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Flores Cortes E, Saddoris SM, Owens AK, Gibeault R, Depledge DP, Schang LM. Histone H2A variant H2A.B is enriched in transcriptionally active and replicating HSV-1 lytic chromatin. J Virol 2024; 98:e0201523. [PMID: 38451083 PMCID: PMC11019955 DOI: 10.1128/jvi.02015-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/19/2024] [Indexed: 03/08/2024] Open
Abstract
Herpes simplex virus 1 (HSV-1) transcription is restricted in latently infected neurons and the genomes are in mostly silenced chromatin, whereas all viral genes are transcribed in lytically infected cells, in which the genomes are dynamically chromatinized. Epigenetic regulation modulates HSV-1 transcription during lytic, latent, and reactivating infections but the precise mechanisms are not fully defined. Nucleosomes are dynamic: they slide, breathe, assemble, and disassemble. We and others have proposed that the most dynamic HSV-1 chromatin is transcriptionally competent, whereas the least dynamic is silenced. However, the mechanisms yielding the unusually dynamic viral chromatin remain unknown. Histone variants affect nucleosome dynamics. The dynamics of H2A, H2A.X, and macroH2A were enhanced in infected cells, whereas those of H2A.B were uniquely decreased. We constructed stably transduced cells expressing tagged histone H2A, H2A.B, macroH2A, or H2B, which assembles the H2A/H2B nucleosome dimers with all H2A variants. All H2A variants, as well as ectopic and endogenous H2B were assembled into HSV-1 chromatin evenly throughout the genome but canonical H2A was relatively depleted whereas H2A.B was enriched, particularly in the most dynamic viral chromatin. When viral transcription and DNA replication were restricted, H2A.B became as depleted from the viral chromatin through the entire genome as H2A. We propose that lytic HSV-1 nucleosomes are enriched in the dynamic variant H2A.B/H2B dimers to promote HSV-1 chromatin dynamics and transcriptional competency and conclude that the dynamics of HSV-1 chromatin are determined in part by the H2A variants. IMPORTANCE Herpes simplex virus 1 (HSV-1) transcription is epigenetically regulated during latent and lytic infections, and epigenetic inhibitors have been proposed as potential antiviral drugs to modulate latency and reactivation. However, the detailed epigenetic mechanisms of regulation of HSV-1 transcription have not been fully characterized and may differ from those regulating cellular transcription. Whereas lytic HSV-1 chromatin is unusually dynamic, latent silenced HSV-1 chromatin is not. The mechanisms resulting in the unique dynamics of the lytic chromatin remain unknown. Here we identify the enrichment of the highly dynamic histone 2A variant H2A in the most dynamic viral chromatin, which provides a mechanistic understanding of its unique dynamics. Future work to identify the mechanisms of enrichment in H2A.B on the viral chromatin may identify novel druggable epigenetic regulators that modulate HSV-1 latency and reactivation.
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Affiliation(s)
- Esteban Flores Cortes
- Baker Institute for Animal Health and Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
| | - Sarah M. Saddoris
- Baker Institute for Animal Health and Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
| | - Arryn K. Owens
- Baker Institute for Animal Health and Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
| | - Rebecca Gibeault
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Daniel P. Depledge
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner site Hannover-Braunschweig, Hannover, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, Hannover, Germany
| | - Luis M. Schang
- Baker Institute for Animal Health and Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
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Flores E, Saddoris SM, Owens AK, Gibeault R, Depledge DP, Schang LM. Histone H2A variant H2A.B is enriched in transcriptionally active HSV-1 lytic chromatin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.22.573075. [PMID: 38187672 PMCID: PMC10769327 DOI: 10.1101/2023.12.22.573075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Herpes simplex virus 1 (HSV-1) transcription is restricted in latently infected neurons and the genomes are in mostly silenced chromatin, whereas all viral genes are transcribed in lytically infected cells, in which the genomes are dynamically chromatinized. Epigenetic regulation modulates HSV-1 transcription during lytic, latent, and reactivating infections, but the precise mechanisms are not fully defined. Nucleosomes are dynamic; they slide, breathe, assemble and disassemble. We and others have proposed that the most dynamic HSV-1 chromatin is transcriptionally competent whereas the least dynamic is silenced. However, the mechanisms yielding the unusually dynamic viral chromatin remain unknown. Histone variants affect nucleosome dynamics. The dynamics of H2A, H2A.X and macroH2A were enhanced in infected cells, whereas those of H2A.B uniquely decreased. We constructed stably transduced cells expressing tagged histone H2A, H2A.B, macroH2A, or H2B, which assembles the H2A/H2B nucleosome dimers with all H2A variants. All H2A variants, ectopic, and endogenous H2B, were assembled into HSV-1 chromatin evenly throughout the genome, but canonical H2A was relatively depleted from the viral chromatin whereas H2A.B was enriched in the most dynamic viral chromatin. When viral transcription was restricted, H2A.B became as depleted from the viral chromatin through the entire genome as H2A. We propose that lytic HSV-1 nucleosomes are enriched in the dynamic variant H2A.B/H2B dimers to promote HSV-1 chromatin dynamics and transcriptional competency, and conclude that the dynamics of HSV-1 chromatin are determined in part by the H2A variants. Importance HSV-1 transcription is epigenetically regulated during latent and lytic infections, and epigenetic inhibitors have been proposed as potential antiviral drugs to modulate latency and reactivation. However, the detailed mechanisms of regulation of HSV-1 transcription by epigenetics have not been fully characterized and may differ from those regulating cellular transcription. In particular, the lytic HSV-1 chromatin is unusually dynamic, whereas the latent silenced one is not, but the mechanisms resulting in the unique dynamics of the lytic chromatin remain unknown. Here we identify the enrichment on the highly dynamic histone 2A variant H2A in the most dynamic viral chromatin, which provides a mechanistic understanding for its unique dynamics. Future work to identify the mechanisms of enrichment in H2A.B on the viral chromatin may identify novel druggable epigenetic regulators that modulate HSV-1 latency and reactivation.
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Kirkiz E, Meers O, Grebien F, Buschbeck M. Histone Variants and Their Chaperones in Hematological Malignancies. Hemasphere 2023; 7:e927. [PMID: 37449197 PMCID: PMC10337764 DOI: 10.1097/hs9.0000000000000927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 06/13/2023] [Indexed: 07/18/2023] Open
Abstract
Epigenetic regulation occurs on the level of compacting DNA into chromatin. The functional unit of chromatin is the nucleosome, which consists of DNA wrapped around a core of histone proteins. While canonical histone proteins are incorporated into chromatin through a replication-coupled process, structural variants of histones, commonly named histone variants, are deposited into chromatin in a replication-independent manner. Specific chaperones and chromatin remodelers mediate the locus-specific deposition of histone variants. Although histone variants comprise one of the least understood layers of epigenetic regulation, it has been proposed that they play an essential role in directly regulating gene expression in health and disease. Here, we review the emerging evidence suggesting that histone variants have a role at different stages of hematopoiesis, with a particular focus on the histone variants H2A, H3, and H1. Moreover, we discuss the current knowledge on how the dysregulation of histone variants can contribute to hematopoietic malignancies.
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Affiliation(s)
- Ecem Kirkiz
- Institute for Medical Biochemistry, University of Veterinary Medicine, Vienna, Austria
| | - Oliver Meers
- Cancer and Leukaemia Epigenetics and Biology Program, Josep Carreras Leukaemia Research Institute (IJC), Campus Can Ruti, Badalona, Spain
- PhD Programme in Biomedicine, University of Barcelona, Spain
| | - Florian Grebien
- Institute for Medical Biochemistry, University of Veterinary Medicine, Vienna, Austria
- St. Anna Children’s Cancer Research Institute (CCRI), Vienna, Austria
| | - Marcus Buschbeck
- Cancer and Leukaemia Epigenetics and Biology Program, Josep Carreras Leukaemia Research Institute (IJC), Campus Can Ruti, Badalona, Spain
- Germans Trias i Pujol Research Institute (IGTP), Badalona, Spain
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4
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Oberdoerffer P, Miller KM. Histone H2A variants: Diversifying chromatin to ensure genome integrity. Semin Cell Dev Biol 2023; 135:59-72. [PMID: 35331626 PMCID: PMC9489817 DOI: 10.1016/j.semcdb.2022.03.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 03/07/2022] [Accepted: 03/08/2022] [Indexed: 12/12/2022]
Abstract
Histone variants represent chromatin components that diversify the structure and function of the genome. The variants of H2A, primarily H2A.X, H2A.Z and macroH2A, are well-established participants in DNA damage response (DDR) pathways, which function to protect the integrity of the genome. Through their deposition, post-translational modifications and unique protein interaction networks, these variants guard DNA from endogenous threats including replication stress and genome fragility as well as from DNA lesions inflicted by exogenous sources. A growing body of work is now providing a clearer picture on the involvement and mechanistic basis of H2A variant contribution to genome integrity. Beyond their well-documented role in gene regulation, we review here how histone H2A variants promote genome stability and how alterations in these pathways contribute to human diseases including cancer.
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Affiliation(s)
- Philipp Oberdoerffer
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287 USA.
| | - Kyle M Miller
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Livestrong Cancer Institutes, Dell Medical School, The University of Texas at Austin, Austin, TX 78712, USA.
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5
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Sokolova V, Sarkar S, Tan D. Histone variants and chromatin structure, update of advances. Comput Struct Biotechnol J 2022; 21:299-311. [PMID: 36582440 PMCID: PMC9764139 DOI: 10.1016/j.csbj.2022.12.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 12/01/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022] Open
Abstract
Histone proteins are highly conserved among all eukaryotes. They have two important functions in the cell: to package the genomic DNA and to regulate gene accessibility. Fundamental to these functions is the ability of histone proteins to interact with DNA and to form the nucleoprotein complex called chromatin. One of the mechanisms the cells use to regulate chromatin and gene expression is through replacing canonical histones with their variants at specific loci to achieve functional consequence. Recent cryo-electron microscope (cryo-EM) studies of chromatin containing histone variants reveal new details that shed light on how variant-specific features influence the structures and functions of chromatin. In this article, we review the current state of knowledge on histone variants biochemistry and discuss the implication of these new structural information on histone variant biology and their functions in transcription.
