101
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Tesi A, de Pretis S, Furlan M, Filipuzzi M, Morelli MJ, Andronache A, Doni M, Verrecchia A, Pelizzola M, Amati B, Sabò A. An early Myc-dependent transcriptional program orchestrates cell growth during B-cell activation. EMBO Rep 2019; 20:e47987. [PMID: 31334602 PMCID: PMC6726900 DOI: 10.15252/embr.201947987] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 06/18/2019] [Accepted: 06/27/2019] [Indexed: 12/18/2022] Open
Abstract
Upon activation, lymphocytes exit quiescence and undergo substantial increases in cell size, accompanied by activation of energy-producing and anabolic pathways, widespread chromatin decompaction, and elevated transcriptional activity. These changes depend upon prior induction of the Myc transcription factor, but how Myc controls them remains unclear. We addressed this issue by profiling the response to LPS stimulation in wild-type and c-myc-deleted primary mouse B-cells. Myc is rapidly induced, becomes detectable on virtually all active promoters and enhancers, but has no direct impact on global transcriptional activity. Instead, Myc contributes to the swift up- and down-regulation of several hundred genes, including many known regulators of the aforementioned cellular processes. Myc-activated promoters are enriched for E-box consensus motifs, bind Myc at the highest levels, and show enhanced RNA Polymerase II recruitment, the opposite being true at down-regulated loci. Remarkably, the Myc-dependent signature identified in activated B-cells is also enriched in Myc-driven B-cell lymphomas: hence, besides modulation of new cancer-specific programs, the oncogenic action of Myc may largely rely on sustained deregulation of its normal physiological targets.
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Affiliation(s)
- Alessandra Tesi
- Center for Genomic Science of IIT@SEMMFondazione Istituto Italiano di Tecnologia (IIT)MilanItaly
| | - Stefano de Pretis
- Center for Genomic Science of IIT@SEMMFondazione Istituto Italiano di Tecnologia (IIT)MilanItaly
| | - Mattia Furlan
- Center for Genomic Science of IIT@SEMMFondazione Istituto Italiano di Tecnologia (IIT)MilanItaly
| | - Marco Filipuzzi
- Department of Experimental OncologyEuropean Institute of Oncology (IEO)‐IRCCSMilanItaly
| | - Marco J Morelli
- Center for Genomic Science of IIT@SEMMFondazione Istituto Italiano di Tecnologia (IIT)MilanItaly
- Present address:
Center for Translational Genomics and BioinformaticsIRCCS San Raffaele Scientific InstituteMilanItaly
| | - Adrian Andronache
- Center for Genomic Science of IIT@SEMMFondazione Istituto Italiano di Tecnologia (IIT)MilanItaly
- Present address:
Experimental Therapeutics Program of IFOM ‐ The FIRC Institute of Molecular OncologyMilanItaly
| | - Mirko Doni
- Department of Experimental OncologyEuropean Institute of Oncology (IEO)‐IRCCSMilanItaly
| | - Alessandro Verrecchia
- Department of Experimental OncologyEuropean Institute of Oncology (IEO)‐IRCCSMilanItaly
| | - Mattia Pelizzola
- Center for Genomic Science of IIT@SEMMFondazione Istituto Italiano di Tecnologia (IIT)MilanItaly
| | - Bruno Amati
- Department of Experimental OncologyEuropean Institute of Oncology (IEO)‐IRCCSMilanItaly
| | - Arianna Sabò
- Department of Experimental OncologyEuropean Institute of Oncology (IEO)‐IRCCSMilanItaly
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102
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El Khattabi L, Zhao H, Kalchschmidt J, Young N, Jung S, Van Blerkom P, Kieffer-Kwon P, Kieffer-Kwon KR, Park S, Wang X, Krebs J, Tripathi S, Sakabe N, Sobreira DR, Huang SC, Rao SSP, Pruett N, Chauss D, Sadler E, Lopez A, Nóbrega MA, Aiden EL, Asturias FJ, Casellas R. A Pliable Mediator Acts as a Functional Rather Than an Architectural Bridge between Promoters and Enhancers. Cell 2019; 178:1145-1158.e20. [PMID: 31402173 PMCID: PMC7533040 DOI: 10.1016/j.cell.2019.07.011] [Citation(s) in RCA: 148] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 05/24/2019] [Accepted: 07/09/2019] [Indexed: 12/11/2022]
Abstract
While Mediator plays a key role in eukaryotic transcription, little is known about its mechanism of action. This study combines CRISPR-Cas9 genetic screens, degron assays, Hi-C, and cryoelectron microscopy (cryo-EM) to dissect the function and structure of mammalian Mediator (mMED). Deletion analyses in B, T, and embryonic stem cells (ESC) identified a core of essential subunits required for Pol II recruitment genome-wide. Conversely, loss of non-essential subunits mostly affects promoters linked to multiple enhancers. Contrary to current models, however, mMED and Pol II are dispensable to physically tether regulatory DNA, a topological activity requiring architectural proteins. Cryo-EM analysis revealed a conserved core, with non-essential subunits increasing structural complexity of the tail module, a primary transcription factor target. Changes in tail structure markedly increase Pol II and kinase module interactions. We propose that Mediator's structural pliability enables it to integrate and transmit regulatory signals and act as a functional, rather than an architectural bridge, between promoters and enhancers.
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Affiliation(s)
| | - Haiyan Zhao
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical School, Aurora CO 80045, USA
| | | | - Natalie Young
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical School, Aurora CO 80045, USA
| | - Seolkyoung Jung
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Peter Van Blerkom
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical School, Aurora CO 80045, USA
| | | | | | - Solji Park
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Xiang Wang
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Jordan Krebs
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA
| | | | - Noboru Sakabe
- Department of Human Genetics, University of Chicago, Chicago, IL, USA
| | - Débora R Sobreira
- Department of Human Genetics, University of Chicago, Chicago, IL, USA
| | - Su-Chen Huang
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
| | - Suhas S P Rao
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | - Daniel Chauss
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Erica Sadler
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Andrea Lopez
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Marcelo A Nóbrega
- Department of Human Genetics, University of Chicago, Chicago, IL, USA
| | - Erez Lieberman Aiden
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Center for Theoretical Biological Physics, Rice University, Houston, TX 77030, USA; Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
| | - Francisco J Asturias
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical School, Aurora CO 80045, USA.
| | - Rafael Casellas
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA; Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA.
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103
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Hung KH, Woo YH, Lin IY, Liu CH, Wang LC, Chen HY, Chiang BL, Lin KI. The KDM4A/KDM4C/NF-κB and WDR5 epigenetic cascade regulates the activation of B cells. Nucleic Acids Res 2019; 46:5547-5560. [PMID: 29718303 PMCID: PMC6009645 DOI: 10.1093/nar/gky281] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 04/04/2018] [Indexed: 12/13/2022] Open
Abstract
T follicular helper (Tfh) cell-derived signals promote activation and proliferation of antigen-primed B cells. It remains unclear whether epigenetic regulation is involved in the B cell responses to Tfh cell-derived signals. Here, we demonstrate that Tfh cell-mimicking signals induce the expression of histone demethylases KDM4A and KDM4C, and the concomitant global down-regulation of their substrates, H3K9me3/me2, in B cells. Depletion of KDM4A and KDM4C potentiates B cell activation and proliferation in response to Tfh cell-derived signals. ChIP-seq and de novo motif analysis reveals NF-κB p65 as a binding partner of KDM4A and KDM4C. Their co-targeting to Wdr5, a MLL complex member promoting H3K4 methylation, up-regulates cell cycle inhibitors Cdkn2c and Cdkn3. Thus, Tfh cell-derived signals trigger KDM4A/KDM4C - WDR5 - Cdkn2c/Cdkn3 cascade in vitro, an epigenetic mechanism regulating proper proliferation of activated B cells. This pathway is dysregulated in B cells from systemic lupus erythematosus patients and may represent a pathological link.
