1
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Yustis JC, Devoucoux M, Côté J. The Functional Relationship Between RNA Splicing and the Chromatin Landscape. J Mol Biol 2024; 436:168614. [PMID: 38762032 DOI: 10.1016/j.jmb.2024.168614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/27/2024] [Accepted: 05/13/2024] [Indexed: 05/20/2024]
Abstract
Chromatin is a highly regulated and dynamic structure that has been shown to play an essential role in transcriptional and co-transcriptional regulation. In the context of RNA splicing, early evidence suggested a loose connection between the chromatin landscape and splicing. More recently, it has been shown that splicing occurs in a co-transcriptional manner, meaning that the splicing process occurs in the context of chromatin. Experimental and computational evidence have also shown that chromatin dynamics can influence the splicing process and vice versa. However, much of this evidence provides mainly correlative relationships between chromatin and splicing with just a few concrete examples providing defined molecular mechanisms by which these two processes are functionally related. Nevertheless, it is clear that chromatin and RNA splicing are tightly interconnected to one another. In this review, we highlight the current state of knowledge of the relationship between chromatin and splicing.
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Affiliation(s)
- Juan-Carlos Yustis
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of the CHU de Québec-Université Laval Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Maëva Devoucoux
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of the CHU de Québec-Université Laval Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Jacques Côté
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of the CHU de Québec-Université Laval Research Center, Quebec City, Quebec G1R 3S3, Canada.
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2
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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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3
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Lai PM, Chan KM. Roles of Histone H2A Variants in Cancer Development, Prognosis, and Treatment. Int J Mol Sci 2024; 25:3144. [PMID: 38542118 PMCID: PMC10969971 DOI: 10.3390/ijms25063144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/09/2024] [Accepted: 02/09/2024] [Indexed: 07/16/2024] Open
Abstract
Histones are nuclear proteins essential for packaging genomic DNA and epigenetic gene regulation. Paralogs that can substitute core histones (H2A, H2B, H3, and H4), named histone variants, are constitutively expressed in a replication-independent manner throughout the cell cycle. With specific chaperones, they can be incorporated to chromatin to modify nucleosome stability by modulating interactions with nucleosomal DNA. This allows the regulation of essential fundamental cellular processes for instance, DNA damage repair, chromosomal segregation, and transcriptional regulation. Among all the histone families, histone H2A family has the largest number of histone variants reported to date. Each H2A variant has multiple functions apart from their primary role and some, even be further specialized to perform additional tasks in distinct lineages, such as testis specific shortH2A (sH2A). In the past decades, the discoveries of genetic alterations and mutations in genes encoding H2A variants in cancer had revealed variants' potentiality in driving carcinogenesis. In addition, there is growing evidence that H2A variants may act as novel prognostic indicators or biomarkers for both early cancer detection and therapeutic treatments. Nevertheless, no studies have ever concluded all identified variants in a single report. Here, in this review, we summarize the respective functions for all the 19 mammalian H2A variants and their roles in cancer biology whilst potentiality being used in clinical setting.
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Affiliation(s)
| | - Kui Ming Chan
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong SAR, China;
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4
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Leszczynska KB, Freitas-Huhtamäki A, Jayaprakash C, Dzwigonska M, Vitorino FNL, Horth C, Wojnicki K, Gielniewski B, Szadkowska P, Kaza B, Nazarian J, Ciolkowski MK, Trubicka J, Grajkowska W, Garcia BA, Majewski J, Kaminska B, Mieczkowski J. H2A.Z histone variants facilitate HDACi-dependent removal of H3.3K27M mutant protein in pediatric high-grade glioma cells. Cell Rep 2024; 43:113707. [PMID: 38306270 PMCID: PMC11026119 DOI: 10.1016/j.celrep.2024.113707] [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: 05/29/2023] [Revised: 10/22/2023] [Accepted: 01/11/2024] [Indexed: 02/04/2024] Open
Abstract
Diffuse intrinsic pontine gliomas (DIPGs) are deadly pediatric brain tumors, non-resectable due to brainstem localization and diffusive growth. Over 80% of DIPGs harbor a mutation in histone 3 (H3.3 or H3.1) resulting in a lysine-to-methionine substitution (H3K27M). Patients with DIPG have a dismal prognosis with no effective therapy. We show that histone deacetylase (HDAC) inhibitors lead to a significant reduction in the H3.3K27M protein (up to 80%) in multiple glioma cell lines. We discover that the SB939-mediated H3.3K27M loss is partially blocked by a lysosomal inhibitor, chloroquine. The H3.3K27M loss is facilitated by co-occurrence of H2A.Z, as evidenced by the knockdown of H2A.Z isoforms. Chromatin immunoprecipitation sequencing (ChIP-seq) analysis confirms the occupancy of H3.3K27M and H2A.Z at the same SB939-inducible genes. We discover a mechanism showing that HDAC inhibition in DIPG leads to pharmacological modulation of the oncogenic H3.3K27M protein levels. These findings show the possibility of directly targeting the H3.3K27M oncohistone.
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Affiliation(s)
- Katarzyna B Leszczynska
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland.
| | | | - Chinchu Jayaprakash
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Monika Dzwigonska
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Francisca N L Vitorino
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Cynthia Horth
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Kamil Wojnicki
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Bartlomiej Gielniewski
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Paulina Szadkowska
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Beata Kaza
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Javad Nazarian
- Center for Genetic Medicine Research, Children's National Hospital, Washington, DC, USA; Department of Pediatrics, University Children's Hospital Zürich, Zürich, Switzerland
| | | | | | | | - Benjamin A Garcia
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Jacek Majewski
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Bozena Kaminska
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Jakub Mieczkowski
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland; 3P-Medicine Laboratory, Medical University of Gdansk, Gdansk, Poland.
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5
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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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6
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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: 20] [Impact Index Per Article: 20.0] [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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7
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The Role of PARP1 and PAR in ATP-Independent Nucleosome Reorganisation during the DNA Damage Response. Genes (Basel) 2022; 14:genes14010112. [PMID: 36672853 PMCID: PMC9859207 DOI: 10.3390/genes14010112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 12/31/2022] Open
Abstract
The functioning of the eukaryotic cell genome is mediated by sophisticated protein-nucleic-acid complexes, whose minimal structural unit is the nucleosome. After the damage to genomic DNA, repair proteins need to gain access directly to the lesion; therefore, the initiation of the DNA damage response inevitably leads to local chromatin reorganisation. This review focuses on the possible involvement of PARP1, as well as proteins acting nucleosome compaction, linker histone H1 and non-histone chromatin protein HMGB1. The polymer of ADP-ribose is considered the main regulator during the development of the DNA damage response and in the course of assembly of the correct repair complex.