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Torres-Arciga K, Flores-León M, Ruiz-Pérez S, Trujillo-Pineda M, González-Barrios R, Herrera LA. Histones and their chaperones: Adaptive remodelers of an ever-changing chromatinic landscape. Front Genet 2022; 13:1057846. [PMID: 36468032 PMCID: PMC9709290 DOI: 10.3389/fgene.2022.1057846] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/02/2022] [Indexed: 07/29/2023] Open
Abstract
Chromatin maintenance and remodeling are processes that take place alongside DNA repair, replication, or transcription to ensure the survival and adaptability of a cell. The environment and the needs of the cell dictate how chromatin is remodeled; particularly where and which histones are deposited, thus changing the canonical histone array to regulate chromatin structure and gene expression. Chromatin is highly dynamic, and histone variants and their chaperones play a crucial role in maintaining the epigenetic regulation at different genomic regions. Despite the large number of histone variants reported to date, studies on their roles in physiological processes and pathologies are emerging but continue to be scarce. Here, we present recent advances in the research on histone variants and their chaperones, with a focus on their importance in molecular mechanisms such as replication, transcription, and DNA damage repair. Additionally, we discuss the emerging role they have in transposable element regulation, aging, and chromatin remodeling syndromes. Finally, we describe currently used methods and their limitations in the study of these proteins and highlight the importance of improving the experimental approaches to further understand this epigenetic machinery.
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Affiliation(s)
- Karla Torres-Arciga
- Doctorado en Ciencias Biológicas, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
- Unidad de Investigación Biomédica en Cáncer, Instituto Nacional de Cancerología (INCan)-Instituto de Investigaciones Biomédicas (IIBO), Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | - Manuel Flores-León
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas (IIBO), Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | - Samuel Ruiz-Pérez
- Unidad de Investigación Biomédica en Cáncer, Instituto Nacional de Cancerología (INCan)-Instituto de Investigaciones Biomédicas (IIBO), Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | - Magalli Trujillo-Pineda
- Unidad de Investigación Biomédica en Cáncer, Instituto Nacional de Cancerología (INCan)-Instituto de Investigaciones Biomédicas (IIBO), Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | - Rodrigo González-Barrios
- Unidad de Investigación Biomédica en Cáncer, Instituto Nacional de Cancerología (INCan)-Instituto de Investigaciones Biomédicas (IIBO), Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | - Luis A. Herrera
- Unidad de Investigación Biomédica en Cáncer, Instituto Nacional de Cancerología (INCan)-Instituto de Investigaciones Biomédicas (IIBO), Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
- Instituto Nacional de Medicina Genómica (INMEGEN), Mexico City, Mexico
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7
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Takizawa Y, Kurumizaka H. Chromatin structure meets cryo-EM: Dynamic building blocks of the functional architecture. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2022; 1865:194851. [PMID: 35952957 DOI: 10.1016/j.bbagrm.2022.194851] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/04/2022] [Accepted: 08/04/2022] [Indexed: 06/15/2023]
Abstract
Chromatin is a dynamic molecular complex composed of DNA and proteins that package the DNA in the nucleus of eukaryotic cells. The basic structural unit of chromatin is the nucleosome core particle, composed of ~150 base pairs of genomic DNA wrapped around a histone octamer containing two copies each of four histones, H2A, H2B, H3, and H4. Individual nucleosome core particles are connected by short linker DNAs, forming a nucleosome array known as a beads-on-a-string fiber. Higher-order structures of chromatin are closely linked to nuclear events such as replication, transcription, recombination, and repair. Recently, a variety of chromatin structures have been determined by single-particle cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET), and their structural details have provided clues about the chromatin architecture functions in the cell. In this review, we highlight recent cryo-EM structural studies of a fundamental chromatin unit to clarify the functions of chromatin.
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Affiliation(s)
- Yoshimasa Takizawa
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
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8
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Herchenröther A, Wunderlich TM, Lan J, Hake SB. Spotlight on histone H2A variants: From B to X to Z. Semin Cell Dev Biol 2022; 135:3-12. [PMID: 35365397 DOI: 10.1016/j.semcdb.2022.03.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 03/18/2022] [Accepted: 03/20/2022] [Indexed: 12/30/2022]
Abstract
Chromatin, the functional organization of DNA with histone proteins in eukaryotic nuclei, is the tightly-regulated template for several biological processes, such as transcription, replication, DNA damage repair, chromosome stability and sister chromatid segregation. In order to achieve a reversible control of local chromatin structure and DNA accessibility, various interconnected mechanisms have evolved. One of such processes includes the deposition of functionally-diverse variants of histone proteins into nucleosomes, the building blocks of chromatin. Among core histones, the family of H2A histone variants exhibits the largest number of members and highest sequence-divergence. In this short review, we report and discuss recent discoveries concerning the biological functions of the animal histone variants H2A.B, H2A.X and H2A.Z and how dysregulation or mutation of the latter impacts the development of disease.
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Affiliation(s)
| | - Tim M Wunderlich
- Institute for Genetics, Justus Liebig University, 35390 Giessen, Germany
| | - Jie Lan
- Institute for Genetics, Justus Liebig University, 35390 Giessen, Germany.
| | - Sandra B Hake
- Institute for Genetics, Justus Liebig University, 35390 Giessen, Germany.
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9
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Phillips EO, Gunjan A. Histone Variants: The Unsung Guardians of the Genome. DNA Repair (Amst) 2022; 112:103301. [DOI: 10.1016/j.dnarep.2022.103301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 02/01/2022] [Accepted: 02/12/2022] [Indexed: 12/15/2022]
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Jiang X, Wen J, Paver E, Wu YH, Sun G, Bullman A, Dahlstrom JE, Tremethick DJ, Soboleva TA. H2A.B is a cancer/testis factor involved in the activation of ribosome biogenesis in Hodgkin lymphoma. EMBO Rep 2021; 22:e52462. [PMID: 34350706 DOI: 10.15252/embr.202152462] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 06/02/2021] [Accepted: 06/15/2021] [Indexed: 12/12/2022] Open
Abstract
Testis-specific regulators of chromatin function are commonly ectopically expressed in human cancers, but their roles are poorly understood. Examination of 81 primary Hodgkin lymphoma (HL) samples showed that the ectopic expression of the eutherian testis-specific histone variant H2A.B is an inherent feature of HL. In experiments using two HL cell lines derived from different subtypes of HL, H2A.B knockdown inhibited cell proliferation. H2A.B was enriched in both nucleoli of these HL cell lines and primary HL samples. We found that H2A.B enhanced ribosomal DNA (rDNA) transcription, was enriched at the rDNA promoter and transcribed regions, and interacted with RNA Pol I. Depletion of H2A.B caused the loss of RNA Pol I from rDNA chromatin. Remarkably, H2A.B was also required for high levels of ribosomal protein gene expression being located at the transcriptional start site and within the gene body. H2A.B knockdown reduced gene body chromatin accessibility of active RNA Pol II genes concurrent with a decrease in transcription. Taken together, our data show that in HL H2A.B has acquired a new function, the ability to increase ribosome biogenesis.
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Affiliation(s)
- Xuanzhao Jiang
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Jiayu Wen
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Elizabeth Paver
- Department of Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Sydney, NSW, Australia
| | - Yu-Huan Wu
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Gege Sun
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Amanda Bullman
- Department of Anatomical Pathology, ACT Pathology, The Canberra Hospital, Canberra, ACT, Australia
| | - Jane E Dahlstrom
- Department of Anatomical Pathology, ACT Pathology, The Canberra Hospital, Canberra, ACT, Australia.,Australian National University Medical School, The Australian National University, Canberra, ACT, Australia
| | - David J Tremethick
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Tatiana A Soboleva
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
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11
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Morrison O, Thakur J. Molecular Complexes at Euchromatin, Heterochromatin and Centromeric Chromatin. Int J Mol Sci 2021; 22:6922. [PMID: 34203193 PMCID: PMC8268097 DOI: 10.3390/ijms22136922] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 01/19/2023] Open
Abstract
Chromatin consists of a complex of DNA and histone proteins as its core components and plays an important role in both packaging DNA and regulating DNA metabolic pathways such as DNA replication, transcription, recombination, and chromosome segregation. Proper functioning of chromatin further involves a network of interactions among molecular complexes that modify chromatin structure and organization to affect the accessibility of DNA to transcription factors leading to the activation or repression of the transcription of target DNA loci. Based on its structure and compaction state, chromatin is categorized into euchromatin, heterochromatin, and centromeric chromatin. In this review, we discuss distinct chromatin factors and molecular complexes that constitute euchromatin-open chromatin structure associated with active transcription; heterochromatin-less accessible chromatin associated with silencing; centromeric chromatin-the site of spindle binding in chromosome segregation.
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Affiliation(s)
| | - Jitendra Thakur
- Department of Biology, Emory University, 1510 Clifton Rd #2006, Atlanta, GA 30322, USA;
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12
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Hsu CJ, Meers O, Buschbeck M, Heidel FH. The Role of MacroH2A Histone Variants in Cancer. Cancers (Basel) 2021; 13:cancers13123003. [PMID: 34203934 PMCID: PMC8232725 DOI: 10.3390/cancers13123003] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/07/2021] [Accepted: 06/14/2021] [Indexed: 02/06/2023] Open
Abstract
Simple Summary The structural unit of chromatin is the nucleosome that is composed of DNA wrapped around a core of eight histone proteins. Histone variants can replace ‘standard’ histones at specific sites of the genome. Thus, histone variants modulate all functions in the context of chromatin, such as gene expression. Here, we provide a concise review on a group of histone variants termed macroH2A. They contain two additional domains that contribute to their increased size. We discuss how these domains mediate molecular functions in normal cells and the role of macroH2As in gene expression and cancer. Abstract The epigenome regulates gene expression and provides a molecular memory of cellular events. A growing body of evidence has highlighted the importance of epigenetic regulation in physiological tissue homeostasis and malignant transformation. Among epigenetic mechanisms, the replacement of replication-coupled histones with histone variants is the least understood. Due to differences in protein sequence and genomic distribution, histone variants contribute to the plasticity of the epigenome. Here, we focus on the family of macroH2A histone variants that are particular in having a tripartite structure consisting of a histone fold, an intrinsically disordered linker and a globular macrodomain. We discuss how these domains mediate different molecular functions related to chromatin architecture, transcription and DNA repair. Dysregulated expression of macroH2A histone variants has been observed in different subtypes of cancer and has variable prognostic impact, depending on cellular context and molecular background. We aim to provide a concise review regarding the context- and isoform-dependent contributions of macroH2A histone variants to cancer development and progression.
