1
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Rawal CC, Loubiere V, Butova NL, Gracia J, Parreno V, Merigliano C, Martinez AM, Cavalli G, Chiolo I. Sustained inactivation of the Polycomb PRC1 complex induces DNA repair defects and genomic instability in epigenetic tumors. Histochem Cell Biol 2024:10.1007/s00418-024-02302-z. [PMID: 38888809 DOI: 10.1007/s00418-024-02302-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2024] [Indexed: 06/20/2024]
Abstract
Cancer initiation and progression are typically associated with the accumulation of driver mutations and genomic instability. However, recent studies demonstrated that cancer can also be driven purely by epigenetic alterations, without driver mutations. Specifically, a 24-h transient downregulation of polyhomeotic (ph-KD), a core component of the Polycomb complex PRC1, is sufficient to induce epigenetically initiated cancers (EICs) in Drosophila, which are proficient in DNA repair and characterized by a stable genome. Whether genomic instability eventually occurs when PRC1 downregulation is performed for extended periods of time remains unclear. Here, we show that prolonged depletion of PH, which mimics cancer initiating events, results in broad dysregulation of DNA replication and repair genes, along with the accumulation of DNA breaks, defective repair, and widespread genomic instability in the cancer tissue. A broad misregulation of H2AK118 ubiquitylation and to a lesser extent of H3K27 trimethylation also occurs and might contribute to these phenotypes. Together, this study supports a model where DNA repair and replication defects accumulate during the tumorigenic transformation epigenetically induced by PRC1 loss, resulting in genomic instability and cancer progression.
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Affiliation(s)
- Chetan C Rawal
- Department of Molecular and Computational Biology, University of Southern California, 1050 Childs Way, Los Angeles, CA, 90089, USA
| | - Vincent Loubiere
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Nadejda L Butova
- Department of Molecular and Computational Biology, University of Southern California, 1050 Childs Way, Los Angeles, CA, 90089, USA
| | - Juliette Gracia
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France
| | - Victoria Parreno
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France
| | - Chiara Merigliano
- Department of Molecular and Computational Biology, University of Southern California, 1050 Childs Way, Los Angeles, CA, 90089, USA
| | - Anne-Marie Martinez
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France.
| | - Giacomo Cavalli
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France.
| | - Irene Chiolo
- Department of Molecular and Computational Biology, University of Southern California, 1050 Childs Way, Los Angeles, CA, 90089, USA.
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2
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Xu W, Kim JS, Yang T, Ya A, Sadzewicz L, Tallon L, Harris BT, Sarkaria J, Jin F, Waldman T. STAG2 mutations regulate 3D genome organization, chromatin loops, and Polycomb signaling in glioblastoma multiforme. J Biol Chem 2024; 300:107341. [PMID: 38705393 PMCID: PMC11157269 DOI: 10.1016/j.jbc.2024.107341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 04/18/2024] [Accepted: 04/25/2024] [Indexed: 05/07/2024] Open
Abstract
Inactivating mutations of genes encoding the cohesin complex are common in a wide range of human cancers. STAG2 is the most commonly mutated subunit. Here we report the impact of stable correction of endogenous, naturally occurring STAG2 mutations on gene expression, 3D genome organization, chromatin loops, and Polycomb signaling in glioblastoma multiforme (GBM). In two GBM cell lines, correction of their STAG2 mutations significantly altered the expression of ∼10% of all expressed genes. Virtually all the most highly regulated genes were negatively regulated by STAG2 (i.e., expressed higher in STAG2-mutant cells), and one of them-HEPH-was regulated by STAG2 in uncultured GBM tumors as well. While STAG2 correction had little effect on large-scale features of 3D genome organization (A/B compartments, TADs), STAG2 correction did alter thousands of individual chromatin loops, some of which controlled the expression of adjacent genes. Loops specific to STAG2-mutant cells, which were regulated by STAG1-containing cohesin complexes, were very large, supporting prior findings that STAG1-containing cohesin complexes have greater loop extrusion processivity than STAG2-containing cohesin complexes and suggesting that long loops may be a general feature of STAG2-mutant cancers. Finally, STAG2 mutation activated Polycomb activity leading to increased H3K27me3 marks, identifying Polycomb signaling as a potential target for therapeutic intervention in STAG2-mutant GBM tumors. Together, these findings illuminate the landscape of STAG2-regulated genes, A/B compartments, chromatin loops, and pathways in GBM, providing important clues into the largely still unknown mechanism of STAG2 tumor suppression.
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Affiliation(s)
- Wanying Xu
- Department of Genetics and Genome Sciences, Case Comprehensive Cancer Center, Case Western Reserve School of Medicine, Cleveland, Ohio, USA; The Biomedical Sciences Training Program, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Jung-Sik Kim
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University School of Medicine, Washington, District of Columbia, USA
| | - Tianyi Yang
- Department of Genetics and Genome Sciences, Case Comprehensive Cancer Center, Case Western Reserve School of Medicine, Cleveland, Ohio, USA; The Biomedical Sciences Training Program, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Alvin Ya
- MD/PhD Program, Georgetown University School of Medicine, Washington, District of Columbia, USA; Tumor Biology Training Program, Georgetown University School of Medicine, Washington, District of Columbia, USA
| | - Lisa Sadzewicz
- Institute for Genome Sciences, University of Maryland, Baltimore, Maryland, USA
| | - Luke Tallon
- Institute for Genome Sciences, University of Maryland, Baltimore, Maryland, USA
| | - Brent T Harris
- Departments of Neurology and Pathology, Georgetown University School of Medicine, Washington, District of Columbia, USA
| | - Jann Sarkaria
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, USA
| | - Fulai Jin
- Department of Genetics and Genome Sciences, Case Comprehensive Cancer Center, Case Western Reserve School of Medicine, Cleveland, Ohio, USA; Department of Computer and Data Sciences, Department of Population and Quantitative Health Sciences, Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio, USA.
| | - Todd Waldman
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University School of Medicine, Washington, District of Columbia, USA.
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3
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Guan S, Tang J, Ma X, Miao R, Cheng B. CBX7C⋅PHC2 interaction facilitates PRC1 assembly and modulates its phase separation properties. iScience 2024; 27:109548. [PMID: 38600974 PMCID: PMC11004992 DOI: 10.1016/j.isci.2024.109548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 02/04/2024] [Accepted: 03/19/2024] [Indexed: 04/12/2024] Open
Abstract
CBX7 is a key component of PRC1 complex. Cbx7C is an uncharacterized Cbx7 splicing isoform specifically expressed in mouse embryonic stem cells (mESCs). We demonstrate that CBX7C functions as an epigenetic repressor at the classic PRC1 targets in mESCs, and its preferential interaction to PHC2 facilitates PRC1 assembly. Both Cbx7C and Phc2 are significantly upregulated during cell differentiation, and knockdown of Cbx7C abolishes the differentiation of mESCs to embryoid bodies. Interestingly, CBX7C⋅PHC2 interaction at low levels efficiently undergoes the formation of functional Polycomb bodies with high mobility, whereas the coordination of the two factors at high doses results in the formation of large, low-mobility, chromatin-free aggregates. Overall, these findings uncover the unique roles and molecular basis of the CBX7C⋅PHC2 interaction in PRC1 assembly on chromatin and Pc body formation and open a new avenue of controlling PRC1 activities via modulation of its phase separation properties.
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Affiliation(s)
- Shanli Guan
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, P.R. China
| | - Jiajia Tang
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, P.R. China
| | - Xiaojun Ma
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, P.R. China
| | - Ruidong Miao
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, P.R. China
| | - Bo Cheng
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, P.R. China
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, Lanzhou University, Lanzhou 730000, Gansu, P.R. China
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4
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Seif E, Francis NJ. A Two-Step Mechanism for Creating Stable, Condensed Chromatin with the Polycomb Complex PRC1. Molecules 2024; 29:323. [PMID: 38257239 PMCID: PMC10821450 DOI: 10.3390/molecules29020323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 12/26/2023] [Accepted: 01/05/2024] [Indexed: 01/24/2024] Open
Abstract
The Drosophila PRC1 complex regulates gene expression by modifying histone proteins and chromatin architecture. Two PRC1 subunits, PSC and Ph, are most implicated in chromatin architecture. In vitro, PRC1 compacts chromatin and inhibits transcription and nucleosome remodeling. The long disordered C-terminal region of PSC (PSC-CTR) is important for these activities, while Ph has little effect. In cells, Ph is important for condensate formation, long-range chromatin interactions, and gene regulation, and its polymerizing sterile alpha motif (SAM) is implicated in these activities. In vitro, truncated Ph containing the SAM and two other conserved domains (mini-Ph) undergoes phase separation with chromatin, suggesting a mechanism for SAM-dependent condensate formation in vivo. How the distinct activities of PSC and Ph on chromatin function together in PRC1 is not known. To address this question, we analyzed structures formed with large chromatin templates and PRC1 in vitro. PRC1 bridges chromatin into extensive fibrillar networks. Ph, its SAM, and SAM polymerization activity have little effect on these structures. Instead, the PSC-CTR controls their growth, and is sufficient for their formation. To understand how phase separation driven by Ph SAM intersects with the chromatin bridging activity of the PSC-CTR, we used mini-Ph to form condensates with chromatin and then challenged them with PRC1 lacking Ph (PRC1ΔPh). PRC1ΔPh converts mini-Ph chromatin condensates into clusters of small non-fusing condensates and bridged fibers. These condensates retain a high level of chromatin compaction and do not intermix. Thus, phase separation of chromatin by mini-Ph, followed by the action of the PSC-CTR, creates a unique chromatin organization with regions of high nucleosome density and extraordinary stability. We discuss how this coordinated sequential activity of two proteins found in the same complex may occur and the possible implications of stable chromatin architectures in maintaining transcription states.