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Affiliation(s)
- Kuo-Hsuan Hung
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Yong H Woo
- Division of Biological Sciences, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - I-Ying Lin
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Chin-Hsiu Liu
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan.,PhD Program in Translational Medicine, Kaohsiung Medical University and Academia Sinica, Division of Allergy, Immunology and Rheumatology, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City 231, Taiwan
| | - Li-Chieh Wang
- Department of Pediatrics, National Taiwan University Hospital, Taipei 100, Taiwan
| | - Hsin-Yu Chen
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Bor-Luen Chiang
- Department of Pediatrics, National Taiwan University Hospital, Taipei 100, Taiwan.,Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Kuo-I Lin
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
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104
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Morrish RB, Hermes M, Metz J, Stone N, Pagliara S, Chahwan R, Palombo F. Single Cell Imaging of Nuclear Architecture Changes. Front Cell Dev Biol 2019; 7:141. [PMID: 31396512 PMCID: PMC6668442 DOI: 10.3389/fcell.2019.00141] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 07/10/2019] [Indexed: 12/31/2022] Open
Abstract
The dynamic architecture of chromatin, the macromolecular complex comprised primarily of DNA and histones, is vital for eukaryotic cell growth. Chemical and conformational changes to chromatin are important markers of functional and developmental processes in cells. However, chromatin architecture regulation has not yet been fully elucidated. Therefore, novel approaches to assessing chromatin changes at the single-cell level are required. Here we report the use of FTIR imaging and microfluidic cell-stretcher chips to assess changes to chromatin architecture and its effect on the mechanical properties of the nucleus in immune cells. FTIR imaging enables label-free chemical imaging with subcellular resolution. By optimizing the FTIR methodology and coupling it with cell segmentation analysis approach, we have identified key spectral changes corresponding to changes in DNA levels and chromatin conformation at the single cell level. By further manipulating live single cells using pressure-driven microfluidics, we found that chromatin decondensation - either during general transcriptional activation or during specific immune cell maturation - can ultimately lead to nuclear auxeticity which is a new biological phenomenon recently identified. Taken together our findings demonstrate the tight and, potentially bilateral, link between extra-cellular mechanotransduction and intra-cellular nuclear architecture.
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Affiliation(s)
- Rikke Brandstrup Morrish
- School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
- Living Systems Institute and School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Michael Hermes
- School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - Jeremy Metz
- Living Systems Institute and School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Nicholas Stone
- School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - Stefano Pagliara
- Living Systems Institute and School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Richard Chahwan
- Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
| | - Francesca Palombo
- School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
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105
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Placek K, Schultze JL, Aschenbrenner AC. Epigenetic reprogramming of immune cells in injury, repair, and resolution. J Clin Invest 2019; 129:2994-3005. [PMID: 31329166 DOI: 10.1172/jci124619] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Immune cells are pivotal in the reaction to injury, whereupon, under ideal conditions, repair and resolution phases restore homeostasis following initial acute inflammation. Immune cell activation and reprogramming require transcriptional changes that can only be initiated if epigenetic alterations occur. Recently, accelerated deciphering of epigenetic mechanisms has extended knowledge of epigenetic regulation, including long-distance chromatin remodeling, DNA methylation, posttranslational histone modifications, and involvement of small and long noncoding RNAs. Epigenetic changes have been linked to aspects of immune cell development, activation, and differentiation. Furthermore, genome-wide epigenetic landscapes have been established for some immune cells, including tissue-resident macrophages, and blood-derived cells including T cells. The epigenetic mechanisms underlying developmental steps from hematopoietic stem cells to fully differentiated immune cells led to development of epigenetic technologies and insights into general rules of epigenetic regulation. Compared with more advanced research areas, epigenetic reprogramming of immune cells in injury remains in its infancy. While the early epigenetic mechanisms supporting activation of the immune response to injury have been studied, less is known about resolution and repair phases and cell type-specific changes. We review prominent recent findings concerning injury-mediated epigenetic reprogramming, particularly in stroke and myocardial infarction. Lastly, we illustrate how single-cell technologies will be crucial to understanding epigenetic reprogramming in the complex sequential processes following injury.
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Affiliation(s)
- Katarzyna Placek
- Immunology and Metabolism, LIMES Institute, University of Bonn, Bonn, Germany
| | - Joachim L Schultze
- Platform for Single Cell Genomics and Epigenomics at the German Center for Neurodegenerative Diseases and the University of Bonn, Bonn, Germany.,Genomics and Immunoregulation, LIMES Institute, University of Bonn, Bonn, Germany
| | - Anna C Aschenbrenner
- Genomics and Immunoregulation, LIMES Institute, University of Bonn, Bonn, Germany
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106
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Chemical genomics reveals histone deacetylases are required for core regulatory transcription. Nat Commun 2019; 10:3004. [PMID: 31285436 PMCID: PMC6614369 DOI: 10.1038/s41467-019-11046-7] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 05/28/2019] [Indexed: 01/08/2023] Open
Abstract
Identity determining transcription factors (TFs), or core regulatory (CR) TFs, are governed by cell-type specific super enhancers (SEs). Drugs to selectively inhibit CR circuitry are of high interest for cancer treatment. In alveolar rhabdomyosarcoma, PAX3-FOXO1 activates SEs to induce the expression of other CR TFs, providing a model system for studying cancer cell addiction to CR transcription. Using chemical genetics, the systematic screening of chemical matter for a biological outcome, here we report on a screen for epigenetic chemical probes able to distinguish between SE-driven transcription and constitutive transcription. We find that chemical probes along the acetylation-axis, and not the methylation-axis, selectively disrupt CR transcription. Additionally, we find that histone deacetylases (HDACs) are essential for CR TF transcription. We further dissect the contribution of HDAC isoforms using selective inhibitors, including the newly developed selective HDAC3 inhibitor LW3. We show HDAC1/2/3 are the co-essential isoforms that when co-inhibited halt CR transcription, making CR TF sites hyper-accessible and disrupting chromatin looping. Core regulatory transcription factors are usually regulated by cell-type specific super enhancers (SEs). Here, the authors screen for chemical probes able to distinguish between SE-driven and promoter-driven transcription and find that histone deacetylases are selectively required for core regulatory transcription.
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107
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Abstract
PURPOSE OF REVIEW Chromatin organization during interphase is nonrandom, and dictated by a delicate equilibrium between biophysics, transcription factor expression, and topological regulators of the chromatin. Emerging evidence demonstrate a role for chromosomal conformation at different stages of B-cell development. In the present review, we provide an updated picture of the current knowledge regarding how chromosomal conformation regulates the B-cell phenotype and how disruption of this architecture could lead to B-cell lymphoma. RECENT FINDINGS B-cell development requires proper assembly of a rearranged VDJ locus, which will determine antigen receptor specificity. Recently, evidence pointed to a role for topological regulators during VDJ recombination. Research studies also demonstrated a link between shifts in nuclear chromosomal architecture during B-cell activation and in formation of germinal centers, which is required for immunoglobulin affinity maturation. Class-switch recombination was shown to be dependent on the presence of topology regulators. Loss of topological insulation of enhancers may lead to oncogene activation, suggesting that misfolding of chromatin may constitute a new epigenetic mechanism of malignant transformation. Finally, CCCTC-binding factor and cohesin binding sites have shown a higher probability of mutations and translocations in lymphomas, lending further support to the potential role of chromatin architecture in cancer development. SUMMARY Chromosomal conformation is now recognized as a key feature in the development of a robust humoral immune response. Several examples from the literature show that dysregulation of chromosomal architecture may be a foundational event during malignancy. Therefore, understanding the mechanisms that regulate chromosomal folding and drive gene activation are instrumental for a better understanding of immune regulation and lymphomagenesis.
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Affiliation(s)
- Martin A Rivas
- Division of Hematology and Medical Oncology, Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medicine, Sandra and Edward Meyer Cancer Center, New York, New York, USA
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108
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Chen D, Lei EP. Function and regulation of chromatin insulators in dynamic genome organization. Curr Opin Cell Biol 2019; 58:61-68. [PMID: 30875678 PMCID: PMC6692201 DOI: 10.1016/j.ceb.2019.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/15/2019] [Accepted: 02/12/2019] [Indexed: 12/21/2022]
Abstract
Chromatin insulators are DNA-protein complexes that play a crucial role in regulating chromatin organization. Within the past two years, a plethora of genome-wide conformation capture studies have helped reveal that insulators are necessary for proper genome-wide organization of topologically associating domains, which are formed in a manner distinct from that of compartments. These studies have also provided novel insights into the mechanics of how CTCF/cohesin-dependent loops form in mammals, strongly supporting the loop extrusion model. In combination with single-cell imaging approaches in both Drosophila and mammals, the dynamics of insulator-mediated chromatin interactions are also coming to light. Insulator-dependent structures vary across individual cells and tissues, highlighting the need to study the regulation of insulators in particular temporal and spatial contexts throughout development.
