polycomb repressive complex 1. Here, we present a comprehensive characterization of the human MBT family with emphasis on histone binding specificity. SPOT-blot peptide arrays were used to screen for the methyllysine-containing histone peptides that bind to MBT domains found in nine human proteins. Selected interactions were quantified using fluorescence polarization assays. We show that all MBT proteins recognize only monomethyllysine and/or dimethyllysine marks and provide evidence that some MBT domains recognize a defined consensus sequence while others bind in a promiscuous, non-sequence-specific manner. Furthermore, using structure-based mutants, we identify a triad of residues in the methyllysine binding pocket that imparts discrimination between monomethyllysine and dimethyllysine. This study represents a comprehensive analysis of MBT substrate specificity, establishing a foundation for the rational design of selective MBT domain inhibitors that may enable elucidation of their role in human biology and disease.
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Affiliation(s)
- Nataliya Nady
- Ontario Cancer Institute, Campbell Family Cancer Research Institute and Department of Medical Biophysics, University of Toronto, 101 College Street, Toronto, ON, Canada M5G 1L7
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17
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Herold JM, Ingerman LA, Gao C, Frye SV. Drug discovery toward antagonists of methyl-lysine binding proteins. CURRENT CHEMICAL GENOMICS 2011; 5:51-61. [PMID: 22145013 PMCID: PMC3229088 DOI: 10.2174/1875397301005010051] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 02/22/2011] [Accepted: 04/25/2011] [Indexed: 12/04/2022]
Abstract
The recognition of methyl-lysine and -arginine residues on both histone and other proteins by specific "reader" elements is important for chromatin regulation, gene expression, and control of cell-cycle progression. Recently the crucial role of these reader proteins in cancer development and dedifferentiation has emerged, owing to the increased interest among the scientific community. The methyl-lysine and -arginine readers are a large and very diverse set of effector proteins and targeting them with small molecule probes in drug discovery will inevitably require a detailed understanding of their structural biology and mechanism of binding. In the following review, the critical elements of methyl-lysine and -arginine recognition will be summarized with respect to each protein family and initial results in assay development, probe design, and drug discovery will be highlighted.
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Affiliation(s)
| | | | | | - Stephen V Frye
- Center for Integrated Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, Division of Medicinal Chemistry and Natural Products, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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18
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L3MBTL2 protein acts in concert with PcG protein-mediated monoubiquitination of H2A to establish a repressive chromatin structure. Mol Cell 2011; 42:438-50. [PMID: 21596310 DOI: 10.1016/j.molcel.2011.04.004] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2010] [Revised: 02/01/2011] [Accepted: 03/31/2011] [Indexed: 01/15/2023]
Abstract
We have identified human MBT domain-containing protein L3MBTL2 as an integral component of a protein complex that we termed Polycomb repressive complex 1 (PRC1)-like 4 (PRC1L4), given the copresence of PcG proteins RING1, RING2, and PCGF6/MBLR. PRC1L4 also contained E2F6 and CBX3/HP1γ, known to function in transcriptional repression. PRC1L4-mediated repression necessitated L3MBTL2 that compacted chromatin in a histone modification-independent manner. Genome-wide location analyses identified several hundred genes simultaneously bound by L3MBTL2 and E2F6, preferentially around transcriptional start sites that exhibited little overlap with those targeted by other E2Fs or by L3MBTL1, another MBT domain-containing protein that interacts with RB1. L3MBTL2-specific RNAi resulted in increased expression of target genes that exhibited a significant reduction in H2A lysine 119 monoubiquitination. Our findings highlight a PcG/MBT collaboration that attains repressive chromatin without entailing histone lysine methylation marks.
