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Serra-Bardenys G, Blanco E, Escudero-Iriarte C, Serra-Camprubí Q, Querol J, Pascual-Reguant L, Morancho B, Escorihuela M, Tissera NS, Sabé A, Martín L, Segura-Bayona S, Verde G, Aiese Cigliano R, Millanes-Romero A, Jerónimo C, Cebrià-Costa JP, Nuciforo P, Simonetti S, Viaplana C, Dienstmann R, Oliveira M, Peg V, Stracker TH, Arribas J, Canals F, Villanueva J, Di Croce L, García de Herreros A, Tian TV, Peiró S. LOXL2-mediated chromatin compaction is required to maintain the oncogenic properties of triple-negative breast cancer cells. FEBS J 2024; 291:2423-2448. [PMID: 38451841 DOI: 10.1111/febs.17112] [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: 06/01/2023] [Revised: 01/02/2024] [Accepted: 02/23/2024] [Indexed: 03/09/2024]
Abstract
Oxidation of histone H3 at lysine 4 (H3K4ox) is catalyzed by lysyl oxidase homolog 2 (LOXL2). This histone modification is enriched in heterochromatin in triple-negative breast cancer (TNBC) cells and has been linked to the maintenance of compacted chromatin. However, the molecular mechanism underlying this maintenance is still unknown. Here, we show that LOXL2 interacts with RuvB-Like 1 (RUVBL1), RuvB-Like 2 (RUVBL2), Actin-like protein 6A (ACTL6A), and DNA methyltransferase 1associated protein 1 (DMAP1), a complex involved in the incorporation of the histone variant H2A.Z. Our experiments indicate that this interaction and the active form of RUVBL2 are required to maintain LOXL2-dependent chromatin compaction. Genome-wide experiments showed that H2A.Z, RUVBL2, and H3K4ox colocalize in heterochromatin regions. In the absence of LOXL2 or RUVBL2, global levels of the heterochromatin histone mark H3K9me3 were strongly reduced, and the ATAC-seq signal in the H3K9me3 regions was increased. Finally, we observed that the interplay between these series of events is required to maintain H3K4ox-enriched heterochromatin regions, which in turn is key for maintaining the oncogenic properties of the TNBC cell line tested (MDA-MB-231).
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Affiliation(s)
- Gemma Serra-Bardenys
- Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
- Institut Bonanova FP Sanitaria, Consorci Mar Parc de Salut de Barcelona, Spain
| | - Enrique Blanco
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Spain
| | | | | | - Jessica Querol
- Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - Laura Pascual-Reguant
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Spain
| | | | | | | | - Anna Sabé
- Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - Luna Martín
- Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | | | - Gaetano Verde
- Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | | | - Alba Millanes-Romero
- Institute for Research in Biomedicine (IRB Barcelona) and Barcelona Institute of Science and Technology, Spain
| | - Celia Jerónimo
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Spain
- Institut de Recherches Cliniques de Montréal, Canada
| | | | - Paolo Nuciforo
- Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - Sara Simonetti
- Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | | | | | - Mafalda Oliveira
- Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
- Medical Oncology Department, Vall d'Hebron University Hospital, Barcelona, Spain
| | - Vicente Peg
- Medical Oncology Department, Vall d'Hebron University Hospital, Barcelona, Spain
- Centro de Investigación Biomédica en Red en Oncología (CIBERONC), Barcelona, Spain
- Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
- Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Travis H Stracker
- Radiation Oncology Branch, National Cancer Institute, Bethesda, MD, USA
| | - Joaquín Arribas
- Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
- Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
- Programa de Recerca en Càncer, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain
| | - Francesc Canals
- Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | | | - Luciano Di Croce
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Antonio García de Herreros
- Programa de Recerca en Càncer, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain
- Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
| | - Tian V Tian
- Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - Sandra Peiró
- Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
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2