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Affiliation(s)
- Chen-Jen Hsu
- Internal Medicine C, Greifswald University Medicine, 17475 Greifswald, Germany;
| | - Oliver Meers
- Cancer and Leukaemia Epigenetics and Biology Program, Josep Carreras Leukaemia Research Institute (IJC), Campus Can Ruti, 08916 Badalona, Spain;
| | - Marcus Buschbeck
- Cancer and Leukaemia Epigenetics and Biology Program, Josep Carreras Leukaemia Research Institute (IJC), Campus Can Ruti, 08916 Badalona, Spain;
- Program for Predictive and Personalized Medicine of Cancer, Germans Trias i Pujol Research Institute (PMPPC-IGTP), Campus Can Ruti, 08916 Badalona, Spain
- Correspondence: (M.B.); (F.H.H.); Tel.: +34-935-572-800 (M.B.); +49-383-486-6698 (F.H.H.); Fax: +49-383-486-6713 (F.H.H.)
| | - Florian H. Heidel
- Internal Medicine C, Greifswald University Medicine, 17475 Greifswald, Germany;
- Leibniz Institute on Aging, Fritz-Lipmann Institute, 07745 Jena, Germany
- Correspondence: (M.B.); (F.H.H.); Tel.: +34-935-572-800 (M.B.); +49-383-486-6698 (F.H.H.); Fax: +49-383-486-6713 (F.H.H.)
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13
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Amatori S, Tavolaro S, Gambardella S, Fanelli M. The dark side of histones: genomic organization and role of oncohistones in cancer. Clin Epigenetics 2021; 13:71. [PMID: 33827674 PMCID: PMC8025322 DOI: 10.1186/s13148-021-01057-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/22/2021] [Indexed: 02/07/2023] Open
Abstract
Background The oncogenic role of histone mutations is one of the most relevant discovery in cancer epigenetics. Recurrent mutations targeting histone genes have been described in pediatric brain tumors, chondroblastoma, giant cell tumor of bone and other tumor types. The demonstration that mutant histones can be oncogenic and drive the tumorigenesis in pediatric tumors, led to the coining of the term “oncohistones.” The first identified histone mutations were localized at or near residues normally targeted by post-translational modifications (PTMs) in the histone N-terminal tails and suggested a possible interference with histone PTMs regulation and reading. Main body In this review, we describe the peculiar organization of the multiple genes that encode histone proteins, and the latter advances in both the identification and the biological role of histone mutations in cancer. Recent works show that recurrent somatic mutations target both N-terminal tails and globular histone fold domain in diverse tumor types. Oncohistones are often dominant-negative and occur at higher frequencies in tumors affecting children and adolescents. Notably, in many cases the mutations target selectively only some of the genes coding the same histone protein and are frequently associated with specific tumor types or, as documented for histone variant H3.3 in pediatric glioma, with peculiar tumors arising from specific anatomic locations. Conclusion The overview of the most recent advances suggests that the oncogenic potential of histone mutations can be exerted, together with the alteration of histone PTMs, through the destabilization of nucleosome and DNA–nucleosome interactions, as well as through the disruption of higher-order chromatin structure. However, further studies are necessary to fully elucidate the mechanism of action of oncohistones, as well as to evaluate their possible application to cancer classification, prognosis and to the identification of new therapies.
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Affiliation(s)
- Stefano Amatori
- Department of Biomolecular Sciences, Molecular Pathology Laboratory "PaoLa", University of Urbino Carlo Bo, Via Arco d'Augusto 2, 61032, Fano, PU, Italy.
| | - Simona Tavolaro
- Fredis Associazione, Via Edoardo Jenner 30, 00151, Rome, Italy
| | - Stefano Gambardella
- Department of Biomolecular Sciences, Molecular Pathology Laboratory "PaoLa", University of Urbino Carlo Bo, Via Arco d'Augusto 2, 61032, Fano, PU, Italy.,IRCCS Neuromed, Via Atinense 18, 86077, Pozzilli, IS, Italy
| | - Mirco Fanelli
- Department of Biomolecular Sciences, Molecular Pathology Laboratory "PaoLa", University of Urbino Carlo Bo, Via Arco d'Augusto 2, 61032, Fano, PU, Italy.
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14
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Kohestani H, Wereszczynski J. Effects of H2A.B incorporation on nucleosome structures and dynamics. Biophys J 2021; 120:1498-1509. [PMID: 33609493 DOI: 10.1016/j.bpj.2021.01.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 12/31/2020] [Accepted: 01/12/2021] [Indexed: 01/20/2023] Open
Abstract
The H2A.B histone variant is an epigenetic regulator involved in transcriptional upregulation, DNA synthesis, and splicing that functions by replacing the canonical H2A histone in the nucleosome core particle. Introduction of H2A.B results in less compact nucleosome states with increased DNA unwinding and accessibility at the nucleosomal entry and exit sites. Despite being well characterized experimentally, the molecular mechanisms by which H2A.B incorporation alters nucleosome stability and dynamics remain poorly understood. To study the molecular mechanisms of H2A.B, we have performed a series of conventional and enhanced sampling molecular dynamics simulation of H2A.B- and canonical H2A-containing nucleosomes. Results of conventional simulations show that H2A.B weakens protein-protein and protein-DNA interactions at specific locations throughout the nucleosome. These weakened interactions result in significantly more DNA opening from both the entry and exit sites in enhanced sampling simulations. Furthermore, free energy profiles show that H2A.B-containing nucleosomes have significantly broader free wells and that H2A.B allows for sampling of states with increased DNA breathing, which are shown to be stable on the hundreds of nanoseconds timescale with further conventional simulations. Together, our results show the molecular mechanisms by which H2A.B creates less compacted nucleosome states as a means of increasing genetic accessibility and gene transcription.
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Affiliation(s)
- Havva Kohestani
- Department of Biology, Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, Illinois
| | - Jeff Wereszczynski
- Department of Physics, Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, Illinois.
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15
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Histone variant H2A.B-H2B dimers are spontaneously exchanged with canonical H2A-H2B in the nucleosome. Commun Biol 2021; 4:191. [PMID: 33580188 PMCID: PMC7881002 DOI: 10.1038/s42003-021-01707-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 01/11/2021] [Indexed: 01/07/2023] Open
Abstract
H2A.B is an evolutionarily distant histone H2A variant that accumulates on DNA repair sites, DNA replication sites, and actively transcribing regions in genomes. In cells, H2A.B exchanges rapidly in chromatin, but the mechanism has remained enigmatic. In the present study, we found that the H2A.B-H2B dimer incorporated within the nucleosome exchanges with the canonical H2A-H2B dimer without assistance from additional factors, such as histone chaperones and nucleosome remodelers. High-speed atomic force microscopy revealed that the H2A.B nucleosome, but not the canonical H2A nucleosome, transiently forms an intermediate "open conformation", in which two H2A.B-H2B dimers may be detached from the H3-H4 tetramer and bind to the DNA regions near the entry/exit sites. Mutational analyses revealed that the H2A.B C-terminal region is responsible for the adoption of the open conformation and the H2A.B-H2B exchange in the nucleosome. These findings provide mechanistic insights into the histone exchange of the H2A.B nucleosome.
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16
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Caffrey PJ, Delaney S. Chromatin and other obstacles to base excision repair: potential roles in carcinogenesis. Mutagenesis 2021; 35:39-50. [PMID: 31612219 DOI: 10.1093/mutage/gez029] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 09/13/2019] [Indexed: 12/29/2022] Open
Abstract
DNA is comprised of chemically reactive nucleobases that exist under a constant barrage from damaging agents. Failure to repair chemical modifications to these nucleobases can result in mutations that can cause various diseases, including cancer. Fortunately, the base excision repair (BER) pathway can repair modified nucleobases and prevent these deleterious mutations. However, this pathway can be hindered through several mechanisms. For instance, mutations to the enzymes in the BER pathway have been identified in cancers. Biochemical characterisation of these mutants has elucidated various mechanisms that inhibit their activity. Furthermore, the packaging of DNA into chromatin poses another obstacle to the ability of BER enzymes to function properly. Investigations of BER in the base unit of chromatin, the nucleosome core particle (NCP), have revealed that the NCP acts as a complex substrate for BER enzymes. The constituent proteins of the NCP, the histones, also have variants that can further impact the structure of the NCP and may modulate access of enzymes to the packaged DNA. These histone variants have also displayed significant clinical effects both in carcinogenesis and patient prognosis. This review focuses on the underlying molecular mechanisms that present obstacles to BER and the relationship of these obstacles to cancer. In addition, several chemotherapeutics induce DNA damage that can be repaired by the BER pathway and understanding obstacles to BER can inform how resistance and/or sensitivity to these therapies may occur. With the understanding of these molecular mechanisms, current chemotherapeutic treatment regiments may be improved, and future therapies developed.
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Affiliation(s)
- Paul J Caffrey
- Department of Chemistry, Brown University, Providence, RI
| | - Sarah Delaney
- Department of Chemistry, Brown University, Providence, RI
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17
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Chew GL, Bleakley M, Bradley RK, Malik HS, Henikoff S, Molaro A, Sarthy J. Short H2A histone variants are expressed in cancer. Nat Commun 2021; 12:490. [PMID: 33473122 PMCID: PMC7817690 DOI: 10.1038/s41467-020-20707-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/09/2020] [Indexed: 12/23/2022] Open
Abstract
Short H2A (sH2A) histone variants are primarily expressed in the testes of placental mammals. Their incorporation into chromatin is associated with nucleosome destabilization and modulation of alternate splicing. Here, we show that sH2As innately possess features similar to recurrent oncohistone mutations associated with nucleosome instability. Through analyses of existing cancer genomics datasets, we find aberrant sH2A upregulation in a broad array of cancers, which manifest splicing patterns consistent with global nucleosome destabilization. We posit that short H2As are a class of "ready-made" oncohistones, whose inappropriate expression contributes to chromatin dysfunction in cancer.