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8
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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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9
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Herbert A. Nucleosomes and flipons exchange energy to alter chromatin conformation, the readout of genomic information, and cell fate. Bioessays 2022; 44:e2200166. [DOI: 10.1002/bies.202200166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/24/2022] [Accepted: 09/28/2022] [Indexed: 11/27/2022]
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10
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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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11
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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: 12] [Impact Index Per Article: 6.0] [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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12
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Maree JP, Tvardovskiy A, Ravnsborg T, Jensen ON, Rudenko G, Patterton HG. Trypanosoma brucei histones are heavily modified with combinatorial post-translational modifications and mark Pol II transcription start regions with hyperacetylated H2A. Nucleic Acids Res 2022; 50:9705-9723. [PMID: 36095123 PMCID: PMC9508842 DOI: 10.1093/nar/gkac759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 08/09/2022] [Accepted: 08/30/2022] [Indexed: 11/12/2022] Open
Abstract
Trypanosomes diverged from the main eukaryotic lineage about 600 million years ago, and display some unusual genomic and epigenetic properties that provide valuable insight into the early processes employed by eukaryotic ancestors to regulate chromatin-mediated functions. We analysed Trypanosoma brucei core histones by high mass accuracy middle-down mass spectrometry to map core histone post-translational modifications (PTMs) and elucidate cis-histone combinatorial PTMs (cPTMs). T. brucei histones are heavily modified and display intricate cPTMs patterns, with numerous hypermodified cPTMs that could contribute to the formation of non-repressive euchromatic states. The Trypanosoma brucei H2A C-terminal tail is hyperacetylated, containing up to five acetylated lysine residues. MNase-ChIP-seq revealed a striking enrichment of hyperacetylated H2A at Pol II transcription start regions, and showed that H2A histones that are hyperacetylated in different combinations localised to different genomic regions, suggesting distinct epigenetic functions. Our genomics and proteomics data provide insight into the complex epigenetic mechanisms used by this parasite to regulate a genome that lacks the transcriptional control mechanisms found in later-branched eukaryotes. The findings further demonstrate the complexity of epigenetic mechanisms that were probably shared with the last eukaryotic common ancestor.
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Affiliation(s)
- Johannes P Maree
- Department of Biochemistry, Stellenbosch University, Stellenbosch 7600, South Africa
| | - Andrey Tvardovskiy
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, and Center for Epigenetics, University of Southern Denmark, Odense M DK-5230, Denmark
| | - Tina Ravnsborg
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, and Center for Epigenetics, University of Southern Denmark, Odense M DK-5230, Denmark
| | - Ole N Jensen
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, and Center for Epigenetics, University of Southern Denmark, Odense M DK-5230, Denmark
| | - Gloria Rudenko
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Hugh-G Patterton
- Center for Bioinformatics and Computational Biology, Stellenbosch University, Stellenbosch 7600, South Africa
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13
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Imbriano C, Belluti S. Histone Marks-Dependent Effect on Alternative Splicing: New Perspectives for Targeted Splicing Modulation in Cancer? Int J Mol Sci 2022; 23:ijms23158304. [PMID: 35955433 PMCID: PMC9368390 DOI: 10.3390/ijms23158304] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/23/2022] [Accepted: 07/25/2022] [Indexed: 11/16/2022] Open
Abstract
Alternative splicing (AS) is a tightly regulated mechanism that generates the complex human proteome from a small number of genes. Cis-regulatory RNA motifs in exons and introns control AS, recruiting positive and negative trans-acting splicing regulators. At a higher level, chromatin affects splicing events. Growing evidence indicates that the popular histone code hypothesis can be extended to RNA-level processes, such as AS. In addition to nucleosome positioning, which can generate transcriptional barriers to shape the final splicing outcome, histone post-translational modifications can contribute to the detailed regulation of single exon inclusion/exclusion. A histone-based system can identify alternatively spliced chromatin stretches, affecting RNAPII elongation locally or recruiting splicing components via adaptor complexes. In tumor cells, several mechanisms trigger misregulated AS events and produce cancer-associated transcripts. On a genome-wide level, aberrant AS can be the consequence of dysfunctional epigenetic splicing code, including altered enrichment in histone post-translational modifications. This review describes the main findings related to the effect of histone modifications and variants on splicing outcome and how a dysfunctional epigenetic splicing code triggers aberrant AS in cancer. In addition, it highlights recent advances in programmable DNA-targeting technologies and their possible application for AS targeted epigenetic modulation.
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14
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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: 5] [Impact Index Per Article: 2.5] [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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15
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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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16
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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: 40] [Impact Index Per Article: 13.3] [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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17
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Begum NA, Haque F, Stanlie A, Husain A, Mondal S, Nakata M, Taniguchi T, Taniguchi H, Honjo T. Phf5a regulates DNA repair in class switch recombination via p400 and histone H2A variant deposition. EMBO J 2021; 40:e106393. [PMID: 33938017 PMCID: PMC8204862 DOI: 10.15252/embj.2020106393] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 03/15/2021] [Accepted: 03/22/2021] [Indexed: 11/09/2022] Open
Abstract
Antibody class switch recombination (CSR) is a locus-specific genomic rearrangement mediated by switch (S) region transcription, activation-induced cytidine deaminase (AID)-induced DNA breaks, and their resolution by non-homologous end joining (NHEJ)-mediated DNA repair. Due to the complex nature of the recombination process, numerous cofactors are intimately involved, making it important to identify rate-limiting factors that impact on DNA breaking and/or repair. Using an siRNA-based loss-of-function screen of genes predicted to encode PHD zinc-finger-motif proteins, we identify the splicing factor Phf5a/Sf3b14b as a novel modulator of the DNA repair step of CSR. Loss of Phf5a severely impairs AID-induced recombination, but does not perturb DNA breaks and somatic hypermutation. Phf5a regulates NHEJ-dependent DNA repair by preserving chromatin integrity to elicit optimal DNA damage response and subsequent recruitment of NHEJ factors at the S region. Phf5a stabilizes the p400 histone chaperone complex at the locus, which in turn promotes deposition of H2A variant such as H2AX and H2A.Z that are critical for the early DNA damage response and NHEJ, respectively. Depletion of Phf5a or p400 blocks the repair of both AID- and I-SceI-induced DNA double-strand breaks, supporting an important contribution of this axis to programmed as well as aberrant recombination.