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19
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Nady N, Lemak A, Walker JR, Avvakumov GV, Kareta MS, Achour M, Xue S, Duan S, Allali-Hassani A, Zuo X, Wang YX, Bronner C, Chédin F, Arrowsmith CH, Dhe-Paganon S. Recognition of multivalent histone states associated with heterochromatin by UHRF1 protein. J Biol Chem 2011; 286:24300-11. [PMID: 21489993 PMCID: PMC3129210 DOI: 10.1074/jbc.m111.234104] [Citation(s) in RCA: 148] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 03/27/2011] [Indexed: 11/06/2022] Open
Abstract
Histone modifications and DNA methylation represent two layers of heritable epigenetic information that regulate eukaryotic chromatin structure and gene activity. UHRF1 is a unique factor that bridges these two layers; it is required for maintenance DNA methylation at hemimethylated CpG sites, which are specifically recognized through its SRA domain and also interacts with histone H3 trimethylated on lysine 9 (H3K9me3) in an unspecified manner. Here we show that UHRF1 contains a tandem Tudor domain (TTD) that recognizes H3 tail peptides with the heterochromatin-associated modification state of trimethylated lysine 9 and unmodified lysine 4 (H3K4me0/K9me3). Solution NMR and crystallographic data reveal the TTD simultaneously recognizes H3K9me3 through a conserved aromatic cage in the first Tudor subdomain and unmodified H3K4 within a groove between the tandem subdomains. The subdomains undergo a conformational adjustment upon peptide binding, distinct from previously reported mechanisms for dual histone mark recognition. Mutant UHRF1 protein deficient for H3K4me0/K9me3 binding shows altered localization to heterochromatic chromocenters and fails to reduce expression of a target gene, p16(INK4A), when overexpressed. Our results demonstrate a novel recognition mechanism for the combinatorial readout of histone modification states associated with gene silencing and add to the growing evidence for coordination of, and cross-talk between, the modification states of H3K4 and H3K9 in regulation of gene expression.
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Affiliation(s)
- Nataliya Nady
- From the Ontario Cancer Institute, Campbell Family Cancer Research Institute and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Alexander Lemak
- From the Ontario Cancer Institute, Campbell Family Cancer Research Institute and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - John R. Walker
- the Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - George V. Avvakumov
- the Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Michael S. Kareta
- the Department of Molecular & Cellular Biology, University of California, Davis, California 95616
| | - Mayada Achour
- CNRS UMR7213, Laboratoire de Biophotonique et Pharmacologie, Faculté de Pharmacie, 74 route du rhin, 67401 Illkirch cedex, France
| | - Sheng Xue
- the Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Shili Duan
- From the Ontario Cancer Institute, Campbell Family Cancer Research Institute and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | | | - Xiaobing Zuo
- the Protein Nucleic Acid Interaction Section, Structural Biophysics Laboratory, NCI-Frederick, National Institutes of Health, Frederick, Maryland 21702, and
| | - Yun-Xing Wang
- the Protein Nucleic Acid Interaction Section, Structural Biophysics Laboratory, NCI-Frederick, National Institutes of Health, Frederick, Maryland 21702, and
| | - Christian Bronner
- CNRS UMR7213, Laboratoire de Biophotonique et Pharmacologie, Faculté de Pharmacie, 74 route du rhin, 67401 Illkirch cedex, France
| | - Frédéric Chédin
- the Department of Molecular & Cellular Biology, University of California, Davis, California 95616
| | - Cheryl H. Arrowsmith
- From the Ontario Cancer Institute, Campbell Family Cancer Research Institute and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada
- the Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Sirano Dhe-Paganon
- the Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada
- the Department of Physiology, University of Toronto, Toronto, Ontario M5G 1L5, Canada
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20
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Wang Z, Patel DJ. Combinatorial readout of dual histone modifications by paired chromatin-associated modules. J Biol Chem 2011; 286:18363-8. [PMID: 21454653 DOI: 10.1074/jbc.r111.219139] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The study of histone modifications and their interaction with effector modules/proteins has attracted increasing attention in recent years. Accumulating evidence indicates that epigenetic regulation, which involves post-translational modification on histones and DNAs or the participation of RNAs, plays an important role in many cellular processes. Histone modifications can function individually but are also capable of functioning combinatorially as a pattern. Recently, much more attention has focused on interpreting combined histone patterns by their downstream effectors. Structure/function-based studies on paired module-mediated histone cross-talk have greatly enhanced our understanding of the plasticity of the "histone code" hypothesis.
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Affiliation(s)
- Zhanxin Wang
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA.