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Affiliation(s)
- Dahong Chen
- Nuclear Organization and Gene Expression Section, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Elissa P Lei
- Nuclear Organization and Gene Expression Section, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
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109
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Magli A, Baik J, Pota P, Cordero CO, Kwak IY, Garry DJ, Love PE, Dynlacht BD, Perlingeiro RCR. Pax3 cooperates with Ldb1 to direct local chromosome architecture during myogenic lineage specification. Nat Commun 2019; 10:2316. [PMID: 31127120 PMCID: PMC6534668 DOI: 10.1038/s41467-019-10318-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 04/26/2019] [Indexed: 12/12/2022] Open
Abstract
Chromatin looping allows enhancer-bound regulatory factors to influence transcription. Large domains, referred to as topologically associated domains, participate in genome organization. However, the mechanisms underlining interactions within these domains, which control gene expression, are not fully understood. Here we report that activation of embryonic myogenesis is associated with establishment of long-range chromatin interactions centered on Pax3-bound loci. Using mass spectrometry and genomic studies, we identify the ubiquitously expressed LIM-domain binding protein 1 (Ldb1) as the mediator of looping interactions at a subset of Pax3 binding sites. Ldb1 is recruited to Pax3-bound elements independently of CTCF-Cohesin, and is necessary for efficient deposition of H3K4me1 at these sites and chromatin looping. When Ldb1 is deleted in Pax3-expressing cells in vivo, specification of migratory myogenic progenitors is severely impaired. These results highlight Ldb1 requirement for Pax3 myogenic activity and demonstrate how transcription factors can promote formation of sub-topologically associated domain interactions involved in lineage specification.
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Affiliation(s)
- Alessandro Magli
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA.
- Stem Cell Institute, University of Minnesota, Minneapolis, MN, 55455, USA.
| | - June Baik
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Pruthvi Pota
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Carolina Ortiz Cordero
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Il-Youp Kwak
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Daniel J Garry
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Paul E Love
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Brian D Dynlacht
- Department of Pathology, New York University Cancer Institute, New York University School of Medicine, New York, NY, 10016, USA
| | - Rita C R Perlingeiro
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA.
- Stem Cell Institute, University of Minnesota, Minneapolis, MN, 55455, USA.
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110
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Wright RHG, Le Dily F, Beato M. ATP, Mg 2+, Nuclear Phase Separation, and Genome Accessibility. Trends Biochem Sci 2019; 44:565-574. [PMID: 31072688 DOI: 10.1016/j.tibs.2019.03.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 02/13/2019] [Accepted: 03/07/2019] [Indexed: 12/23/2022]
Abstract
Misregulation of the processes controlling eukaryotic gene expression can result in disease. Gene expression is influenced by the surrounding chromatin; hence the nuclear environment is also of vital importance. Recently, understanding of chromatin hierarchical folding has increased together with the discovery of membrane-less organelles which are distinct, dynamic liquid droplets that merge and expand within the nucleus. These 'sieve'-like regions may compartmentalize and separate functionally distinct regions of chromatin. This article aims to discuss recent studies on nuclear phase within the context of poly(ADP-ribose), ATP, and Mg2+ levels, and we propose a combinatorial complex role for these molecules in phase separation and genome regulation. We also discuss the implications of this process for gene regulation and discuss possible strategies to test this.
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Affiliation(s)
- Roni H G Wright
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain
| | - Francois Le Dily
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain
| | - Miguel Beato
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain.
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111
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Lio CWJ, Shukla V, Samaniego-Castruita D, González-Avalos E, Chakraborty A, Yue X, Schatz DG, Ay F, Rao A. TET enzymes augment activation-induced deaminase (AID) expression via 5-hydroxymethylcytosine modifications at the Aicda superenhancer. Sci Immunol 2019; 4:eaau7523. [PMID: 31028100 PMCID: PMC6599614 DOI: 10.1126/sciimmunol.aau7523] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 03/19/2019] [Indexed: 12/15/2022]
Abstract
TET enzymes are dioxygenases that promote DNA demethylation by oxidizing the methyl group of 5-methylcytosine to 5-hydroxymethylcytosine (5hmC). Here, we report a close correspondence between 5hmC-marked regions, chromatin accessibility and enhancer activity in B cells, and a strong enrichment for consensus binding motifs for basic region-leucine zipper (bZIP) transcription factors at TET-responsive genomic regions. Functionally, Tet2 and Tet3 regulate class switch recombination (CSR) in murine B cells by enhancing expression of Aicda, which encodes the activation-induced cytidine deaminase (AID) enzyme essential for CSR. TET enzymes deposit 5hmC, facilitate DNA demethylation, and maintain chromatin accessibility at two TET-responsive enhancer elements, TetE1 and TetE2, located within a superenhancer in the Aicda locus. Our data identify the bZIP transcription factor, ATF-like (BATF) as a key transcription factor involved in TET-dependent Aicda expression. 5hmC is not deposited at TetE1 in activated Batf-deficient B cells, indicating that BATF facilitates TET recruitment to this Aicda enhancer. Our study emphasizes the importance of TET enzymes for bolstering AID expression and highlights 5hmC as an epigenetic mark that captures enhancer dynamics during cell activation.
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Affiliation(s)
- Chan-Wang J Lio
- Division of Signaling and Gene Expression, La Jolla Institute, San Diego, CA, USA.
| | - Vipul Shukla
- Division of Signaling and Gene Expression, La Jolla Institute, San Diego, CA, USA
| | | | | | | | - Xiaojing Yue
- Division of Signaling and Gene Expression, La Jolla Institute, San Diego, CA, USA
| | - David G Schatz
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Ferhat Ay
- Division of Vaccine Discovery, La Jolla Institute, San Diego, CA, USA
| | - Anjana Rao
- Division of Signaling and Gene Expression, La Jolla Institute, San Diego, CA, USA.
- Sanford Consortium for Regenerative Medicine, San Diego, CA, USA
- Department of Pharmacology, University of California, San Diego, San Diego, CA, USA
- Moores Cancer Center, University of California, San Diego, San Diego, CA, USA
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112
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Unraveling the multiplex folding of nucleosome chains in higher order chromatin. Essays Biochem 2019; 63:109-121. [PMID: 31015386 DOI: 10.1042/ebc20180066] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/25/2019] [Accepted: 03/01/2019] [Indexed: 12/19/2022]
Abstract
The DNA of eukaryotic chromatin and chromosomes is repeatedly supercoiled around histone octamers forming 'beads-on-a-string' chains of nucleosomes. The extent of nucleosome chain folding and DNA accessibility vary between different functional and epigenetic states of nuclear chromatin and change dramatically upon cell differentiation, but the molecular mechanisms that direct 3D folding of the nucleosome chain in vivo are still enigmatic. Recent advances in cell imaging and chromosome capture techniques have radically challenged the established paradigm of regular and hierarchical chromatin fibers by highlighting irregular chromatin organization and the importance of the nuclear skeletal structures hoisting the nucleosome chains. Here, we argue that, by analyzing individual structural elements of the nucleosome chain - nucleosome spacing, linker DNA conformations, internucleosomal interactions, and nucleosome chain flexibility - and integrating these elements in multiplex 3D structural models, we can predict the features of the multiplex chromatin folding assemblies underlying distinct developmental and epigenetic states in living cells. Furthermore, partial disassembly of the nuclear structures suspending chromatin fibers may reveal the intrinsic mechanisms of nucleosome chain folding. These mechanisms and structures are expected to provide molecular cues to modify chromatin structure and functions related to developmental and disease processes.
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113
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Braadland PR, Urbanucci A. Chromatin reprogramming as an adaptation mechanism in advanced prostate cancer. Endocr Relat Cancer 2019; 26:R211-R235. [PMID: 30844748 DOI: 10.1530/erc-18-0579] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 02/15/2019] [Indexed: 12/13/2022]
Abstract
Tumor evolution is based on the ability to constantly mutate and activate different pathways under the selective pressure of targeted therapies. Epigenetic alterations including those of the chromatin structure are associated with tumor initiation, progression and drug resistance. Many cancers, including prostate cancer, present enlarged nuclei, and chromatin appears altered and irregular. These phenotypic changes are likely to result from epigenetic dysregulation. High-throughput sequencing applied to bulk samples and now to single cells has made it possible to study these processes in unprecedented detail. It is therefore timely to review the impact of chromatin relaxation and increased DNA accessibility on prostate cancer growth and drug resistance, and their effects on gene expression. In particular, we focus on the contribution of chromatin-associated proteins such as the bromodomain-containing proteins to chromatin relaxation. We discuss the consequence of this for androgen receptor transcriptional activity and briefly summarize wider gain-of-function effects on other oncogenic transcription factors and implications for more effective prostate cancer treatment.