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Affiliation(s)
- Nasim A Begum
- Department of Immunology and Genomic MedicineGraduate School of MedicineKyoto UniversityKyotoJapan
| | - Farazul Haque
- Department of Immunology and Genomic MedicineGraduate School of MedicineKyoto UniversityKyotoJapan
| | - Andre Stanlie
- Department of Immunology and Genomic MedicineGraduate School of MedicineKyoto UniversityKyotoJapan
- BioMedicine DesignPfizer Inc.CambridgeMAUSA
| | - Afzal Husain
- Department of Immunology and Genomic MedicineGraduate School of MedicineKyoto UniversityKyotoJapan
- Department of BiochemistryFaculty of Life SciencesAligarh Muslim UniversityAligarhIndia
| | - Samiran Mondal
- Department of Immunology and Genomic MedicineGraduate School of MedicineKyoto UniversityKyotoJapan
- Department of ChemistryRammohan CollegeKolkataIndia
| | - Mikiyo Nakata
- Department of Immunology and Genomic MedicineGraduate School of MedicineKyoto UniversityKyotoJapan
| | - Takako Taniguchi
- Division of Disease ProteomicsInstitute for Enzyme ResearchUniversity of TokushimaTokushimaJapan
| | - Hisaaki Taniguchi
- Division of Disease ProteomicsInstitute for Enzyme ResearchUniversity of TokushimaTokushimaJapan
| | - Tasuku Honjo
- Department of Immunology and Genomic MedicineGraduate School of MedicineKyoto UniversityKyotoJapan
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18
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Golson ML. Islet Epigenetic Impacts on β-Cell Identity and Function. Compr Physiol 2021; 11:1961-1978. [PMID: 34061978 DOI: 10.1002/cphy.c200004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The development and maintenance of differentiation is vital to the function of mature cells. Terminal differentiation is achieved by locking in the expression of genes essential for the function of those cells. Gene expression and its memory through generations of cell division is controlled by transcription factors and a host of epigenetic marks. In type 2 diabetes, β cells have altered gene expression compared to controls, accompanied by altered chromatin marks. Mutations, diet, and environment can all disrupt the implementation and preservation of the distinctive β-cell transcriptional signature. Understanding of the full complement of genomic control in β cells is still nascent. This article describes the known effects of histone marks and variants, DNA methylation, how they are regulated in the β cell, and how they affect cell-fate specification, maintenance, and lineage propagation. © 2021 American Physiological Society. Compr Physiol 11:1-18, 2021.
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Affiliation(s)
- Maria L Golson
- Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
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19
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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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20
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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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21
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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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22
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Nucleosome Positioning and Spacing: From Mechanism to Function. J Mol Biol 2021; 433:166847. [PMID: 33539878 DOI: 10.1016/j.jmb.2021.166847] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 01/16/2021] [Accepted: 01/22/2021] [Indexed: 02/08/2023]
Abstract
Eukaryotes associate their genomes with histone proteins, forming nucleosome particles. Nucleosomes regulate and protect the genetic information. They often assemble into evenly spaced arrays of nucleosomes. These regular nucleosome arrays cover significant portions of the genome, in particular over genes. The presence of these evenly spaced nucleosome arrays is highly conserved throughout the entire eukaryotic domain. Here, we review the mechanisms behind the establishment of this primary structure of chromatin with special emphasis on the biogenesis of evenly spaced nucleosome arrays. We highlight the roles that transcription, nucleosome remodelers, DNA sequence, and histone density play towards the formation of evenly spaced nucleosome arrays and summarize our current understanding of their cellular functions. We end with key unanswered questions that remain to be explored to obtain an in-depth understanding of the biogenesis and function of the nucleosome landscape.
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23
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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: 24] [Impact Index Per Article: 8.0] [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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24
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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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25
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Seefelder M, Alva V, Huang B, Engler T, Baumeister W, Guo Q, Fernández-Busnadiego R, Lupas AN, Kochanek S. The evolution of the huntingtin-associated protein 40 (HAP40) in conjunction with huntingtin. BMC Evol Biol 2020; 20:162. [PMID: 33297953 PMCID: PMC7725122 DOI: 10.1186/s12862-020-01705-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 10/20/2020] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The huntingtin-associated protein 40 (HAP40) abundantly interacts with huntingtin (HTT), the protein that is altered in Huntington's disease (HD). Therefore, we analysed the evolution of HAP40 and its interaction with HTT. RESULTS We found that in amniotes HAP40 is encoded by a single-exon gene, whereas in all other organisms it is expressed from multi-exon genes. HAP40 co-occurs with HTT in unikonts, including filastereans such as Capsaspora owczarzaki and the amoebozoan Dictyostelium discoideum, but both proteins are absent from fungi. Outside unikonts, a few species, such as the free-living amoeboflagellate Naegleria gruberi, contain putative HTT and HAP40 orthologs. Biochemically we show that the interaction between HTT and HAP40 extends to fish, and bioinformatic analyses provide evidence for evolutionary conservation of this interaction. The closest homologue of HAP40 in current protein databases is the family of soluble N-ethylmaleimide-sensitive factor attachment proteins (SNAPs). CONCLUSION Our results indicate that the transition from a multi-exon to a single-exon gene appears to have taken place by retroposition during the divergence of amphibians and amniotes, followed by the loss of the parental multi-exon gene. Furthermore, it appears that the two proteins probably originated at the root of eukaryotes. Conservation of the interaction between HAP40 and HTT and their likely coevolution strongly indicate functional importance of this interaction.
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Affiliation(s)
| | - Vikram Alva
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, 72076, Tübingen, Germany
| | - Bin Huang
- Department of Gene Therapy, Ulm University, 89081, Ulm, Germany
| | - Tatjana Engler
- Department of Gene Therapy, Ulm University, 89081, Ulm, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Qiang Guo
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
- Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Rubén Fernández-Busnadiego
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
- Institute of Neuropathology, University Medical Center Göttingen, 37099, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines To Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Andrei N Lupas
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, 72076, Tübingen, Germany.
| | - Stefan Kochanek
- Department of Gene Therapy, Ulm University, 89081, Ulm, Germany.
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26
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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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27
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Martire S, Banaszynski LA. The roles of histone variants in fine-tuning chromatin organization and function. Nat Rev Mol Cell Biol 2020; 21:522-541. [PMID: 32665685 PMCID: PMC8245300 DOI: 10.1038/s41580-020-0262-8] [Citation(s) in RCA: 194] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/28/2020] [Indexed: 12/15/2022]
Abstract
Histones serve to both package and organize DNA within the nucleus. In addition to histone post-translational modification and chromatin remodelling complexes, histone variants contribute to the complexity of epigenetic regulation of the genome. Histone variants are characterized by a distinct protein sequence and a selection of designated chaperone systems and chromatin remodelling complexes that regulate their localization in the genome. In addition, histone variants can be enriched with specific post-translational modifications, which in turn can provide a scaffold for recruitment of variant-specific interacting proteins to chromatin. Thus, through these properties, histone variants have the capacity to endow specific regions of chromatin with unique character and function in a regulated manner. In this Review, we provide an overview of recent advances in our understanding of the contribution of histone variants to chromatin function in mammalian systems. First, we discuss new molecular insights into chaperone-mediated histone variant deposition. Next, we discuss mechanisms by which histone variants influence chromatin properties such as nucleosome stability and the local chromatin environment both through histone variant sequence-specific effects and through their role in recruiting different chromatin-associated complexes. Finally, we focus on histone variant function in the context of both embryonic development and human disease, specifically developmental syndromes and cancer.