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Affiliation(s)
- Elias Seif
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada;
| | - Nicole J. Francis
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada;
- Division of Experimental Medicine, McGill University, 1001 Decarie Boulevard, Montréal, QC H4A 3J1, Canada
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, 2900 Boulevard Edouard-Montpetit, Montréal, QC H3T 1J4, Canada
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5
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Miller A, Dasen JS. Establishing and maintaining Hox profiles during spinal cord development. Semin Cell Dev Biol 2024; 152-153:44-57. [PMID: 37029058 PMCID: PMC10524138 DOI: 10.1016/j.semcdb.2023.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/18/2023] [Accepted: 03/30/2023] [Indexed: 04/09/2023]
Abstract
The chromosomally-arrayed Hox gene family plays central roles in embryonic patterning and the specification of cell identities throughout the animal kingdom. In vertebrates, the relatively large number of Hox genes and pervasive expression throughout the body has hindered understanding of their biological roles during differentiation. Studies on the subtype diversification of spinal motor neurons (MNs) have provided a tractable system to explore the function of Hox genes during differentiation, and have provided an entry point to explore how neuronal fate determinants contribute to motor circuit assembly. Recent work, using both in vitro and in vivo models of MN subtype differentiation, have revealed how patterning morphogens and regulation of chromatin structure determine cell-type specific programs of gene expression. These studies have not only shed light on basic mechanisms of rostrocaudal patterning in vertebrates, but also have illuminated mechanistic principles of gene regulation that likely operate in the development and maintenance of terminal fates in other systems.
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Affiliation(s)
- Alexander Miller
- NYU Neuroscience Institute and Developmental Genetics Programs, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA.
| | - Jeremy S Dasen
- NYU Neuroscience Institute and Developmental Genetics Programs, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA.
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6
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Krug B, Hu B, Chen H, Ptack A, Chen X, Gretarsson KH, Deshmukh S, Kabir N, Andrade AF, Jabbour E, Harutyunyan AS, Lee JJY, Hulswit M, Faury D, Russo C, Xu X, Johnston MJ, Baguette A, Dahl NA, Weil AG, Ellezam B, Dali R, Blanchette M, Wilson K, Garcia BA, Soni RK, Gallo M, Taylor MD, Kleinman CL, Majewski J, Jabado N, Lu C. H3K27me3 spreading organizes canonical PRC1 chromatin architecture to regulate developmental programs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.28.567931. [PMID: 38116029 PMCID: PMC10729739 DOI: 10.1101/2023.11.28.567931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Polycomb Repressive Complex 2 (PRC2)-mediated histone H3K27 tri-methylation (H3K27me3) recruits canonical PRC1 (cPRC1) to maintain heterochromatin. In early development, polycomb-regulated genes are connected through long-range 3D interactions which resolve upon differentiation. Here, we report that polycomb looping is controlled by H3K27me3 spreading and regulates target gene silencing and cell fate specification. Using glioma-derived H3 Lys-27-Met (H3K27M) mutations as tools to restrict H3K27me3 deposition, we show that H3K27me3 confinement concentrates the chromatin pool of cPRC1, resulting in heightened 3D interactions mirroring chromatin architecture of pluripotency, and stringent gene repression that maintains cells in progenitor states to facilitate tumor development. Conversely, H3K27me3 spread in pluripotent stem cells, following neural differentiation or loss of the H3K36 methyltransferase NSD1, dilutes cPRC1 concentration and dissolves polycomb loops. These results identify the regulatory principles and disease implications of polycomb looping and nominate histone modification-guided distribution of reader complexes as an important mechanism for nuclear compartment organization. Highlights The confinement of H3K27me3 at PRC2 nucleation sites without its spreading correlates with increased 3D chromatin interactions.The H3K27M oncohistone concentrates canonical PRC1 that anchors chromatin loop interactions in gliomas, silencing developmental programs.Stem and progenitor cells require factors promoting H3K27me3 confinement, including H3K36me2, to maintain cPRC1 loop architecture.The cPRC1-H3K27me3 interaction is a targetable driver of aberrant self-renewal in tumor cells.
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7
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de Potter B, Raas MWD, Seidl MF, Verrijzer CP, Snel B. Uncoupled evolution of the Polycomb system and deep origin of non-canonical PRC1. Commun Biol 2023; 6:1144. [PMID: 37949928 PMCID: PMC10638273 DOI: 10.1038/s42003-023-05501-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 10/24/2023] [Indexed: 11/12/2023] Open
Abstract
Polycomb group proteins, as part of the Polycomb repressive complexes, are essential in gene repression through chromatin compaction by canonical PRC1, mono-ubiquitylation of histone H2A by non-canonical PRC1 and tri-methylation of histone H3K27 by PRC2. Despite prevalent models emphasizing tight functional coupling between PRC1 and PRC2, it remains unclear whether this paradigm indeed reflects the evolution and functioning of these complexes. Here, we conduct a comprehensive analysis of the presence or absence of cPRC1, nPRC1 and PRC2 across the entire eukaryotic tree of life, and find that both complexes were present in the Last Eukaryotic Common Ancestor (LECA). Strikingly, ~42% of organisms contain only PRC1 or PRC2, showing that their evolution since LECA is largely uncoupled. The identification of ncPRC1-defining subunits in unicellular relatives of animals and fungi suggests ncPRC1 originated before cPRC1, and we propose a scenario for the evolution of cPRC1 from ncPRC1. Together, our results suggest that crosstalk between these complexes is a secondary development in evolution.
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Affiliation(s)
- Bastiaan de Potter
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, Netherlands
- Hubrecht institute, Royal Netherlands Academy of Arts and Sciences, Utrecht, Netherlands
| | - Maximilian W D Raas
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, Netherlands
- Hubrecht institute, Royal Netherlands Academy of Arts and Sciences, Utrecht, Netherlands
| | - Michael F Seidl
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, Netherlands
| | - C Peter Verrijzer
- Department of Biochemistry, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Berend Snel
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, Netherlands.
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8
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Gemeinhardt TM, Regy RM, Mendiola AJ, Ledterman HJ, Henrickson A, Phan TM, Kim YC, Demeler B, Kim CA, Mittal J, Francis NJ. How a disordered linker in the Polycomb protein Polyhomeotic tunes phase separation and oligomerization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.26.564264. [PMID: 37961422 PMCID: PMC10634872 DOI: 10.1101/2023.10.26.564264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The Polycomb Group (PcG) complex PRC1 represses transcription, forms condensates in cells, and modifies chromatin architecture. These processes are connected through the essential, polymerizing Sterile Alpha Motif (SAM) present in the PRC1 subunit Polyhomeotic (Ph). In vitro, Ph SAM drives formation of short oligomers and phase separation with DNA or chromatin in the context of a Ph truncation ("mini-Ph"). Oligomer length is controlled by the long disordered linker (L) that connects the SAM to the rest of Ph--replacing Drosophila PhL with the evolutionarily diverged human PHC3L strongly increases oligomerization. How the linker controls SAM polymerization, and how polymerization and the linker affect condensate formation are not know. We analyzed PhL and PHC3L using biochemical assays and molecular dynamics (MD) simulations. PHC3L promotes mini-Ph phase separation and makes it relatively independent of DNA. In MD simulations, basic amino acids in PHC3L form contacts with acidic amino acids in the SAM. Engineering the SAM to make analogous charge-based contacts with PhL increased polymerization and phase separation, partially recapitulating the effects of the PHC3L. Ph to PHC3 linker swaps and SAM surface mutations alter Ph condensate formation in cells, and Ph function in Drosophila imaginal discs. Thus, SAM-driven phase separation and polymerization are conserved between flies and mammals, but the underlying mechanisms have diverged through changes to the disordered linker.