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Affiliation(s)
- Peder Rustøen Braadland
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Alfonso Urbanucci
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Institute for Cancer Genetics and Informatics, Oslo University Hospital, Oslo, Norway
- Centre for Molecular Medicine Norway, Nordic European Molecular Biology Laboratory Partnership, Forskningsparken, University of Oslo, Oslo, Norway
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114
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115
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Francesconi M, Di Stefano B, Berenguer C, de Andrés-Aguayo L, Plana-Carmona M, Mendez-Lago M, Guillaumet-Adkins A, Rodriguez-Esteban G, Gut M, Gut IG, Heyn H, Lehner B, Graf T. Single cell RNA-seq identifies the origins of heterogeneity in efficient cell transdifferentiation and reprogramming. eLife 2019; 8:41627. [PMID: 30860479 PMCID: PMC6435319 DOI: 10.7554/elife.41627] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 03/11/2019] [Indexed: 12/31/2022] Open
Abstract
Forced transcription factor expression can transdifferentiate somatic cells into other specialised cell types or reprogram them into induced pluripotent stem cells (iPSCs) with variable efficiency. To better understand the heterogeneity of these processes, we used single-cell RNA sequencing to follow the transdifferentation of murine pre-B cells into macrophages as well as their reprogramming into iPSCs. Even in these highly efficient systems, there was substantial variation in the speed and path of fate conversion. We predicted and validated that these differences are inversely coupled and arise in the starting cell population, with Mychigh large pre-BII cells transdifferentiating slowly but reprogramming efficiently and Myclow small pre-BII cells transdifferentiating rapidly but failing to reprogram. Strikingly, differences in Myc activity predict the efficiency of reprogramming across a wide range of somatic cell types. These results illustrate how single cell expression and computational analyses can identify the origins of heterogeneity in cell fate conversion processes.
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Affiliation(s)
- Mirko Francesconi
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Bruno Di Stefano
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.,Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, United States
| | - Clara Berenguer
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Luisa de Andrés-Aguayo
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Marcos Plana-Carmona
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Maria Mendez-Lago
- CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Amy Guillaumet-Adkins
- CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Gustavo Rodriguez-Esteban
- CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Marta Gut
- CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Ivo G Gut
- CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Holger Heyn
- CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Ben Lehner
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Thomas Graf
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain
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116
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Petrovic J, Zhou Y, Fasolino M, Goldman N, Schwartz GW, Mumbach MR, Nguyen SC, Rome KS, Sela Y, Zapataro Z, Blacklow SC, Kruhlak MJ, Shi J, Aster JC, Joyce EF, Little SC, Vahedi G, Pear WS, Faryabi RB. Oncogenic Notch Promotes Long-Range Regulatory Interactions within Hyperconnected 3D Cliques. Mol Cell 2019; 73:1174-1190.e12. [PMID: 30745086 DOI: 10.1016/j.molcel.2019.01.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 11/21/2018] [Accepted: 01/03/2019] [Indexed: 01/10/2023]
Abstract
Chromatin loops enable transcription-factor-bound distal enhancers to interact with their target promoters to regulate transcriptional programs. Although developmental transcription factors such as active forms of Notch can directly stimulate transcription by activating enhancers, the effect of their oncogenic subversion on the 3D organization of cancer genomes is largely undetermined. By mapping chromatin looping genome-wide in Notch-dependent triple-negative breast cancer and B cell lymphoma, we show that beyond the well-characterized role of Notch as an activator of distal enhancers, Notch regulates its direct target genes by instructing enhancer repositioning. Moreover, a large fraction of Notch-instructed regulatory loops form highly interacting enhancer and promoter spatial clusters termed "3D cliques." Loss- and gain-of-function experiments show that Notch preferentially targets hyperconnected 3D cliques that regulate the expression of crucial proto-oncogenes. Our observations suggest that oncogenic hijacking of developmental transcription factors can dysregulate transcription through widespread effects on the spatial organization of cancer genomes.
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Affiliation(s)
- Jelena Petrovic
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yeqiao Zhou
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Maria Fasolino
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Naomi Goldman
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gregory W Schwartz
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Biomedical Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Maxwell R Mumbach
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Son C Nguyen
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kelly S Rome
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yogev Sela
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Zachary Zapataro
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Stephen C Blacklow
- Department of Biological Chemistry, Harvard Medical School, Boston, MA 02215, USA
| | | | - Junwei Shi
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jon C Aster
- Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Eric F Joyce
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shawn C Little
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Golnaz Vahedi
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Warren S Pear
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Robert B Faryabi
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Biomedical Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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117
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Abstract
In this review from Murre, the evolution of HLH genes, the structures of HLH domains, and the elaborate activities of HLH proteins in multicellular life are discussed. Helix–loop–helix (HLH) proteins are dimeric transcription factors that control lineage- and developmental-specific gene programs. Genes encoding for HLH proteins arose in unicellular organisms >600 million years ago and then duplicated and diversified from ancestral genes across the metazoan and plant kingdoms to establish multicellularity. Hundreds of HLH proteins have been identified with diverse functions in a wide variety of cell types. HLH proteins orchestrate lineage specification, commitment, self-renewal, proliferation, differentiation, and homing. HLH proteins also regulate circadian clocks, protect against hypoxic stress, promote antigen receptor locus assembly, and program transdifferentiation. HLH proteins deposit or erase epigenetic marks, activate noncoding transcription, and sequester chromatin remodelers across the chromatin landscape to dictate enhancer–promoter communication and somatic recombination. Here the evolution of HLH genes, the structures of HLH domains, and the elaborate activities of HLH proteins in multicellular life are discussed.
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Affiliation(s)
- Cornelis Murre
- Division of Biological Sciences, University of California at San Diego, La Jolla, California 92903, USA
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118
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Chory EJ, Calarco JP, Hathaway NA, Bell O, Neel DS, Crabtree GR. Nucleosome Turnover Regulates Histone Methylation Patterns over the Genome. Mol Cell 2019; 73:61-72.e3. [PMID: 30472189 PMCID: PMC6510544 DOI: 10.1016/j.molcel.2018.10.028] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 09/04/2018] [Accepted: 10/16/2018] [Indexed: 12/18/2022]
Abstract
Recent studies have indicated that nucleosome turnover is rapid, occurring several times per cell cycle. To access the effect of nucleosome turnover on the epigenetic landscape, we investigated H3K79 methylation, which is produced by a single methyltransferase (Dot1l) with no known demethylase. Using chemical-induced proximity (CIP), we find that the valency of H3K79 methylation (mono-, di-, and tri-) is determined by nucleosome turnover rates. Furthermore, propagation of this mark is predicted by nucleosome turnover simulations over the genome and accounts for the asymmetric distribution of H3K79me toward the transcriptional unit. More broadly, a meta-analysis of other conserved histone modifications demonstrates that nucleosome turnover models predict both valency and chromosomal propagation of methylation marks. Based on data from worms, flies, and mice, we propose that the turnover of modified nucleosomes is a general means of propagation of epigenetic marks and a determinant of methylation valence.
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Affiliation(s)
- Emma J Chory
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA; Departments of Pathology and Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Joseph P Calarco
- Departments of Pathology and Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Nathaniel A Hathaway
- Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, Chapel Hill, NC 27599, USA
| | - Oliver Bell
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria; Department of Biochemistry and Molecular Medicine and the Norris Comprehensive Cancer Center, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089-9601, USA
| | - Dana S Neel
- Departments of Pathology and Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Gerald R Crabtree
- Departments of Pathology and Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
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119
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He B, Deng T, Zhu I, Furusawa T, Zhang S, Tang W, Postnikov Y, Ambs S, Li CC, Livak F, Landsman D, Bustin M. Binding of HMGN proteins to cell specific enhancers stabilizes cell identity. Nat Commun 2018; 9:5240. [PMID: 30532006 PMCID: PMC6286339 DOI: 10.1038/s41467-018-07687-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 11/15/2018] [Indexed: 01/10/2023] Open
Abstract
The dynamic nature of the chromatin epigenetic landscape plays a key role in the establishment and maintenance of cell identity, yet the factors that affect the dynamics of the epigenome are not fully known. Here we find that the ubiquitous nucleosome binding proteins HMGN1 and HMGN2 preferentially colocalize with epigenetic marks of active chromatin, and with cell-type specific enhancers. Loss of HMGNs enhances the rate of OSKM induced reprogramming of mouse embryonic fibroblasts (MEFs) into induced pluripotent stem cells (iPSCs), and the ASCL1 induced conversion of fibroblast into neurons. During transcription factor induced reprogramming to pluripotency, loss of HMGNs accelerates the erasure of the MEF-specific epigenetic landscape and the establishment of an iPSCs-specific chromatin landscape, without affecting the pluripotency potential and the differentiation potential of the reprogrammed cells. Thus, HMGN proteins modulate the plasticity of the chromatin epigenetic landscape thereby stabilizing, rather than determining cell identity. HMGN1 and HMGN2 are ubiquitous nucleosome binding proteins. Here the authors provide evidence that HMGN proteins preferentially localize to chromatin regulatory sites to modulate the plasticity of the epigenetic landscape, proposing that HGMNs stabilize, rather than determine, cell identity.
