1
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Goto N, Suke K, Yonezawa N, Nishihara H, Handa T, Sato Y, Kujirai T, Kurumizaka H, Yamagata K, Kimura H. ISWI chromatin remodeling complexes recruit NSD2 and H3K36me2 in pericentromeric heterochromatin. J Cell Biol 2024; 223:e202310084. [PMID: 38709169 PMCID: PMC11076809 DOI: 10.1083/jcb.202310084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 03/04/2024] [Accepted: 04/16/2024] [Indexed: 05/07/2024] Open
Abstract
Histone H3 lysine36 dimethylation (H3K36me2) is generally distributed in the gene body and euchromatic intergenic regions. However, we found that H3K36me2 is enriched in pericentromeric heterochromatin in some mouse cell lines. We here revealed the mechanism of heterochromatin targeting of H3K36me2. Among several H3K36 methyltransferases, NSD2 was responsible for inducing heterochromatic H3K36me2. Depletion and overexpression analyses of NSD2-associating proteins revealed that NSD2 recruitment to heterochromatin was mediated through the imitation switch (ISWI) chromatin remodeling complexes, such as BAZ1B-SMARCA5 (WICH), which directly binds to AT-rich DNA via a BAZ1B domain-containing AT-hook-like motifs. The abundance and stoichiometry of NSD2, SMARCA5, and BAZ1B could determine the localization of H3K36me2 in different cell types. In mouse embryos, H3K36me2 heterochromatin localization was observed at the two- to four-cell stages, suggesting its physiological relevance.
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Affiliation(s)
- Naoki Goto
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Kazuma Suke
- Faculty of Biology-Oriented Science and Technology, Kindai University, Kinokawa, Japan
| | - Nao Yonezawa
- Faculty of Biology-Oriented Science and Technology, Kindai University, Kinokawa, Japan
| | - Hidenori Nishihara
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
- Department of Advanced Bioscience, Graduate School of Agriculture, Kindai University, Nara, Japan
| | - Tetsuya Handa
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Yuko Sato
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Tomoya Kujirai
- Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Hitoshi Kurumizaka
- Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Kazuo Yamagata
- Faculty of Biology-Oriented Science and Technology, Kindai University, Kinokawa, Japan
| | - Hiroshi Kimura
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
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2
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Charlton SJ, Flury V, Kanoh Y, Genzor AV, Kollenstart L, Ao W, Brøgger P, Weisser MB, Adamus M, Alcaraz N, Delvaux de Fenffe CM, Mattiroli F, Montoya G, Masai H, Groth A, Thon G. The fork protection complex promotes parental histone recycling and epigenetic memory. Cell 2024:S0092-8674(24)00777-3. [PMID: 39094569 DOI: 10.1016/j.cell.2024.07.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 03/16/2024] [Accepted: 07/09/2024] [Indexed: 08/04/2024]
Abstract
The inheritance of parental histones across the replication fork is thought to mediate epigenetic memory. Here, we reveal that fission yeast Mrc1 (CLASPIN in humans) binds H3-H4 tetramers and operates as a central coordinator of symmetric parental histone inheritance. Mrc1 mutants in a key connector domain disrupted segregation of parental histones to the lagging strand comparable to Mcm2 histone-binding mutants. Both mutants showed clonal and asymmetric loss of H3K9me-mediated gene silencing. AlphaFold predicted co-chaperoning of H3-H4 tetramers by Mrc1 and Mcm2, with the Mrc1 connector domain bridging histone and Mcm2 binding. Biochemical and functional analysis validated this model and revealed a duality in Mrc1 function: disabling histone binding in the connector domain disrupted lagging-strand recycling while another histone-binding mutation impaired leading strand recycling. We propose that Mrc1 toggles histones between the lagging and leading strand recycling pathways, in part by intra-replisome co-chaperoning, to ensure epigenetic transmission to both daughter cells.
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Affiliation(s)
- Sebastian Jespersen Charlton
- Department of Biology, University of Copenhagen, Copenhagen 2200, Denmark; Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | - Valentin Flury
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | - Yutaka Kanoh
- Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | | | - Leonie Kollenstart
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | - Wantong Ao
- Department of Biology, University of Copenhagen, Copenhagen 2200, Denmark
| | - Peter Brøgger
- Department of Biology, University of Copenhagen, Copenhagen 2200, Denmark
| | - Melanie Bianca Weisser
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | - Marek Adamus
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | - Nicolas Alcaraz
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | | | - Francesca Mattiroli
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Utrecht, The Netherlands
| | - Guillermo Montoya
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | - Hisao Masai
- Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Anja Groth
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark; Biotech Research & Innovation Centre, University of Copenhagen, Copenhagen 2200, Denmark; Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen 2200, Denmark.
| | - Geneviève Thon
- Department of Biology, University of Copenhagen, Copenhagen 2200, Denmark.
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3
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Gao J, Li F. Heterochromatin repeat organization at an individual level: Rex1BD and the 14-3-3 protein coordinate to shape the epigenetic landscape within heterochromatin repeats. Bioessays 2024; 46:e2400030. [PMID: 38679759 DOI: 10.1002/bies.202400030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/09/2024] [Accepted: 04/15/2024] [Indexed: 05/01/2024]
Abstract
In eukaryotic cells, heterochromatin is typically composed of tandem DNA repeats and plays crucial roles in gene expression and genome stability. It has been reported that silencing at individual units within tandem heterochromatin repeats exhibits a position-dependent variation. However, how the heterochromatin is organized at an individual repeat level remains poorly understood. Using a novel genetic approach, our recent study identified a conserved protein Rex1BD required for position-dependent silencing within heterochromatin repeats. We further revealed that Rex1BD interacts with the 14-3-3 protein to regulate heterochromatin silencing by linking RNAi and HDAC pathways. In this review, we discuss how Rex1BD and the 14-3-3 protein coordinate to modulate heterochromatin organization at the individual repeat level, and comment on the biological significance of the position-dependent effect in heterochromatin repeats. We also identify the knowledge gaps that still need to be unveiled in the field.
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Affiliation(s)
- Jinxin Gao
- Department of Biology, New York University, New York, New York, USA
| | - Fei Li
- Department of Biology, New York University, New York, New York, USA
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4
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Khanduja JS, Joh RI, Perez MM, Paulo JA, Palmieri CM, Zhang J, Gulka AOD, Haas W, Gygi SP, Motamedi M. RNA quality control factors nucleate Clr4/SUV39H and trigger constitutive heterochromatin assembly. Cell 2024; 187:3262-3283.e23. [PMID: 38815580 PMCID: PMC11227895 DOI: 10.1016/j.cell.2024.04.042] [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: 01/19/2023] [Revised: 11/10/2023] [Accepted: 04/29/2024] [Indexed: 06/01/2024]
Abstract
In eukaryotes, the Suv39 family of proteins tri-methylate lysine 9 of histone H3 (H3K9me) to form constitutive heterochromatin. However, how Suv39 proteins are nucleated at heterochromatin is not fully described. In the fission yeast, current models posit that Argonaute1-associated small RNAs (sRNAs) nucleate the sole H3K9 methyltransferase, Clr4/SUV39H, to centromeres. Here, we show that in the absence of all sRNAs and H3K9me, the Mtl1 and Red1 core (MTREC)/PAXT complex nucleates Clr4/SUV39H at a heterochromatic long noncoding RNA (lncRNA) at which the two H3K9 deacetylases, Sir2 and Clr3, also accumulate by distinct mechanisms. Iterative cycles of H3K9 deacetylation and methylation spread Clr4/SUV39H from the nucleation center in an sRNA-independent manner, generating a basal H3K9me state. This is acted upon by the RNAi machinery to augment and amplify the Clr4/H3K9me signal at centromeres to establish heterochromatin. Overall, our data reveal that lncRNAs and RNA quality control factors can nucleate heterochromatin and function as epigenetic silencers in eukaryotes.
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Affiliation(s)
- Jasbeer S Khanduja
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Richard I Joh
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Monica M Perez
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Christina M Palmieri
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Jingyu Zhang
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Alex O D Gulka
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Willhelm Haas
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Mo Motamedi
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA.
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5
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Uneme Y, Maeda R, Nakayama G, Narita H, Takeda N, Hiramatsu R, Nishihara H, Nakato R, Kanai Y, Araki K, Siomi MC, Yamanaka S. Morc1 reestablishes H3K9me3 heterochromatin on piRNA-targeted transposons in gonocytes. Proc Natl Acad Sci U S A 2024; 121:e2317095121. [PMID: 38502704 PMCID: PMC10990106 DOI: 10.1073/pnas.2317095121] [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: 10/02/2023] [Accepted: 01/23/2024] [Indexed: 03/21/2024] Open
Abstract
To maintain fertility, male mice re-repress transposable elements (TEs) that were de-silenced in the early gonocytes before their differentiation into spermatogonia. However, the mechanism of TE silencing re-establishment remains unknown. Here, we found that the DNA-binding protein Morc1, in cooperation with the methyltransferase SetDB1, deposits the repressive histone mark H3K9me3 on a large fraction of activated TEs, leading to heterochromatin. Morc1 also triggers DNA methylation, but TEs targeted by Morc1-driven DNA methylation only slightly overlapped with those repressed by Morc1/SetDB1-dependent heterochromatin formation, suggesting that Morc1 silences TEs in two different manners. In contrast, TEs regulated by Morc1 and Miwi2, the nuclear PIWI-family protein, almost overlapped. Miwi2 binds to PIWI-interacting RNAs (piRNAs) that base-pair with TE mRNAs via sequence complementarity, while Morc1 DNA binding is not sequence specific, suggesting that Miwi2 selects its targets, and then, Morc1 acts to repress them with cofactors. A high-ordered mechanism of TE repression in gonocytes has been identified.
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Affiliation(s)
- Yuta Uneme
- Department of Biophysics and Biochemistry, Faculty of Science, The University of Tokyo, Tokyo113-0032, Japan
| | - Ryu Maeda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo113-0032, Japan
| | - Gen Nakayama
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo113-0032, Japan
| | - Haruka Narita
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo113-0032, Japan
| | - Naoki Takeda
- Division of Developmental Genetics, Institute of Resource Development and Analysis, Kumamoto University, Kumamoto860-0811, Japan
| | - Ryuji Hiramatsu
- Department of Veterinary Anatomy, The University of Tokyo, Tokyo113-8657, Japan
| | - Hidenori Nishihara
- Department of Advanced Bioscience, Graduate School of Agriculture, Kindai University, Nara631-8505, Japan
| | - Ryuichiro Nakato
- Institute for Quantitative Biosciences, The University of Tokyo, Tokyo113-0032, Japan
| | - Yoshiakira Kanai
- Department of Veterinary Anatomy, The University of Tokyo, Tokyo113-8657, Japan
| | - Kimi Araki
- Division of Developmental Genetics, Institute of Resource Development and Analysis, Kumamoto University, Kumamoto860-0811, Japan
- Faculty of Life Sciences, Center for Metabolic Regulation of Healthy Aging, Kumamoto University, Honjo, Kumamoto860-8556, Japan
| | - Mikiko C. Siomi
- Department of Biophysics and Biochemistry, Faculty of Science, The University of Tokyo, Tokyo113-0032, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo113-0032, Japan
| | - Soichiro Yamanaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo113-0032, Japan
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6
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Shehzada S, Noto T, Saksouk J, Mochizuki K. A SUMO E3 ligase promotes long non-coding RNA transcription to regulate small RNA-directed DNA elimination. eLife 2024; 13:e95337. [PMID: 38197489 PMCID: PMC10830130 DOI: 10.7554/elife.95337] [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: 12/14/2023] [Accepted: 01/03/2024] [Indexed: 01/11/2024] Open
Abstract
Small RNAs target their complementary chromatin regions for gene silencing through nascent long non-coding RNAs (lncRNAs). In the ciliated protozoan Tetrahymena, the interaction between Piwi-associated small RNAs (scnRNAs) and the nascent lncRNA transcripts from the somatic genome has been proposed to induce target-directed small RNA degradation (TDSD), and scnRNAs not targeted for TDSD later target the germline-limited sequences for programmed DNA elimination. In this study, we show that the SUMO E3 ligase Ema2 is required for the accumulation of lncRNAs from the somatic genome and thus for TDSD and completing DNA elimination to make viable sexual progeny. Ema2 interacts with the SUMO E2 conjugating enzyme Ubc9 and enhances SUMOylation of the transcription regulator Spt6. We further show that Ema2 promotes the association of Spt6 and RNA polymerase II with chromatin. These results suggest that Ema2-directed SUMOylation actively promotes lncRNA transcription, which is a prerequisite for communication between the genome and small RNAs.