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21
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Koester-Eiserfunke N, Fischle W. H3K9me2/3 binding of the MBT domain protein LIN-61 is essential for Caenorhabditis elegans vulva development. PLoS Genet 2011; 7:e1002017. [PMID: 21437264 PMCID: PMC3060068 DOI: 10.1371/journal.pgen.1002017] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Accepted: 01/18/2011] [Indexed: 11/18/2022] Open
Abstract
MBT domain proteins are involved in developmental processes and tumorigenesis. In vitro binding and mutagenesis studies have shown that individual MBT domains within clustered MBT repeat regions bind mono- and dimethylated histone lysine residues with little to no sequence specificity but discriminate against the tri- and unmethylated states. However, the exact function of promiscuous histone methyl-lysine binding in the biology of MBT domain proteins has not been elucidated. Here, we show that the Caenorhabditis elegans four MBT domain protein LIN-61, in contrast to other MBT repeat factors, specifically interacts with histone H3 when methylated on lysine 9, displaying a strong preference for di- and trimethylated states (H3K9me2/3). Although the fourth MBT repeat is implicated in this interaction, H3K9me2/3 binding minimally requires MBT repeats two to four. Further, mutagenesis of residues conserved with other methyl-lysine binding MBT regions in the fourth MBT repeat does not abolish interaction, implicating a distinct binding mode. In vivo, H3K9me2/3 interaction of LIN-61 is required for C. elegans vulva development within the synMuvB pathway. Mutant LIN-61 proteins deficient in H3K9me2/3 binding fail to rescue lin-61 synMuvB function. Also, previously identified point mutant synMuvB alleles are deficient in H3K9me2/3 interaction although these target residues that are outside of the fourth MBT repeat. Interestingly, lin-61 genetically interacts with two other synMuvB genes, hpl-2, an HP1 homologous H3K9me2/3 binding factor, and met-2, a SETDB1 homologous H3K9 methyl transferase (H3K9MT), in determining C. elegans vulva development and fertility. Besides identifying the first sequence specific and di-/trimethylation binding MBT domain protein, our studies imply complex multi-domain regulation of ligand interaction of MBT domains. Our results also introduce a mechanistic link between LIN-61 function and biology, and they establish interplay of the H3K9me2/3 binding proteins, LIN-61 and HPL-2, as well as the H3K9MT MET-2 in distinct developmental pathways.
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Affiliation(s)
- Nora Koester-Eiserfunke
- Laboratory of Chromatin Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Wolfgang Fischle
- Laboratory of Chromatin Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- * E-mail:
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22
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Kireev D, Wigle TJ, Norris-Drouin J, Herold JM, Janzen WP, Frye SV. Identification of non-peptide malignant brain tumor (MBT) repeat antagonists by virtual screening of commercially available compounds. J Med Chem 2010; 53:7625-31. [PMID: 20931980 DOI: 10.1021/jm1007374] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The malignant brain tumor (MBT) repeat is an important epigenetic-code "reader" and is functionally associated with differentiation, gene silencing, and tumor suppression. (1-3) Small molecule probes of MBT domains should enable a systematic study of MBT-containing proteins and potentially reveal novel druggable targets. We designed and applied a virtual screening strategy that identified potential MBT antagonists in a large database of commercially available compounds. A small set of virtual hits was purchased and submitted to experimental testing. Nineteen of the purchased compounds showed a specific dose-dependent protein binding and will provide critical structure-activity information for subsequent lead generation and optimization.
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Affiliation(s)
- Dmitri Kireev
- Center for Integrative Chemical Biology and Drug Discovery, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina 27599-7363, United States.
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23
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Yap KL, Zhou MM. Keeping it in the family: diverse histone recognition by conserved structural folds. Crit Rev Biochem Mol Biol 2010; 45:488-505. [PMID: 20923397 DOI: 10.3109/10409238.2010.512001] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Epigenetic regulation of gene transcription relies on an array of recurring structural domains that have evolved to recognize post-translational modifications on histones. The roles of bromodomains, PHD fingers, and the Royal family domains in the recognition of histone modifications to direct transcription have been well characterized. However, only through recent structural studies has it been realized that these basic folds are capable of interacting with increasingly more complex histone modification landscapes, illuminating how nature has concocted a way to accomplish more with less. Here we review the recent biochemical and structural studies of several conserved folds that recognize modified as well as unmodified histone sequences, and discuss their implications on gene expression.
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Affiliation(s)
- Kyoko L Yap
- Department of Structural and Chemical Biology, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY, USA
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24
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Comparative analysis of chromatin binding by Sex Comb on Midleg (SCM) and other polycomb group repressors at a Drosophila Hox gene. Mol Cell Biol 2010; 30:2584-93. [PMID: 20351181 DOI: 10.1128/mcb.01451-09] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Sex Comb on Midleg (SCM) is a transcriptional repressor in the Polycomb group (PcG), but its molecular role in PcG silencing is not known. Although SCM can interact with Polycomb repressive complex 1 (PRC1) in vitro, biochemical studies have indicated that SCM is not a core constituent of PRC1 or PRC2. Nevertheless, SCM is just as critical for Drosophila Hox gene silencing as canonical subunits of these well-characterized PcG complexes. To address functional relationships between SCM and other PcG components, we have performed chromatin immunoprecipitation studies using cultured Drosophila Schneider line 2 (S2) cells and larval imaginal discs. We find that SCM associates with a Polycomb response element (PRE) upstream of the Ubx gene which also binds PRC1, PRC2, and the DNA-binding PcG protein Pleiohomeotic (PHO). However, SCM is retained at this Ubx PRE despite genetic disruption or knockdown of PHO, PRC1, or PRC2, suggesting that SCM chromatin targeting does not require prior association of these other PcG components. Chromatin immunoprecipitations (IPs) to test the consequences of SCM genetic disruption or knockdown revealed that PHO association is unaffected, but reduced levels of PRE-bound PRC2 and PRC1 were observed. We discuss these results in light of current models for recruitment of PcG complexes to chromatin targets.