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Affiliation(s)
- Bing He
- Protein Section, Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Tao Deng
- Protein Section, Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Iris Zhu
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Takashi Furusawa
- Protein Section, Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Shaofei Zhang
- Protein Section, Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Wei Tang
- Laboratory of Human Carcinogenesis, Center for Cancer Research, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Yuri Postnikov
- Protein Section, Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Stefan Ambs
- Laboratory of Human Carcinogenesis, Center for Cancer Research, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Caiyi Cherry Li
- Laboratory of Genomic Integrity, Center for Cancer Research National Cancer Institute National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ferenc Livak
- Laboratory of Genomic Integrity, Center for Cancer Research National Cancer Institute National Institutes of Health, Bethesda, MD, 20892, USA
| | - David Landsman
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Michael Bustin
- Protein Section, Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
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120
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Pękowska A, Klaus B, Xiang W, Severino J, Daigle N, Klein FA, Oleś M, Casellas R, Ellenberg J, Steinmetz LM, Bertone P, Huber W. Gain of CTCF-Anchored Chromatin Loops Marks the Exit from Naive Pluripotency. Cell Syst 2018; 7:482-495.e10. [PMID: 30414923 PMCID: PMC6327227 DOI: 10.1016/j.cels.2018.09.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 03/06/2018] [Accepted: 09/24/2018] [Indexed: 11/30/2022]
Abstract
The genome of pluripotent stem cells adopts a unique three-dimensional architecture featuring weakly condensed heterochromatin and large nucleosome-free regions. Yet, it is unknown whether structural loops and contact domains display characteristics that distinguish embryonic stem cells (ESCs) from differentiated cell types. We used genome-wide chromosome conformation capture and super-resolution imaging to determine nuclear organization in mouse ESC and neural stem cell (NSC) derivatives. We found that loss of pluripotency is accompanied by widespread gain of structural loops. This general architectural change correlates with enhanced binding of CTCF and cohesins and more pronounced insulation of contacts across chromatin boundaries in lineage-committed cells. Reprogramming NSCs to pluripotency restores the unique features of ESC domain topology. Domains defined by the anchors of loops established upon differentiation are enriched for developmental genes. Chromatin loop formation is a pervasive structural alteration to the genome that accompanies exit from pluripotency and delineates the spatial segregation of developmentally regulated genes.
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Affiliation(s)
- Aleksandra Pękowska
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany.
| | - Bernd Klaus
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Wanqing Xiang
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Jacqueline Severino
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Nathalie Daigle
- Genomics & Immunity, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Felix A Klein
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Małgorzata Oleś
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Rafael Casellas
- Genomics & Immunity, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Center for Cancer Research, NCI, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jan Ellenberg
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Lars M Steinmetz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany; Stanford Genome Technology Center, 855 California Ave, Palo Alto, CA 94305, USA; Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Paul Bertone
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany; European Molecular Biology Laboratory (EMBL), European Bioinformatics Institute, Wellcome Trust Genome Campus, Cambridge CB10 1SD, UK; Wellcome Trust - Medical Research Council Stem Cell Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK.
| | - Wolfgang Huber
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany.
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121
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Su Y, Pelz C, Huang T, Torkenczy K, Wang X, Cherry A, Daniel CJ, Liang J, Nan X, Dai MS, Adey A, Impey S, Sears RC. Post-translational modification localizes MYC to the nuclear pore basket to regulate a subset of target genes involved in cellular responses to environmental signals. Genes Dev 2018; 32:1398-1419. [PMID: 30366908 PMCID: PMC6217735 DOI: 10.1101/gad.314377.118] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 09/04/2018] [Indexed: 12/14/2022]
Abstract
In this study, Su et al. investigate how post-translational modifications of Myc that affect stability and oncogenic activity regulate its function. They show that Ser62 phosphorylation and PIN1-mediated isomerization of MYC dynamically regulate the spatial distribution of MYC in the nucleus, promoting its association with the inner basket of the nuclear pore in response to proliferative signals, where it recruits the histone acetyltransferase GCN5 to bind and regulate local gene acetylation and expression, thus providing new insights into how post-translational modification of MYC controls its spatial activity. The transcription factor MYC (also c-Myc) induces histone modification, chromatin remodeling, and the release of paused RNA polymerase to broadly regulate transcription. MYC is subject to a series of post-translational modifications that affect its stability and oncogenic activity, but how these control MYC's function on the genome is largely unknown. Recent work demonstrates an intimate connection between nuclear compartmentalization and gene regulation. Here, we report that Ser62 phosphorylation and PIN1-mediated isomerization of MYC dynamically regulate the spatial distribution of MYC in the nucleus, promoting its association with the inner basket of the nuclear pore in response to proliferative signals, where it recruits the histone acetyltransferase GCN5 to bind and regulate local gene acetylation and expression. We demonstrate that PIN1-mediated localization of MYC to the nuclear pore regulates MYC target genes responsive to mitogen stimulation that are involved in proliferation and migration pathways. These changes are also present at the chromatin level, with an increase in open regulatory elements in response to stimulation that is PIN1-dependent and associated with MYC chromatin binding. Taken together, our study indicates that post-translational modification of MYC controls its spatial activity to optimally regulate gene expression in response to extrinsic signals in normal and diseased states.
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Affiliation(s)
- Yulong Su
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Oregon 97239, USA
| | - Carl Pelz
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Oregon 97239, USA.,Oregon Stem Cell Center, Oregon Health and Science University, Oregon 97239, USA
| | - Tao Huang
- Department of Biomedical Engineering, Oregon Health and Science University, Oregon 97239, USA
| | - Kristof Torkenczy
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Oregon 97239, USA
| | - Xiaoyan Wang
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Oregon 97239, USA
| | - Allison Cherry
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Oregon 97239, USA
| | - Colin J Daniel
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Oregon 97239, USA
| | - Juan Liang
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Oregon 97239, USA
| | - Xiaolin Nan
- Department of Biomedical Engineering, Oregon Health and Science University, Oregon 97239, USA
| | - Mu-Shui Dai
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Oregon 97239, USA
| | - Andrew Adey
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Oregon 97239, USA
| | - Soren Impey
- Oregon Stem Cell Center, Oregon Health and Science University, Oregon 97239, USA
| | - Rosalie C Sears
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Oregon 97239, USA
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122
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Andrews JM, Payton JE. Epigenetic dynamics in normal and malignant B cells: die a hero or live to become a villain. Curr Opin Immunol 2018; 57:15-22. [PMID: 30342313 DOI: 10.1016/j.coi.2018.09.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/26/2018] [Indexed: 12/27/2022]
Abstract
Normal B cell development, activation, and terminal differentiation depend on the intricate dynamics of cooperating epigenetic and non-coding components to control the level and timing of expression of thousands of genes. Recent genome-wide studies have integratively mapped changes in the chromatin landscape, DNA methylome, 3-dimensional interactome, and coding and non-coding transcriptomes of normal and malignant B cells. Genetic ablation in human cells and mouse models has begun to elucidate the coordinated roles of essential epigenetic modifiers, key transcription factors, and long non-coding RNAs in B cell biology. Perturbation of these stewards of the epigenome drive B cell oncogenesis, but may be exploited to develop new avenues of therapy.
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Affiliation(s)
- Jared M Andrews
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Jacqueline E Payton
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO 63110, USA.
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123
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Johanson TM, Lun ATL, Coughlan HD, Tan T, Smyth GK, Nutt SL, Allan RS. Transcription-factor-mediated supervision of global genome architecture maintains B cell identity. Nat Immunol 2018; 19:1257-1264. [PMID: 30323344 DOI: 10.1038/s41590-018-0234-8] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 09/04/2018] [Indexed: 01/09/2023]
Abstract
Recent studies have elucidated cell-lineage-specific three-dimensional genome organization; however, how such specific architecture is established or maintained is unclear. We hypothesized that lineage-defining transcription factors maintain cell identity via global control of genome organization. These factors bind many genomic sites outside of the genes that they directly regulate and thus are potentially implicated in three-dimensional genome organization. Using chromosome-conformation-capture techniques, we show that the transcription factor Paired box 5 (Pax5) is critical for the establishment and maintenance of the global lineage-specific architecture of B cells. Pax5 was found to supervise genome architecture throughout B cell differentiation, until the plasmablast stage, in which Pax5 is naturally silenced and B cell-specific genome structure is lost. Crucially, Pax5 did not rely on ongoing transcription to organize the genome. These results implicate sequence-specific DNA-binding proteins in global genome organization to establish and maintain lineage fidelity.