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Affiliation(s)
- Salman Shehzada
- Institute of Human Genetics (IGH), CNRS, University of MontpellierMontpellierFrance
| | - Tomoko Noto
- Institute of Human Genetics (IGH), CNRS, University of MontpellierMontpellierFrance
| | - Julie Saksouk
- Institute of Human Genetics (IGH), CNRS, University of MontpellierMontpellierFrance
| | - Kazufumi Mochizuki
- Institute of Human Genetics (IGH), CNRS, University of MontpellierMontpellierFrance
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7
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Grypioti E, Richard H, Kryovrysanaki N, Jaubert M, Falciatore A, Verret F, Kalantidis K. Dicer-dependent heterochromatic small RNAs in the model diatom species Phaeodactylum tricornutum. THE NEW PHYTOLOGIST 2024; 241:811-826. [PMID: 38044751 DOI: 10.1111/nph.19429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 10/17/2023] [Indexed: 12/05/2023]
Abstract
Diatoms are eukaryotic microalgae responsible for nearly half of the marine productivity. RNA interference (RNAi) is a mechanism of regulation of gene expression mediated by small RNAs (sRNAs) processed by the endoribonuclease Dicer (DCR). To date, the mechanism and physiological role of RNAi in diatoms are unknown. We mined diatom genomes and transcriptomes for key RNAi effectors and retraced their phylogenetic history. We generated DCR knockout lines in the model diatom species Phaeodactylum tricornutum and analyzed their mRNA and sRNA populations, repression-associated histone marks, and acclimatory response to nitrogen starvation. Diatoms presented a diversification of key RNAi effectors whose distribution across species suggests the presence of distinct RNAi pathways. P. tricornutum DCR was found to process 26-31-nt-long double-stranded sRNAs originating mostly from transposons covered by repression-associated epigenetic marks. In parallel, P. tricornutum DCR was necessary for the maintenance of the repression-associated histone marks H3K9me2/3 and H3K27me3. Finally, PtDCR-KO lines presented a compromised recovery post nitrogen starvation suggesting a role for P. tricornutum DCR in the acclimation to nutrient stress. Our study characterized the molecular function of the single DCR homolog of P. tricornutum suggesting an association between RNAi and heterochromatin maintenance in this model diatom species.
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Affiliation(s)
- Emilia Grypioti
- Department of Biology, University of Crete, PO Box 2208, 70013, Heraklion, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Crete, Greece
- Institute of Marine Biology and Aquaculture, Hellenic Center for Marine Research, 71500, Gournes, Crete, Greece
- Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, UMR 7238 Sorbonne Université, 75005, Paris, France
| | - Hugues Richard
- Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, UMR 7238 Sorbonne Université, 75005, Paris, France
- Bioinformatics Unit, Genome Competence Center (MF1), Robert Koch Institute, 13353, Berlin, Germany
| | - Nikoleta Kryovrysanaki
- Department of Biology, University of Crete, PO Box 2208, 70013, Heraklion, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Crete, Greece
| | - Marianne Jaubert
- Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, UMR 7238 Sorbonne Université, 75005, Paris, France
- Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light Sensing in Microalgae, UMR7141 Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, 75005, Paris, France
| | - Angela Falciatore
- Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, UMR 7238 Sorbonne Université, 75005, Paris, France
- Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light Sensing in Microalgae, UMR7141 Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, 75005, Paris, France
| | - Frédéric Verret
- Department of Biology, University of Crete, PO Box 2208, 70013, Heraklion, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Crete, Greece
- Institute of Marine Biology and Aquaculture, Hellenic Center for Marine Research, 71500, Gournes, Crete, Greece
| | - Kriton Kalantidis
- Department of Biology, University of Crete, PO Box 2208, 70013, Heraklion, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Crete, Greece
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8
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Gao J, Sun W, Li J, Ban H, Zhang T, Liao J, Kim N, Lee SH, Dong Q, Madramootoo R, Chen Y, Li F. Rex1BD and the 14-3-3 protein control heterochromatin organization at tandem repeats by linking RNAi and HDAC. Proc Natl Acad Sci U S A 2023; 120:e2309359120. [PMID: 38048463 PMCID: PMC10723143 DOI: 10.1073/pnas.2309359120] [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: 06/03/2023] [Accepted: 10/30/2023] [Indexed: 12/06/2023] Open
Abstract
Tandem DNA repeats are often organized into heterochromatin that is crucial for genome organization and stability. Recent studies revealed that individual repeats within tandem DNA repeats can behave very differently. How DNA repeats are assembled into distinct heterochromatin structures remains poorly understood. Here, we developed a genome-wide genetic screen using a reporter gene at different units in a repeat array. This screen led to identification of a conserved protein Rex1BD required for heterochromatin silencing. Our structural analysis revealed that Rex1BD forms a four-helix bundle structure with a distinct charged electrostatic surface. Mechanistically, Rex1BD facilitates the recruitment of Clr6 histone deacetylase (HDAC) by interacting with histones. Interestingly, Rex1BD also interacts with the 14-3-3 protein Rad25, which is responsible for recruiting the RITS (RNA-induced transcriptional silencing) complex to DNA repeats. Our results suggest that coordinated action of Rex1BD and Rad25 mediates formation of distinct heterochromatin structure at DNA repeats via linking RNAi and HDAC pathways.
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Affiliation(s)
- Jinxin Gao
- Department of Biology, New York University, New York, NY10003
| | - Wenqi Sun
- Key Laboratory of Epigenetic Regulation and Intervention, State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai200031, China
| | - Jie Li
- National Facility for Protein Science Shanghai, Zhangjiang Lab, Shanghai Advanced Research Institute, Chinese Academy of Science, Shanghai201210, China
| | - Hyoju Ban
- Department of Biology, New York University, New York, NY10003
| | - Tuokai Zhang
- Department of Biology, New York University, New York, NY10003
| | - Junwei Liao
- Department of Biology, New York University, New York, NY10003
| | - Namho Kim
- Department of Biology, New York University, New York, NY10003
| | - Soon Hoo Lee
- Department of Biology, New York University, New York, NY10003
| | - Qianhua Dong
- Department of Biology, New York University, New York, NY10003
| | | | - Yong Chen
- Key Laboratory of Epigenetic Regulation and Intervention, State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai200031, China
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou310024, China
| | - Fei Li
- Department of Biology, New York University, New York, NY10003
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9
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Lam UTF, Nguyen TTT, Raechell R, Yang J, Singer H, Chen ES. A Normalization Protocol Reduces Edge Effect in High-Throughput Analyses of Hydroxyurea Hypersensitivity in Fission Yeast. Biomedicines 2023; 11:2829. [PMID: 37893202 PMCID: PMC10604075 DOI: 10.3390/biomedicines11102829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 10/05/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
Edge effect denotes better growth of microbial organisms situated at the edge of the solid agar media. Although the precise reason underlying edge effect is unresolved, it is generally attributed to greater nutrient availability with less competing neighbors at the edge. Nonetheless, edge effect constitutes an unavoidable confounding factor that results in misinterpretation of cell fitness, especially in high-throughput screening experiments widely employed for genome-wide investigation using microbial gene knockout or mutant libraries. Here, we visualize edge effect in high-throughput high-density pinning arrays and report a normalization approach based on colony growth rate to quantify drug (hydroxyurea)-hypersensitivity in fission yeast strains. This normalization procedure improved the accuracy of fitness measurement by compensating cell growth rate discrepancy at different locations on the plate and reducing false-positive and -negative frequencies. Our work thus provides a simple and coding-free solution for a struggling problem in robotics-based high-throughput screening experiments.
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Affiliation(s)
- Ulysses Tsz-Fung Lam
- Department of Biochemistry, National University of Singapore, Singapore 117596, Singapore; (U.T.-F.L.); (T.T.T.N.); (R.R.)
| | - Thi Thuy Trang Nguyen
- Department of Biochemistry, National University of Singapore, Singapore 117596, Singapore; (U.T.-F.L.); (T.T.T.N.); (R.R.)
| | - Raechell Raechell
- Department of Biochemistry, National University of Singapore, Singapore 117596, Singapore; (U.T.-F.L.); (T.T.T.N.); (R.R.)
| | - Jay Yang
- Singer Instruments, Roadwater, Watchet TA23 0RE, UK; (J.Y.); (H.S.)
| | - Harry Singer
- Singer Instruments, Roadwater, Watchet TA23 0RE, UK; (J.Y.); (H.S.)
| | - Ee Sin Chen
- Department of Biochemistry, National University of Singapore, Singapore 117596, Singapore; (U.T.-F.L.); (T.T.T.N.); (R.R.)
- NUS Center for Cancer Research, National University of Singapore, Singapore 117599, Singapore
- NUS Synthetic Biology for Clinical & Technological Innovation (SynCTI), Life Science Institute, National University of Singapore, Singapore 117456, Singapore
- National University Health System (NUHS), Singapore 119228, Singapore
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10
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Challal D, Menant A, Goksal C, Leroy E, Al-Sady B, Rougemaille M. A dual, catalytic role for the fission yeast Ccr4-Not complex in gene silencing and heterochromatin spreading. Genetics 2023; 224:iyad108. [PMID: 37279920 PMCID: PMC10411572 DOI: 10.1093/genetics/iyad108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 04/11/2023] [Accepted: 05/31/2023] [Indexed: 06/08/2023] Open
Abstract
Heterochromatic gene silencing relies on combinatorial control by specific histone modifications, the occurrence of transcription, and/or RNA degradation. Once nucleated, heterochromatin propagates within defined chromosomal regions and is maintained throughout cell divisions to warrant proper genome expression and integrity. In the fission yeast Schizosaccharomyces pombe, the Ccr4-Not complex partakes in gene silencing, but its relative contribution to distinct heterochromatin domains and its role in nucleation versus spreading have remained elusive. Here, we unveil major functions for Ccr4-Not in silencing and heterochromatin spreading at the mating type locus and subtelomeres. Mutations of the catalytic subunits Caf1 or Mot2, involved in RNA deadenylation and protein ubiquitinylation, respectively, result in impaired propagation of H3K9me3 and massive accumulation of nucleation-distal heterochromatic transcripts. Both silencing and spreading defects are suppressed upon disruption of the heterochromatin antagonizing factor Epe1. Overall, our results position the Ccr4-Not complex as a critical, dual regulator of heterochromatic gene silencing and spreading.
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Affiliation(s)
- Drice Challal
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Alexandra Menant
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Can Goksal
- Department of Microbiology & Immunology, George Williams Hooper Foundation, University of California San Francisco, San Francisco, CA 94143, USA
| | - Estelle Leroy
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Bassem Al-Sady
- Department of Microbiology & Immunology, George Williams Hooper Foundation, University of California San Francisco, San Francisco, CA 94143, USA
| | - Mathieu Rougemaille
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
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11
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Zhang Z, Zhu Q. WD Repeat and HMG Box DNA Binding Protein 1: An Oncoprotein at the Hub of Tumorigenesis and a Novel Therapeutic Target. Int J Mol Sci 2023; 24:12494. [PMID: 37569867 PMCID: PMC10420296 DOI: 10.3390/ijms241512494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/01/2023] [Accepted: 08/04/2023] [Indexed: 08/13/2023] Open
Abstract
WD repeat and HMG-box DNA binding protein 1 (WDHD1) is a highly conserved gene from yeast to humans. It actively participates in DNA replication, playing a crucial role in DNA damage repair and the cell cycle, contributing to centromere formation and sister chromosome segregation. Notably, several studies have implicated WDHD1 in the development and progression of diverse tumor types, including esophageal carcinoma, pulmonary carcinoma, and breast carcinoma. Additionally, the inhibitor of WDHD1 has been found to enhance radiation sensitivity, improve drug resistance, and significantly decrease tumor cell proliferation. This comprehensive review aims to provide an overview of the molecular structure, biological functions, and regulatory mechanisms of WDHD1 in tumors, thereby establishing a foundation for future investigations and potential clinical applications of WDHD1.