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Affiliation(s)
- Guo-Liang Chew
- The Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Marie Bleakley
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Robert K Bradley
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Harmit S Malik
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Antoine Molaro
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
- Genetics, Reproduction and Development (GReD) Institute, Université Clermont Auvergne, Clermont-Ferrand, France.
| | - Jay Sarthy
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
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18
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JAZF1, A Novel p400/TIP60/NuA4 Complex Member, Regulates H2A.Z Acetylation at Regulatory Regions. Int J Mol Sci 2021; 22:ijms22020678. [PMID: 33445503 PMCID: PMC7826843 DOI: 10.3390/ijms22020678] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/07/2021] [Accepted: 01/09/2021] [Indexed: 12/22/2022] Open
Abstract
Histone variants differ in amino acid sequence, expression timing and genomic localization sites from canonical histones and convey unique functions to eukaryotic cells. Their tightly controlled spatial and temporal deposition into specific chromatin regions is accomplished by dedicated chaperone and/or remodeling complexes. While quantitatively identifying the chaperone complexes of many human H2A variants by using mass spectrometry, we also found additional members of the known H2A.Z chaperone complexes p400/TIP60/NuA4 and SRCAP. We discovered JAZF1, a nuclear/nucleolar protein, as a member of a p400 sub-complex containing MBTD1 but excluding ANP32E. Depletion of JAZF1 results in transcriptome changes that affect, among other pathways, ribosome biogenesis. To identify the underlying molecular mechanism contributing to JAZF1's function in gene regulation, we performed genome-wide ChIP-seq analyses. Interestingly, depletion of JAZF1 leads to reduced H2A.Z acetylation levels at > 1000 regulatory sites without affecting H2A.Z nucleosome positioning. Since JAZF1 associates with the histone acetyltransferase TIP60, whose depletion causes a correlated H2A.Z deacetylation of several JAZF1-targeted enhancer regions, we speculate that JAZF1 acts as chromatin modulator by recruiting TIP60's enzymatic activity. Altogether, this study uncovers JAZF1 as a member of a TIP60-containing p400 chaperone complex orchestrating H2A.Z acetylation at regulatory regions controlling the expression of genes, many of which are involved in ribosome biogenesis.
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19
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Zhou M, Dai L, Li C, Shi L, Huang Y, Guo Z, Wu F, Zhu P, Zhou Z. Structural basis of nucleosome dynamics modulation by histone variants H2A.B and H2A.Z.2.2. EMBO J 2021; 40:e105907. [PMID: 33073403 PMCID: PMC7780145 DOI: 10.15252/embj.2020105907] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 09/15/2020] [Accepted: 09/22/2020] [Indexed: 01/03/2023] Open
Abstract
Nucleosomes are dynamic entities with wide-ranging compositional variations. Human histone variants H2A.B and H2A.Z.2.2 play critical roles in multiple biological processes by forming unstable nucleosomes and open chromatin structures, but how H2A.B and H2A.Z.2.2 confer these dynamic features to nucleosomes remains unclear. Here, we report cryo-EM structures of nucleosome core particles containing human H2A.B (H2A.B-NCP) at atomic resolution, identifying large-scale structural rearrangements in the histone octamer in H2A.B-NCP. H2A.B-NCP compacts approximately 103 bp of DNA wrapping around the core histones in approximately 1.2 left-handed superhelical turns, in sharp contrast to canonical nucleosome encompassing approximately 1.7 turns of DNA. Micrococcal nuclease digestion assay reveals that nineteen H2A.B-specific residues, including a ROF ("regulating-octamer-folding") sequence of six consecutive residues, are responsible for loosening of H2A.B-NCPs. Unlike H2A.B-NCP, the H2A.Z.2.2-containing nucleosome (Z.2.2-NCP) adopts a less-extended structure and compacts around 125 bp of DNA. Further investigation uncovers a crucial role for the H2A.Z.2.2-specific ROF in both H2A.Z.2.2-NCP opening and SWR1-dependent histone replacement. Taken together, these first high-resolution structure of unstable nucleosomes induced by histone H2A variants elucidate specific functions of H2A.B and H2A.Z.2.2 in enhancing chromatin dynamics.
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Affiliation(s)
- Min Zhou
- National Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Linchang Dai
- National Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of SciencesBeijingChina
| | - Chengmin Li
- National Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Liuxin Shi
- National Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Yan Huang
- National Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Zhenqian Guo
- National Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of SciencesBeijingChina
| | - Fei Wu
- National Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Ping Zhu
- National Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Zheng Zhou
- National Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
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20
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Nicosia L, Bonaldi T. Native Chromatin Proteomics (N-ChroP) to Characterize Histone Post-translational Modification (PTM) Combinatorics at Distinct Genomic Regions. Methods Mol Biol 2021; 2351:251-274. [PMID: 34382194 DOI: 10.1007/978-1-0716-1597-3_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In this chapter, we describe the proteomic approach named "Native Chromatin Proteomics" (N-ChroP) that couples a modified Chromatin ImmunoPrecipitation (ChIP) protocol with the mass spectrometry (MS) analysis of immunoprecipitated proteins to study the combinatorial enrichment or exclusion of histone post-translational modifications (PTMs) at specific genomic regions, such as promoters or enhancers. We describe the protocol steps from the digestion of chromatin and nucleosome immunoprecipitation to histone digestion and peptide enrichment prior to MS analysis, up to the MS raw data analysis. We also discuss current challenges and offer suggestions based on the direct hands-on experience acquired during the method setup.
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Affiliation(s)
- Luciano Nicosia
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Tiziana Bonaldi
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy.
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21
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Molaro A, Wood AJ, Janssens D, Kindelay SM, Eickbush MT, Wu S, Singh P, Muller CH, Henikoff S, Malik HS. Biparental contributions of the H2A.B histone variant control embryonic development in mice. PLoS Biol 2020; 18:e3001001. [PMID: 33362208 PMCID: PMC7757805 DOI: 10.1371/journal.pbio.3001001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 11/30/2020] [Indexed: 12/15/2022] Open
Abstract
Histone variants expand chromatin functions in eukaryote genomes. H2A.B genes are testis-expressed short histone H2A variants that arose in placental mammals. Their biological functions remain largely unknown. To investigate their function, we generated a knockout (KO) model that disrupts all 3 H2A.B genes in mice. We show that H2A.B KO males have globally altered chromatin structure in postmeiotic germ cells. Yet, they do not show impaired spermatogenesis or testis function. Instead, we find that H2A.B plays a crucial role postfertilization. Crosses between H2A.B KO males and females yield embryos with lower viability and reduced size. Using a series of genetic crosses that separate parental and zygotic contributions, we show that the H2A.B status of both the father and mother, but not of the zygote, affects embryonic viability and growth during gestation. We conclude that H2A.B is a novel parental-effect gene, establishing a role for short H2A histone variants in mammalian development. We posit that parental antagonism over embryonic growth drove the origin and ongoing diversification of short histone H2A variants in placental mammals.
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Affiliation(s)
- Antoine Molaro
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Anna J. Wood
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Derek Janssens
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Selina M. Kindelay
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Michael T. Eickbush
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Steven Wu
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Priti Singh
- Comparative Medicine, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Charles H. Muller
- Male Fertility Laboratory, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Steven Henikoff
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Harmit S. Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
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22
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Ferrand J, Rondinelli B, Polo SE. Histone Variants: Guardians of Genome Integrity. Cells 2020; 9:E2424. [PMID: 33167489 PMCID: PMC7694513 DOI: 10.3390/cells9112424] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/30/2020] [Accepted: 11/03/2020] [Indexed: 12/12/2022] Open
Abstract
Chromatin integrity is key for cell homeostasis and for preventing pathological development. Alterations in core chromatin components, histone proteins, recently came into the spotlight through the discovery of their driving role in cancer. Building on these findings, in this review, we discuss how histone variants and their associated chaperones safeguard genome stability and protect against tumorigenesis. Accumulating evidence supports the contribution of histone variants and their chaperones to the maintenance of chromosomal integrity and to various steps of the DNA damage response, including damaged chromatin dynamics, DNA damage repair, and damage-dependent transcription regulation. We present our current knowledge on these topics and review recent advances in deciphering how alterations in histone variant sequence, expression, and deposition into chromatin fuel oncogenic transformation by impacting cell proliferation and cell fate transitions. We also highlight open questions and upcoming challenges in this rapidly growing field.
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Affiliation(s)
| | | | - Sophie E. Polo
- Epigenetics & Cell Fate Centre, UMR7216 CNRS, Université de Paris, 75013 Paris, France; (J.F.); (B.R.)
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23
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Abstract
Histone variants regulate chromatin accessibility and gene transcription. Given their distinct properties and functions, histone varint substitutions allow for profound alteration of nucleosomal architecture and local chromatin landscape. Skeletal myogenesis driven by the key transcription factor MyoD is characterized by precise temporal regulation of myogenic genes. Timed substitution of variants within the nucleosomes provides a powerful means to ensure sequential expression of myogenic genes. Indeed, growing evidence has shown H3.3, H2A.Z, macroH2A, and H1b to be critical for skeletal myogenesis. However, the relative importance of various histone variants and their associated chaperones in myogenesis is not fully appreciated. In this review, we summarize the role that histone variants play in altering chromatin landscape to ensure proper muscle differentiation. The temporal regulation and cross talk between histones variants and their chaperones in conjunction with other forms of epigenetic regulation could be critical to understanding myogenesis and their involvement in myopathies.