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Affiliation(s)
- Tim M Gemeinhardt
- Montreal Clinical Research Institute (IRCM), Montreal, QC, Canada
- Division of Experimental Medicine, McGill University, Montreal, QC, Canada
| | - Roshan M Regy
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, USA
| | - Andrea J Mendiola
- Department of Biochemistry and Molecular Genetics, Midwestern University, Glendale, AZ, USA
| | - Heather J Ledterman
- Department of Biochemistry and Molecular Genetics, Midwestern University, Glendale, AZ, USA
| | - Amy Henrickson
- Department of Chemistry and Biochemistry, The University of Lethbridge, Lethbridge, AB, Canada
| | - Tien M Phan
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, USA
| | - Young C Kim
- Center for Materials Physics and Technology, Naval Research Laboratory, Washington, DC 20375, USA
| | - Borries Demeler
- Department of Chemistry and Biochemistry, The University of Lethbridge, Lethbridge, AB, Canada
- Department of Chemistry, University of Montana, Missoula, MT, United States
| | - Chongwoo A Kim
- Department of Biochemistry and Molecular Genetics, Midwestern University, Glendale, AZ, USA
| | - Jeetain Mittal
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, USA
- Department of Chemistry, Texas A&M University, College Station, TX, USA
- Interdisciplinary Graduate Program in Genetics and Genomics, Texas A&M University, College Station, TX, USA
| | - Nicole J Francis
- Montreal Clinical Research Institute (IRCM), Montreal, QC, Canada
- Division of Experimental Medicine, McGill University, Montreal, QC, Canada
- Department of Biochemistry and Molecular Medicine, University of Montreal, Montreal, QC, Canada
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9
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Ong ALC, Kokaji T, Kishi A, Takihara Y, Shinozuka T, Shimamoto R, Isotani A, Shirai M, Sasai N. Acquisition of neural fate by combination of BMP blockade and chromatin modification. iScience 2023; 26:107887. [PMID: 37771660 PMCID: PMC10522999 DOI: 10.1016/j.isci.2023.107887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 08/07/2023] [Accepted: 09/07/2023] [Indexed: 09/30/2023] Open
Abstract
Neural induction is a process where naive cells are converted into committed cells with neural characteristics, and it occurs at the earliest step during embryogenesis. Although the signaling molecules and chromatin remodeling for neural induction have been identified, the mutual relationships between these molecules are yet to be fully understood. By taking advantage of the neural differentiation system of mouse embryonic stem (ES) cells, we discovered that the BMP signal regulates the expression of several polycomb repressor complex (PRC) component genes. We particularly focused on Polyhomeotic Homolog 1 (Phc1) and established Phc1-knockout (Phc1-KO) ES cells. We found that Phc1-KO failed to acquire the neural fate, and the cells remained in pluripotent or primitive non-neural states. Chromatin accessibility analysis suggests that Phc1 is essential for chromatin packing. Aberrant upregulation of the BMP signal was confirmed in the Phc1 homozygotic mutant embryos. Taken together, Phc1 is required for neural differentiation through epigenetic modification.
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Affiliation(s)
- Agnes Lee Chen Ong
- Division of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma 630-0192, Japan
| | - Toshiya Kokaji
- Data-driven biology, NAIST Data Science Center, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma 630-0192, Japan
| | - Arisa Kishi
- Division of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma 630-0192, Japan
| | - Yoshihiro Takihara
- Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-0037, Japan
| | - Takuma Shinozuka
- Division of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma 630-0192, Japan
| | - Ren Shimamoto
- Division of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma 630-0192, Japan
| | - Ayako Isotani
- Division of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma 630-0192, Japan
| | - Manabu Shirai
- Omics Research Center (ORC), National Cerebral and Cardiovascular Center, 6-1 Kishibe Shinmachi, Suita, Osaka 564-8565, Japan
| | - Noriaki Sasai
- Division of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma 630-0192, Japan
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10
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Lyu X, Rowley MJ, Kulik MJ, Dalton S, Corces VG. Regulation of CTCF loop formation during pancreatic cell differentiation. Nat Commun 2023; 14:6314. [PMID: 37813869 PMCID: PMC10562423 DOI: 10.1038/s41467-023-41964-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 09/22/2023] [Indexed: 10/11/2023] Open
Abstract
Transcription reprogramming during cell differentiation involves targeting enhancers to genes responsible for establishment of cell fates. To understand the contribution of CTCF-mediated chromatin organization to cell lineage commitment, we analyzed 3D chromatin architecture during the differentiation of human embryonic stem cells into pancreatic islet organoids. We find that CTCF loops are formed and disassembled at different stages of the differentiation process by either recruitment of CTCF to new anchor sites or use of pre-existing sites not previously involved in loop formation. Recruitment of CTCF to new sites in the genome involves demethylation of H3K9me3 to H3K9me2, demethylation of DNA, recruitment of pioneer factors, and positioning of nucleosomes flanking the new CTCF sites. Existing CTCF sites not involved in loop formation become functional loop anchors via the establishment of new cohesin loading sites containing NIPBL and YY1 at sites between the new anchors. In both cases, formation of new CTCF loops leads to strengthening of enhancer promoter interactions and increased transcription of genes adjacent to loop anchors. These results suggest an important role for CTCF and cohesin in controlling gene expression during cell differentiation.
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Affiliation(s)
- Xiaowen Lyu
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA.
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Reproductive Health Research, School of Medicine, Faculty of Medicine and Life Sciences, Xiamen University, 361102, Xiamen, China.
- Fujian Provincial Key Laboratory of Organ and Tissue Regeneration, School of Medicine, Faculty of Medicine and Life Sciences, Xiamen University, 361102, Xiamen, China.
| | - M Jordan Rowley
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Michael J Kulik
- Department of Biochemistry and Molecular Biology, The University of Georgia, Athens, GA, 30602, USA
- Center for Molecular Medicine, The University of Georgia, Athens, GA, 30602, USA
| | - Stephen Dalton
- Department of Biochemistry and Molecular Biology, The University of Georgia, Athens, GA, 30602, USA
- Center for Molecular Medicine, The University of Georgia, Athens, GA, 30602, USA
- School of Biomedical Sciences, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Victor G Corces
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA.
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11
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Li R, Huang D, Zhao Y, Yuan Y, Sun X, Dai Z, Huo D, Liu X, Helin K, Li MJ, Wu X. PR-DUB safeguards Polycomb repression through H2AK119ub1 restriction. Cell Prolif 2023; 56:e13457. [PMID: 36959757 PMCID: PMC10542648 DOI: 10.1111/cpr.13457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 03/01/2023] [Accepted: 03/11/2023] [Indexed: 03/25/2023] Open
Abstract
Polycomb group (PcG) proteins are critical chromatin regulators for cell fate control. The mono-ubiquitylation on histone H2AK119 (H2AK119ub1) is one of the well-recognized mechanisms for Polycomb repressive complex 1 (PRC1)-mediated transcription repression. Unexpectedly, the specific H2AK119 deubiquitylation complex composed by additional sex comb-like proteins and BAP1 has also been genetically characterized as Polycomb repressive deubiquitnase (PR-DUB) for unclear reasons. However, it remains a mystery whether and how PR-DUB deficiency affects chromatin states and cell fates through impaired PcG silencing. Here through a careful epigenomic analysis, we demonstrate that a bulk of H2AK119ub1 is diffusely distributed away from promoter regions and their enrichment is positively correlated with PRC1 occupancy. Upon deletion of Asxl2 in mouse embryonic stem cells (ESCs), a pervasive gain of H2AK119ub1 is coincident with increased PRC1 sampling at chromatin. Accordingly, PRC1 is significantly lost from a subset of highly occupied promoters, leading to impaired silencing of associated genes before and after lineage differentiation of Asxl2-null ESCs. Therefore, our study highlights the importance of genome-wide H2AK119ub1 restriction by PR-DUB in safeguarding robust PRC1 deposition and its roles in developmental regulation.
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Affiliation(s)
- Rui Li
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co‐sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Cell Biology, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
| | - Dandan Huang
- Wuxi School of MedicineJiangnan UniversityWuxi214000China
| | - Yingying Zhao
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co‐sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Cell Biology, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
| | - Ye Yuan
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co‐sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Cell Biology, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
| | - Xiaoyu Sun
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co‐sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Cell Biology, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
| | - Zhongye Dai
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co‐sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Cell Biology, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
| | - Dawei Huo
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co‐sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Cell Biology, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
| | - Xiaozhi Liu
- Pediatric Center, Tianjin Key Laboratory of Epigenetics for Organ Development of Premature InfantsThe Fifth Central Hospital of TianjinTianjin300450China
| | - Kristian Helin
- Biotech Research and Innovation CentreUniversity of CopenhagenCopenhagenDenmark
- The Institute of Cancer Research (ICR)LondonUK
| | - Mulin Jun Li
- Department of Bioinformatics, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
- Department of Epidemiology and Biostatistics, National Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and HospitalTianjin Medical UniversityTianjin300070China
| | - Xudong Wu
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co‐sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Cell Biology, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
- Department of OrthopedicsTianjin Medical University General HospitalTianjin300052China
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12
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Rappoport N, Chomsky E, Nagano T, Seibert C, Lubling Y, Baran Y, Lifshitz A, Leung W, Mukamel Z, Shamir R, Fraser P, Tanay A. Single cell Hi-C identifies plastic chromosome conformations underlying the gastrulation enhancer landscape. Nat Commun 2023; 14:3844. [PMID: 37386027 PMCID: PMC10310791 DOI: 10.1038/s41467-023-39549-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 06/19/2023] [Indexed: 07/01/2023] Open
Abstract
Embryonic development involves massive proliferation and differentiation of cell lineages. This must be supported by chromosome replication and epigenetic reprogramming, but how proliferation and cell fate acquisition are balanced in this process is not well understood. Here we use single cell Hi-C to map chromosomal conformations in post-gastrulation mouse embryo cells and study their distributions and correlations with matching embryonic transcriptional atlases. We find that embryonic chromosomes show a remarkably strong cell cycle signature. Despite that, replication timing, chromosome compartment structure, topological associated domains (TADs) and promoter-enhancer contacts are shown to be variable between distinct epigenetic states. About 10% of the nuclei are identified as primitive erythrocytes, showing exceptionally compact and organized compartment structure. The remaining cells are broadly associated with ectoderm and mesoderm identities, showing only mild differentiation of TADs and compartment structures, but more specific localized contacts in hundreds of ectoderm and mesoderm promoter-enhancer pairs. The data suggest that while fully committed embryonic lineages can rapidly acquire specific chromosomal conformations, most embryonic cells are showing plastic signatures driven by complex and intermixed enhancer landscapes.