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Affiliation(s)
| | - Qing Zhu
- Division of Abdominal Tumor Multimodality Treatment, Cancer Center, West China Hospital, Sichuan University, No. 37 Guoxue Alley, Chengdu 610041, China;
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12
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Lim KK, Koh NZH, Zeng YB, Chuan JK, Raechell R, Chen ES. Resistance to Chemotherapeutic 5-Fluorouracil Conferred by Modulation of Heterochromatic Integrity through Ino80 Function in Fission Yeast. Int J Mol Sci 2023; 24:10687. [PMID: 37445861 DOI: 10.3390/ijms241310687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/23/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
5-Fluorouracil (5-FU) is a conventional chemotherapeutic drug widely used in clinics worldwide, but development of resistance that compromises responsiveness remains a major hurdle to its efficacy. The mechanism underlying 5-FU resistance is conventionally attributed to the disruption of nucleotide synthesis, even though research has implicated other pathways such as RNA processing and chromatin dysregulation. Aiming to clarify resistance mechanisms of 5-FU, we tested the response of a collection of fission yeast (Schizosaccharomyces pombe) null mutants, which confer multiple environmental factor responsiveness (MER). Our screen identified disruption of membrane transport, chromosome segregation and mitochondrial oxidative phosphorylation to increase cellular susceptibility towards 5-FU. Conversely, we revealed several null mutants of Ino80 complex factors exhibited resistance to 5-FU. Furthermore, attenuation of Ino80 function via deleting several subunit genes reversed loss of chromosome-segregation fidelity in 5-FU in the loss-of-function mutant of the Argonaute protein, which regulates RNA interference (RNAi)-dependent maintenance of pericentromeric heterochromatin. Our study thus uncovered a critical role played by chromatin remodeling Ino80 complex factors in 5-FU resistance, which may constitute a possible target to modulate in reversing 5-FU resistance.
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Affiliation(s)
- Kim Kiat Lim
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
| | - Nathaniel Zhi Hao Koh
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
| | - Yi Bing Zeng
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
| | - Jun Kai Chuan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
| | - Raechell Raechell
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
| | - Ee Sin Chen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
- National University Health System (NUHS), Singapore 119228, Singapore
- NUS Center for Cancer Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117599, Singapore
- NUS Graduate School-Integrative Sciences & Engineering Programme, National University of Singapore, Singapore 119077, Singapore
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13
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Grewal SIS. The molecular basis of heterochromatin assembly and epigenetic inheritance. Mol Cell 2023; 83:1767-1785. [PMID: 37207657 PMCID: PMC10309086 DOI: 10.1016/j.molcel.2023.04.020] [Citation(s) in RCA: 47] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 04/10/2023] [Accepted: 04/20/2023] [Indexed: 05/21/2023]
Abstract
Heterochromatin plays a fundamental role in gene regulation, genome integrity, and silencing of repetitive DNA elements. Histone modifications are essential for the establishment of heterochromatin domains, which is initiated by the recruitment of histone-modifying enzymes to nucleation sites. This leads to the deposition of histone H3 lysine-9 methylation (H3K9me), which provides the foundation for building high-concentration territories of heterochromatin proteins and the spread of heterochromatin across extended domains. Moreover, heterochromatin can be epigenetically inherited during cell division in a self-templating manner. This involves a "read-write" mechanism where pre-existing modified histones, such as tri-methylated H3K9 (H3K9me3), support chromatin association of the histone methyltransferase to promote further deposition of H3K9me. Recent studies suggest that a critical density of H3K9me3 and its associated factors is necessary for the propagation of heterochromatin domains across multiple generations. In this review, I discuss the key experiments that have highlighted the importance of modified histones for epigenetic inheritance.
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Affiliation(s)
- Shiv I S Grewal
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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14
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Arcangioli B, Gangloff S. The Fission Yeast Mating-Type Switching Motto: "One-for-Two" and "Two-for-One". Microbiol Mol Biol Rev 2023; 87:e0000821. [PMID: 36629411 PMCID: PMC10029342 DOI: 10.1128/mmbr.00008-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Schizosaccharomyces pombe is an ascomycete fungus that divides by medial fission; it is thus commonly referred to as fission yeast, as opposed to the distantly related budding yeast Saccharomyces cerevisiae. The reproductive lifestyle of S. pombe relies on an efficient genetic sex determination system generating a 1:1 sex ratio and using alternating haploid/diploid phases in response to environmental conditions. In this review, we address how one haploid cell manages to generate two sister cells with opposite mating types, a prerequisite to conjugation and meiosis. This mating-type switching process depends on two highly efficient consecutive asymmetric cell divisions that rely on DNA replication, repair, and recombination as well as the structure and components of heterochromatin. We pay special attention to the intimate interplay between the genetic and epigenetic partners involved in this process to underscore the importance of basic research and its profound implication for a better understanding of chromatin biology.
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Affiliation(s)
- Benoît Arcangioli
- Genome Dynamics Unit, Genomes and Genetics Department, Pasteur Institute, Paris, France
| | - Serge Gangloff
- Genome Dynamics Unit, Genomes and Genetics Department, Pasteur Institute, Paris, France
- UMR3525, Genetics of Genomes, CNRS-Pasteur Institute, Paris, France
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15
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Shan CM, Fang Y, Jia S. Leaving histone unturned for epigenetic inheritance. FEBS J 2023; 290:310-320. [PMID: 34726351 PMCID: PMC9058036 DOI: 10.1111/febs.16260] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/09/2021] [Accepted: 11/01/2021] [Indexed: 02/05/2023]
Abstract
Post-translational modifications in histones play important roles in regulating chromatin structure and gene expression programs, and the modified histones can be passed on to subsequent generations as an epigenetic memory. The fission yeast has been a great model organism for studying histone modifications in heterochromatin assembly and epigenetic inheritance. Here, we review findings in this organism that cemented the idea of chromatin-based inheritance and highlight recent studies that reveal the role of histone turnover in regulating this process.
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Affiliation(s)
- Chun-Min Shan
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
- Present address: State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yimeng Fang
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Songtao Jia
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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16
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Esquivel-Chávez A, Maki T, Tsubouchi H, Handa T, Kimura H, Haber JE, Thon G, Iwasaki H. Euchromatin factors HULC and Set1C affect heterochromatin organization and mating-type switching in fission yeast Schizosaccharomyces pombe. Genes Genet Syst 2022; 97:123-138. [PMID: 35908934 DOI: 10.1266/ggs.22-00012] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Mating-type (P or M) of fission yeast Schizosaccharomyces pombe is determined by the transcriptionally active mat1 cassette and is switched by gene conversion using a donor, either mat2 or mat3, located in an adjacent heterochromatin region (mating-type switching; MTS). In the switching process, heterochromatic donors of genetic information are selected based on the P or M cell type and on the action of two recombination enhancers, SRE2 promoting the use of mat2-P and SRE3 promoting the use of mat3-M, leading to replacement of the content of the expressed mat1 cassette. Recently, we found that the histone H3K4 methyltransferase complex Set1C participates in donor selection, raising the question of how a complex best known for its effects in euchromatin controls recombination in heterochromatin. Here, we report that the histone H2BK119 ubiquitin ligase complex HULC functions with Set1C in MTS, as mutants in the shf1, brl1, brl2 and rad6 genes showed defects similar to Set1C mutants and belonged to the same epistasis group as set1Δ. Moreover, using H3K4R and H2BK119R histone mutants and a Set1-Y897A catalytic mutant, we found that ubiquitylation of histone H2BK119 by HULC and methylation of histone H3K4 by Set1C are functionally coupled in MTS. Cell-type biases in MTS in these mutants suggested that HULC and Set1C inhibit the use of the SRE3 recombination enhancer in M cells, thus favoring SRE2 and mat2-P. Consistent with this, imbalanced switching in the mutants was traced to compromised association of the directionality factor Swi6 with the recombination enhancers in M cells. Based on their known effects at other chromosomal locations, we speculate that HULC and Set1C control nucleosome mobility and strand invasion near the SRE elements. In addition, we uncovered distinct effects of HULC and Set1C on histone H3K9 methylation and gene silencing, consistent with additional functions in the heterochromatic domain.
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Affiliation(s)
- Alfredo Esquivel-Chávez
- Department of Life Science and Technology, School of Life Science and Technology, Tokyo Institute of Technology
- Institute of Innovative Research, Tokyo Institute of Technology
| | - Takahisa Maki
- Institute of Innovative Research, Tokyo Institute of Technology
| | - Hideo Tsubouchi
- Department of Life Science and Technology, School of Life Science and Technology, Tokyo Institute of Technology
- Institute of Innovative Research, Tokyo Institute of Technology
| | - Testuya Handa
- Institute of Innovative Research, Tokyo Institute of Technology
| | - Hiroshi Kimura
- Department of Life Science and Technology, School of Life Science and Technology, Tokyo Institute of Technology
- Institute of Innovative Research, Tokyo Institute of Technology
| | - James E Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University
| | | | - Hiroshi Iwasaki
- Department of Life Science and Technology, School of Life Science and Technology, Tokyo Institute of Technology
- Institute of Innovative Research, Tokyo Institute of Technology
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17
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HIV-1 Preintegration Complex Preferentially Integrates the Viral DNA into Nucleosomes Containing Trimethylated Histone 3-Lysine 36 Modification and Flanking Linker DNA. J Virol 2022; 96:e0101122. [PMID: 36094316 PMCID: PMC9517705 DOI: 10.1128/jvi.01011-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
HIV-1 DNA is preferentially integrated into chromosomal hot spots by the preintegration complex (PIC). To understand the mechanism, we measured the DNA integration activity of PICs-extracted from infected cells-and intasomes, biochemically assembled PIC substructures using a number of relevant target substrates. We observed that PIC-mediated integration into human chromatin is preferred compared to genomic DNA. Surprisingly, nucleosomes lacking histone modifications were not preferred integration compared to the analogous naked DNA. Nucleosomes containing the trimethylated histone 3 lysine 36 (H3K36me3), an epigenetic mark linked to active transcription, significantly stimulated integration, but the levels remained lower than the naked DNA. Notably, H3K36me3-modified nucleosomes with linker DNA optimally supported integration mediated by the PIC but not by the intasome. Interestingly, optimal intasome-mediated integration required the cellular cofactor LEDGF. Unexpectedly, LEDGF minimally affected PIC-mediated integration into naked DNA but blocked integration into nucleosomes. The block for the PIC-mediated integration was significantly relieved by H3K36me3 modification. Mapping the integration sites in the preferred substrates revealed that specific features of the nucleosome-bound DNA are preferred for integration, whereas integration into naked DNA was random. Finally, biochemical and genetic studies demonstrate that DNA condensation by the H1 protein dramatically reduces integration, providing further evidence that features inherent to the open chromatin are preferred for HIV-1 integration. Collectively, these results identify the optimal target substrate for HIV-1 integration, report a mechanistic link between H3K36me3 and integration preference, and importantly, reveal distinct mechanisms utilized by the PIC for integration compared to the intasomes. IMPORTANCE HIV-1 infection is dependent on integration of the viral DNA into the host chromosomes. The preintegration complex (PIC) containing the viral DNA, the virally encoded integrase (IN) enzyme, and other viral/host factors carries out HIV-1 integration. HIV-1 integration is not dependent on the target DNA sequence, and yet the viral DNA is selectively inserted into specific "hot spots" of human chromosomes. A growing body of literature indicates that structural features of the human chromatin are important for integration targeting. However, the mechanisms that guide the PIC and enable insertion of the PIC-associated viral DNA into specific hot spots of the human chromosomes are not fully understood. In this study, we describe a biochemical mechanism for the preference of the HIV-1 DNA integration into open chromatin. Furthermore, our study defines a direct role for the histone epigenetic mark H3K36me3 in HIV-1 integration preference and identify an optimal substrate for HIV-1 PIC-mediated viral DNA integration.