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Affiliation(s)
- Nandini Karthik
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore , Singapore
| | - Reshma Taneja
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore , Singapore
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24
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Khan KA, Ng MK, Cheung P. The Use of Mononucleosome Immunoprecipitation for Analysis of Combinatorial Histone Post-translational Modifications and Purification of Nucleosome-Interacting Proteins. Front Cell Dev Biol 2020; 8:331. [PMID: 32457909 PMCID: PMC7225312 DOI: 10.3389/fcell.2020.00331] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/16/2020] [Indexed: 01/05/2023] Open
Abstract
The nucleosome is the principal structural unit of chromatin. Although many studies focus on individual histone post-translational modifications (PTMs) in isolation, it is important to recognize that multiple histone PTMs can function together or cross-regulate one another within the nucleosome context. In addition, different modifications or histone-binding surfaces can synergize to stabilize the binding of nuclear factors to nucleosomes. To facilitate these types of studies, we present here a step-by-step protocol for isolating high yields of mononucleosomes for biochemical analyses. Furthermore, we discuss differences and variations of the basic protocol used in different publications and characterize the relative abundance of selected histone PTMs and chromatin-binding proteins in the different chromatin fractions obtained by this method.
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Affiliation(s)
| | - Marlee K Ng
- Department of Biology, York University, Toronto, ON, Canada
| | - Peter Cheung
- Department of Biology, York University, Toronto, ON, Canada
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25
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Short Histone H2A Variants: Small in Stature but not in Function. Cells 2020; 9:cells9040867. [PMID: 32252453 PMCID: PMC7226823 DOI: 10.3390/cells9040867] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 03/24/2020] [Accepted: 03/31/2020] [Indexed: 12/19/2022] Open
Abstract
The dynamic packaging of DNA into chromatin regulates all aspects of genome function by altering the accessibility of DNA and by providing docking pads to proteins that copy, repair and express the genome. Different epigenetic-based mechanisms have been described that alter the way DNA is organised into chromatin, but one fundamental mechanism alters the biochemical composition of a nucleosome by substituting one or more of the core histones with their variant forms. Of the core histones, the largest number of histone variants belong to the H2A class. The most divergent class is the designated “short H2A variants” (H2A.B, H2A.L, H2A.P and H2A.Q), so termed because they lack a H2A C-terminal tail. These histone variants appeared late in evolution in eutherian mammals and are lineage-specific, being expressed in the testis (and, in the case of H2A.B, also in the brain). To date, most information about the function of these peculiar histone variants has come from studies on the H2A.B and H2A.L family in mice. In this review, we describe their unique protein characteristics, their impact on chromatin structure, and their known functions plus other possible, even non-chromatin, roles in an attempt to understand why these peculiar histone variants evolved in the first place.
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26
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Wang T, Chuffart F, Bourova-Flin E, Wang J, Mi J, Rousseaux S, Khochbin S. Histone variants: critical determinants in tumour heterogeneity. Front Med 2019; 13:289-297. [PMID: 30280307 DOI: 10.1007/s11684-018-0667-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 07/02/2018] [Indexed: 12/25/2022]
Abstract
Malignant cell transformation could be considered as a series of cell reprogramming events driven by oncogenic transcription factors and upstream signalling pathways. Chromatin plasticity and dynamics are critical determinants in the control of cell reprograming. An increase in chromatin dynamics could therefore constitute an essential step in driving oncogenesis and in generating tumour cell heterogeneity, which is indispensable for the selection of aggressive properties, including the ability of cells to disseminate and acquire resistance to treatments. Histone supply and dosage, as well as histone variants, are the best-known regulators of chromatin dynamics. By facilitating cell reprogramming, histone under-dosage and histone variants should also be crucial in cell transformation and tumour metastasis. Here we summarize and discuss our knowledge of the role of histone supply and histone variants in chromatin dynamics and their ability to enhance oncogenic cell reprogramming and tumour heterogeneity.
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Affiliation(s)
- Tao Wang
- CNRS UMR 5309, Inserm, U1209, University of Grenoble Alpes, Institute for Advanced Biosciences, 38706, Grenoble, France.,State Key Laboratory for Medical Genomics and Department of Hematology, Shanghai Institute of Hematology, Collaborative Innovation Center of Systems Biomedicine, Pôle Sino-Français des Sciences du Vivant et Genomique, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Florent Chuffart
- CNRS UMR 5309, Inserm, U1209, University of Grenoble Alpes, Institute for Advanced Biosciences, 38706, Grenoble, France
| | - Ekaterina Bourova-Flin
- CNRS UMR 5309, Inserm, U1209, University of Grenoble Alpes, Institute for Advanced Biosciences, 38706, Grenoble, France
| | - Jin Wang
- State Key Laboratory for Medical Genomics and Department of Hematology, Shanghai Institute of Hematology, Collaborative Innovation Center of Systems Biomedicine, Pôle Sino-Français des Sciences du Vivant et Genomique, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jianqing Mi
- State Key Laboratory for Medical Genomics and Department of Hematology, Shanghai Institute of Hematology, Collaborative Innovation Center of Systems Biomedicine, Pôle Sino-Français des Sciences du Vivant et Genomique, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Sophie Rousseaux
- CNRS UMR 5309, Inserm, U1209, University of Grenoble Alpes, Institute for Advanced Biosciences, 38706, Grenoble, France
| | - Saadi Khochbin
- CNRS UMR 5309, Inserm, U1209, University of Grenoble Alpes, Institute for Advanced Biosciences, 38706, Grenoble, France.
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27
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Histone variant macroH2A: from chromatin deposition to molecular function. Essays Biochem 2019; 63:59-74. [DOI: 10.1042/ebc20180062] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 02/28/2019] [Accepted: 03/01/2019] [Indexed: 01/01/2023]
Abstract
Abstract
The eukaryotic genome is regulated in the context of chromatin. Specialized histones, known as histone variants, incorporate into chromatin to replace their canonical counterparts and represent an important layer of regulation to diversify the structural characteristics and functional outputs of chromatin. MacroH2A is an unusual histone variant with a bulky C-terminal non-histone domain that distinguishes it from all other histones. It is a critical player in stabilizing differentiated cell identity by posing as a barrier to somatic cell reprogramming toward pluripotency and acts as a tumor suppressor in a wide range of cancers. MacroH2A histones are generally regarded as repressive variants that are enriched at the inactive X chromosome (Xi) and broad domains across autosomal chromatin. Recent studies have shed light on to how macroH2A influences transcriptional outputs within distinct genomic contexts and revealed new intriguing molecular functions of macroH2A variants beyond transcriptional regulation. Furthermore, the mechanisms of its mysterious chromatin deposition are beginning to be unraveled, facilitating our understanding of its complex regulation of genome function.
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28
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Bowerman S, Hickok RJ, Wereszczynski J. Unique Dynamics in Asymmetric macroH2A-H2A Hybrid Nucleosomes Result in Increased Complex Stability. J Phys Chem B 2019; 123:419-427. [PMID: 30557018 DOI: 10.1021/acs.jpcb.8b10668] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The fundamental unit of eukaryotic chromatin is the nucleosome core particle, a protein/DNA complex that binds ∼147 base pairs of DNA to a histone octamer. These histones-H3, H4, H2A, H2B-form the nucleosome core through a stacked interaction in which two H2A-H2B dimers flank the (H3-H4)2 tetramer. In vivo, genetic accessibility can be modulated by the substitution of canonical histones with variant proteins that contain the same structural motif but a different amino acid sequence, such as the transcriptional repression-associated macroH2A variant. Previously, Chakravarthy and Luger published a crystal study that showed that H2A substitution is not necessarily required of both H2A moieties, but that in vitro recombination of nucleosomes in the presence of both macroH2A and H2A histone folds results in a hybrid macroH2A-H2A nucleosome with one dimer of each type. Here, we present molecular dynamics simulations of this hybrid construct and compare the results to our previous study on homogeneous H2A- and macroH2A-containing nucleosomes. We find that the hybrid contains a unique set of dynamics that stabilize the interactions between protein constituents and create an altogether more stable nucleosome, both in terms of protein-DNA and protein-protein binding. While dimer-tetramer interactions are asymmetric, as the difference in moieties would suggest, we observe that it is the canonical dimer that is pulled further into the nucleosome core, resulting in more secure dimer-tetramer bonds and a more stable histone core, and we also find significantly more interaction between the dimer subunits. Together, these models provide evidence for hybrid H2A-macroH2A nucleosome formation being not only possible but actually energetically more favorable than a homogeneous construct, with dynamics that are unique from their homogeneous H2A or macroH2A nucleosome counterparts. These effects of hybrid substitution likely propagate into higher-order chromatin structures to hinder transcriptional activity.
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Affiliation(s)
- Samuel Bowerman
- Department of Physics and the Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology , Chicago , Illinois 60616 , United States
| | - Robert J Hickok
- Department of Physics and the Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology , Chicago , Illinois 60616 , United States
| | - Jeff Wereszczynski
- Department of Physics and the Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology , Chicago , Illinois 60616 , United States
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Transcription-associated histone pruning demarcates macroH2A chromatin domains. Nat Struct Mol Biol 2018; 25:958-970. [PMID: 30291361 PMCID: PMC6178985 DOI: 10.1038/s41594-018-0134-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 08/17/2018] [Indexed: 02/01/2023]
Abstract
The histone variant macroH2A occupies large repressive domains throughout the genome, however mechanisms underlying its precise deposition remain poorly understood. Here, we characterized de novo chromatin deposition of macroH2A2 using temporal genomic profiling in murine-derived fibroblasts devoid of all macroH2A isoforms. We find that macroH2A2 is first pervasively deposited genome-wide at both steady state domains and adjacent transcribed regions, the latter of which are subsequently pruned, establishing mature macroH2A2 domains. Pruning of macroH2A2 can be counteracted by chemical inhibition of transcription. Further, CRISPR/Cas9-based locus-specific transcriptional manipulation reveals that gene activation depletes pre-existing macroH2A2, while silencing triggers ectopic macroH2A2 accumulation. We demonstrate that the FACT (facilitates chromatin transcription) complex is required for macroH2A2 pruning within transcribed chromatin. Taken together, we have identified active chromatin as a boundary for macroH2A domains through a transcription-associated ‘pruning’ mechanism that establishes and maintains the faithful genomic localization of macroH2A variants.