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Affiliation(s)
- Sara Martire
- Green Center for Reproductive Biology Sciences, Department of Obstetrics and Gynecology, Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Laura A Banaszynski
- Green Center for Reproductive Biology Sciences, Department of Obstetrics and Gynecology, Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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28
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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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29
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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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30
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Spiniello M, Steinbrink MI, Cesnik AJ, Miller RM, Scalf M, Shortreed MR, Smith LM. Comprehensive in vivo identification of the c-Myc mRNA protein interactome using HyPR-MS. RNA (NEW YORK, N.Y.) 2019; 25:1337-1352. [PMID: 31296583 PMCID: PMC6800478 DOI: 10.1261/rna.072157.119] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 06/27/2019] [Indexed: 05/10/2023]
Abstract
Proteins bind mRNA through their entire life cycle from transcription to degradation. We analyzed c-Myc mRNA protein interactors in vivo using the HyPR-MS method to capture the crosslinked mRNA by hybridization and then analyzed the bound proteins using mass spectrometry proteomics. Using HyPR-MS, 229 c-Myc mRNA-binding proteins were identified, confirming previously proposed interactors, suggesting new interactors, and providing information related to the roles and pathways known to involve c-Myc. We performed structural and functional analysis of these proteins and validated our findings with a combination of RIP-qPCR experiments, in vitro results released in past studies, publicly available RIP- and eCLIP-seq data, and results from software tools for predicting RNA-protein interactions.
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Affiliation(s)
- Michele Spiniello
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
- Department of Medicine of Precision, University of Studi della Campania Luigi Vanvitelli, Naples 80138, Italy
- Division of Immuno-Hematology and Transfusion Medicine, Cardarelli Hospital, Naples 80131, Italy
| | - Maisie I Steinbrink
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Anthony J Cesnik
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Rachel M Miller
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Mark Scalf
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Michael R Shortreed
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Lloyd M Smith
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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31
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Bilokapic S, Halic M. Nucleosome and ubiquitin position Set2 to methylate H3K36. Nat Commun 2019; 10:3795. [PMID: 31439846 PMCID: PMC6706414 DOI: 10.1038/s41467-019-11726-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 08/01/2019] [Indexed: 12/19/2022] Open
Abstract
Histone H3 lysine 36 methylation (H3K36me) is a conserved histone modification deposited by the Set2 methyltransferases. Recent findings show that over-expression or mutation of Set2 enzymes promotes cancer progression, however, mechanisms of H3K36me are poorly understood. Set2 enzymes show spurious activity on histones and histone tails, and it is unknown how they obtain specificity to methylate H3K36 on the nucleosome. In this study, we present 3.8 Å cryo-EM structure of Set2 bound to the mimic of H2B ubiquitinated nucleosome. Our structure shows that Set2 makes extensive interactions with the H3 αN, the H3 tail, the H2A C-terminal tail and stabilizes DNA in the unwrapped conformation, which positions Set2 to specifically methylate H3K36. Moreover, we show that ubiquitin contributes to Set2 positioning on the nucleosome and stimulates the methyltransferase activity. Notably, our structure uncovers interfaces that can be targeted by small molecules for development of future cancer therapies.
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Affiliation(s)
- Silvija Bilokapic
- Department of Structural Biology, St. Jude Children's Research Hospital, 263 Danny Thomas Place, Memphis, TN, 38105, USA.
| | - Mario Halic
- Department of Structural Biology, St. Jude Children's Research Hospital, 263 Danny Thomas Place, Memphis, TN, 38105, USA.
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32
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Pritchard AL. The Role of Histone Variants in Cancer. Clin Epigenetics 2019. [DOI: 10.1007/978-981-13-8958-0_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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33
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Crystal structure of the histone heterodimer containing histone variant H2A.Bbd. Biochem Biophys Res Commun 2018; 503:1786-1791. [PMID: 30064909 DOI: 10.1016/j.bbrc.2018.07.114] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 07/23/2018] [Indexed: 11/20/2022]
Abstract
H2A.Bbd, the most divergent histone variant among all known H2A type histones, is involved in gene transcription, spermiogenesis, DNA replication and RNA splicing. Incorporation of H2A.Bbd-H2B dimer, a fundamental unit of H2A.Bbd nucleosome, modulate structures of nucleosome or chromatin, but the underlying mechanism remains elusive. Here we determined a crystal structure of H2A.Bbd-H2B dimer at 2.6 Å resolution. Although the H2A.Bbd-H2B dimer structure largely resembles that of H2A-H2B, substitution of H2A αC helix residues by H2A.Bbd counterparts lead to the transition of a long αC-helix to the short 310-helix, likely owing to the rearrangement of the hydrogen-bond network. Moreover, structural comparison revealed a strikingly altered electrostatic potential surface for H2A.Bbd-H2B dimer displaying a diminished DNA binding capability. Our study provides the first high-resolution structure of histone variant H2A.Bbd and shed a light on biological function of H2A.Bbd.
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34
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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: 39] [Impact Index Per Article: 6.5] [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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35
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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: 5] [Impact Index Per Article: 0.8] [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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36
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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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37
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Koyama M, Kurumizaka H. Structural diversity of the nucleosome. J Biochem 2017; 163:85-95. [DOI: 10.1093/jb/mvx081] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 10/31/2017] [Indexed: 02/06/2023] Open
Affiliation(s)
- Masako Koyama
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
- Research Institute for 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
| | - 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
- Research Institute for 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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38
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Wang Y, Chen Y, Zhang Y, Wei W, Li Y, Zhang T, He F, Gao Y, Xu P. Multi-Protease Strategy Identifies Three PE2 Missing Proteins in Human Testis Tissue. J Proteome Res 2017; 16:4352-4363. [PMID: 28959888 DOI: 10.1021/acs.jproteome.7b00340] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Although 5 years of the missing proteins (MPs) study have been completed, searching for MPs remains one of the core missions of the Chromosome-Centric Human Proteome Project (C-HPP). Following the next-50-MPs challenge of the C-HPP, we have focused on the testis-enriched MPs by various strategies since 2015. On the basis of the theoretical analysis of MPs (2017-01, neXtProt) using multiprotease digestion, we found that nonconventional proteases (e.g. LysargiNase, GluC) could improve the peptide diversity and sequence coverage compared with Trypsin. Therefore, a multiprotease strategy was used for searching more MPs in the same human testis tissues separated by 10% SDS-PAGE, followed by high resolution LC-MS/MS system (Q Exactive HF). A total of 7838 proteins were identified. Among them, three PE2 MPs in neXtProt 2017-01 have been identified: beta-defensin 123 ( Q8N688 , chr 20q), cancer/testis antigen family 45 member A10 ( P0DMU9 , chr Xq), and Histone H2A-Bbd type 2/3 ( P0C5Z0 , chr Xq). However, because only one unique peptide of ≥9 AA was identified in beta-defensin 123 and Histone H2A-Bbd type 2/3, respectively, further analysis indicates that each falls under the exceptions clause of the HPP Guidelines v2.1. After a spectrum quality check, isobaric PTM and single amino acid variant (SAAV) filtering, and verification with a synthesized peptide, and based on overlapping peptides from different proteases, these three MPs should be considered as exemplary examples of MPs found by exceptional criteria. Other MPs were considered as candidates but need further validation. All MS data sets have been deposited to the ProteomeXchange with identifier PXD006465.