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18
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GRANT Motif Regulates CENP-A Incorporation and Restricts RNA Polymerase II Accessibility at Centromere. Genes (Basel) 2022; 13:genes13101697. [PMID: 36292582 PMCID: PMC9602348 DOI: 10.3390/genes13101697] [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: 07/22/2022] [Revised: 09/10/2022] [Accepted: 09/12/2022] [Indexed: 11/24/2022] Open
Abstract
Precise chromosome segregation is essential for maintaining genomic stability, and its proper execution centers on the centromere, a chromosomal locus that mounts the kinetochore complex to mediate attachment of chromosomes to the spindle microtubules. The location of the centromere is epigenetically determined by a centromere-specific histone H3 variant, CENP-A. Many human cancers exhibit overexpression of CENP-A, which correlates with occurrence of aneuploidy in these malignancies. Centromeric targeting of CENP-A depends on its histone fold, but recent studies showed that the N-terminal tail domain (NTD) also plays essential roles. Here, we investigated implications of NTD in conferring aneuploidy formation when CENP-A is overexpressed in fission yeast. A series of mutant genes progressively lacking one amino acid of the NTD have been constructed for overexpression in wild-type cells using the intermediate strength nmt41 promoter. Constructs hosting disrupted GRANT (Genomic stability-Regulating site within CENP-A N-Terminus) motif in NTD results in growth retardation, aneuploidy, increased localization to the centromere, upregulated RNA polymerase II accessibility and transcriptional derepression of the repressive centromeric chromatin, suggesting that GRANT residues fine-tune centromeric CENP-A incorporation and restrict RNA polymerase II accessibility. This work highlighted the importance of CENP-A NTD, particularly the GRANT motif, in aneuploidy formation of overexpressed CENP-A in fission yeast.
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19
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Katava M, Shi G, Thirumalai D. Chromatin dynamics controls epigenetic domain formation. Biophys J 2022; 121:2895-2905. [PMID: 35799447 PMCID: PMC9388564 DOI: 10.1016/j.bpj.2022.07.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 04/17/2022] [Accepted: 06/30/2022] [Indexed: 11/28/2022] Open
Abstract
In multicellular organisms, nucleosomes carry epigenetic information that defines distinct patterns of gene expression, which are inherited over multiple generations. The enhanced capacity for information storage arises by nucleosome modifications, which are triggered by enzymes. Modified nucleosomes can transfer the mark to others that are in proximity by a positive-feedback (modification begets modification) mechanism. We created a generic polymer model, referred to as 3DSpreader, in which each bead, representing a nucleosome, stochastically switches between unmodified (U) and modified (M) states depending on the states of the neighbors. Modification begins at a specific nucleation site (NS) that is permanently in the M state, and could spread to other loci that is dictated by chromatin dynamics. Transfer of marks among the non-nucleation loci occurs stochastically as chromatin evolves in time. If the spreading rate is slower than the chromatin relaxation rate, which is biologically pertinent, then finite-sized domains form, driven by contacts between nucleosomes through a three-dimensional looping mechanism. Surprisingly, simulations based on the 3DSpreader model result in finite bounded domains that arise without the need for any boundary elements. Maintenance of spatially and temporally stable domains requires the presence of the NS, whose removal eliminates finite-sized modified domains. The theoretical predictions are in excellent agreement with experimental data for H3K9me3 spreading in mouse embryonic stem cells.
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Affiliation(s)
- Marina Katava
- Laboratoire de Biochimie Théorique, CNRS, Université de Paris, Paris, France
| | - Guang Shi
- Department of Chemistry, The University of Texas, Austin, Texas
| | - D Thirumalai
- Department of Chemistry, The University of Texas, Austin, Texas.
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20
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Lam UTF, Tan BKY, Poh JJX, Chen ES. Structural and functional specificity of H3K36 methylation. Epigenetics Chromatin 2022; 15:17. [PMID: 35581654 PMCID: PMC9116022 DOI: 10.1186/s13072-022-00446-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 04/04/2022] [Indexed: 12/20/2022] Open
Abstract
The methylation of histone H3 at lysine 36 (H3K36me) is essential for maintaining genomic stability. Indeed, this methylation mark is essential for proper transcription, recombination, and DNA damage response. Loss- and gain-of-function mutations in H3K36 methyltransferases are closely linked to human developmental disorders and various cancers. Structural analyses suggest that nucleosomal components such as the linker DNA and a hydrophobic patch constituted by histone H2A and H3 are likely determinants of H3K36 methylation in addition to the histone H3 tail, which encompasses H3K36 and the catalytic SET domain. Interaction of H3K36 methyltransferases with the nucleosome collaborates with regulation of their auto-inhibitory changes fine-tunes the precision of H3K36me in mediating dimethylation by NSD2 and NSD3 as well as trimethylation by Set2/SETD2. The identification of specific structural features and various cis-acting factors that bind to different forms of H3K36me, particularly the di-(H3K36me2) and tri-(H3K36me3) methylated forms of H3K36, have highlighted the intricacy of H3K36me functional significance. Here, we consolidate these findings and offer structural insight to the regulation of H3K36me2 to H3K36me3 conversion. We also discuss the mechanisms that underlie the cooperation between H3K36me and other chromatin modifications (in particular, H3K27me3, H3 acetylation, DNA methylation and N6-methyladenosine in RNAs) in the physiological regulation of the epigenomic functions of chromatin.
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Affiliation(s)
- Ulysses Tsz Fung Lam
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Bryan Kok Yan Tan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - John Jia Xin Poh
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Ee Sin Chen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
- National University Health System (NUHS), Singapore, Singapore.
- NUS Center for Cancer Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
- Integrative Sciences & Engineering Programme, National University of Singapore, Singapore, Singapore.
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21
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He D, Guo Y, Cheng J, Wang Y. Chl1 coordinates with H3K9 methyltransferase Clr4 to reduce the accumulation of RNA-DNA hybrids and maintain genome stability. iScience 2022; 25:104313. [PMID: 35602970 PMCID: PMC9118164 DOI: 10.1016/j.isci.2022.104313] [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: 10/15/2021] [Revised: 01/30/2022] [Accepted: 04/22/2022] [Indexed: 11/28/2022] Open
Abstract
A genome-wide analysis in Schizosaccharomyces pombe indicated that double-deletion mutants of Chl1 and histone H3K9 methyltransferase complex factors are synthetically sick. Here, we show that loss of Chl1 increases the accumulation of RNA-DNA hybrids at pericentromeric dg and dh repeats in the absence of the H3K9 methyltransferase Clr4, which leads to genome instability, including more severe defects in chromosome segregation and increased chromatin accessibility. Localization of Chl1 at pericentromeric regions depends on a subunit of replication protein A (RPA), Ssb1. In wild-type (WT) cells, transcriptionally repressed heterochromatin prevents the formation of RNA-DNA hybrids. When Clr4 is deleted, dg and dh repeats are highly transcribed. Then Ssb1 associates with the displaced single-stranded DNA (ssDNA) and recruits Chl1 to resolve the RNA-DNA hybrids. Together, our data suggest that Chl1 coordinates with Clr4 to eliminate RNA-DNA hybrids, which contributes to the maintenance of genome integrity. Double mutant of Chl1 and Chl1 leads to the accumulation of RNA-DNA hybrids RNA-DNA hybrids at pericentromeric regions affect genome stability and cell viability Ssb1 recruits Chl1 to unwind RNA-DNA hybrids in the absence of Clr4
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Affiliation(s)
- Deyun He
- College of Biological Sciences, China Agricultural University, Beijing, 100193, China
- College of Bioengineering, Key Laboratory of Shandong Microbial Engineering, State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, Shandong 250353, China
| | - Yazhen Guo
- College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jinkui Cheng
- College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yu Wang
- College of Biological Sciences, China Agricultural University, Beijing, 100193, China
- Corresponding author
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22
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Molecular mechanisms in governing genomic stability and tumor suppression by the SETD2 H3K36 methyltransferase. Int J Biochem Cell Biol 2022; 144:106155. [PMID: 34990836 DOI: 10.1016/j.biocel.2021.106155] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 12/29/2021] [Accepted: 12/30/2021] [Indexed: 01/15/2023]
Abstract
Epigenetic dysregulation is an important contributor to carcinogenesis. This is not surprising, as chromatin-genomic DNA organized around structural histone scaffolding-serves as the template on which occurs essential nuclear processes, such as transcription, DNA replication and DNA repair. Histone H3 lysine 36 (H3K36) methyltransferases, such as the SET-domain 2 protein (SETD2), have emerged as critical tumor suppressors. Previous work on mammalian SETD2 and its counterpart in model organisms, Set2, has highlighted the role of this protein in governing genomic stability through transcriptional elongation and splicing, as well as in DNA damage response processes and cell cycle progression. A compendium of SETD2 mutations have been documented, garnered from sequenced cancer patient genome data, and these findings underscore the cancer-driving properties of SETD2 loss-of-function. In this review, we consolidate the molecular mechanisms regulated by SETD2/Set2 and discuss evidence of its dysregulation in tumorigenesis. Insight into the genetic interactions that exist between SETD2 and various canonical intracellular signaling pathways has not only empowered pharmacological intervention by taking advantage of synthetic lethality but underscores SETD2 as a druggable target for precision cancer therapy.
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23
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The histone chaperone FACT facilitates heterochromatin spreading by regulating histone turnover and H3K9 methylation states. Cell Rep 2021; 37:109944. [PMID: 34731638 PMCID: PMC8608617 DOI: 10.1016/j.celrep.2021.109944] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/14/2021] [Accepted: 10/13/2021] [Indexed: 12/13/2022] Open
Abstract
Heterochromatin formation requires three distinct steps: nucleation, self-propagation (spreading) along the chromosome, and faithful maintenance after each replication cycle. Impeding any of those steps induces heterochromatin defects and improper gene expression. The essential histone chaperone FACT (facilitates chromatin transcription) has been implicated in heterochromatin silencing, but the mechanisms by which FACT engages in this process remain opaque. Here, we pinpoint its function to the heterochromatin spreading process in fission yeast. FACT impairment reduces nucleation-distal H3K9me3 and HP1/Swi6 accumulation at subtelomeres and derepresses genes in the vicinity of heterochromatin boundaries. FACT promotes spreading by repressing heterochromatic histone turnover, which is crucial for the H3K9me2 to me3 transition that enables spreading. FACT mutant spreading defects are suppressed by removal of the H3K9 methylation antagonist Epe1. Together, our study identifies FACT as a histone chaperone that promotes heterochromatin spreading and lends support to the model that regulated histone turnover controls the propagation of repressive methylation marks. Heterochromatin establishment requires distinct nucleation and spreading steps. Murawska et al. show that the conserved and essential histone chaperone FACT facilitates the heterochromatin spreading process by maintaining low heterochromatic histone turnover, which enables a productive H3K9 trimethylation step by the methyltransferase Clr4 in fission yeast.
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24
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Delbarre E, Janicki SM. Modulation of H3.3 chromatin assembly by PML: A way to regulate epigenetic inheritance. Bioessays 2021; 43:e2100038. [PMID: 34423467 DOI: 10.1002/bies.202100038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 08/04/2021] [Accepted: 08/06/2021] [Indexed: 12/15/2022]
Abstract
Although the promyelocytic leukemia (PML) protein is renowned for regulating a wide range of cellular processes and as an essential component of PML nuclear bodies (PML-NBs), the mechanisms through which it exerts its broad physiological impact are far from fully elucidated. Here, we review recent studies supporting an emerging view that PML's pleiotropic effects derive, at least partially, from its role in regulating histone H3.3 chromatin assembly, a critical epigenetic mechanism. These studies suggest that PML maintains heterochromatin organization by restraining H3.3 incorporation. Examination of PML's contribution to H3.3 chromatin assembly in the context of the cell cycle and PML-NB assembly suggests that PML represses heterochromatic H3.3 deposition during S phase and that transcription and SUMOylation regulate PML's recruitment to heterochromatin. Elucidating PML' s contributions to H3.3-mediated epigenetic regulation will provide insight into PML's expansive influence on cellular physiology and open new avenues for studying oncogenesis linked to PML malfunction.
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Affiliation(s)
- Erwan Delbarre
- Faculty of Health Sciences, OsloMet-Oslo Metropolitan University, Oslo, Norway
| | - Susan M Janicki
- Drexel University Thomas R. Kline School of Law, Philadelphia, Pennsylvania, USA
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Onishi R, Yamanaka S, Siomi MC. piRNA- and siRNA-mediated transcriptional repression in Drosophila, mice, and yeast: new insights and biodiversity. EMBO Rep 2021; 22:e53062. [PMID: 34347367 PMCID: PMC8490990 DOI: 10.15252/embr.202153062] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/10/2021] [Accepted: 07/19/2021] [Indexed: 12/26/2022] Open
Abstract
The PIWI‐interacting RNA (piRNA) pathway acts as a self‐defense mechanism against transposons to maintain germline genome integrity. Failures in the piRNA pathway cause DNA damage in the germline genome, disturbing inheritance of “correct” genetic information by the next generations and leading to infertility. piRNAs execute transposon repression in two ways: degrading their RNA transcripts and compacting the genomic loci via heterochromatinization. The former event is mechanistically similar to siRNA‐mediated RNA cleavage that occurs in the cytoplasm and has been investigated in many species including nematodes, fruit flies, and mammals. The latter event seems to be mechanistically parallel to siRNA‐centered kinetochore assembly and subsequent chromosome segregation, which has so far been studied particularly in fission yeast. Despite the interspecies conservations, the overall schemes of the nuclear events show clear biodiversity across species. In this review, we summarize the recent progress regarding piRNA‐mediated transcriptional silencing in Drosophila and discuss the biodiversity by comparing it with the equivalent piRNA‐mediated system in mice and the siRNA‐mediated system in fission yeast.