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Zahedi Y, Zeng S, Ekwall K. An essential role for the Ino80 chromatin remodeling complex in regulation of gene expression during cellular quiescence. Chromosome Res 2023; 31:14. [PMID: 37043046 PMCID: PMC10097750 DOI: 10.1007/s10577-023-09723-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 03/15/2023] [Accepted: 03/31/2023] [Indexed: 04/13/2023]
Abstract
Cellular quiescence is an important physiological state both in unicellular and multicellular eukaryotes. Quiescent cells are halted for proliferation and stop the cell cycle at the G0 stage. Using fission yeast as a model organism, we have previously found that several subunits of a conserved chromatin remodeling complex, Ino80C (INOsitol requiring nucleosome remodeling factor), are required for survival in quiescence. Here, we demonstrate that Ino80C has a key function in the regulation of gene expression in G0 cells. We show that null mutants for two Ino80C subunits, Iec1 and Ies2, a putative subunit Arp42, a null mutant for the histone variant H2A.Z, and a null mutant for the Inositol kinase Asp1 have very similar phenotypes in quiescence. These mutants show reduced transcription genome-wide and specifically fail to activate 149 quiescence genes, of which many are localized to the subtelomeric regions. Using spike in normalized ChIP-seq experiments, we show that there is a global reduction of H2A.Z levels in quiescent wild-type cells but not in iec1∆ cells and that a subtelomeric chromosome boundary element is strongly affected by Ino80C. Based on these observations, we propose a model in which Ino80C is evicting H2A.Z from chromatin in quiescent cells, thereby inactivating the subtelomeric boundary element, leading to a reorganization of the chromosome structure and activation of genes required to survive in quiescence.
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Affiliation(s)
- Yasaman Zahedi
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo Building, 141 83, Huddinge, Sweden
| | - Shengyuan Zeng
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo Building, 141 83, Huddinge, Sweden
| | - Karl Ekwall
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo Building, 141 83, Huddinge, Sweden.
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3
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Wang Q, Qi Y, Xiong F, Wang D, Wang B, Chen Y. The H2A.Z-KDM1A complex promotes tumorigenesis by localizing in the nucleus to promote SFRP1 promoter methylation in cholangiocarcinoma cells. BMC Cancer 2022; 22:1166. [PMID: 36368958 PMCID: PMC9652970 DOI: 10.1186/s12885-022-10279-y] [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: 06/27/2022] [Accepted: 11/03/2022] [Indexed: 11/13/2022] Open
Abstract
Background Intrahepatic cholangiocarcinoma (ICC), originating from the bile ducts, is the second most common primary liver malignancy, and its incidence has recently increased. H2A.Z, a highly conserved H2A variant, is emerging as a key regulatory molecule in cancer. However, its underlying mechanism of action in ICC cells remains unclear. Methods Here, we examined the expression of H2A.Z and SFRP1 in normal intrahepatic cholangiocytes, ICC cell lines, ICC tissue microarrays, and fresh specimens. The correlations between H2A.Z or SFRP1 expression and clinical features were analysed. The overall survival rate was analysed based on H2A.Z and SFRP1 expression. Immunoprecipitation was used to analyse the recruitment of KDM1A, and ChIP sequencing and BSP were used to analyse the enrichment of methylation-related molecules such as H3K4me1 and H3K4me2 in the SFRP1 promoter and reveal the underlying mechanisms. Knockdown and rescue experiments were used to determine the potential mechanism by which H2A.Z and SFRP1 promote tumorigenesis in vitro. Results We showed that upregulation of H2A.Z expression is linked to downregulation of SFRP1 expression in ICC tissues and poor overall survival in patients with ICC. H2A.Z interacted with KDM1A in the nucleus to bind to the -151 ~ -136 bp region upstream of the SFRP1 promoter to increase its demethylation in ICC cells. Functionally, H2A.Z silencing inhibited the proliferation and invasion of ICC cells, and these effects were mitigated by SFRP1 silencing in ICC cells. Conclusions Our findings reveal that H2A.Z inhibits SFRP1 expression through chromatin modification in the context of ICC by forming a complex with KDM1A in the nucleus. Supplementary Information The online version contains supplementary material available at 10.1186/s12885-022-10279-y.