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Affiliation(s)
- Yihao Wang
- State Key Laboratory of Proteomics, National Center for Protein Sciences Beijing, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine , Beijing 102206, China.,Department of Pharmacology and Toxicology, Beijing Institute of Radiation Medicine , Beijing 100850, China
| | - Yang Chen
- State Key Laboratory of Proteomics, National Center for Protein Sciences Beijing, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine , Beijing 102206, China
| | - Yao Zhang
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, College of Ecology and Evolution, Sun Yat-Sen University , Guangzhou 510275, China
| | - Wei Wei
- State Key Laboratory of Proteomics, National Center for Protein Sciences Beijing, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine , Beijing 102206, China
| | - Yanchang Li
- State Key Laboratory of Proteomics, National Center for Protein Sciences Beijing, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine , Beijing 102206, China
| | - Tao Zhang
- State Key Laboratory of Proteomics, National Center for Protein Sciences Beijing, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine , Beijing 102206, China
| | - Fuchu He
- State Key Laboratory of Proteomics, National Center for Protein Sciences Beijing, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine , Beijing 102206, China
| | - Yue Gao
- Department of Pharmacology and Toxicology, Beijing Institute of Radiation Medicine , Beijing 100850, China
| | - Ping Xu
- State Key Laboratory of Proteomics, National Center for Protein Sciences Beijing, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine , Beijing 102206, China.,Key Laboratory of Combinatorial Biosynthesis and Drug Discovery of Ministry of Education, School of Pharmaceutical Sciences, Wuhan University , Wuhan 430072, China.,Graduate School, Anhui Medical University , Hefei 230032, China.,Tianjin Baodi Hospital , Tianjin 301800, China
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39
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Nissen KE, Homer CM, Ryan CJ, Shales M, Krogan NJ, Patrick KL, Guthrie C. The histone variant H2A.Z promotes splicing of weak introns. Genes Dev 2017; 31:688-701. [PMID: 28446597 PMCID: PMC5411709 DOI: 10.1101/gad.295287.116] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/22/2017] [Indexed: 12/12/2022]
Abstract
In this study, Nissen et al. investigated the function of the highly conserved histone variant H2A.Z in pre-mRNA splicing using the intron-rich model yeast S. pombe. The findings suggest that H2A.Z occupancy promotes cotranscriptional splicing of suboptimal introns that may otherwise be discarded via proofreading ATPases. Multiple lines of evidence implicate chromatin in the regulation of premessenger RNA (pre-mRNA) splicing. However, the influence of chromatin factors on cotranscriptional splice site usage remains unclear. Here we investigated the function of the highly conserved histone variant H2A.Z in pre-mRNA splicing using the intron-rich model yeast Schizosaccharomyces pombe. Using epistatic miniarray profiles (EMAPs) to survey the genetic interaction landscape of the Swr1 nucleosome remodeling complex, which deposits H2A.Z, we uncovered evidence for functional interactions with components of the spliceosome. In support of these genetic connections, splicing-specific microarrays show that H2A.Z and the Swr1 ATPase are required during temperature stress for the efficient splicing of a subset of introns. Notably, affected introns are enriched for H2A.Z occupancy and more likely to contain nonconsensus splice sites. To test the significance of the latter correlation, we mutated the splice sites in an affected intron to consensus and found that this suppressed the requirement for H2A.Z in splicing of that intron. These data suggest that H2A.Z occupancy promotes cotranscriptional splicing of suboptimal introns that may otherwise be discarded via proofreading ATPases. Consistent with this model, we show that overexpression of splicing ATPase Prp16 suppresses both the growth and splicing defects seen in the absence of H2A.Z.
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Affiliation(s)
- Kelly E Nissen
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco 94158, California, USA
| | - Christina M Homer
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco 94158, California, USA
| | - Colm J Ryan
- Systems Biology Ireland, University College Dublin, Belfield, Dublin 4, Ireland
| | - Michael Shales
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco 94158, California, USA.,California Institute for Quantitative Biosciences (QB3), San Francisco 94158, California, USA
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco 94158, California, USA.,California Institute for Quantitative Biosciences (QB3), San Francisco 94158, California, USA.,J. David Gladstone Institutes, San Francisco 94158, California, USA
| | - Kristin L Patrick
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco 94158, California, USA.,Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, Texas 77807, USA
| | - Christine Guthrie
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco 94158, California, USA
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40
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Neves LT, Douglass S, Spreafico R, Venkataramanan S, Kress TL, Johnson TL. The histone variant H2A.Z promotes efficient cotranscriptional splicing in S. cerevisiae. Genes Dev 2017; 31:702-717. [PMID: 28446598 PMCID: PMC5411710 DOI: 10.1101/gad.295188.116] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/27/2017] [Indexed: 01/01/2023]
Abstract
In eukaryotes, a dynamic ribonucleic protein machine known as the spliceosome catalyzes the removal of introns from premessenger RNA (pre-mRNA). Recent studies show the processes of RNA synthesis and RNA processing to be spatio-temporally coordinated, indicating that RNA splicing takes place in the context of chromatin. H2A.Z is a highly conserved histone variant of the canonical histone H2A. In Saccharomyces cerevisiae, H2A.Z is deposited into chromatin by the SWR-C complex, is found near the 5' ends of protein-coding genes, and has been implicated in transcription regulation. Here we show that splicing of intron-containing genes in cells lacking H2A.Z is impaired, particularly under suboptimal splicing conditions. Cells lacking H2A.Z are especially dependent on a functional U2 snRNP (small nuclear RNA [snRNA] plus associated proteins), as H2A.Z shows extensive genetic interactions with U2 snRNP-associated proteins, and RNA sequencing (RNA-seq) reveals that introns with nonconsensus branch points are particularly sensitive to H2A.Z loss. Consistently, H2A.Z promotes efficient spliceosomal rearrangements involving the U2 snRNP, as H2A.Z loss results in persistent U2 snRNP association and decreased recruitment of downstream snRNPs to nascent RNA. H2A.Z impairs transcription elongation, suggesting that spliceosome rearrangements are tied to H2A.Z's role in elongation. Depletion of disassembly factor Prp43 suppresses H2A.Z-mediated splice defects, indicating that, in the absence of H2A.Z, stalled spliceosomes are disassembled, and unspliced RNAs are released. Together, these data demonstrate that H2A.Z is required for efficient pre-mRNA splicing and indicate a role for H2A.Z in coordinating the kinetics of transcription elongation and splicing.