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Affiliation(s)
- Ryo Onishi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Soichiro Yamanaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Mikiko C Siomi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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Donczew R, Hahn S. BET family members Bdf1/2 modulate global transcription initiation and elongation in Saccharomyces cerevisiae. eLife 2021; 10:e69619. [PMID: 34137374 PMCID: PMC8266393 DOI: 10.7554/elife.69619] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/16/2021] [Indexed: 01/10/2023] Open
Abstract
Human bromodomain and extra-terminal domain (BET) family members are promising targets for therapy of cancer and immunoinflammatory diseases, but their mechanisms of action and functional redundancies are poorly understood. Bdf1/2, yeast homologues of the human BET factors, were previously proposed to target transcription factor TFIID to acetylated histone H4, analogous to bromodomains that are present within the largest subunit of metazoan TFIID. We investigated the genome-wide roles of Bdf1/2 and found that their important contributions to transcription extend beyond TFIID function as transcription of many genes is more sensitive to Bdf1/2 than to TFIID depletion. Bdf1/2 co-occupy the majority of yeast promoters and affect preinitiation complex formation through recruitment of TFIID, Mediator, and basal transcription factors to chromatin. Surprisingly, we discovered that hypersensitivity of genes to Bdf1/2 depletion results from combined defects in transcription initiation and early elongation, a striking functional similarity to human BET proteins, most notably Brd4. Our results establish Bdf1/2 as critical for yeast transcription and provide important mechanistic insights into the function of BET proteins in all eukaryotes.
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Affiliation(s)
- Rafal Donczew
- Fred Hutchinson Cancer Research Center, Division of Basic SciencesSeattleUnited States
| | - Steven Hahn
- Fred Hutchinson Cancer Research Center, Division of Basic SciencesSeattleUnited States
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Connacher J, Josling GA, Orchard LM, Reader J, Llinás M, Birkholtz LM. H3K36 methylation reprograms gene expression to drive early gametocyte development in Plasmodium falciparum. Epigenetics Chromatin 2021; 14:19. [PMID: 33794978 PMCID: PMC8017609 DOI: 10.1186/s13072-021-00393-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/26/2021] [Indexed: 12/12/2022] Open
Abstract
Background The Plasmodium sexual gametocyte stages are the only transmissible form of the malaria parasite and are thus responsible for the continued transmission of the disease. Gametocytes undergo extensive functional and morphological changes from commitment to maturity, directed by an equally extensive control program. However, the processes that drive the differentiation and development of the gametocyte post-commitment, remain largely unexplored. A previous study reported enrichment of H3K36 di- and tri-methylated (H3K36me2&3) histones in early-stage gametocytes. Using chromatin immunoprecipitation followed by high-throughput sequencing, we identify a stage-specific association between these repressive histone modifications and transcriptional reprogramming that define a stage II gametocyte transition point. Results Here, we show that H3K36me2 and H3K36me3 from stage II gametocytes are associated with repression of genes involved in asexual proliferation and sexual commitment, indicating that H3K36me2&3-mediated repression of such genes is essential to the transition from early gametocyte differentiation to intermediate development. Importantly, we show that the gene encoding the transcription factor AP2-G as commitment master regulator is enriched with H3K36me2&3 and actively repressed in stage II gametocytes, providing the first evidence of ap2-g gene repression in post-commitment gametocytes. Lastly, we associate the enhanced potency of the pan-selective Jumonji inhibitor JIB-04 in gametocytes with the inhibition of histone demethylation including H3K36me2&3 and a disruption of normal transcriptional programs. Conclusions Taken together, our results provide the first description of an association between global gene expression reprogramming and histone post-translational modifications during P. falciparum early sexual development. The stage II gametocyte-specific abundance of H3K36me2&3 manifests predominantly as an independent regulatory mechanism targeted towards genes that are repressed post-commitment. H3K36me2&3-associated repression of genes is therefore involved in key transcriptional shifts that accompany the transition from early gametocyte differentiation to intermediate development. Supplementary Information The online version contains supplementary material available at 10.1186/s13072-021-00393-9.
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Affiliation(s)
- Jessica Connacher
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Gabrielle A Josling
- Department of Biochemistry & Molecular Biology and the Huck Center for Malaria Research, Pennsylvania State University, University Park, PA, 16802, USA
| | - Lindsey M Orchard
- Department of Biochemistry & Molecular Biology and the Huck Center for Malaria Research, Pennsylvania State University, University Park, PA, 16802, USA
| | - Janette Reader
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Manuel Llinás
- Department of Biochemistry & Molecular Biology and the Huck Center for Malaria Research, Pennsylvania State University, University Park, PA, 16802, USA.,Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
| | - Lyn-Marié Birkholtz
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa.
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Ban H, Sun W, Chen YH, Chen Y, Li F. Dri1 mediates heterochromatin assembly via RNAi and histone deacetylation. Genetics 2021; 218:6162161. [PMID: 33693625 DOI: 10.1093/genetics/iyab032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 02/22/2021] [Indexed: 12/13/2022] Open
Abstract
Heterochromatin, a transcriptionally silenced chromatin domain, is important for genome stability and gene expression. Histone 3 lysine 9 methylation (H3K9me) and histone hypoacetylation are conserved epigenetic hallmarks of heterochromatin. In fission yeast, RNA interference (RNAi) plays a key role in H3K9 methylation and heterochromatin silencing. However, how RNAi machinery and histone deacetylases (HDACs) are coordinated to ensure proper heterochromatin assembly is still unclear. Previously, we showed that Dpb4, a conserved DNA polymerase epsilon subunit, plays a key role in the recruitment of HDACs to heterochromatin during S phase. Here, we identified a novel RNA-binding protein Dri1 that interacts with Dpb4. GFP-tagged Dri1 forms distinct foci mostly in the nucleus, showing a high degree of colocalization with Swi6/Heterochromatin Protein 1. Deletion of dri1+ leads to defects in silencing, H3K9me, and heterochromatic siRNA generation. We also showed that Dri1 physically associates with heterochromatic transcripts, and is required for the recruitment of the RNA-induced transcriptional silencing (RITS) complex via interacting with the complex. Furthermore, loss of Dri1 decreases the association of the Sir2 HDAC with heterochromatin. We further demonstrated that the C-terminus of Dri1 that includes an intrinsically disordered (IDR) region and three zinc fingers is crucial for its role in silencing. Together, our evidences suggest that Dri1 facilitates heterochromatin assembly via the RNAi pathway and HDAC.
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Affiliation(s)
- Hyoju Ban
- Department of Biology, New York University, New York, NY 10003, USA
| | - Wenqi Sun
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yu-Hang Chen
- Institute of Genetics and Developmental Biology, CAS Center for Excellence in Biomacromolecules, Chinese Academy of Sciences, Beijing 100101, China
| | - Yong Chen
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Fei Li
- Department of Biology, New York University, New York, NY 10003, USA
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29
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Emerging roles of centromeric RNAs in centromere formation and function. Genes Genomics 2021; 43:217-226. [PMID: 33523401 DOI: 10.1007/s13258-021-01041-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 01/04/2021] [Indexed: 12/14/2022]
Abstract
BACKGROUND Centromeres are specialized chromosomal domains involved in kinetochore formation and faithful chromosome segregation. Despite a high level of functional conservation, centromeres are not identified by DNA sequences, but by epigenetic means. Universally, centromeres are typically formed on highly repetitive DNA, which were previously considered to be silent. However, recent studies have shown that transcription occurs in this region, known as centromeric-derived RNAs (cenRNAs). CenRNAs that contribute to fundamental aspects of centromere function have been recently investigated in detail. However, the distribution, behavior and contributions of centromeric transcripts are still poorly understood. OBJECTIVE The aim of this article is to provide an overview of the roles of cenRNAs in centromere formation and function. METHODS We describe the structure and DNA sequence of centromere from yeast to human. In addition, we briefly introduce the roles of cenRNAs in centromere formation and function, kinetochore structure, accurate chromosome segregation, and pericentromeric heterochromatin assembly. Centromeric circular RNAs (circRNAs) and R-loops are rising stars in centromere function. CircRNAs have been successfully identified in various species with the assistance of high-throughput sequencing and novel computational approaches for non-polyadenylated RNA transcripts. Centromeric R-loops can be identified by the single-strand DNA ligation-based library preparation technique. But the molecular features and function of these centromeric R-loops and circRNAs are still being investigated. CONCLUSION In this review, we summarize recent findings on the epigenetic regulation of cenRNAs across species, which would provide useful information about cenRNAs and interesting hints for further studies.
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30
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Weigt M, Gao Q, Ban H, He H, Mastrobuoni G, Kempa S, Chen W, Li F. Rbm10 facilitates heterochromatin assembly via the Clr6 HDAC complex. Epigenetics Chromatin 2021; 14:8. [PMID: 33468217 PMCID: PMC7816512 DOI: 10.1186/s13072-021-00382-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 01/08/2021] [Indexed: 01/13/2023] Open
Abstract
Splicing factors have recently been shown to be involved in heterochromatin formation, but their role in controlling heterochromatin structure and function remains poorly understood. In this study, we identified a fission yeast homologue of human splicing factor RBM10, which has been linked to TARP syndrome. Overexpression of Rbm10 in fission yeast leads to strong global intron retention. Rbm10 also interacts with splicing factors in a pattern resembling that of human RBM10, suggesting that the function of Rbm10 as a splicing regulator is conserved. Surprisingly, our deep-sequencing data showed that deletion of Rbm10 caused only minor effect on genome-wide gene expression and splicing. However, the mutant displays severe heterochromatin defects. Further analyses indicated that the heterochromatin defects in the mutant did not result from mis-splicing of heterochromatin factors. Our proteomic data revealed that Rbm10 associates with the histone deacetylase Clr6 complex and chromatin remodelers known to be important for heterochromatin silencing. Deletion of Rbm10 results in significant reduction of Clr6 in heterochromatin. Our work together with previous findings further suggests that different splicing subunits may play distinct roles in heterochromatin regulation.
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Affiliation(s)
- Martina Weigt
- Laboratory for Functional Genomics and Systems Biology, Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, 13125, Berlin, Germany
| | - Qingsong Gao
- Laboratory for Functional Genomics and Systems Biology, Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, 13125, Berlin, Germany
| | - Hyoju Ban
- Department of Biology, New York University, New York, NY, 10003-6688, USA
| | - Haijin He
- Department of Biology, New York University, New York, NY, 10003-6688, USA
| | - Guido Mastrobuoni
- Integrative Metabolomics and Proteomics, Berlin Institute of Medical Systems Biology, Max-Delbrueck Center for Molecular Medicine, 13125, Berlin, Germany
| | - Stefan Kempa
- Integrative Metabolomics and Proteomics, Berlin Institute of Medical Systems Biology, Max-Delbrueck Center for Molecular Medicine, 13125, Berlin, Germany
| | - Wei Chen
- Laboratory for Functional Genomics and Systems Biology, Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, 13125, Berlin, Germany. .,Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China. .,Medi-X Institute, SUSTech Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Fei Li
- Department of Biology, New York University, New York, NY, 10003-6688, USA.