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4
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Cohen A, Pataki E, Kupiec M, Weisman R. TOR complex 2 contributes to regulation of gene expression via inhibiting Gcn5 recruitment to subtelomeric and DNA replication stress genes. PLoS Genet 2022; 18:e1010061. [PMID: 35157728 PMCID: PMC8880919 DOI: 10.1371/journal.pgen.1010061] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 02/25/2022] [Accepted: 01/28/2022] [Indexed: 11/18/2022] Open
Abstract
The fission yeast TOR complex 2 (TORC2) is required for gene silencing at subtelomeric regions and for the induction of gene transcription in response to DNA replication stress. Thus, TORC2 affects transcription regulation both negatively and positively. Whether these two TORC2-dependent functions share a common molecular mechanism is currently unknown. Here, we show that Gad8 physically interacts with proteins that regulate transcription, including subunits of the Spt-Ada-Gcn5-acetyltransferase (SAGA) complex and the BET bromodomain protein Bdf2. We demonstrate that in the absence of TORC2, Gcn5, the histone acetyltransferase subunit of SAGA, accumulates at subtelomeric genes and at non-induced promoters of DNA replication genes. Remarkably, the loss of Gcn5 in TORC2 mutant cells restores gene silencing as well as transcriptional induction in response to DNA replication stress. Loss of Bdf2 alleviates excess of Gcn5 binding in TORC2 mutant cells and also rescues the aberrant regulation of transcription in these cells. Furthermore, the loss of either SAGA or Bdf2 suppresses the sensitivity of TORC2 mutant cells to a variety of stresses, including DNA replication, DNA damage, temperature and nutrient stresses. We suggest a role of TORC2 in transcriptional regulation that is critical for gene silencing and gene induction in response to stress and involves the binding of Gcn5 to the chromatin.
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Affiliation(s)
- Adiel Cohen
- Department of Natural and Life Sciences, The Open University of Israel, Ra’anana, Israel
| | - Emese Pataki
- Department of Natural and Life Sciences, The Open University of Israel, Ra’anana, Israel
| | - Martin Kupiec
- The Shmunis School of Biomedicine & Cancer Research, Tel Aviv University, Tel Aviv, Israel
| | - Ronit Weisman
- Department of Natural and Life Sciences, The Open University of Israel, Ra’anana, Israel
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5
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Tsukii K, Takahata S, Murakami Y. Histone variant H2A.Z plays multiple roles in the maintenance of heterochromatin integrity. Genes Cells 2021; 27:93-112. [PMID: 34910346 DOI: 10.1111/gtc.12911] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 01/04/2023]
Abstract
H2A.Z, an evolutionally well-conserved histone H2A variant, is involved in many biological processes. Although the function of H2A.Z in euchromatic gene regulation is well known, its function and deposition mechanism in heterochromatin are still unclear. Here, we report that H2A.Z plays multiple roles in fission yeast heterochromatin. While a small amount of H2A.Z localizes at pericentromeric heterochromatin, loss of methylation of histone H3 at Lys9 (H3K9me) induces the accumulation of H2A.Z, which is dependent on the H2A.Z loader, SWR complex. The accumulated H2A.Z suppresses heterochromatic non-coding RNA transcription. This transcriptional repression activity requires the N-terminal tail of H2A.Z, which is involved in the regulation of euchromatic gene transcription. RNAi-defective cells, in which a substantial amount of H3K9me is retained by RNAi-independent heterochromatin assembly, also accumulate H2A.Z at heterochromatin, and the additional loss of H2A.Z in these cells triggers a further decrease in H3K9me. Our results suggest that H2A.Z facilitates RNAi-independent heterochromatin assembly by antagonizing the demethylation activity of Epe1, an eraser of H3K9me. Furthermore, H2A.Z suppresses Epe1-mediated transcriptional activation, which is required for subtelomeric gene repression. Our results provide novel evidence that H2A.Z plays diverse roles in chromatin silencing.