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Affiliation(s)
- Nimrod Rappoport
- Department of Computer Science and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
- The Blavatnik School of Computer Science, Tel Aviv University, Tel Aviv, Israel
| | - Elad Chomsky
- Department of Computer Science and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Takashi Nagano
- Laboratory for Nuclear Dynamics, Institute for Protein Research, Osaka University, Osaka, Japan
- Nuclear Dynamics Programme, The Babraham Institute, Cambridge, UK
| | - Charlie Seibert
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Yaniv Lubling
- Department of Computer Science and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Yael Baran
- Department of Computer Science and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Aviezer Lifshitz
- Department of Computer Science and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Wing Leung
- Laboratory for Nuclear Dynamics, Institute for Protein Research, Osaka University, Osaka, Japan
- Nuclear Dynamics Programme, The Babraham Institute, Cambridge, UK
| | - Zohar Mukamel
- Department of Computer Science and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Ron Shamir
- The Blavatnik School of Computer Science, Tel Aviv University, Tel Aviv, Israel
| | - Peter Fraser
- Nuclear Dynamics Programme, The Babraham Institute, Cambridge, UK.
- Department of Biological Science, Florida State University, Tallahassee, FL, USA.
| | - Amos Tanay
- Department of Computer Science and Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel.
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13
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Nepita I, Piazza S, Ruglioni M, Cristiani S, Bosurgi E, Salvadori T, Vicidomini G, Diaspro A, Castello M, Cerase A, Bianchini P, Storti B, Bizzarri R. On the Advent of Super-Resolution Microscopy in the Realm of Polycomb Proteins. BIOLOGY 2023; 12:374. [PMID: 36979066 PMCID: PMC10044799 DOI: 10.3390/biology12030374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/02/2023]
Abstract
The genomes of metazoans are organized at multiple spatial scales, ranging from the double helix of DNA to whole chromosomes. The intermediate genomic scale of kilobases to megabases, which corresponds to the 50-300 nm spatial scale, is particularly interesting, as the 3D arrangement of chromatin is implicated in multiple regulatory mechanisms. In this context, polycomb group (PcG) proteins stand as major epigenetic modulators of chromatin function, acting prevalently as repressors of gene transcription by combining chemical modifications of target histones with physical crosslinking of distal genomic regions and phase separation. The recent development of super-resolution microscopy (SRM) has strongly contributed to improving our comprehension of several aspects of nano-/mesoscale (10-200 nm) chromatin domains. Here, we review the current state-of-the-art SRM applied to PcG proteins, showing that the application of SRM to PcG activity and organization is still quite limited and mainly focused on the 3D assembly of PcG-controlled genomic loci. In this context, SRM approaches have mostly been applied to multilabel fluorescence in situ hybridization (FISH). However, SRM data have complemented the maps obtained from chromosome capture experiments and have opened a new window to observe how 3D chromatin topology is modulated by PcGs.
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Affiliation(s)
- Irene Nepita
- Nanoscopy, Istituto Italiano di Tecnologia, Via E. Melen 83, 16152 Genova, Italy
| | - Simonluca Piazza
- Molecular Microscopy and Spectroscopy, Istituto Italiano di Tecnologia, Via E. Melen 83, 16152 Genova, Italy
- R&D Department, Genoa Instruments s.r.l., Via E. Melen 83, 16152 Genova, Italy
| | - Martina Ruglioni
- Department of Surgical, Medical and Molecular Pathology, and Critical Care Medicine, University of Pisa, Via Roma 65, 56126 Pisa, Italy
| | - Sofia Cristiani
- Department of Surgical, Medical and Molecular Pathology, and Critical Care Medicine, University of Pisa, Via Roma 65, 56126 Pisa, Italy
| | - Emanuele Bosurgi
- Department of Surgical, Medical and Molecular Pathology, and Critical Care Medicine, University of Pisa, Via Roma 65, 56126 Pisa, Italy
| | - Tiziano Salvadori
- Department of Surgical, Medical and Molecular Pathology, and Critical Care Medicine, University of Pisa, Via Roma 65, 56126 Pisa, Italy
| | - Giuseppe Vicidomini
- Molecular Microscopy and Spectroscopy, Istituto Italiano di Tecnologia, Via E. Melen 83, 16152 Genova, Italy
| | - Alberto Diaspro
- Nanoscopy, Istituto Italiano di Tecnologia, Via E. Melen 83, 16152 Genova, Italy
- DIFILAB, Dipartimento di Fisica, Università degli Studi di Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - Marco Castello
- Nanoscopy, Istituto Italiano di Tecnologia, Via E. Melen 83, 16152 Genova, Italy
- R&D Department, Genoa Instruments s.r.l., Via E. Melen 83, 16152 Genova, Italy
| | - Andrea Cerase
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, Strada Statale dell’Abetone Brennero 4, 56123 Pisa, Italy
| | - Paolo Bianchini
- Nanoscopy, Istituto Italiano di Tecnologia, Via E. Melen 83, 16152 Genova, Italy
- DIFILAB, Dipartimento di Fisica, Università degli Studi di Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - Barbara Storti
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Ranieri Bizzarri
- Nanoscopy, Istituto Italiano di Tecnologia, Via E. Melen 83, 16152 Genova, Italy
- Department of Surgical, Medical and Molecular Pathology, and Critical Care Medicine, University of Pisa, Via Roma 65, 56126 Pisa, Italy
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza San Silvestro 12, 56127 Pisa, Italy
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14
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Regulation of Polyhomeotic Condensates by Intrinsically Disordered Sequences That Affect Chromatin Binding. EPIGENOMES 2022; 6:epigenomes6040040. [PMID: 36412795 PMCID: PMC9680516 DOI: 10.3390/epigenomes6040040] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 10/30/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022] Open
Abstract
The Polycomb group (PcG) complex PRC1 localizes in the nucleus in condensed structures called Polycomb bodies. The PRC1 subunit Polyhomeotic (Ph) contains an oligomerizing sterile alpha motif (SAM) that is implicated in both PcG body formation and chromatin organization in Drosophila and mammalian cells. A truncated version of Ph containing the SAM (mini-Ph) forms phase-separated condensates with DNA or chromatin in vitro, suggesting that PcG bodies may form through SAM-driven phase separation. In cells, Ph forms multiple small condensates, while mini-Ph typically forms a single large nuclear condensate. We therefore hypothesized that sequences outside of mini-Ph, which are predicted to be intrinsically disordered, are required for proper condensate formation. We identified three distinct low-complexity regions in Ph based on sequence composition. We systematically tested the role of each of these sequences in Ph condensates using live imaging of transfected Drosophila S2 cells. Each sequence uniquely affected Ph SAM-dependent condensate size, number, and morphology, but the most dramatic effects occurred when the central, glutamine-rich intrinsically disordered region (IDR) was removed, which resulted in large Ph condensates. Like mini-Ph condensates, condensates lacking the glutamine-rich IDR excluded chromatin. Chromatin fractionation experiments indicated that the removal of the glutamine-rich IDR reduced chromatin binding and that the removal of either of the other IDRs increased chromatin binding. Our data suggest that all three IDRs, and functional interactions among them, regulate Ph condensate size and number. Our results can be explained by a model in which tight chromatin binding by Ph IDRs antagonizes Ph SAM-driven phase separation. Our observations highlight the complexity of regulation of biological condensates housed in single proteins.
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15
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Scholl A, De S. Epigenetic Regulation by Polycomb Complexes from Drosophila to Human and Its Relation to Communicable Disease Pathogenesis. Int J Mol Sci 2022; 23:ijms232012285. [PMID: 36293135 PMCID: PMC9603650 DOI: 10.3390/ijms232012285] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/04/2022] [Accepted: 10/10/2022] [Indexed: 12/05/2022] Open
Abstract
Although all cells in the human body are made of the same DNA, these cells undergo differentiation and behave differently during development, through integration of external and internal stimuli via 'specific mechanisms.' Epigenetics is one such mechanism that comprises DNA/RNA, histone modifications, and non-coding RNAs that regulate transcription without changing the genetic code. The discovery of the first Polycomb mutant phenotype in Drosophila started the study of epigenetics more than 80 years ago. Since then, a considerable number of Polycomb Group (PcG) genes in Drosophila have been discovered to be preserved in mammals, including humans. PcG proteins exert their influence through gene repression by acting in complexes, modifying histones, and compacting the chromatin within the nucleus. In this article, we discuss how our knowledge of the PcG repression mechanism in Drosophila translates to human communicable disease research.
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16
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Abstract
The Polycomb system modulates chromatin structure to maintain gene repression during cell differentiation. Polycomb repression involves methylation of histone H3K27 (H3K27me3) by Polycomb repressive complex 2 (PRC2), monoubiquitylation of H2A (H2Aub1) by noncanonical PRC1 (ncPRC1), and chromatin compaction by canonical PRC1 (cPRC1), which is independent of its enzymatic activity. Puzzlingly, Polycomb repression also requires deubiquitylation of H2Aub1 by Polycomb repressive deubiquitinase (PR-DUB). In this issue of Genes & Development, Bonnet and colleagues (pp. 1046-1061) resolve this paradox by showing that high levels of H2Aub1 in Drosophila lacking PR-DUB activity promotes open chromatin and gene expression in spite of normal H3K27me3 levels and PRC binding. Pertinently, gene repression is restored by concomitant loss of PRC1 E3 ubiquitin ligase activity but depends on its chromatin compaction activity. These findings suggest that PR-DUB ensures just-right levels of H2Aub1 to allow chromatin compaction by cPRC1.