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25
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Abstract
Epigenetics refers to heritable changes that control how the genome is accessed in different cell-types and during development and differentiation. Even though each cell contains essentially the same genetic code, epigenetic mechanisms permit specialization of function between cells. The state of chromatin, the complex of histone proteins, RNA and DNA that efficiently package the genome, is largely regulated by specific modifications to histone proteins and DNA, and the recognition of these marks by other proteins and protein complexes. The enzymes that produce these modifications (the 'writers'), the proteins that recognize them (the 'readers'), and the enzymes that remove them (the 'erasers') are critical targets for manipulation in order to further understand the histone code and its role in biology and human disease.
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26
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Eryilmaz J, Pan P, Amaya MF, Allali-Hassani A, Dong A, Adams-Cioaba MA, MacKenzie F, Vedadi M, Min J. Structural studies of a four-MBT repeat protein MBTD1. PLoS One 2009; 4:e7274. [PMID: 19841675 PMCID: PMC2747274 DOI: 10.1371/journal.pone.0007274] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 09/08/2009] [Indexed: 11/18/2022] Open
Abstract
Background The Polycomb group (PcG) of proteins is a family of important developmental regulators. The respective members function as large protein complexes involved in establishment and maintenance of transcriptional repression of developmental control genes. MBTD1, Malignant Brain Tumor domain-containing protein 1, is one such PcG protein. MBTD1 contains four MBT repeats. Methodology/Principal Findings We have determined the crystal structure of MBTD1 (residues 130–566aa covering the 4 MBT repeats) at 2.5 Å resolution by X-ray crystallography. The crystal structure of MBTD1 reveals its similarity to another four-MBT-repeat protein L3MBTL2, which binds lower methylated lysine histones. Fluorescence polarization experiments confirmed that MBTD1 preferentially binds mono- and di-methyllysine histone peptides, like L3MBTL1 and L3MBTL2. All known MBT-peptide complex structures characterized to date do not exhibit strong histone peptide sequence selectivity, and use a “cavity insertion recognition mode” to recognize the methylated lysine with the deeply buried methyl-lysine forming extensive interactions with the protein while the peptide residues flanking methyl-lysine forming very few contacts [1]. Nevertheless, our mutagenesis data based on L3MBTL1 suggested that the histone peptides could not bind to MBT repeats in any orientation. Conclusions The four MBT repeats in MBTD1 exhibits an asymmetric rhomboid architecture. Like other MBT repeat proteins characterized so far, MBTD1 binds mono- or dimethylated lysine histones through one of its four MBT repeats utilizing a semi-aromatic cage. Enhanced version This article can also be viewed as an enhanced version in which the text of the article is integrated with interactive 3D representations and animated transitions. Please note that a web plugin is required to access this enhanced functionality. Instructions for the installation and use of the web plugin are available in Text S1.
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Affiliation(s)
- Jitka Eryilmaz
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Patricia Pan
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Maria F. Amaya
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | | | - Aiping Dong
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | | | - Farrell MacKenzie
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Masoud Vedadi
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Jinrong Min
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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27
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Bonasio R, Lecona E, Reinberg D. MBT domain proteins in development and disease. Semin Cell Dev Biol 2009; 21:221-30. [PMID: 19778625 DOI: 10.1016/j.semcdb.2009.09.010] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2009] [Accepted: 09/11/2009] [Indexed: 12/22/2022]
Abstract
The Malignant Brain Tumor (MBT) domain is a "chromatin reader", a protein module that binds to post-translational modifications on histone tails that are thought to affect a variety of chromatin processes, including transcription. More specifically, MBT domains recognize mono- and di-methylated lysines at a number of different positions on histone H3 and H4 tails. Three Drosophila proteins, SCM, L(3)MBT and SFMBT contain multiple adjacent MBT repeats and have critical roles in development, maintenance of cell identity, and tumor suppression. Although they function in different pathways, these proteins all localize to chromatin in vivo and repress transcription by a currently unknown molecular mechanism that requires the MBT domains. The human genome contains several homologues of these MBT proteins, some of which have been linked to important gene regulatory pathways, such as E2F/Rb- and Polycomb-mediated repression, and to the insurgence of certain neurological tumors. Here, we review the genetics, biochemistry, and cell biology of MBT proteins and their role in development and disease.