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Affiliation(s)
- Kazuki Tsukii
- Laboratory of Bioorganic Chemistry, Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Japan
| | - Shinya Takahata
- Laboratory of Bioorganic Chemistry, Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Japan.,Laboratory of Bioorganic Chemistry, Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Yota Murakami
- Laboratory of Bioorganic Chemistry, Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Japan.,Laboratory of Bioorganic Chemistry, Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
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6
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Subtelomeric Chromatin in the Fission Yeast S. pombe. Microorganisms 2021; 9:microorganisms9091977. [PMID: 34576871 PMCID: PMC8466458 DOI: 10.3390/microorganisms9091977] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/06/2021] [Accepted: 09/14/2021] [Indexed: 01/15/2023] Open
Abstract
Telomeres play important roles in safeguarding the genome. The specialized repressive chromatin that assembles at telomeres and subtelomeric domains is key to this protective role. However, in many organisms, the repetitive nature of telomeric and subtelomeric sequences has hindered research efforts. The fission yeast S. pombe has provided an important model system for dissection of chromatin biology due to the relative ease of genetic manipulation and strong conservation of important regulatory proteins with higher eukaryotes. Telomeres and the telomere-binding shelterin complex are highly conserved with mammals, as is the assembly of constitutive heterochromatin at subtelomeres. In this review, we seek to summarize recent work detailing the assembly of distinct chromatin structures within subtelomeric domains in fission yeast. These include the heterochromatic SH subtelomeric domains, the telomere-associated sequences (TAS), and ST chromatin domains that assemble highly condensed chromatin clusters called knobs. Specifically, we review new insights into the sequence of subtelomeric domains, the distinct types of chromatin that assemble on these sequences and how histone H3 K36 modifications influence these chromatin structures. We address the interplay between the subdomains of chromatin structure and how subtelomeric chromatin is influenced by both the telomere-bound shelterin complexes and by euchromatic chromatin regulators internal to the subtelomeric domain. Finally, we demonstrate that telomere clustering, which is mediated via the condensed ST chromatin knob domains, does not depend on knob assembly within these domains but on Set2, which mediates H3K36 methylation.
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7
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Lowe BR, Yadav RK, Henry RA, Schreiner P, Matsuda A, Fernandez AG, Finkelstein D, Campbell M, Kallappagoudar S, Jablonowski CM, Andrews AJ, Hiraoka Y, Partridge JF. Surprising phenotypic diversity of cancer-associated mutations of Gly 34 in the histone H3 tail. eLife 2021; 10:e65369. [PMID: 33522486 PMCID: PMC7872514 DOI: 10.7554/elife.65369] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 01/30/2021] [Indexed: 12/11/2022] Open
Abstract
Sequencing of cancer genomes has identified recurrent somatic mutations in histones, termed oncohistones, which are frequently poorly understood. Previously we showed that fission yeast expressing only the H3.3G34R mutant identified in aggressive pediatric glioma had reduced H3K36 trimethylation and acetylation, increased genomic instability and replicative stress, and defective homology-dependent DNA damage repair. Here we show that surprisingly distinct phenotypes result from G34V (also in glioma) and G34W (giant cell tumors of bone) mutations, differentially affecting H3K36 modifications, subtelomeric silencing, genomic stability; sensitivity to irradiation, alkylating agents, and hydroxyurea; and influencing DNA repair. In cancer, only 1 of 30 alleles encoding H3 is mutated. Whilst co-expression of wild-type H3 rescues most G34 mutant phenotypes, G34R causes dominant hydroxyurea sensitivity, homologous recombination defects, and dominant subtelomeric silencing. Together, these studies demonstrate the complexity associated with different substitutions at even a single residue in H3 and highlight the utility of genetically tractable systems for their analysis.