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17
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De Novo Polycomb Recruitment and Repressive Domain Formation. EPIGENOMES 2022; 6:epigenomes6030025. [PMID: 35997371 PMCID: PMC9397058 DOI: 10.3390/epigenomes6030025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/15/2022] [Accepted: 08/18/2022] [Indexed: 11/29/2022] Open
Abstract
Every cell of an organism shares the same genome; even so, each cellular lineage owns a different transcriptome and proteome. The Polycomb group proteins (PcG) are essential regulators of gene repression patterning during development and homeostasis. However, it is unknown how the repressive complexes, PRC1 and PRC2, identify their targets and elicit new Polycomb domains during cell differentiation. Classical recruitment models consider the pre-existence of repressive histone marks; still, de novo target binding overcomes the absence of both H3K27me3 and H2AK119ub. The CpG islands (CGIs), non-core proteins, and RNA molecules are involved in Polycomb recruitment. Nonetheless, it is unclear how de novo targets are identified depending on the physiological context and developmental stage and which are the leading players stabilizing Polycomb complexes at domain nucleation sites. Here, we examine the features of de novo sites and the accessory elements bridging its recruitment and discuss the first steps of Polycomb domain formation and transcriptional regulation, comprehended by the experimental reconstruction of the repressive domains through time-resolved genomic analyses in mammals.
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18
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Sudarshan D, Avvakumov N, Lalonde ME, Alerasool N, Joly-Beauparlant C, Jacquet K, Mameri A, Lambert JP, Rousseau J, Lachance C, Paquet E, Herrmann L, Thonta Setty S, Loehr J, Bernardini MQ, Rouzbahman M, Gingras AC, Coulombe B, Droit A, Taipale M, Doyon Y, Côté J. Recurrent chromosomal translocations in sarcomas create a megacomplex that mislocalizes NuA4/TIP60 to Polycomb target loci. Genes Dev 2022; 36:664-683. [PMID: 35710139 DOI: 10.1101/gad.348982.121] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 05/31/2022] [Indexed: 11/25/2022]
Abstract
Chromosomal translocations frequently promote carcinogenesis by producing gain-of-function fusion proteins. Recent studies have identified highly recurrent chromosomal translocations in patients with endometrial stromal sarcomas (ESSs) and ossifying fibromyxoid tumors (OFMTs), leading to an in-frame fusion of PHF1 (PCL1) to six different subunits of the NuA4/TIP60 complex. While NuA4/TIP60 is a coactivator that acetylates chromatin and loads the H2A.Z histone variant, PHF1 is part of the Polycomb repressive complex 2 (PRC2) linked to transcriptional repression of key developmental genes through methylation of histone H3 on lysine 27. In this study, we characterize the fusion protein produced by the EPC1-PHF1 translocation. The chimeric protein assembles a megacomplex harboring both NuA4/TIP60 and PRC2 activities and leads to mislocalization of chromatin marks in the genome, in particular over an entire topologically associating domain including part of the HOXD cluster. This is linked to aberrant gene expression-most notably increased expression of PRC2 target genes. Furthermore, we show that JAZF1-implicated with a PRC2 component in the most frequent translocation in ESSs, JAZF1-SUZ12-is a potent transcription activator that physically associates with NuA4/TIP60, its fusion creating outcomes similar to those of EPC1-PHF1 Importantly, the specific increased expression of PRC2 targets/HOX genes was also confirmed with ESS patient samples. Altogether, these results indicate that most chromosomal translocations linked to these sarcomas use the same molecular oncogenic mechanism through a physical merge of NuA4/TIP60 and PRC2 complexes, leading to mislocalization of histone marks and aberrant Polycomb target gene expression.
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Affiliation(s)
- Deepthi Sudarshan
- Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Nikita Avvakumov
- Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Marie-Eve Lalonde
- Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Nader Alerasool
- Donnelly Centre for Cellular and Biomolecular Research, Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Charles Joly-Beauparlant
- Computational Biology Laboratory, CHU de Québec-Université Laval Research Center, Quebec City, Quebec G1V 4G2, Canada
| | - Karine Jacquet
- Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Amel Mameri
- Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Jean-Philippe Lambert
- Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Quebec G1R 3S3, Canada.,Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Justine Rousseau
- Institut de Recherches Cliniques de Montréal, Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, Quebec H3T 1J4, Canada
| | - Catherine Lachance
- Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Eric Paquet
- Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Lara Herrmann
- Computational Biology Laboratory, CHU de Québec-Université Laval Research Center, Quebec City, Quebec G1V 4G2, Canada
| | - Samarth Thonta Setty
- Computational Biology Laboratory, CHU de Québec-Université Laval Research Center, Quebec City, Quebec G1V 4G2, Canada
| | - Jeremy Loehr
- Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Marcus Q Bernardini
- Department of Gynecologic Oncology, Princess Margaret Cancer Center, University Health Network, Sinai Health System, Toronto, Ontario M5B 2M9, Canada.,Department of Obstetrics and Gynecology, University of Toronto, Toronto, Ontario M5G 1X8, Canada
| | - Marjan Rouzbahman
- Department of Laboratory Medicine and Pathobiology, Princess Margaret Hospital Cancer Centre, Toronto, Ontario M5G 2C4, Canada
| | - Anne-Claude Gingras
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Benoit Coulombe
- Institut de Recherches Cliniques de Montréal, Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, Quebec H3T 1J4, Canada
| | - Arnaud Droit
- Computational Biology Laboratory, CHU de Québec-Université Laval Research Center, Quebec City, Quebec G1V 4G2, Canada
| | - Mikko Taipale
- Donnelly Centre for Cellular and Biomolecular Research, Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Yannick Doyon
- Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Jacques Côté
- Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Laval University Cancer Research Center, Quebec City, Quebec G1R 3S3, Canada
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19
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Parreno V, Martinez AM, Cavalli G. Mechanisms of Polycomb group protein function in cancer. Cell Res 2022; 32:231-253. [PMID: 35046519 PMCID: PMC8888700 DOI: 10.1038/s41422-021-00606-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 12/10/2021] [Indexed: 02/01/2023] Open
Abstract
AbstractCancer arises from a multitude of disorders resulting in loss of differentiation and a stem cell-like phenotype characterized by uncontrolled growth. Polycomb Group (PcG) proteins are members of multiprotein complexes that are highly conserved throughout evolution. Historically, they have been described as essential for maintaining epigenetic cellular memory by locking homeotic genes in a transcriptionally repressed state. What was initially thought to be a function restricted to a few target genes, subsequently turned out to be of much broader relevance, since the main role of PcG complexes is to ensure a dynamically choregraphed spatio-temporal regulation of their numerous target genes during development. Their ability to modify chromatin landscapes and refine the expression of master genes controlling major switches in cellular decisions under physiological conditions is often misregulated in tumors. Surprisingly, their functional implication in the initiation and progression of cancer may be either dependent on Polycomb complexes, or specific for a subunit that acts independently of other PcG members. In this review, we describe how misregulated Polycomb proteins play a pleiotropic role in cancer by altering a broad spectrum of biological processes such as the proliferation-differentiation balance, metabolism and the immune response, all of which are crucial in tumor progression. We also illustrate how interfering with PcG functions can provide a powerful strategy to counter tumor progression.
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20
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Titelbaum M, Brant B, Baumel D, Burstein-Willensky A, Perez S, Barsheshet Y, Avni O. Ezh2 harnesses the intranuclear actin cytoskeleton to remodel chromatin in differentiating Th cells. iScience 2021; 24:103093. [PMID: 34622148 PMCID: PMC8479699 DOI: 10.1016/j.isci.2021.103093] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 07/20/2021] [Accepted: 09/07/2021] [Indexed: 12/15/2022] Open
Abstract
Following their first interaction with the antigen, quiescent naive T-helper (Th; CD4+) cells enlarge, differentiate, and proliferate; these processes are accompanied by substantial epigenetic alterations. We showed previously that the epigenetic regulators the polycomb-group (PcG) proteins have a dual function as both positive and negative transcriptional regulators; however, the underlying mechanisms remain poorly understood. Here, we demonstrate that during Th cell differentiation the methyltransferase activity of the PcG protein Ezh2 regulates post-transcriptionally inducible assembly of intranuclear actin filaments. These filaments are colocalized with the actin regulators Vav1 and WASp, vertically oriented to the T cell receptor, and intermingle with the chromatin fibers. Ezh2 and Vav1 are observed together at chromatin-actin intersections. Furthermore, the inducible assembly of nuclear actin filaments is required for chromatin spreading and nuclear growth. Altogether these findings delineate a model in which the epigenetic machinery orchestrates the dynamic mechanical force of the intranuclear cytoskeleton to reorganize chromatin during differentiation. Ezh2 regulates post-transcriptionally the inducible assembly of intranuclear F-actin F-actin is oriented toward the TCR and intermingled with the chromatin fibers F-actin is required for chromatin spreading and nuclear growth The epigenetic machinery harnesses intranuclear cytoskeleton to reorganize chromatin
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Affiliation(s)
- Moran Titelbaum
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Boris Brant
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Daniel Baumel
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | | | - Shira Perez
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | | | - Orly Avni
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
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21
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Flora P, Dalal G, Cohen I, Ezhkova E. Polycomb Repressive Complex(es) and Their Role in Adult Stem Cells. Genes (Basel) 2021; 12:1485. [PMID: 34680880 PMCID: PMC8535826 DOI: 10.3390/genes12101485] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/13/2021] [Accepted: 09/22/2021] [Indexed: 12/31/2022] Open
Abstract
Populations of resident stem cells (SCs) are responsible for maintaining, repairing, and regenerating adult tissues. In addition to having the capacity to generate all the differentiated cell types of the tissue, adult SCs undergo long periods of quiescence within the niche to maintain themselves. The process of SC renewal and differentiation is tightly regulated for proper tissue regeneration throughout an organisms' lifetime. Epigenetic regulators, such as the polycomb group (PcG) of proteins have been implicated in modulating gene expression in adult SCs to maintain homeostatic and regenerative balances in adult tissues. In this review, we summarize the recent findings that elucidate the composition and function of the polycomb repressive complex machinery and highlight their role in diverse adult stem cell compartments.