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Affiliation(s)
- Lauren T Neves
- Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California, 90095 USA.,Graduate Program in Molecular Biology Interdepartmental Program, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Stephen Douglass
- Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California, 90095 USA
| | - Roberto Spreafico
- Institute for Quantitative and Computational Biosciences, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Srivats Venkataramanan
- Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California, 90095 USA
| | - Tracy L Kress
- Department of Biology, The College of New Jersey, Ewing, New Jersey 08628, USA
| | - Tracy L Johnson
- Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California, 90095 USA.,Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095, USA
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41
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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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42
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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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43
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El Kennani S, Adrait A, Shaytan AK, Khochbin S, Bruley C, Panchenko AR, Landsman D, Pflieger D, Govin J. MS_HistoneDB, a manually curated resource for proteomic analysis of human and mouse histones. Epigenetics Chromatin 2017; 10:2. [PMID: 28096900 PMCID: PMC5223428 DOI: 10.1186/s13072-016-0109-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 12/14/2016] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Histones and histone variants are essential components of the nuclear chromatin. While mass spectrometry has opened a large window to their characterization and functional studies, their identification from proteomic data remains challenging. Indeed, the current interpretation of mass spectrometry data relies on public databases which are either not exhaustive (Swiss-Prot) or contain many redundant entries (UniProtKB or NCBI). Currently, no protein database is ideally suited for the analysis of histones and the complex array of mammalian histone variants. RESULTS We propose two proteomics-oriented manually curated databases for mouse and human histone variants. We manually curated >1700 gene, transcript and protein entries to produce a non-redundant list of 83 mouse and 85 human histones. These entries were annotated in accordance with the current nomenclature and unified with the "HistoneDB2.0 with Variants" database. This resource is provided in a format that can be directly read by programs used for mass spectrometry data interpretation. In addition, it was used to interpret mass spectrometry data acquired on histones extracted from mouse testis. Several histone variants, which had so far only been inferred by homology or detected at the RNA level, were detected by mass spectrometry, confirming the existence of their protein form. CONCLUSIONS Mouse and human histone entries were collected from different databases and subsequently curated to produce a non-redundant protein-centric resource, MS_HistoneDB. It is dedicated to the proteomic study of histones in mouse and human and will hopefully facilitate the identification and functional study of histone variants.
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Affiliation(s)
- Sara El Kennani
- INSERM, U1038, CEA, BIG FR CNRS 3425-BGE, Université Grenoble Alpes, Grenoble, France
| | - Annie Adrait
- INSERM, U1038, CEA, BIG FR CNRS 3425-BGE, Université Grenoble Alpes, Grenoble, France
| | - Alexey K Shaytan
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894 USA
| | - Saadi Khochbin
- CNRS UMR 5309 INSERM U1209, Institute of Advanced Biosciences, Université Grenoble Alpes, Grenoble, France
| | - Christophe Bruley
- INSERM, U1038, CEA, BIG FR CNRS 3425-BGE, Université Grenoble Alpes, Grenoble, France
| | - Anna R Panchenko
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894 USA
| | - David Landsman
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894 USA
| | - Delphine Pflieger
- INSERM, U1038, CEA, BIG FR CNRS 3425-BGE, Université Grenoble Alpes, Grenoble, France
| | - Jérôme Govin
- INSERM, U1038, CEA, BIG FR CNRS 3425-BGE, Université Grenoble Alpes, Grenoble, France
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44
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Gibeault RL, Conn KL, Bildersheim MD, Schang LM. An Essential Viral Transcription Activator Modulates Chromatin Dynamics. PLoS Pathog 2016; 12:e1005842. [PMID: 27575707 PMCID: PMC5004865 DOI: 10.1371/journal.ppat.1005842] [Citation(s) in RCA: 16] [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: 05/20/2016] [Accepted: 08/03/2016] [Indexed: 12/02/2022] Open
Abstract
Although ICP4 is the only essential transcription activator of herpes simplex virus 1 (HSV-1), its mechanisms of action are still only partially understood. We and others propose a model in which HSV-1 genomes are chromatinized as a cellular defense to inhibit HSV-1 transcription. To counteract silencing, HSV-1 would have evolved proteins that prevent or destabilize chromatinization to activate transcription. These proteins should act as HSV-1 transcription activators. We have shown that HSV-1 genomes are organized in highly dynamic nucleosomes and that histone dynamics increase in cells infected with wild type HSV-1. We now show that whereas HSV-1 mutants encoding no functional ICP0 or VP16 partially enhanced histone dynamics, mutants encoding no functional ICP4 did so only minimally. Transient expression of ICP4 was sufficient to enhance histone dynamics in the absence of other HSV-1 proteins or HSV-1 DNA. The dynamics of H3.1 were increased in cells expressing ICP4 to a greater extent than those of H3.3. The dynamics of H2B were increased in cells expressing ICP4, whereas those of canonical H2A were not. ICP4 preferentially targets silencing H3.1 and may also target the silencing H2A variants. In infected cells, histone dynamics were increased in the viral replication compartments, where ICP4 localizes. These results suggest a mechanism whereby ICP4 activates transcription by disrupting, or preventing the formation of, stable silencing nucleosomes on HSV-1 genomes. The nuclear-replicating DNA viruses of the family herpesviridae cause a variety of diseases. Eight herpesviruses infect humans. Three of them, including herpes simplex virus 1 (HSV-1), belong to the alpha-herpesvirus sub-family. Viruses in this family have the fastest replication cycles of all herpesviruses, producing acute symptoms. During lytic infection, the genomes of HSV-1 associate with histones in more dynamic chromatin than those of the beta- and gamma- herpesviruses. The transcription activator ICP4 is conserved only among alpha-herpesviruses. Although ICP4 is essential, relatively little is known about its mechanisms of action. We have shown that histone dynamics are enhanced in HSV-1 lytically infected cells. Here we show that HSV-1 mutants in ICP4 are deficient in their ability to enhance histone dynamics. ICP4 was sufficient to enhance histone dynamics in the absence of other HSV-1 proteins or DNA. The dynamics of histones were greater in the viral replication compartments, where ICP4 localizes, than in the cellular chromatin. ICP4 may thus mobilize histones away from HSV-1 genomes to activate transcription. Such a mechanism of transcription activation would result in the highly dynamic nature of the viral chromatin and the fast replication cycles, and the acute pathologies, of the alpha-herpesviruses.