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Affiliation(s)
- Timothy M Johanson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Aaron T L Lun
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Hannah D Coughlan
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Tania Tan
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Gordon K Smyth
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,School of Mathematics and Statistics, University of Melbourne, Melbourne, Victoria, Australia
| | - Stephen L Nutt
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia. .,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia.
| | - Rhys S Allan
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia. .,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia.
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124
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Cryo-ET reveals the macromolecular reorganization of S. pombe mitotic chromosomes in vivo. Proc Natl Acad Sci U S A 2018; 115:10977-10982. [PMID: 30297429 DOI: 10.1073/pnas.1720476115] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Chromosomes condense during mitosis in most eukaryotes. This transformation involves rearrangements at the nucleosome level and has consequences for transcription. Here, we use cryo-electron tomography (cryo-ET) to determine the 3D arrangement of nuclear macromolecular complexes, including nucleosomes, in frozen-hydrated Schizosaccharomyces pombe cells. Using 3D classification analysis, we did not find evidence that nucleosomes resembling the crystal structure are abundant. This observation and those from other groups support the notion that a subset of fission yeast nucleosomes may be partially unwrapped in vivo. In both interphase and mitotic cells, there is also no evidence of monolithic structures the size of Hi-C domains. The chromatin is mingled with two features: pockets, which are positions free of macromolecular complexes; and "megacomplexes," which are multimegadalton globular complexes like preribosomes. Mitotic chromatin is more crowded than interphase chromatin in subtle ways. Nearest-neighbor distance analyses show that mitotic chromatin is more compacted at the oligonucleosome than the dinucleosome level. Like interphase, mitotic chromosomes contain megacomplexes and pockets. This uneven chromosome condensation helps explain a longstanding enigma of mitosis: a subset of genes is up-regulated.
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125
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Bridger JM, Brindley PJ, Knight M. The snail Biomphalaria glabrata as a model to interrogate the molecular basis of complex human diseases. PLoS Negl Trop Dis 2018; 12:e0006552. [PMID: 30091971 PMCID: PMC6084811 DOI: 10.1371/journal.pntd.0006552] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Joanna M. Bridger
- Institute of Environment, Health, and Societies, Brunel University London, Uxbridge, United Kingdom
| | - Paul J. Brindley
- Department of Microbiology, Immunology, and Tropical Medicine, School of Medicine and Health Sciences, George Washington University, Washington DC, United States of America
- Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, George Washington University, Washington DC, United States of America
| | - Matty Knight
- Department of Microbiology, Immunology, and Tropical Medicine, School of Medicine and Health Sciences, George Washington University, Washington DC, United States of America
- Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, George Washington University, Washington DC, United States of America
- Division of Science and Mathematics, University of the District of Columbia, Washington DC, United States of America
- * E-mail: ,
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126
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Wong MM, Belew MD, Kwieraga A, Nhan JD, Michael WM. Programmed DNA Breaks Activate the Germline Genome in Caenorhabditis elegans. Dev Cell 2018; 46:302-315.e5. [PMID: 30086301 DOI: 10.1016/j.devcel.2018.07.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 06/03/2018] [Accepted: 07/01/2018] [Indexed: 12/15/2022]
Abstract
In Caenorhabditis elegans, the primordial germ cells Z2 and Z3 are born during early embryogenesis and then held in a transcriptionally quiescent state where the genome is highly compacted. When hatched L1s feed, the germline genome decompacts, and RNAPII is abruptly and globally activated. A previously documented yet unexplained feature of germline genome activation in the worm is the appearance of numerous DNA breaks coincident with RNAPII transcription. Here, we show that the DNA breaks are induced by topoisomerase II and that they function to recruit the RUVB complex to chromosomes so that RUVB can decompact the chromatin. DNA break- and RUVB-mediated decompaction is required for zygotic genome activation. This work highlights the importance of global chromatin decompaction in the rapid induction of gene expression and shows that one way cells achieve global decompaction is through programmed DNA breaks.
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Affiliation(s)
- Matthew M Wong
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Mezmur D Belew
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Amanda Kwieraga
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - James D Nhan
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - W Matthew Michael
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.
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127
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Comprehensive profiling of transcriptional networks specific for lactogenic differentiation of HC11 mammary epithelial stem-like cells. Sci Rep 2018; 8:11777. [PMID: 30082875 PMCID: PMC6079013 DOI: 10.1038/s41598-018-30122-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 07/13/2018] [Indexed: 12/31/2022] Open
Abstract
The development of mammary gland as a lactogenic tissue is a highly coordinated multistep process. The epithelial cells of lactiferous tubules undergo profound changes during the developmental window of puberty, pregnancy, and lactation. Several hormones including estrogen, progesterone, glucocorticoids and prolactin act in concert, and orchestrate the development of mammary gland. Understanding the gene regulatory networks that coordinate proliferation and differentiation of HC11 Mammary Epithelial stem-like Cells (MEC) under the influence of lactogenic hormones is critical for elucidating the mechanism of lactogenesis in detail. In this study, we analyzed transcriptome profiles of undifferentiated MEC (normal) and compared them with Murine Embryonic Stem Cells (ESC) using next-generation mRNA sequencing. Further, we analyzed the transcriptome output during lactogenic differentiation of MEC following treatment with glucocorticoids (primed state) and both glucocorticoids and prolactin together (prolactin state). We established stage-specific gene regulatory networks in ESC and MEC (normal, priming and prolactin states). We validated the top up-and downregulated genes in each stage of differentiation of MEC by RT-PCR and found that they are comparable with that of RNA-seq data. HC11 MEC display decreased expression of Pou5f1 and Sox2, which is crucial for the differentiation of MEC, which otherwise ensure pluripotency to ESC. Cited4 is induced during priming and is involved in milk secretion. MEC upon exposure to both glucocorticoids and prolactin undergo terminal differentiation, which is associated with the expression of several genes, including Xbp1 and Cbp that are required for cell growth and differentiation. Our study also identified differential expression of transcription factors and epigenetic regulators in each stage of lactogenic differentiation. We also analyzed the transcriptome data for the pathways that are selectively activated during lactogenic differentiation. Further, we found that selective expression of chromatin modulators (Dnmt3l, Chd9) in response to glucocorticoids suggests a highly coordinated stage-specific lactogenic differentiation of MEC.
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128
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Dual Roles of Poly(dA:dT) Tracts in Replication Initiation and Fork Collapse. Cell 2018; 174:1127-1142.e19. [PMID: 30078706 DOI: 10.1016/j.cell.2018.07.011] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 05/25/2018] [Accepted: 07/06/2018] [Indexed: 12/30/2022]
Abstract
Replication origins, fragile sites, and rDNA have been implicated as sources of chromosomal instability. However, the defining genomic features of replication origins and fragile sites are among the least understood elements of eukaryote genomes. Here, we map sites of replication initiation and breakage in primary cells at high resolution. We find that replication initiates between transcribed genes within nucleosome-depleted structures established by long asymmetrical poly(dA:dT) tracts flanking the initiation site. Paradoxically, long (>20 bp) (dA:dT) tracts are also preferential sites of polar replication fork stalling and collapse within early-replicating fragile sites (ERFSs) and late-replicating common fragile sites (CFSs) and at the rDNA replication fork barrier. Poly(dA:dT) sequences are fragile because long single-strand poly(dA) stretches at the replication fork are unprotected by the replication protein A (RPA). We propose that the evolutionary expansion of poly(dA:dT) tracts in eukaryotic genomes promotes replication initiation, but at the cost of chromosome fragility.