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31
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Fission Yeast Methylenetetrahydrofolate Reductase Ensures Mitotic and Meiotic Chromosome Segregation Fidelity. Int J Mol Sci 2021; 22:ijms22020639. [PMID: 33440639 PMCID: PMC7827777 DOI: 10.3390/ijms22020639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 01/05/2021] [Indexed: 12/17/2022] Open
Abstract
Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the folate metabolic pathway, and its loss of function through polymorphisms is often associated with human conditions, including cancer, congenital heart disease, and Down syndrome. MTHFR is also required in the maintenance of heterochromatin, a crucial determinant of genomic stability and precise chromosomal segregation. Here, we characterize the function of a fission yeast gene met11+, which encodes a protein that is highly homologous to the mammalian MTHFR. We show that, although met11+ is not essential for viability, its disruption increases chromosome missegregation and destabilizes constitutive heterochromatic regions at pericentromeric, sub-telomeric and ribosomal DNA (rDNA) loci. Transcriptional silencing at these sites were disrupted, which is accompanied by the reduction in enrichment of histone H3 lysine 9 dimethylation (H3K9me2) and binding of the heterochromatin protein 1 (HP1)-like Swi6. The met11 null mutant also dominantly disrupts meiotic fidelity, as displayed by reduced sporulation efficiency and defects in proper partitioning of the genetic material during meiosis. Interestingly, the faithful execution of these meiotic processes is synergistically ensured by cooperation among Met11, Rec8, a meiosis-specific cohesin protein, and the shugoshin protein Sgo1, which protects Rec8 from untimely cleavage. Overall, our results suggest a key role for Met11 in maintaining pericentromeric heterochromatin for precise genetic inheritance during mitosis and meiosis.
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FBXO44 promotes DNA replication-coupled repetitive element silencing in cancer cells. Cell 2020; 184:352-369.e23. [PMID: 33357448 DOI: 10.1016/j.cell.2020.11.042] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 10/11/2020] [Accepted: 11/24/2020] [Indexed: 02/06/2023]
Abstract
Repetitive elements (REs) compose ∼50% of the human genome and are normally transcriptionally silenced, although the mechanism has remained elusive. Through an RNAi screen, we identified FBXO44 as an essential repressor of REs in cancer cells. FBXO44 bound H3K9me3-modified nucleosomes at the replication fork and recruited SUV39H1, CRL4, and Mi-2/NuRD to transcriptionally silence REs post-DNA replication. FBXO44/SUV39H1 inhibition reactivated REs, leading to DNA replication stress and stimulation of MAVS/STING antiviral pathways and interferon (IFN) signaling in cancer cells to promote decreased tumorigenicity, increased immunogenicity, and enhanced immunotherapy response. FBXO44 expression inversely correlated with replication stress, antiviral pathways, IFN signaling, and cytotoxic T cell infiltration in human cancers, while a FBXO44-immune gene signature correlated with improved immunotherapy response in cancer patients. FBXO44/SUV39H1 were dispensable in normal cells. Collectively, FBXO44/SUV39H1 are crucial repressors of RE transcription, and their inhibition selectively induces DNA replication stress and viral mimicry in cancer cells.
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Shan CM, Bao K, Diedrich J, Chen X, Lu C, Yates JR, Jia S. The INO80 Complex Regulates Epigenetic Inheritance of Heterochromatin. Cell Rep 2020; 33:108561. [PMID: 33378674 PMCID: PMC7896557 DOI: 10.1016/j.celrep.2020.108561] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/31/2020] [Accepted: 12/03/2020] [Indexed: 12/21/2022] Open
Abstract
One key aspect of epigenetic inheritance is that chromatin structures can be stably inherited through generations after the removal of the signals that establish such structures. In fission yeast, the RNA interference (RNAi) pathway is critical for the targeting of histone methyltransferase Clr4 to pericentric repeats to establish heterochromatin. However, pericentric heterochromatin cannot be properly inherited in the absence of RNAi, suggesting the existence of mechanisms that counteract chromatin structure inheritance. Here, we show that mutations of components of the INO80 chromatin-remodeling complex allow pericentric heterochromatin inheritance in RNAi mutants. The ability of INO80 to counter heterochromatin inheritance is attributed to one subunit, Iec5, which promotes histone turnover at heterochromatin but has little effects on nucleosome positioning at heterochromatin, gene expression, or the DNA damage response. These analyses demonstrate the importance of the INO80 chromatin-remodeling complex in controlling heterochromatin inheritance and maintaining the proper heterochromatin landscape of the genome.
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Affiliation(s)
- Chun-Min Shan
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Kehan Bao
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Jolene Diedrich
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Xiao Chen
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Chao Lu
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - John R Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Songtao Jia
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
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Vo TV, Dhakshnamoorthy J, Larkin M, Zofall M, Thillainadesan G, Balachandran V, Holla S, Wheeler D, Grewal SIS. CPF Recruitment to Non-canonical Transcription Termination Sites Triggers Heterochromatin Assembly and Gene Silencing. Cell Rep 2020; 28:267-281.e5. [PMID: 31269446 DOI: 10.1016/j.celrep.2019.05.107] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 04/16/2019] [Accepted: 05/29/2019] [Indexed: 01/01/2023] Open
Abstract
In eukaryotic genomes, heterochromatin is targeted by RNAi machinery and/or by pathways requiring RNA elimination and transcription termination factors. However, a direct connection between termination machinery and RNA polymerase II (RNAPII) transcriptional activity at heterochromatic loci has remained elusive. Here, we show that, in fission yeast, the conserved cleavage and polyadenylation factor (CPF) is a key component involved in RNAi-independent assembly of constitutive and facultative heterochromatin domains and that CPF is broadly required to silence genes regulated by Clr4SUV39H. Remarkably, CPF is recruited to non-canonical termination sites within the body of genes by the YTH family RNA-binding protein Mmi1 and is required for RNAPII transcription termination and facultative heterochromatin assembly. CPF loading by Mmi1 also promotes the selective termination of long non-coding RNAs that regulate gene expression in cis. These analyses delineate a mechanism in which CPF loaded onto non-canonical termination sites specifies targets of heterochromatin assembly and gene silencing.
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Affiliation(s)
- Tommy V Vo
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Jothy Dhakshnamoorthy
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Madeline Larkin
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Martin Zofall
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Gobi Thillainadesan
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Vanivilasini Balachandran
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Sahana Holla
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - David Wheeler
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Shiv I S Grewal
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
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N-Terminus Does Not Govern Protein Turnover of Schizosaccharomyces pombe CENP-A. Int J Mol Sci 2020; 21:ijms21176175. [PMID: 32859127 PMCID: PMC7503380 DOI: 10.3390/ijms21176175] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/18/2020] [Accepted: 08/21/2020] [Indexed: 12/15/2022] Open
Abstract
Centromere integrity underlies an essential framework for precise chromosome segregation and epigenetic inheritance. Although centromeric DNA sequences vary among different organisms, all eukaryotic centromeres comprise a centromere-specific histone H3 variant, centromeric protein A (CENP-A), on which other centromeric proteins assemble into the kinetochore complex. This complex connects chromosomes to mitotic spindle microtubules to ensure accurate partitioning of the genome into daughter cells. Overexpression of CENP-A is associated with many cancers and is correlated with its mistargeting, forming extra-centromeric kinetochore structures. The mislocalization of CENP-A can be counteracted by proteolysis. The amino (N)-terminal domain (NTD) of CENP-A has been implicated in this regulation and shown to be dependent on the proline residues within this domain in Saccharomyces cerevisiae CENP-A, Cse4. We recently identified a proline-rich GRANT motif in the NTD of Schizosaccharomyces pombe CENP-A (SpCENP-A) that regulates the centromeric targeting of CENP-A via binding to the CENP-A chaperone Sim3. Here, we investigated whether the NTD is required to confer SpCENP-A turnover (i.e., counter stability) using various truncation mutants of SpCENP-A. We show that sequential truncation of the NTD did not improve the stability of the protein, indicating that the NTD of SpCENP-A does not drive turnover of the protein. Instead, we reproduced previous observations that heterochromatin integrity is important for SpCENP-A stability, and showed that this occurs in an NTD-independent manner. Cells bearing the null mutant of the histone H3 lysine 9 methyltransferase Clr4 (Δclr4), which have compromised constitutive heterochromatin integrity, showed reductions in the proportion of SpCENP-A in the chromatin-containing insoluble fraction of the cell extract, suggesting that heterochromatin may promote SpCENP-A chromatin incorporation. Thus, a disruption in heterochromatin may result in the delocalization of SpCENP-A from chromatin, thus exposing it to protein turnover. Taken together, we show that the NTD is not required to confer SpCENP-A protein turnover.
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Arunkumar G, Melters DP. Centromeric Transcription: A Conserved Swiss-Army Knife. Genes (Basel) 2020; 11:E911. [PMID: 32784923 PMCID: PMC7463856 DOI: 10.3390/genes11080911] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/05/2020] [Accepted: 08/07/2020] [Indexed: 12/11/2022] Open
Abstract
In most species, the centromere is comprised of repetitive DNA sequences, which rapidly evolve. Paradoxically, centromeres fulfill an essential function during mitosis, as they are the chromosomal sites wherein, through the kinetochore, the mitotic spindles bind. It is now generally accepted that centromeres are transcribed, and that such transcription is associated with a broad range of functions. More than a decade of work on this topic has shown that centromeric transcripts are found across the eukaryotic tree and associate with heterochromatin formation, chromatin structure, kinetochore structure, centromeric protein loading, and inner centromere signaling. In this review, we discuss the conservation of small and long non-coding centromeric RNAs, their associations with various centromeric functions, and their potential roles in disease.
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Affiliation(s)
| | - Daniël P. Melters
- Chromatin Structure and Epigenetic Mechanisms, Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA;
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Hsieh CL, Xia J, Lin H. MIWI prevents aneuploidy during meiosis by cleaving excess satellite RNA. EMBO J 2020; 39:e103614. [PMID: 32677148 DOI: 10.15252/embj.2019103614] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 06/10/2020] [Accepted: 06/16/2020] [Indexed: 01/01/2023] Open
Abstract
MIWI, a murine member of PIWI proteins mostly expressed during male meiosis, is crucial for piRNA biogenesis, post-transcriptional regulation, and spermiogenesis. However, its meiotic function remains unknown. Here, we report that MIWI deficiency alters meiotic kinetochore assembly, significantly increases chromosome misalignment at the meiosis metaphase I plate, and causes chromosome mis-segregation. Consequently, Miwi-deficient mice show elevated aneuploidy in metaphase II and spermatid death. Furthermore, in Miwi-null and Miwi slicer-deficient mutants, major and minor satellite RNAs from centromeric and pericentromeric satellite repeats accumulate in excess. Over-expression of satellite repeats in wild-type spermatocytes also causes elevated chromosome misalignment, whereas reduction of both strands of major or minor satellite RNAs results in lower frequencies of chromosome misalignment. We show that MIWI, guided by piRNA, cleaves major satellite RNAs, generating RNA fragments that may form substrates for subsequent Dicer cleavage. Furthermore, Dicer cleaves all satellite RNAs in conjunction with MIWI. These findings reveal a novel mechanism in which MIWI- and Dicer-mediated cleavage of the satellite RNAs prevents the over-expression of satellite RNAs, thus ensuring proper kinetochore assembly and faithful chromosome segregation during meiosis.
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Affiliation(s)
- Chia-Ling Hsieh
- Yale Stem Cell Center and Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Jing Xia
- Yale Stem Cell Center and Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Haifan Lin
- Yale Stem Cell Center and Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
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38
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Shipkovenska G, Durango A, Kalocsay M, Gygi SP, Moazed D. A conserved RNA degradation complex required for spreading and epigenetic inheritance of heterochromatin. eLife 2020; 9:54341. [PMID: 32491985 PMCID: PMC7269676 DOI: 10.7554/elife.54341] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 05/18/2020] [Indexed: 12/14/2022] Open
Abstract
Heterochromatic domains containing histone H3 lysine 9 methylation (H3K9me) can be epigenetically inherited independently of underlying DNA sequence. To gain insight into the mechanisms that mediate epigenetic inheritance, we used a Schizosaccharomyces pombe inducible heterochromatin formation system to perform a genetic screen for mutations that abolish heterochromatin inheritance without affecting its establishment. We identified mutations in several pathways, including the conserved and essential Rix1-associated complex (henceforth the rixosome), which contains RNA endonuclease and polynucleotide kinase activities with known roles in ribosomal RNA processing. We show that the rixosome is required for spreading and epigenetic inheritance of heterochromatin in fission yeast. Viable rixosome mutations that disrupt its association with Swi6/HP1 fail to localize to heterochromatin, lead to accumulation of heterochromatic RNAs, and block spreading of H3K9me and silencing into actively transcribed regions. These findings reveal a new pathway for degradation of heterochromatic RNAs with essential roles in heterochromatin spreading and inheritance.