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30
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Molaro A, Young JM, Malik HS. Evolutionary origins and diversification of testis-specific short histone H2A variants in mammals. Genome Res 2018; 28:460-473. [PMID: 29549088 PMCID: PMC5880237 DOI: 10.1101/gr.229799.117] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 02/13/2018] [Indexed: 12/11/2022]
Abstract
Eukaryotic genomes must accomplish both compact packaging for genome stability and inheritance, as well as accessibility for gene expression. They do so using post-translational modifications of four ancient canonical histone proteins (H2A, H2B, H3, and H4) and by deploying histone variants with specialized chromatin functions. Some histone variants are conserved across all eukaryotes, whereas others are lineage-specific. Here, we performed detailed phylogenomic analyses of “short H2A histone” variants found in mammalian genomes. We discovered a previously undescribed typically-sized H2A variant in monotremes and marsupials, H2A.R, which may represent the common ancestor of the short H2As. We also discovered a novel class of short H2A histone variants in eutherian mammals, H2A.Q. We show that short H2A variants arose on the X Chromosome in the common ancestor of all eutherian mammals and diverged into four evolutionarily distinct clades: H2A.B, H2A.L, H2A.P, and H2A.Q. However, the repertoires of short histone H2A variants vary extensively among eutherian mammals due to lineage-specific gains and losses. Finally, we show that all four short H2As are subject to accelerated rates of protein evolution relative to both canonical and other variant H2A proteins including H2A.R. Our analyses reveal that short H2As are a unique class of testis-restricted histone variants displaying an unprecedented evolutionary dynamism. Based on their X-Chromosomal localization, genetic turnover, and testis-specific expression, we hypothesize that short H2A variants may participate in genetic conflicts involving sex chromosomes during reproduction.
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Affiliation(s)
- Antoine Molaro
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | - Janet M Young
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | - Harmit S Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.,Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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31
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Giebler M, Staege MS, Blauschmidt S, Ohm LI, Kraus M, Würl P, Taubert H, Greither T. Elevated HERV-K Expression in Soft Tissue Sarcoma Is Associated with Worsened Relapse-Free Survival. Front Microbiol 2018; 9:211. [PMID: 29487589 PMCID: PMC5816752 DOI: 10.3389/fmicb.2018.00211] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 01/30/2018] [Indexed: 01/22/2023] Open
Abstract
A wide variety of endogenous retroviral sequences has been demonstrated in the human genome so far, divided into several different families according to the sequence homology to viral strains. While increased expression of human endogenous retrovirus (HERV) elements has already been linked to unfavorable prognosis in hepatocellular carcinoma, breast cancer, and ovarian carcinoma yet less is known about the impact of the expression of different HERV elements on sarcomagenesis in general as well as the outcome of soft tissue sarcoma (STS) patients. Therefore, in this study the association between expression of HERV-K and HERV-F and the clinicopathological characteristics in a cohort of STSs as well as the patients’ prognosis was evaluated. HERV-K and HERV-F expression was assessed by quantitative real-time PCR in 120 patient specimens. HERV-K and HERV-F expression was significantly correlated (rS = 0.5; p = 6.4 × 10-9; Spearman’s rank bivariate correlation). Also, tumor diameter exhibited a significant negative association to HERV-K and HERV-F expression. Levels of several hypoxia-related RNAs like HIF-1α and miR-210 showed a significant positive correlation with both HERV-K and HERV-F expression. Although in survival analyses no impact of HERV expression on disease-specific survival could be detected, patients with elevated HERV-K expression had a significantly shorter relapse-free survival (p = 0.014, log-rank analysis). In conclusion, we provide evidence for the first time that the increased expression of HERV-K in tumors is associated with STS patients’ prognosis.
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Affiliation(s)
- Maria Giebler
- Center for Reproductive Medicine and Andrology, Martin Luther University of Halle-Wittenberg, Halle, Germany
| | - Martin S Staege
- Department of Pediatrics I, Martin Luther University of Halle-Wittenberg, Halle, Germany
| | - Sindy Blauschmidt
- Center for Reproductive Medicine and Andrology, Martin Luther University of Halle-Wittenberg, Halle, Germany
| | - Lea I Ohm
- Department of Pediatrics I, Martin Luther University of Halle-Wittenberg, Halle, Germany
| | - Matthias Kraus
- Center for Reproductive Medicine and Andrology, Martin Luther University of Halle-Wittenberg, Halle, Germany
| | - Peter Würl
- Department of General, Visceral and Thoracic Surgery, Städtische Klinikum Dessau, Dessau-Roßlau, Germany
| | - Helge Taubert
- Division Molecular Urology, Department of Urology and Pediatric Urology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Thomas Greither
- Center for Reproductive Medicine and Andrology, Martin Luther University of Halle-Wittenberg, Halle, Germany
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32
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Leung JWC, Emery LE, Miller KM. CRISPR/Cas9 Gene Editing of Human Histone H2A Variant H2AX and MacroH2A. Methods Mol Biol 2018; 1832:255-269. [PMID: 30073532 DOI: 10.1007/978-1-4939-8663-7_14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Histone H2A variants play important roles in maintaining the integrity of the genome. For example, the histone variant H2AX is phosphorylated on Ser139 (called γH2AX) at DNA double-strand breaks (DSB) and serves as a signal for the initiation of downstream DNA damage response (DDR) factor recruitment and DNA repair activities within damaged chromatin. For decades, genetic studies in human cells involving DNA damage signaling and repair factors have relied mostly on either knockdown by RNA interference (i.e., shRNA and siRNA) or the use of mouse embryonic fibroblasts derived from knockout (KO) mice. Recent advances in gene editing using ZNF nuclease, TALEN, and CRISPR/Cas9 have allowed the generation of human KO cell lines, allowing genetic models for studying the DDR, including histone H2A variants in human cells. Here, we describe a detailed protocol for generating and verifying KO of H2AX and macroH2A histone H2A variants using CRISPR/Cas9 gene editing in human cancer cell lines. This protocol allows the use and development of genetic systems in human cells to study histone variants and their functions, including within the DDR.
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Affiliation(s)
- Justin W C Leung
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA
- Department of Radiation Oncology, Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Lara E Emery
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA
| | - Kyle M Miller
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA.
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA.
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33
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Quénet D. Histone Variants and Disease. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 335:1-39. [DOI: 10.1016/bs.ircmb.2017.07.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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34
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Chen D, Jin C. Histone variants in environmental-stress-induced DNA damage repair. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 780:55-60. [PMID: 31395349 DOI: 10.1016/j.mrrev.2017.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Revised: 11/15/2017] [Accepted: 11/17/2017] [Indexed: 01/27/2023]
Abstract
Environmental stress such as genotoxic agents can cause DNA damage either indirectly through the generation of reactive oxygen species or directly by interactions with the DNA molecule. Damage to the genetic material may cause mutations and ultimately cancer. Genotoxic mutation can be prevented either by apoptosis or DNA repair. In response to DNA damage, cells have evolved DNA damage responses (DDR) to detect, signal, and repair DNA lesions. Epigenetic mechanisms play critically important roles in DDR, which requires changes in chromatin structure and dynamics to modulate DNA accessibility. Incorporation of histone variants into chromatin is considered as an epigenetic mechanism. Canonical histones can be replaced with variant histones that change chromatin structure, stability, and dynamics. Recent studies have demonstrated involvement of nearly all histone variants in environmental-stress-induced DNA damage repair through various mechanisms, including affecting nucleosome dynamics, carrying variant-specific modification, promoting transcriptional competence or silencing, mediating rearrangement of chromosomes, attracting specific repair proteins, among others. In this review, we will focus on the role of histone variants in DNA damage repair after exposure to environmental genotoxic agents. Understanding the mechanisms regulating environmental exposure-induced epigenetic changes, including replacement of canonical histones with histone variants, will promote the development of strategies to prevent or reverse these changes.
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Affiliation(s)
- Danqi Chen
- Department of Environmental Medicine & Biochemistry and Molecular Pharmacology, New York University School of Medicine, NY 10987, USA
| | - Chunyuan Jin
- Department of Environmental Medicine & Biochemistry and Molecular Pharmacology, New York University School of Medicine, NY 10987, USA.
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35
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Zink LM, Delbarre E, Eberl HC, Keilhauer EC, Bönisch C, Pünzeler S, Bartkuhn M, Collas P, Mann M, Hake SB. H3.Y discriminates between HIRA and DAXX chaperone complexes and reveals unexpected insights into human DAXX-H3.3-H4 binding and deposition requirements. Nucleic Acids Res 2017; 45:5691-5706. [PMID: 28334823 PMCID: PMC5449609 DOI: 10.1093/nar/gkx131] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 02/14/2017] [Indexed: 01/07/2023] Open
Abstract
Histone chaperones prevent promiscuous histone interactions before chromatin assembly. They guarantee faithful deposition of canonical histones and functionally specialized histone variants into chromatin in a spatial- and temporally-restricted manner. Here, we identify the binding partners of the primate-specific and H3.3-related histone variant H3.Y using several quantitative mass spectrometry approaches, and biochemical and cell biological assays. We find the HIRA, but not the DAXX/ATRX, complex to recognize H3.Y, explaining its presence in transcriptionally active euchromatic regions. Accordingly, H3.Y nucleosomes are enriched in the transcription-promoting FACT complex and depleted of repressive post-translational histone modifications. H3.Y mutational gain-of-function screens reveal an unexpected combinatorial amino acid sequence requirement for histone H3.3 interaction with DAXX but not HIRA, and for H3.3 recruitment to PML nuclear bodies. We demonstrate the importance and necessity of specific H3.3 core and C-terminal amino acids in discriminating between distinct chaperone complexes. Further, chromatin immunoprecipitation sequencing experiments reveal that in contrast to euchromatic HIRA-dependent deposition sites, human DAXX/ATRX-dependent regions of histone H3 variant incorporation are enriched in heterochromatic H3K9me3 and simple repeat sequences. These data demonstrate that H3.Y's unique amino acids allow a functional distinction between HIRA and DAXX binding and its consequent deposition into open chromatin.