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Affiliation(s)
- Pooja Flora
- Department of Cell, Developmental, and Regenerative Biology, Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, USA;
| | - Gil Dalal
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel;
| | - Idan Cohen
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel;
| | - Elena Ezhkova
- Department of Cell, Developmental, and Regenerative Biology, Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, USA;
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22
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López H, Schmitz G, Thoma R, Theres K. Super determinant1A, a RAWULdomain-containing protein, modulates axillary meristem formation and compound leaf development in tomato. THE PLANT CELL 2021; 33:2412-2430. [PMID: 34009392 PMCID: PMC8364250 DOI: 10.1093/plcell/koab121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 04/22/2021] [Indexed: 05/28/2023]
Abstract
Shoot branching and complex leaf development relies on the establishment of boundaries that precedes the formation of axillary meristems (AMs) and leaflets. The tomato (Solanum lycopersicum) super determinant mutant is compromised in both processes, due to a mutation in Sde1A. Sde1A encodes a protein with a RAWUL domain, which is also present in Polycomb Group Repressive Complex 1 (PRC1) RING finger proteins and WD Repeat Domain 48 proteins. Genetic analysis revealed that Sde1A and Bmi1A cooperate, whereas Bmi1C antagonizes both activities, indicating the existence of functionally opposing PRC1 complexes that interact with Sde1A. Sde1A is expressed at early stages of boundary development in a small group of cells in the center of the leaf-axil boundary, but its activity is required for meristem formation at later stages. This suggests that Sde1A and Bmi1A promote AM formation and complex leaf development by safeguarding a pool of cells in the developing boundary zones. Genetic and protein interaction analyses showed that Sde1A and Lateral suppressor (Ls) are components of the same genetic pathway. In contrast to ls, sde1a mutants are not compromised in inflorescence branching, suggesting that Sde1A is a potential target for breeding tomato cultivars with reduced side-shoot formation during vegetative development.
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Affiliation(s)
- Hernán López
- Max Planck Institute for Plant Breeding Research, Cologne D-50931, Germany
| | - Gregor Schmitz
- Max Planck Institute for Plant Breeding Research, Cologne D-50931, Germany
| | - Rahere Thoma
- Max Planck Institute for Plant Breeding Research, Cologne D-50931, Germany
| | - Klaus Theres
- Max Planck Institute for Plant Breeding Research, Cologne D-50931, Germany
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23
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Pham K, Masoudi N, Leyva-Díaz E, Hobert O. A nervous system-specific subnuclear organelle in Caenorhabditis elegans. Genetics 2021; 217:1-17. [PMID: 33683371 DOI: 10.1093/genetics/iyaa016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 11/12/2020] [Indexed: 12/26/2022] Open
Abstract
We describe here phase-separated subnuclear organelles in the nematode Caenorhabditis elegans, which we term NUN (NUclear Nervous system-specific) bodies. Unlike other previously described subnuclear organelles, NUN bodies are highly cell type specific. In fully mature animals, 4-10 NUN bodies are observed exclusively in the nucleus of neuronal, glial and neuron-like cells, but not in other somatic cell types. Based on co-localization and genetic loss of function studies, NUN bodies are not related to other previously described subnuclear organelles, such as nucleoli, splicing speckles, paraspeckles, Polycomb bodies, promyelocytic leukemia bodies, gems, stress-induced nuclear bodies, or clastosomes. NUN bodies form immediately after cell cycle exit, before other signs of overt neuronal differentiation and are unaffected by the genetic elimination of transcription factors that control many other aspects of neuronal identity. In one unusual neuron class, the canal-associated neurons, NUN bodies remodel during larval development, and this remodeling depends on the Prd-type homeobox gene ceh-10. In conclusion, we have characterized here a novel subnuclear organelle whose cell type specificity poses the intriguing question of what biochemical process in the nucleus makes all nervous system-associated cells different from cells outside the nervous system.
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Affiliation(s)
- Kenneth Pham
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
| | - Neda Masoudi
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
| | - Eduardo Leyva-Díaz
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
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24
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De Novo Polycomb Recruitment: Lessons from Latent Herpesviruses. Viruses 2021; 13:v13081470. [PMID: 34452335 PMCID: PMC8402699 DOI: 10.3390/v13081470] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/22/2021] [Accepted: 07/24/2021] [Indexed: 12/11/2022] Open
Abstract
The Human Herpesviruses persist in the form of a latent infection in specialized cell types. During latency, the herpesvirus genomes associate with cellular histone proteins and the viral lytic genes assemble into transcriptionally repressive heterochromatin. Although there is divergence in the nature of heterochromatin on latent herpesvirus genomes, in general, the genomes assemble into forms of heterochromatin that can convert to euchromatin to permit gene expression and therefore reactivation. This reversible form of heterochromatin is known as facultative heterochromatin and is most commonly characterized by polycomb silencing. Polycomb silencing is prevalent on the cellular genome and plays a role in developmentally regulated and imprinted genes, as well as X chromosome inactivation. As herpesviruses initially enter the cell in an un-chromatinized state, they provide an optimal system to study how de novo facultative heterochromatin is targeted to regions of DNA and how it contributes to silencing. Here, we describe how polycomb-mediated silencing potentially assembles onto herpesvirus genomes, synergizing what is known about herpesvirus latency with facultative heterochromatin targeting to the cellular genome. A greater understanding of polycomb silencing of herpesviruses will inform on the mechanism of persistence and reactivation of these pathogenic human viruses and provide clues regarding how de novo facultative heterochromatin forms on the cellular genome.
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25
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Simonini S, Bemer M, Bencivenga S, Gagliardini V, Pires ND, Desvoyes B, van der Graaff E, Gutierrez C, Grossniklaus U. The Polycomb group protein MEDEA controls cell proliferation and embryonic patterning in Arabidopsis. Dev Cell 2021; 56:1945-1960.e7. [PMID: 34192526 PMCID: PMC8279741 DOI: 10.1016/j.devcel.2021.06.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/22/2021] [Accepted: 06/07/2021] [Indexed: 12/13/2022]
Abstract
Establishing the embryonic body plan of multicellular organisms relies on precisely orchestrated cell divisions coupled with pattern formation, which, in animals, are regulated by Polycomb group (PcG) proteins. The conserved Polycomb Repressive Complex 2 (PRC2) mediates H3K27 trimethylation and comes in different flavors in Arabidopsis. The PRC2 catalytic subunit MEDEA is required for seed development; however, a role for PRC2 in embryonic patterning has been dismissed. Here, we demonstrate that embryos derived from medea eggs abort because MEDEA is required for patterning and cell lineage determination in the early embryo. Similar to PcG proteins in mammals, MEDEA regulates embryonic patterning and growth by controlling cell-cycle progression through repression of CYCD1;1, which encodes a core cell-cycle component. Thus, Arabidopsis embryogenesis is epigenetically regulated by PcG proteins, revealing that the PRC2-dependent modulation of cell-cycle progression was independently recruited to control embryonic cell proliferation and patterning in animals and plants. MEDEA, a Polycomb Repressive Complex 2 (PRC2) subunit, is required in embryo and endosperm MEDEA links cell proliferation and differentiation during embryonic pattern formation The PRC2 protein MEDEA directly regulates core cell-cycle components, i.e., cyclin CYCD1;1 Body plan and cell proliferation are epigenetically regulated in both animals and plants
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Affiliation(s)
- Sara Simonini
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland
| | - Marian Bemer
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland
| | - Stefano Bencivenga
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland
| | - Valeria Gagliardini
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland
| | - Nuno D Pires
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland
| | - Bénédicte Desvoyes
- Centro de Biología Molecular Severo Ochoa CSIC-UAM, Nicolás Cabrera 1, Cantoblanco 28049, Madrid, Spain
| | - Eric van der Graaff
- BIOSS Centre for Biological Signaling Studies, Faculty of Biology, Albert-Ludwigs-Universität Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Crisanto Gutierrez
- Centro de Biología Molecular Severo Ochoa CSIC-UAM, Nicolás Cabrera 1, Cantoblanco 28049, Madrid, Spain
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland.
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26
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Erokhin M, Gorbenko F, Lomaev D, Mazina MY, Mikhailova A, Garaev AK, Parshikov A, Vorobyeva NE, Georgiev P, Schedl P, Chetverina D. Boundaries potentiate polycomb response element-mediated silencing. BMC Biol 2021; 19:113. [PMID: 34078365 PMCID: PMC8170967 DOI: 10.1186/s12915-021-01047-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 05/07/2021] [Indexed: 12/21/2022] Open
Abstract
Background Epigenetic memory plays a critical role in the establishment and maintenance of cell identities in multicellular organisms. Polycomb and trithorax group (PcG and TrxG) proteins are responsible for epigenetic memory, and in flies, they are recruited to specialized DNA regulatory elements termed polycomb response elements (PREs). Previous transgene studies have shown that PREs can silence reporter genes outside of their normal context, often by pairing sensitive (PSS) mechanism; however, their silencing activity is non-autonomous and depends upon the surrounding chromatin context. It is not known why PRE activity depends on the local environment or what outside factors can induce silencing. Results Using an attP system in Drosophila, we find that the so-called neutral chromatin environments vary substantially in their ability to support the silencing activity of the well-characterized bxdPRE. In refractory chromosomal contexts, factors required for PcG-silencing are unable to gain access to the PRE. Silencing activity can be rescued by linking the bxdPRE to a boundary element (insulator). When placed next to the PRE, the boundaries induce an alteration in chromatin structure enabling factors critical for PcG silencing to gain access to the bxdPRE. When placed at a distance from the bxdPRE, boundaries induce PSS by bringing the bxdPREs on each homolog in close proximity. Conclusion This proof-of-concept study demonstrates that the repressing activity of PREs can be induced or enhanced by nearby boundary elements. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01047-8.