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Affiliation(s)
- Gergana Shipkovenska
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Alexander Durango
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Marian Kalocsay
- Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Danesh Moazed
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, United States
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39
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Epigenetic Factors That Control Pericentric Heterochromatin Organization in Mammals. Genes (Basel) 2020; 11:genes11060595. [PMID: 32481609 PMCID: PMC7349813 DOI: 10.3390/genes11060595] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/17/2020] [Accepted: 05/25/2020] [Indexed: 12/11/2022] Open
Abstract
Pericentric heterochromatin (PCH) is a particular form of constitutive heterochromatin that is localized to both sides of centromeres and that forms silent compartments enriched in repressive marks. These genomic regions contain species-specific repetitive satellite DNA that differs in terms of nucleotide sequences and repeat lengths. In spite of this sequence diversity, PCH is involved in many biological phenomena that are conserved among species, including centromere function, the preservation of genome integrity, the suppression of spurious recombination during meiosis, and the organization of genomic silent compartments in the nucleus. PCH organization and maintenance of its repressive state is tightly regulated by a plethora of factors, including enzymes (e.g., DNA methyltransferases, histone deacetylases, and histone methyltransferases), DNA and histone methylation binding factors (e.g., MECP2 and HP1), chromatin remodeling proteins (e.g., ATRX and DAXX), and non-coding RNAs. This evidence helps us to understand how PCH organization is crucial for genome integrity. It then follows that alterations to the molecular signature of PCH might contribute to the onset of many genetic pathologies and to cancer progression. Here, we describe the most recent updates on the molecular mechanisms known to underlie PCH organization and function.
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40
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Giordano M, Infantino L, Biggiogera M, Montecucco A, Biamonti G. Heat Shock Affects Mitotic Segregation of Human Chromosomes Bound to Stress-Induced Satellite III RNAs. Int J Mol Sci 2020; 21:ijms21082812. [PMID: 32316575 PMCID: PMC7216065 DOI: 10.3390/ijms21082812] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 04/13/2020] [Accepted: 04/14/2020] [Indexed: 12/18/2022] Open
Abstract
Heat shock activates the transcription of arrays of Satellite III (SatIII) DNA repeats in the pericentromeric heterochromatic domains of specific human chromosomes, the longest of which is on chromosome 9. Long non-coding SatIII RNAs remain associated with transcription sites where they form nuclear stress bodies or nSBs. The biology of SatIII RNAs is still poorly understood. Here, we show that SatIII RNAs and nSBs are detectable up to four days after thermal stress and are linked to defects in chromosome behavior during mitosis. Heat shock perturbs the execution of mitosis. Cells reaching mitosis during the first 3 h of recovery accumulate in pro-metaphase. During the ensuing 48 h, this block is no longer detectable; however, a significant fraction of mitoses shows chromosome segregation defects. Notably, most of lagging chromosomes and chromosomal bridges are bound to nSBs and contain arrays of SatIII DNA. Disappearance of mitotic defects at the end of day 2 coincides with the processing of long non-coding SatIII RNAs into a ladder of small RNAs associated with chromatin and ranging in size from 25 to 75 nt. The production of these molecules does not rely on DICER and Argonaute 2 components of the RNA interference apparatus. Thus, massive transcription of SatIII DNA may contribute to chromosomal instability.
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Affiliation(s)
- Manuela Giordano
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche via Abbiategrasso 207, 27100 Pavia, Italy; (M.G.); (L.I.); (A.M.)
| | - Lucia Infantino
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche via Abbiategrasso 207, 27100 Pavia, Italy; (M.G.); (L.I.); (A.M.)
| | - Marco Biggiogera
- Dipartimento di Biologia e Biotecnologie, Università di Pavia, 27100 Pavia, Italy;
| | - Alessandra Montecucco
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche via Abbiategrasso 207, 27100 Pavia, Italy; (M.G.); (L.I.); (A.M.)
| | - Giuseppe Biamonti
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche via Abbiategrasso 207, 27100 Pavia, Italy; (M.G.); (L.I.); (A.M.)
- Correspondence: ; Tel.: +39-0382-546-334
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41
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Marayati BF, Tucker JF, De La Cerda DA, Hou TC, Chen R, Sugiyama T, Pease JB, Zhang K. The Catalytic-Dependent and -Independent Roles of Lsd1 and Lsd2 Lysine Demethylases in Heterochromatin Formation in Schizosaccharomyces pombe. Cells 2020; 9:E955. [PMID: 32295063 PMCID: PMC7226997 DOI: 10.3390/cells9040955] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/06/2020] [Accepted: 04/10/2020] [Indexed: 12/30/2022] Open
Abstract
In eukaryotes, heterochromatin plays a critical role in organismal development and cell fate acquisition, through regulating gene expression. The evolutionarily conserved lysine-specific demethylases, Lsd1 and Lsd2, remove mono- and dimethylation on histone H3, serving complex roles in gene expression. In the fission yeast Schizosaccharomyces pombe, null mutations of Lsd1 and Lsd2 result in either severe growth defects or inviability, while catalytic inactivation causes minimal defects, indicating that Lsd1 and Lsd2 have essential functions beyond their known demethylase activity. Here, we show that catalytic mutants of Lsd1 or Lsd2 partially assemble functional heterochromatin at centromeres in RNAi-deficient cells, while the C-terminal truncated alleles of Lsd1 or Lsd2 exacerbate heterochromatin formation at all major heterochromatic regions, suggesting that Lsd1 and Lsd2 repress heterochromatic transcripts through mechanisms both dependent on and independent of their catalytic activities. Lsd1 and Lsd2 are also involved in the establishment and maintenance of heterochromatin. At constitutive heterochromatic regions, Lsd1 and Lsd2 regulate one another and cooperate with other histone modifiers, including the class II HDAC Clr3 and the Sirtuin family protein Sir2 for gene silencing, but not with the class I HDAC Clr6. Our findings explore the roles of lysine-specific demethylases in epigenetic gene silencing at heterochromatic regions.
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Affiliation(s)
- Bahjat F. Marayati
- Department of Biology, Center for Molecular Signaling, Wake Forest University, Winston-Salem, NC 27109, USA; (B.F.M.); (J.F.T.); (D.A.D.L.C.); (T.-C.H.); (J.B.P.)
| | - James F. Tucker
- Department of Biology, Center for Molecular Signaling, Wake Forest University, Winston-Salem, NC 27109, USA; (B.F.M.); (J.F.T.); (D.A.D.L.C.); (T.-C.H.); (J.B.P.)
| | - David A. De La Cerda
- Department of Biology, Center for Molecular Signaling, Wake Forest University, Winston-Salem, NC 27109, USA; (B.F.M.); (J.F.T.); (D.A.D.L.C.); (T.-C.H.); (J.B.P.)
| | - Tien-Chi Hou
- Department of Biology, Center for Molecular Signaling, Wake Forest University, Winston-Salem, NC 27109, USA; (B.F.M.); (J.F.T.); (D.A.D.L.C.); (T.-C.H.); (J.B.P.)
| | - Rong Chen
- Physiology and pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27101, USA;
| | - Tomoyasu Sugiyama
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China;
| | - James B. Pease
- Department of Biology, Center for Molecular Signaling, Wake Forest University, Winston-Salem, NC 27109, USA; (B.F.M.); (J.F.T.); (D.A.D.L.C.); (T.-C.H.); (J.B.P.)
| | - Ke Zhang
- Department of Biology, Center for Molecular Signaling, Wake Forest University, Winston-Salem, NC 27109, USA; (B.F.M.); (J.F.T.); (D.A.D.L.C.); (T.-C.H.); (J.B.P.)
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42
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Ferreira D, Escudeiro A, Adega F, Anjo SI, Manadas B, Chaves R. FA-SAT ncRNA interacts with PKM2 protein: depletion of this complex induces a switch from cell proliferation to apoptosis. Cell Mol Life Sci 2020; 77:1371-1386. [PMID: 31346634 PMCID: PMC11104958 DOI: 10.1007/s00018-019-03234-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 07/10/2019] [Accepted: 07/15/2019] [Indexed: 01/11/2023]
Abstract
FA-SAT is a highly conserved satellite DNA sequence transcribed in many Bilateria species. To disclose the cellular and functional profile of FA-SAT non-coding RNAs, a comprehensive experimental approach, including the transcripts location in the cell and in the cell cycle, the identification of its putative protein interactors, and silencing/ectopic expression phenotype analysis, was performed. FA-SAT non-coding RNAs play a nuclear function at the G1 phase of the cell cycle and the interactomic assay showed that the PKM2 protein is the main interactor. The disruption of the FA-SAT non-coding RNA/PKM2 protein complex, by the depletion of either FA-SAT or PKM2, results in the same phenotype-apoptosis, and the ectopic overexpression of FA-SAT did not affect the cell-cycle progression, but promotes the PKM2 nuclear accumulation. Overall, our data first describe the importance of this ribonucleoprotein complex in apoptosis and cell-cycle progression, what foresees a promising novel candidate molecular target for cancer therapy and diagnosis.
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Affiliation(s)
- Daniela Ferreira
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes e Alto Douro (UTAD), Vila Real, Portugal
- Biosystems and Integrative Sciences Institute (BioISI), Faculty of Sciences, University of Lisboa, Lisbon, Portugal
| | - Ana Escudeiro
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes e Alto Douro (UTAD), Vila Real, Portugal
- Biosystems and Integrative Sciences Institute (BioISI), Faculty of Sciences, University of Lisboa, Lisbon, Portugal
| | - Filomena Adega
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes e Alto Douro (UTAD), Vila Real, Portugal
- Biosystems and Integrative Sciences Institute (BioISI), Faculty of Sciences, University of Lisboa, Lisbon, Portugal
| | - Sandra I Anjo
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
- Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal
| | - Bruno Manadas
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
| | - Raquel Chaves
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes e Alto Douro (UTAD), Vila Real, Portugal.
- Biosystems and Integrative Sciences Institute (BioISI), Faculty of Sciences, University of Lisboa, Lisbon, Portugal.
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43
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Georgescu PR, Capella M, Fischer-Burkart S, Braun S. The euchromatic histone mark H3K36me3 preserves heterochromatin through sequestration of an acetyltransferase complex in fission yeast. MICROBIAL CELL 2020; 7:80-92. [PMID: 32161768 PMCID: PMC7052950 DOI: 10.15698/mic2020.03.711] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Maintaining the identity of chromatin states requires mechanisms that ensure their structural integrity through the concerted actions of histone modifiers, readers, and erasers. Histone H3K9me and H3K27me are hallmarks of repressed heterochromatin, whereas H3K4me and H3K36me are associated with actively transcribed euchromatin. Paradoxically, several studies have reported that loss of Set2, the methyltransferase responsible for H3K36me, causes de-repression of heterochromatin. Here we show that unconstrained activity of the acetyltransferase complex Mst2C, which antagonizes heterochromatin, is the main cause of the silencing defects observed in Set2-deficient cells. As previously shown, Mst2C is sequestered to actively transcribed chromatin via binding to H3K36me3 that is recognized by the PWWP domain protein Pdp3. We demonstrate that combining deletions of set2+ and pdp3+ results in an epistatic silencing phenotype. In contrast, deleting mst2+, or other members of Mst2C, fully restores silencing in Set2-deficient cells. Suppression of the silencing defect in set2Δ cells is specific for pericentromeres and subtelomeres, which are marked by H3K9me, but is not seen for loci that lack genuine heterochromatin. Mst2 is known to acetylate histone H3K14 redundantly with the HAT Gnc5. Further, it is involved in the acetylation of the non-histone substrate and E3 ubiquitin ligase Brl1, resulting in increased H2B-K119 ubiquitylation at euchromatin. However, we reveal that none of these mechanisms are responsible for the Set2-dependent silencing pathway, implying that Mst2 targets another, unknown substrate critical for heterochromatin silencing. Our findings demonstrate that maintenance of chromatin states requires spatial constraint of opposing chromatin activities.