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Affiliation(s)
- Lisa-Maria Zink
- Department of Molecular Biology, BioMedical Center, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Erwan Delbarre
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, 0317 Oslo, Norway
| | - H Christian Eberl
- Department of Proteomics and Signal Transduction, Max-Planck-Institute of Biochemistry, 82152 Martinsried, Germany
| | - Eva C Keilhauer
- Department of Proteomics and Signal Transduction, Max-Planck-Institute of Biochemistry, 82152 Martinsried, Germany
| | - Clemens Bönisch
- Department of Molecular Biology, BioMedical Center, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Sebastian Pünzeler
- Department of Molecular Biology, BioMedical Center, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Marek Bartkuhn
- Institute for Genetics, Justus-Liebig-University Giessen, 35392 Giessen, Germany
| | - Philippe Collas
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, 0317 Oslo, Norway
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max-Planck-Institute of Biochemistry, 82152 Martinsried, Germany.,Center for Integrated Protein Science Munich (CIPSM), 81377 Munich, Germany
| | - Sandra B Hake
- Department of Molecular Biology, BioMedical Center, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany.,Institute for Genetics, Justus-Liebig-University Giessen, 35392 Giessen, Germany.,Center for Integrated Protein Science Munich (CIPSM), 81377 Munich, Germany
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36
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Pünzeler S, Link S, Wagner G, Keilhauer EC, Kronbeck N, Spitzer RM, Leidescher S, Markaki Y, Mentele E, Regnard C, Schneider K, Takahashi D, Kusakabe M, Vardabasso C, Zink LM, Straub T, Bernstein E, Harata M, Leonhardt H, Mann M, Rupp RA, Hake SB. Multivalent binding of PWWP2A to H2A.Z regulates mitosis and neural crest differentiation. EMBO J 2017. [PMID: 28645917 DOI: 10.15252/embj.201695757] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Replacement of canonical histones with specialized histone variants promotes altering of chromatin structure and function. The essential histone variant H2A.Z affects various DNA-based processes via poorly understood mechanisms. Here, we determine the comprehensive interactome of H2A.Z and identify PWWP2A as a novel H2A.Z-nucleosome binder. PWWP2A is a functionally uncharacterized, vertebrate-specific protein that binds very tightly to chromatin through a concerted multivalent binding mode. Two internal protein regions mediate H2A.Z-specificity and nucleosome interaction, whereas the PWWP domain exhibits direct DNA binding. Genome-wide mapping reveals that PWWP2A binds selectively to H2A.Z-containing nucleosomes with strong preference for promoters of highly transcribed genes. In human cells, its depletion affects gene expression and impairs proliferation via a mitotic delay. While PWWP2A does not influence H2A.Z occupancy, the C-terminal tail of H2A.Z is one important mediator to recruit PWWP2A to chromatin. Knockdown of PWWP2A in Xenopus results in severe cranial facial defects, arising from neural crest cell differentiation and migration problems. Thus, PWWP2A is a novel H2A.Z-specific multivalent chromatin binder providing a surprising link between H2A.Z, chromosome segregation, and organ development.
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Affiliation(s)
- Sebastian Pünzeler
- Department of Molecular Biology, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Stephanie Link
- Department of Molecular Biology, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Gabriele Wagner
- Department of Molecular Biology, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Eva C Keilhauer
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Nina Kronbeck
- Department of Molecular Biology, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Ramona Mm Spitzer
- Department of Molecular Biology, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Susanne Leidescher
- Department of Biology, Biozentrum, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Yolanda Markaki
- Department of Biology, Biozentrum, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Edith Mentele
- Department of Molecular Biology, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Catherine Regnard
- Department of Molecular Biology, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Katrin Schneider
- Department of Biology, Biozentrum, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Daisuke Takahashi
- Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University, Aoba-ku Sendai, Japan
| | - Masayuki Kusakabe
- Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University, Aoba-ku Sendai, Japan
| | - Chiara Vardabasso
- Department of Oncological Sciences and Dermatology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Lisa M Zink
- Department of Molecular Biology, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Tobias Straub
- Department of Molecular Biology, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Emily Bernstein
- Department of Oncological Sciences and Dermatology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Masahiko Harata
- Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University, Aoba-ku Sendai, Japan
| | - Heinrich Leonhardt
- Department of Biology, Biozentrum, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany.,Center for Integrated Protein Science Munich (CIPSM), Munich, Germany
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany.,Center for Integrated Protein Science Munich (CIPSM), Munich, Germany
| | - Ralph Aw Rupp
- Department of Molecular Biology, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Sandra B Hake
- Department of Molecular Biology, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany .,Center for Integrated Protein Science Munich (CIPSM), Munich, Germany
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Reinhart M, Cardoso MC. A journey through the microscopic ages of DNA replication. PROTOPLASMA 2017; 254:1151-1162. [PMID: 27943022 PMCID: PMC5376393 DOI: 10.1007/s00709-016-1058-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 12/01/2016] [Indexed: 06/06/2023]
Abstract
Scientific discoveries and technological advancements are inseparable but not always take place in a coherent chronological manner. In the next, we will provide a seemingly unconnected and serendipitous series of scientific facts that, in the whole, converged to unveil DNA and its duplication. We will not cover here the many and fundamental contributions from microbial genetics and in vitro biochemistry. Rather, in this journey, we will emphasize the interplay between microscopy development culminating on super resolution fluorescence microscopy (i.e., nanoscopy) and digital image analysis and its impact on our understanding of DNA duplication. We will interlace the journey with landmark concepts and experiments that have brought the cellular DNA replication field to its present state.
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Affiliation(s)
- Marius Reinhart
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 10, 64287, Darmstadt, Germany
| | - M Cristina Cardoso
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 10, 64287, Darmstadt, Germany.
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38
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Soboleva TA, Parker BJ, Nekrasov M, Hart-Smith G, Tay YJ, Tng WQ, Wilkins M, Ryan D, Tremethick DJ. A new link between transcriptional initiation and pre-mRNA splicing: The RNA binding histone variant H2A.B. PLoS Genet 2017; 13:e1006633. [PMID: 28234895 PMCID: PMC5345878 DOI: 10.1371/journal.pgen.1006633] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 03/10/2017] [Accepted: 02/14/2017] [Indexed: 01/08/2023] Open
Abstract
The replacement of histone H2A with its variant forms is critical for regulating all aspects of genome organisation and function. The histone variant H2A.B appeared late in evolution and is most highly expressed in the testis followed by the brain in mammals. This raises the question of what new function(s) H2A.B might impart to chromatin in these important tissues. We have immunoprecipitated the mouse orthologue of H2A.B, H2A.B.3 (H2A.Lap1), from testis chromatin and found this variant to be associated with RNA processing factors and RNA Polymerase (Pol) II. Most interestingly, many of these interactions with H2A.B.3 (Sf3b155, Spt6, DDX39A and RNA Pol II) were inhibited by the presence of endogenous RNA. This histone variant can bind to RNA directly in vitro and in vivo, and associates with mRNA at intron—exon boundaries. This suggests that the ability of H2A.B to bind to RNA negatively regulates its capacity to bind to these factors (Sf3b155, Spt6, DDX39A and RNA Pol II). Unexpectedly, H2A.B.3 forms highly decompacted nuclear subdomains of active chromatin that co-localizes with splicing speckles in male germ cells. H2A.B.3 ChIP-Seq experiments revealed a unique chromatin organization at active genes being not only enriched at the transcription start site (TSS), but also at the beginning of the gene body (but being excluded from the +1 nucleosome) compared to the end of the gene. We also uncover a general histone variant replacement process whereby H2A.B.3 replaces H2A.Z at intron-exon boundaries in the testis and the brain, which positively correlates with expression and exon inclusion. Taken together, we propose that a special mechanism of splicing may occur in the testis and brain whereby H2A.B.3 recruits RNA processing factors from splicing speckles to active genes following its replacement of H2A.Z. The substitution of core histones with their non-allelic variant forms plays a particular important role in regulating chromatin function because they can directly alter the structure of chromatin, and provide new protein interaction interfaces for the recruitment of proteins involved in gene expression. Despite being discovered over a decade ago, the function of H2A.B, a variant of the H2A class, in its proper physiological context (being expressed in the testis and the brain) is unknown. We provide strong evidence that H2A.B has a role in the processing of RNA. It is found in the gene body of an active gene, directly interacts with RNA polymerase II and splicing factors and is located in the nucleus at distinct regions enriched with RNA processing factors (splicing speckles). Most significantly, we show that H2A.B can directly bind to RNA both in vitro and in germ cells. Therefore, H2A.B has the novel ability to bind to both RNA and DNA (as well as proteins) thus directly linking chromatin structure with the function of RNA. Taken together, this suggests that a special mechanism of splicing may operate in the testis and brain.
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Affiliation(s)
- Tatiana A. Soboleva
- The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Brian J. Parker
- The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Maxim Nekrasov
- The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Gene Hart-Smith
- NSW Systems Biology Initiative, University of New South Wales, Sydney, Australia
| | - Ying Jin Tay
- The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Wei-Quan Tng
- The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Marc Wilkins
- NSW Systems Biology Initiative, University of New South Wales, Sydney, Australia
| | - Daniel Ryan
- The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - David J. Tremethick
- The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
- * E-mail:
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39
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Buschbeck M, Hake SB. Variants of core histones and their roles in cell fate decisions, development and cancer. Nat Rev Mol Cell Biol 2017; 18:299-314. [DOI: 10.1038/nrm.2016.166] [Citation(s) in RCA: 217] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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40
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Abstract
The prognosis of patients with classical Hodgkin lymphoma following chemo- and radiotherapy has been excellent during the last 4 decades. However, the development of secondary malignancies is of major concern. Therefore, the reduction of radiotherapy application is a major objective of ongoing clinical trials. De-escalation of treatment may increase the risk of relapses and thus may lead to reappearance of prognostic factors. Prognostic biomarkers might help to identify patients who are at increased risk of relapse. This review summarizes the current knowledge about potential prognostic biomarkers for patients with classical Hodgkin lymphoma.