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129
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Swinstead EE, Paakinaho V, Hager GL. Chromatin reprogramming in breast cancer. Endocr Relat Cancer 2018; 25:R385-R404. [PMID: 29692347 PMCID: PMC6029727 DOI: 10.1530/erc-18-0033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 04/24/2018] [Indexed: 02/06/2023]
Abstract
Reprogramming of the chromatin landscape is a critical component to the transcriptional response in breast cancer. Effects of sex hormones such as estrogens and progesterone have been well described to have a critical impact on breast cancer proliferation. However, the complex network of the chromatin landscape, enhancer regions and mode of function of steroid receptors (SRs) and other transcription factors (TFs), is an intricate web of signaling and functional processes that is still largely misunderstood at the mechanistic level. In this review, we describe what is currently known about the dynamic interplay between TFs with chromatin and the reprogramming of enhancer elements. Emphasis has been placed on characterizing the different modes of action of TFs in regulating enhancer activity, specifically, how different SRs target enhancer regions to reprogram chromatin in breast cancer cells. In addition, we discuss current techniques employed to study enhancer function at a genome-wide level. Further, we have noted recent advances in live cell imaging technology. These single-cell approaches enable the coupling of population-based assays with real-time studies to address many unsolved questions about SRs and chromatin dynamics in breast cancer.
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Affiliation(s)
- Erin E Swinstead
- Laboratory of Receptor Biology and Gene ExpressionNational Cancer Institute, NIH, Bethesda, Maryland, USA
| | - Ville Paakinaho
- Laboratory of Receptor Biology and Gene ExpressionNational Cancer Institute, NIH, Bethesda, Maryland, USA
- Institute of BiomedicineUniversity of Eastern Finland, Kuopio, Finland
| | - Gordon L Hager
- Laboratory of Receptor Biology and Gene ExpressionNational Cancer Institute, NIH, Bethesda, Maryland, USA
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130
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Vian L, Pękowska A, Rao SSP, Kieffer-Kwon KR, Jung S, Baranello L, Huang SC, El Khattabi L, Dose M, Pruett N, Sanborn AL, Canela A, Maman Y, Oksanen A, Resch W, Li X, Lee B, Kovalchuk AL, Tang Z, Nelson S, Di Pierro M, Cheng RR, Machol I, St Hilaire BG, Durand NC, Shamim MS, Stamenova EK, Onuchic JN, Ruan Y, Nussenzweig A, Levens D, Aiden EL, Casellas R. The Energetics and Physiological Impact of Cohesin Extrusion. Cell 2018; 173:1165-1178.e20. [PMID: 29706548 PMCID: PMC6065110 DOI: 10.1016/j.cell.2018.03.072] [Citation(s) in RCA: 286] [Impact Index Per Article: 47.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 12/29/2017] [Accepted: 03/27/2018] [Indexed: 12/25/2022]
Abstract
Cohesin extrusion is thought to play a central role in establishing the architecture of mammalian genomes. However, extrusion has not been visualized in vivo, and thus, its functional impact and energetics are unknown. Using ultra-deep Hi-C, we show that loop domains form by a process that requires cohesin ATPases. Once formed, however, loops and compartments are maintained for hours without energy input. Strikingly, without ATP, we observe the emergence of hundreds of CTCF-independent loops that link regulatory DNA. We also identify architectural "stripes," where a loop anchor interacts with entire domains at high frequency. Stripes often tether super-enhancers to cognate promoters, and in B cells, they facilitate Igh transcription and recombination. Stripe anchors represent major hotspots for topoisomerase-mediated lesions, which promote chromosomal translocations and cancer. In plasmacytomas, stripes can deregulate Igh-translocated oncogenes. We propose that higher organisms have coopted cohesin extrusion to enhance transcription and recombination, with implications for tumor development.
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Affiliation(s)
- Laura Vian
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA
| | | | - Suhas S P Rao
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | - Seolkyoung Jung
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Laura Baranello
- Gene Regulation, Laboratory of Pathology, NCI, NIH, Bethesda, MD 20892, USA
| | - Su-Chen Huang
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Marei Dose
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA
| | | | - Adrian L Sanborn
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Department of Computer Science, Stanford University, Stanford, CA 94305, USA
| | - Andres Canela
- Laboratory of Genome Integrity, NCI, NIH, Bethesda, MD 20892, USA
| | - Yaakov Maman
- Laboratory of Genome Integrity, NCI, NIH, Bethesda, MD 20892, USA
| | - Anna Oksanen
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Wolfgang Resch
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Xingwang Li
- The Jackson Laboratory for Genomic Medicine and Department of Genetic and Development Biology, University of Connecticut, Farmington, CT 06030, USA
| | - Byoungkoo Lee
- The Jackson Laboratory for Genomic Medicine and Department of Genetic and Development Biology, University of Connecticut, Farmington, CT 06030, USA
| | | | - Zhonghui Tang
- The Jackson Laboratory for Genomic Medicine and Department of Genetic and Development Biology, University of Connecticut, Farmington, CT 06030, USA
| | | | - Michele Di Pierro
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77030, USA
| | - Ryan R Cheng
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77030, USA
| | - Ido Machol
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Neva C Durand
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
| | - Muhammad S Shamim
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
| | - Elena K Stamenova
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
| | - José N Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77030, USA
| | - Yijun Ruan
- The Jackson Laboratory for Genomic Medicine and Department of Genetic and Development Biology, University of Connecticut, Farmington, CT 06030, USA
| | | | - David Levens
- Gene Regulation, Laboratory of Pathology, NCI, NIH, Bethesda, MD 20892, USA
| | - Erez Lieberman Aiden
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Center for Theoretical Biological Physics, Rice University, Houston, TX 77030, USA; Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China.
| | - Rafael Casellas
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA; Center of Cancer Research, NCI, NIH, Bethesda, MD 20892, USA.
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131
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Grigoryev SA. Chromatin Higher-Order Folding: A Perspective with Linker DNA Angles. Biophys J 2018; 114:2290-2297. [PMID: 29628212 DOI: 10.1016/j.bpj.2018.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 03/03/2018] [Accepted: 03/09/2018] [Indexed: 01/24/2023] Open
Abstract
The mechanism by which the "beads-on-a-string" nucleosome chain folds into various higher-order chromatin structures in eukaryotic cell nuclei is still poorly understood. The various models depicting higher-order chromatin as regular helical fibers and the very opposite "polymer melt" theory imply that interactions between nucleosome "beads" make the main contribution to the chromatin compaction. Other models in which the geometry of linker DNA "strings" entering and exiting the nucleosome define the three-dimensional structure predict that small changes in the linker DNA configuration may strongly affect nucleosome chain folding and chromatin higher-order structure. Among those studies, the cross-disciplinary approach pioneered by Jörg Langowski that combines computational modeling with biophysical and biochemical experiments was most instrumental for understanding chromatin higher-order structure in vitro. Strikingly, many recent studies, including genome-wide nucleosome interaction mapping and chromatin imaging, show an excellent agreement with the results of three-dimensional computational modeling based on the primary role of linker DNA geometry in chromatin compaction. This perspective relates nucleosome array models with experimental studies of nucleosome array folding in vitro and in situ. I argue that linker DNA configuration plays a key role in determining nucleosome chain flexibility, topology, and propensity for self-association, thus providing new implications for regulation of chromatin accessibility to DNA binding factors and RNA transcription machinery as well as long-range communications between distant genomic sites.
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Affiliation(s)
- Sergei A Grigoryev
- Department of Biochemistry & Molecular Biology, H171, Milton S. Hershey Medical Center, Penn State University College of Medicine, Hershey, Pennsylvania.
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132
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Zeid R, Lawlor MA, Poon E, Reyes JM, Fulciniti M, Lopez MA, Scott TG, Nabet B, Erb MA, Winter GE, Jacobson Z, Polaski DR, Karlin KL, Hirsch RA, Munshi NP, Westbrook TF, Chesler L, Lin CY, Bradner JE. Enhancer invasion shapes MYCN-dependent transcriptional amplification in neuroblastoma. Nat Genet 2018; 50:515-523. [PMID: 29379199 PMCID: PMC6310397 DOI: 10.1038/s41588-018-0044-9] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 12/18/2017] [Indexed: 11/08/2022]
Abstract
Amplification of the locus encoding the oncogenic transcription factor MYCN is a defining feature of high-risk neuroblastoma. Here we present the first dynamic chromatin and transcriptional landscape of MYCN perturbation in neuroblastoma. At oncogenic levels, MYCN associates with E-box binding motifs in an affinity-dependent manner, binding to strong canonical E-boxes at promoters and invading abundant weaker non-canonical E-boxes clustered at enhancers. Loss of MYCN leads to a global reduction in transcription, which is most pronounced at MYCN target genes with the greatest enhancer occupancy. These highly occupied MYCN target genes show tissue-specific expression and are linked to poor patient survival. The activity of genes with MYCN-occupied enhancers is dependent on the tissue-specific transcription factor TWIST1, which co-occupies enhancers with MYCN and is required for MYCN-dependent proliferation. These data implicate tissue-specific enhancers in defining often highly tumor-specific 'MYC target gene signatures' and identify disruption of the MYCN enhancer regulatory axis as a promising therapeutic strategy in neuroblastoma.