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Affiliation(s)
- Paula R Georgescu
- Department of Physiological Chemistry, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Matías Capella
- Department of Physiological Chemistry, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Sabine Fischer-Burkart
- Department of Physiological Chemistry, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Sigurd Braun
- Department of Physiological Chemistry, BioMedical Center (BMC), Ludwig-Maximilians-Universität München, Martinsried, Germany
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44
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Saha P, Mishra RK. Heterochromatic hues of transcription-the diverse roles of noncoding transcripts from constitutive heterochromatin. FEBS J 2019; 286:4626-4641. [PMID: 31644838 DOI: 10.1111/febs.15104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 08/19/2019] [Accepted: 10/22/2019] [Indexed: 02/05/2023]
Abstract
Constitutive heterochromatin has been canonically considered as transcriptionally inert chromosomal regions, which silences the repeats and transposable elements (TEs), to preserve genomic integrity. However, several studies from the last few decades show that centromeric and pericentromeric regions also get transcribed and these transcripts are involved in multiple cellular processes. Regulation of such spatially and temporally controlled transcription and their relevance to heterochromatin function have emerged as an active area of research in chromatin biology. Here, we review the myriad of roles of noncoding transcripts from the constitutive heterochromatin in the establishment and maintenance of heterochromatin, kinetochore assembly, germline epigenome maintenance, early development, and diseases. Contrary to general expectations, there are active protein-coding genes in the heterochromatin although the regulatory mechanisms of their expression are largely unknown. We propose plausible hypotheses to explain heterochromatic gene expression using Drosophila melanogaster as a model, and discuss the evolutionary significance of these transcripts in the context of Drosophilid speciation. Such analyses offer insights into the regulatory pathways and functions of heterochromatic transcripts which open new avenues for further investigation.
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Affiliation(s)
- Parna Saha
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Rakesh K Mishra
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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45
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Broad Heterochromatic Domains Open in Gonocyte Development Prior to De Novo DNA Methylation. Dev Cell 2019; 51:21-34.e5. [PMID: 31474564 DOI: 10.1016/j.devcel.2019.07.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 03/28/2019] [Accepted: 07/24/2019] [Indexed: 02/03/2023]
Abstract
Facultative heterochromatin forms and reorganizes in response to external stimuli. However, how the initial establishment of such a chromatin state is regulated in cell-cycle-arrested cells remains unexplored. Mouse gonocytes are arrested male germ cells, at which stage the genome-wide DNA methylome forms. Here, we discovered transiently accessible heterochromatin domains of several megabases in size in gonocytes and named them differentially accessible domains (DADs). Open DADs formed in gene desert and gene cluster regions, primarily at transposons, with the reprogramming of histone marks, suggesting DADs as facultative heterochromatin. De novo DNA methylation took place with two waves in gonocytes: the first region specific and the second genome-wide. DADs were resistant to the first wave and their opening preceded the second wave. In addition, the higher-order chromosome architecture was reorganized with less defined chromosome compartments in gonocytes. These findings suggest that multiple layers of chromatin reprogramming facilitate de novo DNA methylation.
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46
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Bao K, Jia S. Noncatalytic Function of a JmjC Domain Protein Disrupts Heterochromatin. Epigenet Insights 2019; 12:2516865719862249. [PMID: 31321383 PMCID: PMC6624913 DOI: 10.1177/2516865719862249] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 06/13/2019] [Indexed: 11/29/2022] Open
Abstract
Chromatin-modifying enzymes are frequently overexpressed in cancer cells, and
their enzymatic activities play important roles in changing the epigenetic
landscape responsible for tumorigenesis. However, many of these proteins also
execute noncatalytic functions, which are poorly understood. In fission yeast,
overexpression of Epe1, a histone demethylase homolog, causes heterochromatin
defects. Interestingly, in our recent work, we discovered that overexpressed
Epe1 recruits SAGA, a histone acetyltransferase complex important for
transcriptional regulation, to disrupt heterochromatin, independent of its
demethylase activity. Our findings suggest that overexpressed
chromatin-modifying enzymes can alter the epigenetic landscape through changing
their proteomic environments, an area that needs to be further explored in
dissecting disease etiology associated with overexpression of chromatin
regulators.
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Affiliation(s)
- Kehan Bao
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Songtao Jia
- Department of Biological Sciences, Columbia University, New York, NY, USA
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47
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A New Portrait of Constitutive Heterochromatin: Lessons from Drosophila melanogaster. Trends Genet 2019; 35:615-631. [PMID: 31320181 DOI: 10.1016/j.tig.2019.06.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 06/05/2019] [Accepted: 06/06/2019] [Indexed: 12/14/2022]
Abstract
Constitutive heterochromatin represents a significant portion of eukaryotic genomes, but its functions still need to be elucidated. Even in the most updated genetics and molecular biology textbooks, constitutive heterochromatin is portrayed mainly as the 'silent' component of eukaryotic genomes. However, there may be more complexity to the relationship between heterochromatin and gene expression. In the fruit fly Drosophila melanogaster, a model for heterochromatin studies, about one-third of the genome is heterochromatic and is concentrated in the centric, pericentric, and telomeric regions of the chromosomes. Recent findings indicate that hundreds of D. melanogaster genes can 'live and work' properly within constitutive heterochromatin. The genomic size of these genes is generally larger than that of euchromatic genes and together they account for a significant fraction of the entire constitutive heterochromatin. Thus, this peculiar genome component in spite its ability to induce silencing, has in fact the means for being quite dynamic. A major scope of this review is to revisit the 'dogma of silent heterochromatin'.
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48
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Ren B, Tan HL, Nguyen TTT, Sayed AMM, Li Y, Mok YK, Yang H, Chen ES. Regulation of transcriptional silencing and chromodomain protein localization at centromeric heterochromatin by histone H3 tyrosine 41 phosphorylation in fission yeast. Nucleic Acids Res 2019; 46:189-202. [PMID: 29136238 PMCID: PMC5758876 DOI: 10.1093/nar/gkx1010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 10/13/2017] [Indexed: 12/29/2022] Open
Abstract
Heterochromatin silencing is critical for genomic integrity and cell survival. It is orchestrated by chromodomain (CD)-containing proteins that bind to methylated histone H3 lysine 9 (H3K9me), a hallmark of heterochromatin. Here, we show that phosphorylation of tyrosine 41 (H3Y41p)—a novel histone H3 modification—participates in the regulation of heterochromatin in fission yeast. We show that a loss-of-function mutant of H3Y41 can suppress heterochromatin de-silencing in the centromere and subtelomere repeat regions, suggesting a de-silencing role for H3Y41p on heterochromatin. Furthermore, we show both in vitro and in vivo that H3Y41p differentially regulates two CD-containing proteins without the change in the level of H3K9 methylation: it promotes the binding of Chp1 to histone H3 and the exclusion of Swi6. H3Y41p is preferentially enriched on centromeric heterochromatin during M- to early S phase, which coincides with the localization switch of Swi6/Chp1. The loss-of-function H3Y41 mutant could suppress the hypersensitivity of the RNAi mutants towards hydroxyurea (HU), which arrests replication in S phase. Overall, we describe H3Y41p as a novel histone modification that differentially regulates heterochromatin silencing in fission yeast via the binding of CD-containing proteins.
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Affiliation(s)
- Bingbing Ren
- Department of Biochemistry, National University of Singapore, Yong Loo Lin School of Medicine, Singapore
| | - Hwei Ling Tan
- Department of Biochemistry, National University of Singapore, Yong Loo Lin School of Medicine, Singapore
| | - Thi Thuy Trang Nguyen
- Department of Biochemistry, National University of Singapore, Yong Loo Lin School of Medicine, Singapore
| | | | - Ying Li
- Cancer Science Institute, National University of Singapore, Yong Loo Lin School of Medicine, Singapore
| | - Yu-Keung Mok
- Department of Biological Sciences, National University of Singapore
| | - Henry Yang
- Cancer Science Institute, National University of Singapore, Yong Loo Lin School of Medicine, Singapore.,National University Health System (NUHS), Singapore
| | - Ee Sin Chen
- Department of Biochemistry, National University of Singapore, Yong Loo Lin School of Medicine, Singapore.,National University Health System (NUHS), Singapore
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49
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Tan HL, Lim KK, Yang Q, Fan JS, Sayed AMM, Low LS, Ren B, Lim TK, Lin Q, Mok YK, Liou YC, Chen ES. Prolyl isomerization of the CENP-A N-terminus regulates centromeric integrity in fission yeast. Nucleic Acids Res 2019; 46:1167-1179. [PMID: 29194511 DOI: 10.1093/nar/gkx1180] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 11/22/2017] [Indexed: 01/15/2023] Open
Abstract
Centromeric identity and chromosome segregation are determined by the precise centromeric targeting of CENP-A, the centromere-specific histone H3 variant. The significance of the amino-terminal domain (NTD) of CENP-A in this process remains unclear. Here, we assessed the functional significance of each residue within the NTD of CENP-A from Schizosaccharomyces pombe (SpCENP-A) and identified a proline-rich 'GRANT' (Genomic stability-Regulating site within CENP-A N-Terminus) motif that is important for CENP-A function. Through sequential mutagenesis, we show that GRANT proline residues are essential for coordinating SpCENP-A centromeric targeting. GRANT proline-15 (P15), in particular, undergoes cis-trans isomerization to regulate chromosome segregation fidelity, which appears to be carried out by two FK506-binding protein (FKBP) family prolyl cis-trans isomerases. Using proteomics analysis, we further identified the SpCENP-A-localizing chaperone Sim3 as a SpCENP-A NTD interacting protein that is dependent on GRANT proline residues. Ectopic expression of sim3+ complemented the chromosome segregation defect arising from the loss of these proline residues. Overall, cis-trans proline isomerization is a post-translational modification of the SpCENP-A NTD that confers precise propagation of centromeric integrity in fission yeast, presumably via targeting SpCENP-A to the centromere.
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Affiliation(s)
- Hwei Ling Tan
- Department of Biochemistry, National University of Singapore, 117597 Singapore
- National University Health System (NUHS), Singapore, 119228 Singapore
| | - Kim Kiat Lim
- Department of Biochemistry, National University of Singapore, 117597 Singapore
- National University Health System (NUHS), Singapore, 119228 Singapore
| | - Qiaoyun Yang
- Department of Biological Sciences, National University of Singapore, 117543 Singapore
| | - Jing-Song Fan
- Department of Biological Sciences, National University of Singapore, 117543 Singapore
| | | | - Liy Sim Low
- Department of Biochemistry, National University of Singapore, 117597 Singapore
- National University Health System (NUHS), Singapore, 119228 Singapore
| | - Bingbing Ren
- Department of Biochemistry, National University of Singapore, 117597 Singapore
- National University Health System (NUHS), Singapore, 119228 Singapore
| | - Teck Kwang Lim
- Department of Biological Sciences, National University of Singapore, 117543 Singapore
| | - Qingsong Lin
- Department of Biological Sciences, National University of Singapore, 117543 Singapore
| | - Yu-Keung Mok
- Department of Biological Sciences, National University of Singapore, 117543 Singapore
| | - Yih-Cherng Liou
- Department of Biological Sciences, National University of Singapore, 117543 Singapore
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456 Singapore
| | - Ee Sin Chen
- Department of Biochemistry, National University of Singapore, 117597 Singapore
- National University Health System (NUHS), Singapore, 119228 Singapore
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456 Singapore
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Bhattacharjee S, Roche B, Martienssen RA. RNA-induced initiation of transcriptional silencing (RITS) complex structure and function. RNA Biol 2019; 16:1133-1146. [PMID: 31213126 DOI: 10.1080/15476286.2019.1621624] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Heterochromatic regions of the genome are epigenetically regulated to maintain a heritable '"silent state"'. In fission yeast and other organisms, epigenetic silencing is guided by nascent transcripts, which are targeted by the RNA interference pathway. The key effector complex of the RNA interference pathway consists of small interfering RNA molecules (siRNAs) associated with Argonaute, assembled into the RNA-induced transcriptional silencing (RITS) complex. This review focuses on our current understanding of how RITS promotes heterochromatin formation, and in particular on the role of Argonaute-containing complexes in many other functions such as quelling, release of RNA polymerases, cellular quiescence and genome defense.
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Affiliation(s)
- Sonali Bhattacharjee
- a Cold Spring Harbor Laboratory, Howard Hughes Medical Institute , Cold Spring Harbor , NY , USA
| | - Benjamin Roche
- a Cold Spring Harbor Laboratory, Howard Hughes Medical Institute , Cold Spring Harbor , NY , USA
| | - Robert A Martienssen
- a Cold Spring Harbor Laboratory, Howard Hughes Medical Institute , Cold Spring Harbor , NY , USA
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