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Affiliation(s)
- Roberto Bonasio
- Howard Hughes Medical Institute and Department of Biochemistry, School of Medicine, New York University, New York, NY 10016, USA
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Grimm C, Matos R, Ly-Hartig N, Steuerwald U, Lindner D, Rybin V, Müller J, Müller CW. Molecular recognition of histone lysine methylation by the Polycomb group repressor dSfmbt. EMBO J 2009; 28:1965-77. [PMID: 19494831 PMCID: PMC2693881 DOI: 10.1038/emboj.2009.147] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 05/11/2009] [Indexed: 11/09/2022] Open
Abstract
Polycomb group (PcG) proteins repress transcription by modifying chromatin structure in target genes. dSfmbt is a subunit of the Drosophila melanogaster PcG protein complex PhoRC and contains four malignant brain tumour (MBT) repeats involved in the recognition of various mono- and dimethylated histone peptides. Here, we present the crystal structure of the four-MBT-repeat domain of dSfmbt in complex with a mono-methylated histone H4 peptide. Only a single histone peptide binds to the four-MBT-repeat domain. Mutational analyses show high-affinity binding with low peptide sequence selectivity through combinatorial interaction of the methyl-lysine with an aromatic cage and positively charged flanking residues with the surrounding negatively charged surface of the fourth MBT repeat. dSfmbt directly interacts with the PcG protein Scm, a related MBT-repeat protein with similar methyl-lysine binding activity. dSfmbt and Scm co-occupy Polycomb response elements of target genes in Drosophila and they strongly synergize in the repression of these target genes, suggesting that the combined action of these two MBT proteins is crucial for Polycomb silencing.
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Affiliation(s)
- Clemens Grimm
- European Molecular Biology Laboratory, Grenoble Outstation, Grenoble, France
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Müller J, Verrijzer P. Biochemical mechanisms of gene regulation by polycomb group protein complexes. Curr Opin Genet Dev 2009; 19:150-8. [PMID: 19345089 DOI: 10.1016/j.gde.2009.03.001] [Citation(s) in RCA: 200] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2009] [Revised: 02/18/2009] [Accepted: 03/03/2009] [Indexed: 10/21/2022]
Abstract
Polycomb group (PcG) proteins are transcriptional repressors that control expression of developmental regulator genes in animals and plants. Recent advances in our understanding of the PcG system include biochemical purifications that revealed a substantial variety in PcG complex composition. These different complexes contain distinct chromatin-modifying activities and engage in cross-talk with other chromatin modifications. Complementing these biochemical analyses, structural studies have begun to provide insight into how PcG proteins interact with each other and with chromatin. Finally, genome-wide binding profiling and the ensuing functional analysis of target gene regulation revealed that the PcG system is not only used for the permanent silencing of developmental regulator genes. Rather, PcG mediated repression also constitutes a mechanism for dynamic control of gene transcription.
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Affiliation(s)
- Jürg Müller
- EMBL, Gene Expression Programme, Heidelberg, Germany.
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Guo Y, Nady N, Qi C, Allali-Hassani A, Zhu H, Pan P, Adams-Cioaba MA, Amaya MF, Dong A, Vedadi M, Schapira M, Read RJ, Arrowsmith CH, Min J. Methylation-state-specific recognition of histones by the MBT repeat protein L3MBTL2. Nucleic Acids Res 2009; 37:2204-10. [PMID: 19233876 PMCID: PMC2673432 DOI: 10.1093/nar/gkp086] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The MBT repeat has been recently identified as a key domain capable of methyl–lysine histone recognition. Functional work has pointed to a role for MBT domain-containing proteins in transcriptional repression of developmental control genes such as Hox genes. In this study, L3MBTL2, a human homolog of Drosophila Sfmbt critical for Hox gene silencing, is demonstrated to preferentially recognize lower methylation states of several histone-derived peptides through its fourth MBT repeat. High-resolution crystallographic analysis of the four MBT repeats of this protein reveals its unique asymmetric rhomboid architecture, as well as binding mechanism, which preclude the interaction of the first three MBT repeats with methylated peptides. Structural elucidation of an L3MBTL2–H4K20me1 complex and comparison with other MBT-histone peptide complexes also suggests that an absence of distinct surface contours surrounding the methyl–lysine-binding pocket may underlie the lack of sequence specificity observed for members of this protein family.
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Affiliation(s)
- Yahong Guo
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, M5G 1L6, Ontario, Canada
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