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Affiliation(s)
- Rebecca L. Gibeault
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Kristen L. Conn
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | | | - Luis M. Schang
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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45
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Ray MK, Wiskow O, King MJ, Ismail N, Ergun A, Wang Y, Plys AJ, Davis CP, Kathrein K, Sadreyev R, Borowsky ML, Eggan K, Zon L, Galloway JL, Kingston RE. CAT7 and cat7l Long Non-coding RNAs Tune Polycomb Repressive Complex 1 Function during Human and Zebrafish Development. J Biol Chem 2016; 291:19558-72. [PMID: 27405765 DOI: 10.1074/jbc.m116.730853] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Indexed: 11/06/2022] Open
Abstract
The essential functions of polycomb repressive complex 1 (PRC1) in development and gene silencing are thought to involve long non-coding RNAs (lncRNAs), but few specific lncRNAs that guide PRC1 activity are known. We screened for lncRNAs, which co-precipitate with PRC1 from chromatin and found candidates that impact polycomb group protein (PcG)-regulated gene expression in vivo A novel lncRNA from this screen, CAT7, regulates expression and polycomb group binding at the MNX1 locus during early neuronal differentiation. CAT7 contains a unique tandem repeat domain that shares high sequence similarity to a non-syntenic zebrafish analog, cat7l Defects caused by interference of cat7l RNA during zebrafish embryogenesis were rescued by human CAT7 RNA, enhanced by interference of a PRC1 component, and suppressed by interference of a known PRC1 target gene, demonstrating cat7l genetically interacts with a PRC1. We propose a model whereby PRC1 acts in concert with specific lncRNAs and that CAT7/cat7l represents convergent lncRNAs that independently evolved to tune PRC1 repression at individual loci.
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Affiliation(s)
- Mridula K Ray
- From the Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
| | - Ole Wiskow
- Harvard Stem Cell Institute, Department of Stem Cell and Regenerative Biology, Harvard University and the Stanley Center for Psychiatric Research, Broad Institute, Cambridge, Massachusetts 02138
| | - Matthew J King
- Center for Regenerative Medicine, Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts 02114
| | - Nidha Ismail
- Center for Regenerative Medicine, Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts 02114
| | - Ayla Ergun
- Department of Molecular Biology, Massachusetts General Hospital, and Department of Pathology, Harvard Medical School, Boston, Massachusetts 02114
| | - Yanqun Wang
- From the Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
| | - Aaron J Plys
- From the Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
| | - Christopher P Davis
- From the Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
| | - Katie Kathrein
- Division of Hematology/Oncology, Boston Children's Hospital, Dana-Farber Cancer Institute, Harvard Stem Cell Institute, Boston, Massachusetts, 02115, and
| | - Ruslan Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, and Department of Pathology, Harvard Medical School, Boston, Massachusetts 02114
| | - Mark L Borowsky
- From the Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
| | - Kevin Eggan
- Harvard Stem Cell Institute, Department of Stem Cell and Regenerative Biology, Harvard University and the Stanley Center for Psychiatric Research, Broad Institute, Cambridge, Massachusetts 02138, The Howard Hughes Medical Institute, Cambridge, MA 02138
| | - Leonard Zon
- Division of Hematology/Oncology, Boston Children's Hospital, Dana-Farber Cancer Institute, Harvard Stem Cell Institute, Boston, Massachusetts, 02115, and
| | - Jenna L Galloway
- Center for Regenerative Medicine, Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts 02114,
| | - Robert E Kingston
- From the Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114,
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46
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Deaton AM, Gómez-Rodríguez M, Mieczkowski J, Tolstorukov MY, Kundu S, Sadreyev RI, Jansen LE, Kingston RE. Enhancer regions show high histone H3.3 turnover that changes during differentiation. eLife 2016; 5. [PMID: 27304074 PMCID: PMC4965263 DOI: 10.7554/elife.15316] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 06/14/2016] [Indexed: 01/09/2023] Open
Abstract
The organization of DNA into chromatin is dynamic; nucleosomes are frequently displaced to facilitate the ability of regulatory proteins to access specific DNA elements. To gain insight into nucleosome dynamics, and to follow how dynamics change during differentiation, we used a technique called time-ChIP to quantitatively assess histone H3.3 turnover genome-wide during differentiation of mouse ESCs. We found that, without prior assumptions, high turnover could be used to identify regions involved in gene regulation. High turnover was seen at enhancers, as observed previously, with particularly high turnover at super-enhancers. In contrast, regions associated with the repressive Polycomb-Group showed low turnover in ESCs. Turnover correlated with DNA accessibility. Upon differentiation, numerous changes in H3.3 turnover rates were observed, the majority of which occurred at enhancers. Thus, time-ChIP measurement of histone turnover shows that active enhancers are unusually dynamic in ESCs and changes in highly dynamic nucleosomes predominate at enhancers during differentiation.
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Affiliation(s)
- Aimee M Deaton
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States.,Department of Genetics, Harvard Medical School, Boston, United States
| | | | - Jakub Mieczkowski
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States.,Department of Genetics, Harvard Medical School, Boston, United States
| | - Michael Y Tolstorukov
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States.,Department of Medicine, Harvard Medical School, Boston, United States
| | - Sharmistha Kundu
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States.,Department of Genetics, Harvard Medical School, Boston, United States
| | - Ruslan I Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States.,Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, United States
| | - Lars Et Jansen
- Laboratory for Epigenetic Mechanisms, Instituto Gulbenkian de Ciencia, Oeiras, Portugal
| | - Robert E Kingston
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States.,Department of Genetics, Harvard Medical School, Boston, United States
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47
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Zhang GL, Zhu Y, Fu WD, Wang P, Zhang RH, Zhang YL, Song Z, Xia GX, Wu JH. iTRAQ Protein Profile Differential Analysis of Dormant and Germinated Grassbur Twin Seeds Reveals that Ribosomal Synthesis and Carbohydrate Metabolism Promote Germination Possibly Through the PI3K Pathway. PLANT & CELL PHYSIOLOGY 2016; 57:1244-1256. [PMID: 27296714 DOI: 10.1093/pcp/pcw074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 04/03/2016] [Indexed: 06/06/2023]
Abstract
Grassbur is a destructive and invasive weed in pastures, and its burs can cause gastric damage to animals. The strong adaptability and reproductive potential of grassbur are partly due to a unique germination mechanism whereby twin seeds develop in a single bur: one seed germinates, but the other remains dormant. To investigate the molecular mechanism of seed germination in twin seeds, we used isobaric tags for relative and absolute quantitation (iTRAQ) to perform a dynamic proteomic analysis of germination and dormancy. A total of 1,984 proteins were identified, 161 of which were considered to be differentially accumulated. The differentially accumulated proteins comprised 102 up-regulated and 59 down-regulated proteins. These proteins were grouped into seven functional categories, ribosomal proteins being the predominant group. The authenticity and accuracy of the results were confirmed by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time reverse transcription-PCR (qPCR). A dynamic proteomic analysis revealed that ribosome synthesis and carbohydrate metabolism affect seed germination possibly through the phosphoinositide 3-kinase (PI3K) pathway. As the PI3K pathway is generally activated by insulin, analyses of seeds treated with exogenous insulin by qPCR, ELISA and iTRAQ confirmed that the PI3K pathway can be activated, which suppresses dormancy and promotes germination in twin grassbur seeds. Together, these results show that the PI3K pathway may play roles in stimulating seed germination in grassbur by modulating ribosomal synthesis and carbohydrate metabolism.