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Affiliation(s)
- Rhamy Zeid
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Matthew A Lawlor
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Evon Poon
- Division of Clinical Studies, The Institute of Cancer Research, London, UK
- Division of Cancer Therapeutics, The Institute of Cancer Research, London, UK
| | - Jaime M Reyes
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Mariateresa Fulciniti
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- LeBow Institute for Myeloma Therapeutics and Jerome Lipper Multiple Myeloma Center, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Michael A Lopez
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- LeBow Institute for Myeloma Therapeutics and Jerome Lipper Multiple Myeloma Center, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Thomas G Scott
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Behnam Nabet
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Michael A Erb
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Georg E Winter
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Zoe Jacobson
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Donald R Polaski
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Kristen L Karlin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Rachel A Hirsch
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Nikhil P Munshi
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- LeBow Institute for Myeloma Therapeutics and Jerome Lipper Multiple Myeloma Center, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Thomas F Westbrook
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Louis Chesler
- Division of Clinical Studies, The Institute of Cancer Research, London, UK
- Division of Cancer Therapeutics, The Institute of Cancer Research, London, UK
| | - Charles Y Lin
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - James E Bradner
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
- Department of Medicine, Harvard Medical School, Boston, MA, USA.
- Novartis Institute for Biomedical Research, Cambridge, MA, USA.
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133
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Loguercio S, Barajas-Mora EM, Shih HY, Krangel MS, Feeney AJ. Variable Extent of Lineage-Specificity and Developmental Stage-Specificity of Cohesin and CCCTC-Binding Factor Binding Within the Immunoglobulin and T Cell Receptor Loci. Front Immunol 2018; 9:425. [PMID: 29593713 PMCID: PMC5859386 DOI: 10.3389/fimmu.2018.00425] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 02/16/2018] [Indexed: 12/19/2022] Open
Abstract
CCCTC-binding factor (CTCF) is largely responsible for the 3D architecture of the genome, in concert with the action of cohesin, through the creation of long-range chromatin loops. Cohesin is hypothesized to be the main driver of these long-range chromatin interactions by the process of loop extrusion. Here, we performed ChIP-seq for CTCF and cohesin in two stages each of T and B cell differentiation and examined the binding pattern in all six antigen receptor (AgR) loci in these lymphocyte progenitors and in mature T and B cells, ES cells, and fibroblasts. The four large AgR loci have many bound CTCF sites, most of which are only occupied in lymphocytes, while only the CTCF sites at the end of each locus near the enhancers or J genes tend to be bound in non-lymphoid cells also. However, despite the generalized lymphocyte restriction of CTCF binding in AgR loci, the Igκ locus is the only locus that also shows significant lineage-specificity (T vs. B cells) and developmental stage-specificity (pre-B vs. pro-B) in CTCF binding. We show that cohesin binding shows greater lineage- and stage-specificity than CTCF at most AgR loci, providing more specificity to the loops. We also show that the culture of pro-B cells in IL7, a common practice to expand the number of cells before ChIP-seq, results in a CTCF-binding pattern resembling pre-B cells, as well as other epigenetic and transcriptional characteristics of pre-B cells. Analysis of the orientation of the CTCF sites show that all sites within the large V portions of the Igh and TCRβ loci have the same orientation. This suggests either a lack of requirement for convergent CTCF sites creating loops, or indicates an absence of any loops between CTCF sites within the V region portion of those loci but only loops to the convergent sites at the D-J-enhancer end of each locus. The V region portions of the Igκ and TCRα/δ loci, by contrast, have CTCF sites in both orientations, providing many options for creating CTCF-mediated convergent loops throughout the loci. CTCF/cohesin loops, along with transcription factors, drives contraction of AgR loci to facilitate the creation of a diverse repertoire of antibodies and T cell receptors.
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Affiliation(s)
- Salvatore Loguercio
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - E. Mauricio Barajas-Mora
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, United States
| | - Han-Yu Shih
- Department of Immunology, Duke University Medical Center, Durham, NC, United States
| | - Michael S. Krangel
- Department of Immunology, Duke University Medical Center, Durham, NC, United States
| | - Ann J. Feeney
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, United States
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134
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Sciumè G, Shih HY, Mikami Y, O'Shea JJ. Epigenomic Views of Innate Lymphoid Cells. Front Immunol 2017; 8:1579. [PMID: 29250060 PMCID: PMC5715337 DOI: 10.3389/fimmu.2017.01579] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 11/02/2017] [Indexed: 12/30/2022] Open
Abstract
The discovery of innate lymphoid cells (ILCs) with selective production of cytokines typically attributed to subsets of T helper cells forces immunologists to reassess the mechanisms by which selective effector functions arise. The parallelism between ILCs and T cells extends beyond these two cell types and comprises other innate-like T lymphocytes. Beyond the recognition of specialized effector functionalities in diverse lymphocytes, features typical of T cells, such as plasticity and memory, are also relevant for innate lymphocytes. Herein, we review what we have learned in terms of the molecular mechanisms underlying these shared functions, focusing on insights provided by next generation sequencing technologies. We review data on the role of lineage-defining- and signal-dependent transcription factors (TFs). ILC regulomes emerge developmentally whereas the much of the open chromatin regions of T cells are generated acutely, in an activation-dependent manner. And yet, these regions of open chromatin in T cells and ILCs have remarkable overlaps, suggesting that though accessibility is acquired by distinct modes, the end result is that convergent signaling pathways may be involved. Although much is left to be learned, substantial progress has been made in understanding how TFs and epigenomic status contribute to ILC biology in terms of differentiation, specification, and plasticity.
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Affiliation(s)
- Giuseppe Sciumè
- Department of Molecular Medicine, Sapienza University of Rome, Laboratory Affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Rome, Italy
| | - Han-Yu Shih
- Lymphocyte and Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD, United States
| | - Yohei Mikami
- Lymphocyte and Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD, United States
| | - John J O'Shea
- Lymphocyte and Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD, United States
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135
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Ma Y, Buttitta L. Chromatin organization changes during the establishment and maintenance of the postmitotic state. Epigenetics Chromatin 2017; 10:53. [PMID: 29126440 PMCID: PMC5681785 DOI: 10.1186/s13072-017-0159-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 10/30/2017] [Indexed: 02/06/2023] Open
Abstract
Background Genome organization changes during development as cells differentiate. Chromatin motion becomes increasingly constrained and heterochromatin clusters as cells become restricted in their developmental potential. These changes coincide with slowing of the cell cycle, which can also influence chromatin organization and dynamics. Terminal differentiation is often coupled with permanent exit from the cell cycle, and existing data suggest a close relationship between a repressive chromatin structure and silencing of the cell cycle in postmitotic cells. Heterochromatin clustering could also contribute to stable gene repression to maintain terminal differentiation or cell cycle exit, but whether clustering is initiated by differentiation, cell cycle changes, or both is unclear. Here we examine the relationship between chromatin organization, terminal differentiation and cell cycle exit. Results We focused our studies on the Drosophila wing, where epithelial cells transition from active proliferation to a postmitotic state in a temporally controlled manner. We find there are two stages of G0 in this tissue, a flexible G0 period where cells can be induced to reenter the cell cycle under specific genetic manipulations and a state we call “robust,” where cells become strongly refractory to cell cycle reentry. Compromising the flexible G0 by driving ectopic expression of cell cycle activators causes a global disruption of the clustering of heterochromatin-associated histone modifications such as H3K27 trimethylation and H3K9 trimethylation, as well as their associated repressors, Polycomb and heterochromatin protein 1 (HP1). However, this disruption is reversible. When cells enter a robust G0 state, even in the presence of ectopic cell cycle activity, clustering of heterochromatin-associated modifications is restored. If cell cycle exit is bypassed, cells in the wing continue to terminally differentiate, but heterochromatin clustering is severely disrupted. Heterochromatin-dependent gene silencing does not appear to be required for cell cycle exit, as compromising the H3K27 methyltransferase Enhancer of zeste, and/or HP1 cannot prevent the robust cell cycle exit, even in the face of normally oncogenic cell cycle activities. Conclusions Heterochromatin clustering during terminal differentiation is a consequence of cell cycle exit, rather than differentiation. Compromising heterochromatin-dependent gene silencing does not disrupt cell cycle exit. Electronic supplementary material The online version of this article (10.1186/s13072-017-0159-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yiqin Ma
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Laura Buttitta
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
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