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Affiliation(s)
- Martin S Staege
- a Department of Pediatrics , Martin Luther University Halle-Wittenberg , Halle , Germany
| | - Stefanie Kewitz
- a Department of Pediatrics , Martin Luther University Halle-Wittenberg , Halle , Germany
| | - Toralf Bernig
- a Department of Pediatrics , Martin Luther University Halle-Wittenberg , Halle , Germany
| | - Caspar Kühnöl
- a Department of Pediatrics , Martin Luther University Halle-Wittenberg , Halle , Germany
| | - Christine Mauz-Körholz
- a Department of Pediatrics , Martin Luther University Halle-Wittenberg , Halle , Germany
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41
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Machida S, Hayashida R, Takaku M, Fukuto A, Sun J, Kinomura A, Tashiro S, Kurumizaka H. Relaxed Chromatin Formation and Weak Suppression of Homologous Pairing by the Testis-Specific Linker Histone H1T. Biochemistry 2016; 55:637-46. [DOI: 10.1021/acs.biochem.5b01126] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shinichi Machida
- Laboratory
of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Ryota Hayashida
- Laboratory
of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Motoki Takaku
- Laboratory
of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Atsuhiko Fukuto
- Department
of Cellular Biology, Research Institute for Radiation Biology and
Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Jiying Sun
- Department
of Cellular Biology, Research Institute for Radiation Biology and
Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Aiko Kinomura
- Department
of Cellular Biology, Research Institute for Radiation Biology and
Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Satoshi Tashiro
- Department
of Cellular Biology, Research Institute for Radiation Biology and
Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Hitoshi Kurumizaka
- Laboratory
of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
- Institute
for Medical-oriented Structural Biology, Waseda University, 2-2
Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
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42
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Replication Stress: A Lifetime of Epigenetic Change. Genes (Basel) 2015; 6:858-77. [PMID: 26378584 PMCID: PMC4584333 DOI: 10.3390/genes6030858] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 09/04/2015] [Accepted: 09/08/2015] [Indexed: 12/29/2022] Open
Abstract
DNA replication is essential for cell division. Challenges to the progression of DNA polymerase can result in replication stress, promoting the stalling and ultimately collapse of replication forks. The latter involves the formation of DNA double-strand breaks (DSBs) and has been linked to both genome instability and irreversible cell cycle arrest (senescence). Recent technological advances have elucidated many of the factors that contribute to the sensing and repair of stalled or broken replication forks. In addition to bona fide repair factors, these efforts highlight a range of chromatin-associated changes at and near sites of replication stress, suggesting defects in epigenome maintenance as a potential outcome of aberrant DNA replication. Here, we will summarize recent insight into replication stress-induced chromatin-reorganization and will speculate on possible adverse effects for gene expression, nuclear integrity and, ultimately, cell function.
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43
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Melters DP, Nye J, Zhao H, Dalal Y. Chromatin Dynamics in Vivo: A Game of Musical Chairs. Genes (Basel) 2015; 6:751-76. [PMID: 26262644 PMCID: PMC4584328 DOI: 10.3390/genes6030751] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 07/17/2015] [Accepted: 07/28/2015] [Indexed: 01/30/2023] Open
Abstract
Histones are a major component of chromatin, the nucleoprotein complex fundamental to regulating transcription, facilitating cell division, and maintaining genome integrity in almost all eukaryotes. In addition to canonical, replication-dependent histones, replication-independent histone variants exist in most eukaryotes. In recent years, steady progress has been made in understanding how histone variants assemble, their involvement in development, mitosis, transcription, and genome repair. In this review, we will focus on the localization of the major histone variants H3.3, CENP-A, H2A.Z, and macroH2A, as well as how these variants have evolved, their structural differences, and their functional significance in vivo.
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Affiliation(s)
- Daniël P Melters
- Chromatin Structure and Epigenetics Mechanisms Unit, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 41 Library Drive, Bethesda, MD 20892, USA.
| | - Jonathan Nye
- Chromatin Structure and Epigenetics Mechanisms Unit, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 41 Library Drive, Bethesda, MD 20892, USA.
| | - Haiqing Zhao
- Chromatin Structure and Epigenetics Mechanisms Unit, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 41 Library Drive, Bethesda, MD 20892, USA.
- Biophysics Graduate Program, University of Maryland, College Park, MD 20742, USA.
| | - Yamini Dalal
- Chromatin Structure and Epigenetics Mechanisms Unit, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 41 Library Drive, Bethesda, MD 20892, USA.
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44
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Abstract
Histone variants are an important part of the histone contribution to chromatin epigenetics. In this review, we describe how the known structural differences of these variants from their canonical histone counterparts impart a chromatin signature ultimately responsible for their epigenetic contribution. In terms of the core histones, H2A histone variants are major players while H3 variant CenH3, with a controversial role in the nucleosome conformation, remains the genuine epigenetic histone variant. Linker histone variants (histone H1 family) haven’t often been studied for their role in epigenetics. However, the micro-heterogeneity of the somatic canonical forms of linker histones appears to play an important role in maintaining the cell-differentiated states, while the cell cycle independent linker histone variants are involved in development. A picture starts to emerge in which histone H2A variants, in addition to their individual specific contributions to the nucleosome structure and dynamics, globally impair the accessibility of linker histones to defined chromatin locations and may have important consequences for determining different states of chromatin metabolism.
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Affiliation(s)
- Manjinder S Cheema
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W-3P6, Canada.
| | - Juan Ausió
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W-3P6, Canada.
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45
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Vardabasso C, Gaspar-Maia A, Hasson D, Pünzeler S, Valle-Garcia D, Straub T, Keilhauer EC, Strub T, Dong J, Panda T, Chung CY, Yao JL, Singh R, Segura MF, Fontanals-Cirera B, Verma A, Mann M, Hernando E, Hake SB, Bernstein E. Histone Variant H2A.Z.2 Mediates Proliferation and Drug Sensitivity of Malignant Melanoma. Mol Cell 2015; 59:75-88. [PMID: 26051178 DOI: 10.1016/j.molcel.2015.05.009] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 03/24/2015] [Accepted: 04/30/2015] [Indexed: 01/19/2023]
Abstract
Histone variants are emerging as key regulatory molecules in cancer. We report a unique role for the H2A.Z isoform H2A.Z.2 as a driver of malignant melanoma. H2A.Z.2 is highly expressed in metastatic melanoma, correlates with decreased patient survival, and is required for cellular proliferation. Our integrated genomic analyses reveal that H2A.Z.2 controls the transcriptional output of E2F target genes in melanoma cells. These genes are highly expressed and display a distinct signature of H2A.Z occupancy. We identify BRD2 as an H2A.Z-interacting protein, levels of which are also elevated in melanoma. We further demonstrate that H2A.Z.2-regulated genes are bound by BRD2 and E2F1 in an H2A.Z.2-dependent manner. Importantly, H2A.Z.2 deficiency sensitizes melanoma cells to chemotherapy and targeted therapies. Collectively, our findings implicate H2A.Z.2 as a mediator of cell proliferation and drug sensitivity in malignant melanoma, holding translational potential for novel therapeutic strategies.
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Affiliation(s)
- Chiara Vardabasso
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Dermatology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Alexandre Gaspar-Maia
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Dan Hasson
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Dermatology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Sebastian Pünzeler
- Center for Integrated Protein Science Munich and Department of Molecular Biology, Adolf-Butenandt Institute, Ludwig-Maximilians University, 80336 Munich, Germany
| | - David Valle-Garcia
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Molecular Genetics Department, Institute for Cellular Physiology, National Autonomous University of Mexico, 04510 Mexico City, Mexico
| | - Tobias Straub
- Center for Integrated Protein Science Munich and Department of Molecular Biology, Adolf-Butenandt Institute, Ludwig-Maximilians University, 80336 Munich, Germany
| | - Eva C Keilhauer
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Thomas Strub
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Dermatology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Joanna Dong
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Dermatology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Taniya Panda
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Chi-Yeh Chung
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jonathan L Yao
- Department of Dermatology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Rajendra Singh
- Department of Dermatology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Miguel F Segura
- Department of Pathology and Interdisciplinary Melanoma Cooperative Group, New York University Langone Medical Center, New York, NY 10016, USA
| | - Barbara Fontanals-Cirera
- Department of Pathology and Interdisciplinary Melanoma Cooperative Group, New York University Langone Medical Center, New York, NY 10016, USA
| | - Amit Verma
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Eva Hernando
- Department of Pathology and Interdisciplinary Melanoma Cooperative Group, New York University Langone Medical Center, New York, NY 10016, USA
| | - Sandra B Hake
- Center for Integrated Protein Science Munich and Department of Molecular Biology, Adolf-Butenandt Institute, Ludwig-Maximilians University, 80336 Munich, Germany.
| | - Emily Bernstein
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Dermatology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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46
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Abstract
DNA damage poses a major threat to cell function and viability by compromising both genome and epigenome integrity. The DNA damage response indeed operates in the context of chromatin and relies on dynamic changes in chromatin organization. Here, we review the molecular bases of chromatin alterations in response to DNA damage, focusing on core histone mobilization in mammalian cells. Building on our current view of nucleosome dynamics in response to DNA damage, we highlight open challenges and avenues for future development. In particular, we discuss the different levels of regulation of chromatin plasticity during the DNA damage response and their potential impact on cell function and epigenome maintenance.
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47
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Chemical “Diversity” of Chromatin Through Histone Variants and Histone Modifications. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/s40610-015-0005-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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48
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Talbert PB, Henikoff S. Environmental responses mediated by histone variants. Trends Cell Biol 2014; 24:642-50. [PMID: 25150594 DOI: 10.1016/j.tcb.2014.07.006] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 07/22/2014] [Accepted: 07/24/2014] [Indexed: 01/19/2023]
Abstract
Fluctuations in the ambient environment can trigger chromatin disruptions, involving replacement of nucleosomes or exchange of their histone subunits. Unlike canonical histones, which are available only during S-phase, replication-independent histone variants are present throughout the cell cycle and are adapted for chromatin repair. The H2A.Z variant mediates responses to environmental perturbations including fluctuations in temperature and seasonal variation. Phosphorylation of histone H2A.X rapidly marks double-strand DNA breaks for chromatin repair, which is mediated by both H2A and H3 histone variants. Other histones are used as weapons in conflicts between parasites and their hosts, which suggests broad involvement of histone variants in environmental responses beyond chromatin repair.
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Affiliation(s)
- Paul B Talbert
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Howard Hughes Medical Institute, Seattle, WA 98109, USA
| | - Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Howard Hughes Medical Institute, Seattle, WA 98109, USA.
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