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Affiliation(s)
- Maksim Erokhin
- Group of Chromatin Biology, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334, Russia.
| | - Fedor Gorbenko
- Group of Chromatin Biology, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334, Russia.,Present address: Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Dmitry Lomaev
- Group of Epigenetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334, Russia
| | - Marina Yu Mazina
- Group of Transcriptional Complexes Dynamics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Anna Mikhailova
- Group of Chromatin Biology, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334, Russia
| | - Azat K Garaev
- Laboratory of Structural and Functional Organization of Chromosomes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334, Russia
| | - Aleksander Parshikov
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334, Russia
| | - Nadezhda E Vorobyeva
- Group of Transcriptional Complexes Dynamics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334, Russia
| | - Paul Schedl
- Department of Molecular Biology Princeton University, Princeton, NJ, 08544, USA.
| | - Darya Chetverina
- Group of Epigenetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334, Russia.
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27
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Polycomb-group proteins in the initiation and progression of cancer. J Genet Genomics 2021; 48:433-443. [PMID: 34266781 DOI: 10.1016/j.jgg.2021.03.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/23/2021] [Accepted: 03/28/2021] [Indexed: 12/13/2022]
Abstract
The Polycomb group (PcG) proteins are a family of chromatin regulators and critical for the maintenance of cellular identity. The PcG machinery can be categorized into at least three multi-protein complexes, namely Polycomb Repressive Complex 1 (PRC1), PRC2, and Polycomb Repressive DeUBiquitinase (PR-DUB). Their deregulation has been associated with human cancer initiation and progression. Here we review the updated understanding for PcG proteins in transcription regulation and DNA damage repair and highlight increasing links to the hallmarks in cancer. Accordingly, we discuss some of the recent advances in drug development or strategies against cancers caused by the gain or loss of PcG functions.
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28
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Chaouch A, Lasko P. Drosophila melanogaster: a fruitful model for oncohistones. Fly (Austin) 2021; 15:28-37. [PMID: 33423597 DOI: 10.1080/19336934.2020.1863124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Drosophila melanogaster has proven to be a powerful genetic model to study human disease. Approximately 75% of human disease-associated genes have homologs in the fruit fly and regulatory pathways are highly conserved in Drosophila compared to humans. Drosophila is an established model organism for the study of genetics and developmental biology related to human disease and has also made a great contribution to epigenetic research. Many key factors that regulate chromatin condensation through effects on histone post-translational modifications were first discovered in genetic screens in Drosophila. Recently, the importance of chromatin regulators in cancer progression has been uncovered, leading to a rapid expansion in the knowledge on how perturbations of chromatin can result in the pathogenesis of human cancer. In this review, we provide examples of how Drosophila melanogaster has contributed to better understanding the detrimental effects of mutant forms of histones, called 'oncohistones', that are found in different human tumours.
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Affiliation(s)
- Amel Chaouch
- Department of Biology, McGill University , Montréal, Québec, Canada
| | - Paul Lasko
- Department of Biology, McGill University , Montréal, Québec, Canada.,Department of Human Genetics, Radboudumc , Nijmegen, Netherlands
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29
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CXCR4 Regulates Temporal Differentiation via PRC1 Complex in Organogenesis of Epithelial Glands. Int J Mol Sci 2021; 22:ijms22020619. [PMID: 33435128 PMCID: PMC7826811 DOI: 10.3390/ijms22020619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/02/2021] [Accepted: 01/06/2021] [Indexed: 11/17/2022] Open
Abstract
CXC-chemokine receptor type 4 (CXCR4), a 7-transmembrane receptor family member, displays multifaceted roles, participating in immune cell migration, angiogenesis, and even adipocyte metabolism. However, the activity of such a ubiquitously expressed receptor in epithelial gland organogenesis has not yet been fully explored. To investigate the relationship between CXCL12/CXCR4 signaling and embryonic glandular organogenesis, we used an ex vivo culture system with live imaging and RNA sequencing to elucidate the transcriptome and protein-level signatures of AMD3100, a potent abrogating reagent of the CXCR4-CXCL12 axis, imprinted on the developing organs. Immunostaining results showed that CXCR4 was highly expressed in embryonic submandibular gland, lung, and pancreas, especially at the periphery of end buds containing numerous embryonic stem/progenitor cells. Despite no significant increase in apoptosis, AMD3100-treated epithelial organs showed a retarded growth with significantly slower branching and expansion. Further analyses with submandibular glands revealed that such responses resulted from the AMD3100-induced precocious differentiation of embryonic epithelial cells, losing mitotic activity. RNA sequencing analysis revealed that inhibition of CXCR4 significantly down-regulated polycomb repressive complex (PRC) components, known as regulators of DNA methylation. Treatment with PRC inhibitor recapitulated the AMD3100-induced precocious differentiation. Our results indicate that the epigenetic modulation by the PRC-CXCR12/CXCR4 signaling axis is crucial for the spatiotemporal regulation of proliferation and differentiation of embryonic epithelial cells during embryonic glandular organogenesis.
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30
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Order and stochasticity in the folding of individual Drosophila genomes. Nat Commun 2021; 12:41. [PMID: 33397980 PMCID: PMC7782554 DOI: 10.1038/s41467-020-20292-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 11/23/2020] [Indexed: 02/06/2023] Open
Abstract
Mammalian and Drosophila genomes are partitioned into topologically associating domains (TADs). Although this partitioning has been reported to be functionally relevant, it is unclear whether TADs represent true physical units located at the same genomic positions in each cell nucleus or emerge as an average of numerous alternative chromatin folding patterns in a cell population. Here, we use a single-nucleus Hi-C technique to construct high-resolution Hi-C maps in individual Drosophila genomes. These maps demonstrate chromatin compartmentalization at the megabase scale and partitioning of the genome into non-hierarchical TADs at the scale of 100 kb, which closely resembles the TAD profile in the bulk in situ Hi-C data. Over 40% of TAD boundaries are conserved between individual nuclei and possess a high level of active epigenetic marks. Polymer simulations demonstrate that chromatin folding is best described by the random walk model within TADs and is most suitably approximated by a crumpled globule build of Gaussian blobs at longer distances. We observe prominent cell-to-cell variability in the long-range contacts between either active genome loci or between Polycomb-bound regions, suggesting an important contribution of stochastic processes to the formation of the Drosophila 3D genome. Genomes are partitioned into topologically associating domains (TADs). Here the authors present single-nucleus Hi-C maps in Drosophila at 10 kb resolution, demonstrating the presence of chromatin compartments in individual nuclei, and partitioning of the genome into non-hierarchical TADs at the scale of 100 kb, which resembles population TAD profiles.
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31
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Seif E, Kang JJ, Sasseville C, Senkovich O, Kaltashov A, Boulier EL, Kapur I, Kim CA, Francis NJ. Phase separation by the polyhomeotic sterile alpha motif compartmentalizes Polycomb Group proteins and enhances their activity. Nat Commun 2020; 11:5609. [PMID: 33154383 PMCID: PMC7644731 DOI: 10.1038/s41467-020-19435-z] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 10/08/2020] [Indexed: 02/07/2023] Open
Abstract
Polycomb Group (PcG) proteins organize chromatin at multiple scales to regulate gene expression. A conserved Sterile Alpha Motif (SAM) in the Polycomb Repressive Complex 1 (PRC1) subunit Polyhomeotic (Ph) has been shown to play an important role in chromatin compaction and large-scale chromatin organization. Ph SAM forms helical head to tail polymers, and SAM-SAM interactions between chromatin-bound Ph/PRC1 are believed to compact chromatin and mediate long-range interactions. To understand the underlying mechanism, here we analyze the effects of Ph SAM on chromatin in vitro. We find that incubation of chromatin or DNA with a truncated Ph protein containing the SAM results in formation of concentrated, phase-separated condensates. Ph SAM-dependent condensates can recruit PRC1 from extracts and enhance PRC1 ubiquitin ligase activity towards histone H2A. We show that overexpression of Ph with an intact SAM increases ubiquitylated H2A in cells. Thus, SAM-induced phase separation, in the context of Ph, can mediate large-scale compaction of chromatin into biochemical compartments that facilitate histone modification.
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Affiliation(s)
- Elias Seif
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
| | - Jin Joo Kang
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
- Division of Experimental Medicine, McGill University, 1001 Decarie Boulevard, Montreal, QC, H4A 3J1, Canada
| | - Charles Sasseville
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
| | - Olga Senkovich
- Department of Biochemistry and Molecular Genetics, Midwestern University, 19555N. 59th St., Glendale, AZ, 85308, USA
| | - Alexander Kaltashov
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
| | - Elodie L Boulier
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
| | - Ibani Kapur
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
- Division of Experimental Medicine, McGill University, 1001 Decarie Boulevard, Montreal, QC, H4A 3J1, Canada
| | - Chongwoo A Kim
- Department of Biochemistry and Molecular Genetics, Midwestern University, 19555N. 59th St., Glendale, AZ, 85308, USA
| | - Nicole J Francis
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada.