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Affiliation(s)
- Guo-Liang Zhang
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 10081, China
| | - Yue Zhu
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 10081, China The State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Wei-Dong Fu
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 10081, China
| | - Peng Wang
- The State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Rui-Hai Zhang
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 10081, China
| | - Yan-Lei Zhang
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 10081, China
| | - Zhen Song
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 10081, China
| | - Gui-Xian Xia
- The State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jia-He Wu
- The State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
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48
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Reynolds D, Hofmeister BT, Cliffe L, Alabady M, Siegel TN, Schmitz RJ, Sabatini R. Histone H3 Variant Regulates RNA Polymerase II Transcription Termination and Dual Strand Transcription of siRNA Loci in Trypanosoma brucei. PLoS Genet 2016; 12:e1005758. [PMID: 26796527 PMCID: PMC4721609 DOI: 10.1371/journal.pgen.1005758] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 12/01/2015] [Indexed: 01/22/2023] Open
Abstract
Base J, β-D-glucosyl-hydroxymethyluracil, is a chromatin modification of thymine in the nuclear DNA of flagellated protozoa of the order Kinetoplastida. In Trypanosoma brucei, J is enriched, along with histone H3 variant (H3.V), at sites involved in RNA Polymerase (RNAP) II termination and telomeric sites involved in regulating variant surface glycoprotein gene (VSG) transcription by RNAP I. Reduction of J in T. brucei indicated a role of J in the regulation of RNAP II termination, where the loss of J at specific sites within polycistronic gene clusters led to read-through transcription and increased expression of downstream genes. We now demonstrate that the loss of H3.V leads to similar defects in RNAP II termination within gene clusters and increased expression of downstream genes. Gene derepression is intensified upon the subsequent loss of J in the H3.V knockout. mRNA-seq indicates gene derepression includes VSG genes within the silent RNAP I transcribed telomeric gene clusters, suggesting an important role for H3.V in telomeric gene repression and antigenic variation. Furthermore, the loss of H3.V at regions of overlapping transcription at the end of convergent gene clusters leads to increased nascent RNA and siRNA production. Our results suggest base J and H3.V can act independently as well as synergistically to regulate transcription termination and expression of coding and non-coding RNAs in T. brucei, depending on chromatin context (and transcribing polymerase). As such these studies provide the first direct evidence for histone H3.V negatively influencing transcription elongation to promote termination.
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Affiliation(s)
- David Reynolds
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Brigitte T. Hofmeister
- Institute of Bioinformatics, University of Georgia, Athens, Georgia, United States of America
| | - Laura Cliffe
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Magdy Alabady
- Department of Plant Biology, University of Georgia, Athens, Georgia, United States of America
| | - T. Nicolai Siegel
- Research Center for Infectious Diseases, University of Wuerzburg, Wuerzburg, Germany
| | - Robert J. Schmitz
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
| | - Robert Sabatini
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
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Gaume X, Torres-Padilla ME. Regulation of Reprogramming and Cellular Plasticity through Histone Exchange and Histone Variant Incorporation. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2015; 80:165-175. [PMID: 26582788 DOI: 10.1101/sqb.2015.80.027458] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Early embryonic cells are totipotent and can generate a complete organism including embryonic and extraembryonic tissues. After division, cells lose their potency as they move toward a pluripotent state characterized by decreased cellular plasticity. During this transition, drastic changes in transcriptional programs occur in parallel with global chromatin reorganization. The epigenetic mechanisms governing the changes in chromatin signatures during the transitions of cellular plasticity states are starting to be understood. Among these mechanisms, recent studies highlight the importance of histone variant incorporation and/or eviction from chromatin in the regulation of the chromatin state that is linked to cellular potential. In this review, we discuss the role of histone variants during in vivo and in vitro reprogramming events. These results sustain the hypothesis that histone variants and histone exchange are key actors in the establishment of cellular plasticity programs.
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Affiliation(s)
- Xavier Gaume
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM U964, U de S, F-67404 Illkirch, CU de Strasbourg, France
| | - Maria-Elena Torres-Padilla
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM U964, U de S, F-67404 Illkirch, CU de Strasbourg, France
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50
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Mattiroli F, D'Arcy S, Luger K. The right place at the right time: chaperoning core histone variants. EMBO Rep 2015; 16:1454-66. [PMID: 26459557 DOI: 10.15252/embr.201540840] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 09/17/2015] [Indexed: 12/13/2022] Open
Abstract
Histone proteins dynamically regulate chromatin structure and epigenetic signaling to maintain cell homeostasis. These processes require controlled spatial and temporal deposition and eviction of histones by their dedicated chaperones. With the evolution of histone variants, a network of functionally specific histone chaperones has emerged. Molecular details of the determinants of chaperone specificity for different histone variants are only slowly being resolved. A complete understanding of these processes is essential to shed light on the genuine biological roles of histone variants, their chaperones, and their impact on chromatin dynamics.
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Affiliation(s)
- Francesca Mattiroli
- Department of Molecular and Radiobiological Sciences, Howard Hughes Medical Institute, Colorado State University, Fort Collins, CO, USA
| | - Sheena D'Arcy
- Department of Molecular and Radiobiological Sciences, Howard Hughes Medical Institute, Colorado State University, Fort Collins, CO, USA
| | - Karolin Luger
- Department of Molecular and Radiobiological Sciences, Howard Hughes Medical Institute, Colorado State University, Fort Collins, CO, USA
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