- Division of Experimental Medicine, McGill University, 1001 Decarie Boulevard, Montreal, QC, H4A 3J1, Canada.
- Département de biochimie et médecine moléculaire Université de Montréal, 2900 Boulevard Edouard-Montpetit, Montréal, QC, H3T 1J4, Canada.
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32
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Abstract
The interaction between polycomb-repressive complexes 1/2 (PRC1/2) and long non-coding RNA (lncRNA), such as the X inactive specific transcript Xist and the HOX transcript antisense RNA (HOTAIR), has been the subject of intense debate. While cross-linking, immuno-precipitation and super-resolution microscopy argue against direct interaction of Polycomb with some lncRNAs, there is increasing evidence supporting the ability of both PRC1 and PRC2 to functionally associate with RNA. Recent data indicate that these interactions are in most cases spurious, but nonetheless crucial for a number of cellular activities. In this review, we suggest that while PRC1/2 recruitment by HOTAIR might be direct, in the case of Xist, it might occur indirectly and, at least in part, through the process of liquid-liquid phase separation. We present recent models of lncRNA-mediated PRC1/2 recruitment to their targets and describe potential RNA-mediated roles in the three-dimensional organization of the nucleus.
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Affiliation(s)
- Andrea Cerase
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK
| | - Gian Gaetano Tartaglia
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain.,Institucio Catalana de Recerca i Estudis Avançats (ICREA), 23 Passeig Lluis Companys, 08010 Barcelona, Spain.,Department of Biology 'Charles Darwin', Sapienza University of Rome, P.le A. Moro 5, Rome 00185, Italy.,Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163, Genoa, Italy
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33
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Abstract
Mutations of the cohesin complex in human cancer were first discovered ~10 years ago. Since then, researchers worldwide have demonstrated that cohesin is among the most commonly mutated protein complexes in cancer. Inactivating mutations in genes encoding cohesin subunits are common in bladder cancers, paediatric sarcomas, leukaemias, brain tumours and other cancer types. Also in those 10 years, the prevailing view of the functions of cohesin in cell biology has undergone a revolutionary transformation. Initially, the predominant view of cohesin was as a ring that encircled and cohered replicated chromosomes until its cleavage triggered the metaphase-to-anaphase transition. As such, early studies focused on the role of tumour-derived cohesin mutations in the fidelity of chromosome segregation and aneuploidy. However, over the past 5 years the cohesin field has shifted dramatically, and research now focuses on the primary role of cohesin in generating, maintaining and regulating the intra-chromosomal DNA looping events that modulate 3D genome organization and gene expression. This Review focuses on recent discoveries in the cohesin field that provide insight into the role of cohesin inactivation in cancer pathogenesis, and opportunities for exploiting these findings for the clinical benefit of patients with cohesin-mutant cancers.
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Affiliation(s)
- Todd Waldman
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University School of Medicine, Washington, DC, USA.
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34
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Santos AP, Gaudin V, Mozgová I, Pontvianne F, Schubert D, Tek AL, Dvořáčková M, Liu C, Fransz P, Rosa S, Farrona S. Tidying-up the plant nuclear space: domains, functions, and dynamics. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:5160-5178. [PMID: 32556244 PMCID: PMC8604271 DOI: 10.1093/jxb/eraa282] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 06/12/2020] [Indexed: 05/07/2023]
Abstract
Understanding how the packaging of chromatin in the nucleus is regulated and organized to guide complex cellular and developmental programmes, as well as responses to environmental cues is a major question in biology. Technological advances have allowed remarkable progress within this field over the last years. However, we still know very little about how the 3D genome organization within the cell nucleus contributes to the regulation of gene expression. The nuclear space is compartmentalized in several domains such as the nucleolus, chromocentres, telomeres, protein bodies, and the nuclear periphery without the presence of a membrane around these domains. The role of these domains and their possible impact on nuclear activities is currently under intense investigation. In this review, we discuss new data from research in plants that clarify functional links between the organization of different nuclear domains and plant genome function with an emphasis on the potential of this organization for gene regulation.
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Affiliation(s)
- Ana Paula Santos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova
de Lisboa, Oeiras, Portugal
| | - Valérie Gaudin
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université
Paris-Saclay, Versailles, France
| | - Iva Mozgová
- Biology Centre of the Czech Academy of Sciences, České
Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České
Budějovice, Czech Republic
| | - Frédéric Pontvianne
- CNRS, Laboratoire Génome et Développement des Plantes (LGDP), Université de
Perpignan Via Domitia, Perpignan, France
| | - Daniel Schubert
- Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | - Ahmet L Tek
- Agricultural Genetic Engineering Department, Niğde Ömer Halisdemir
University, Niğde, Turkey
| | | | - Chang Liu
- Center for Plant Molecular Biology (ZMBP), University of
Tübingen, Tübingen, Germany
- Institute of Biology, University of Hohenheim, Stuttgart,
Germany
| | - Paul Fransz
- University of Amsterdam, Amsterdam, The
Netherlands
| | - Stefanie Rosa
- Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Sara Farrona
- Plant and AgriBiosciences Centre, Ryan Institute, NUI Galway,
Galway, Ireland
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35
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Kang JJ, Faubert D, Boulais J, Francis NJ. DNA Binding Reorganizes the Intrinsically Disordered C-Terminal Region of PSC in Drosophila PRC1. J Mol Biol 2020; 432:4856-4871. [PMID: 32628956 DOI: 10.1016/j.jmb.2020.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/01/2020] [Accepted: 07/01/2020] [Indexed: 12/27/2022]
Abstract
Polycomb Group proteins regulate gene expression by modifying chromatin. Polycomb Repressive Complex 1 (PRC1) has two activities: a ubiquitin ligase activity for histone H2A and a chromatin compacting activity. In Drosophila, the Posterior Sex Combs (PSC) subunit of PRC1 is central to both activities. The N-terminal of PSC assembles into PRC1, including partnering with dRING to form the ubiquitin ligase. The intrinsically disordered C-terminal region of PSC compacts chromatin and inhibits chromatin remodeling and transcription in vitro. Both regions of PSC are essential in vivo. To understand how these two activities may be coordinated in PRC1, we used crosslinking mass spectrometry to analyze the conformations of the C-terminal region of PSC in PRC1 and how they change on binding DNA. Crosslinking identifies interactions between the C-terminal region of PSC and the core of PRC1, including between N and C-terminal regions of PSC. New contacts and overall more compacted PSC C-terminal region conformations are induced by DNA binding. Protein footprinting of accessible lysine residues reveals an extended, bipartite candidate DNA/chromatin binding surface in the C-terminal region of PSC. Our data suggest a model in which DNA (or chromatin) follows a long path on the flexible disordered region of PSC. Intramolecular interactions of PSC detected by crosslinking can bring the high-affinity DNA/chromatin binding region close to the core of PRC1 without disrupting the interface between the ubiquitin ligase and the nucleosome. Our approach may be applicable to understanding the global organization of other large intrinsically disordered regions that bind nucleic acids.
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Affiliation(s)
- Jin Joo Kang
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada; Division of Experimental Medicine, McGill University, 1001 Decarie Boulevard, Montreal, QC H4A 3J1, Canada.
| | - Denis Faubert
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada.
| | - Jonathan Boulais
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada.
| | - Nicole J Francis
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada; Division of Experimental Medicine, McGill University, 1001 Decarie Boulevard, Montreal, QC H4A 3J1, Canada; Département de biochimie et médecine moléculaire Université de Montréal, 2900 Boulevard Edouard-Montpetit, Montréal, QC H3T 1J4, Canada..
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36
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Loubiere V, Papadopoulos GL, Szabo Q, Martinez AM, Cavalli G. Widespread activation of developmental gene expression characterized by PRC1-dependent chromatin looping. SCIENCE ADVANCES 2020; 6:eaax4001. [PMID: 31950077 PMCID: PMC6954061 DOI: 10.1126/sciadv.aax4001] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 11/06/2019] [Indexed: 05/21/2023]
Abstract
Polycomb repressive complexes 1 and 2 have been historically described as transcriptional repressors, but recent reports suggest that PRC1 might also support activation, although the underlying mechanisms remain elusive. Here, we show that stage-specific PRC1 binding at a subset of active promoters and enhancers during Drosophila development coincides with the formation of three-dimensional (3D) loops, an increase in expression during development and repression in PRC1 mutants. Dissection of the dachshund locus indicates that PRC1-anchored loops are versatile architectural platforms that persist when surrounding genes are transcriptionally active and fine-tune their expression. The analysis of RING1B binding profiles and 3D contacts during neural differentiation in mice suggests that this role is conserved in mammals.
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Affiliation(s)
- V. Loubiere
- Institute of Human Genetics, UMR 9002, CNRS–University of Montpellier, 34396 Montpellier, France
| | - G. L. Papadopoulos
- Institute of Human Genetics, UMR 9002, CNRS–University of Montpellier, 34396 Montpellier, France
| | - Q. Szabo
- Institute of Human Genetics, UMR 9002, CNRS–University of Montpellier, 34396 Montpellier, France
| | - A-M. Martinez
- Institute of Human Genetics, UMR 9002, CNRS–University of Montpellier, 34396 Montpellier, France
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