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Affiliation(s)
- Brandon R Lowe
- Department of Pathology, St. Jude Children’s Research HospitalMemphisUnited States
| | - Rajesh K Yadav
- Department of Pathology, St. Jude Children’s Research HospitalMemphisUnited States
| | - Ryan A Henry
- Department of Cancer Biology, Fox Chase Cancer CenterPhiladelphiaUnited States
| | - Patrick Schreiner
- Department of Bioinformatics, St. Jude Children’s Research HospitalMemphisUnited States
| | - Atsushi Matsuda
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications TechnologyKobeJapan
- Graduate School of Frontier Biosciences, Osaka UniversitySuitaJapan
| | - Alfonso G Fernandez
- Department of Pathology, St. Jude Children’s Research HospitalMemphisUnited States
| | - David Finkelstein
- Department of Bioinformatics, St. Jude Children’s Research HospitalMemphisUnited States
| | - Margaret Campbell
- Department of Pathology, St. Jude Children’s Research HospitalMemphisUnited States
| | | | | | - Andrew J Andrews
- Department of Cancer Biology, Fox Chase Cancer CenterPhiladelphiaUnited States
| | - Yasushi Hiraoka
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications TechnologyKobeJapan
- Graduate School of Frontier Biosciences, Osaka UniversitySuitaJapan
| | - Janet F Partridge
- Department of Pathology, St. Jude Children’s Research HospitalMemphisUnited States
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8
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High-Throughput Flow Cytometry Combined with Genetic Analysis Brings New Insights into the Understanding of Chromatin Regulation of Cellular Quiescence. Int J Mol Sci 2020; 21:ijms21239022. [PMID: 33260998 PMCID: PMC7729564 DOI: 10.3390/ijms21239022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/19/2020] [Accepted: 11/23/2020] [Indexed: 11/21/2022] Open
Abstract
Cellular quiescence is a reversible differentiation state when cells are changing the gene expression program to reduce metabolic functions and adapt to a new cellular environment. When fission yeast cells are deprived of nitrogen in the absence of any mating partner, cells can reversibly arrest in a differentiated G0-like cellular state, called quiescence. This change is accompanied by a marked alteration of nuclear organization and a global reduction of transcription. Using high-throughput flow cytometry combined with genetic analysis, we describe the results of a comprehensive screen for genes encoding chromatin components and regulators that are required for the entry and the maintenance of cellular quiescence. We show that the histone acetylase and deacetylase complexes, SAGA and Rpd3, have key roles both for G0 entry and survival during quiescence. We reveal a novel function for the Ino80 nucleosome remodeling complex in cellular quiescence. Finally, we demonstrate that components of the MRN complex, Rad3, the nonhomologous end-joining, and nucleotide excision DNA repair pathways are essential for viability in G0.
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9
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Kalinka A, Achrem M. The distribution pattern of 5-methylcytosine in rye (Secale L.) chromosomes. PLoS One 2020; 15:e0240869. [PMID: 33057421 PMCID: PMC7561101 DOI: 10.1371/journal.pone.0240869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 10/04/2020] [Indexed: 12/02/2022] Open
Abstract
The rye (Secale L.) genome is large, and it contains many classes of repetitive sequences. Secale species differ in terms of genome size, heterochromatin content, and global methylation level; however, the organization of individual types of sequences in chromosomes is relatively similar. The content of the abundant subtelomeric heterochromatin fraction in rye do not correlate with the global level of cytosine methylation, hence immunofluorescence detection of 5-methylcytosine (5-mC) distribution in metaphase chromosomes was performed. The distribution patterns of 5-methylcytosine in the chromosomes of Secale species/subspecies were generally similar. 5-methylcytosine signals were dispersed along the entire length of the chromosome arms of all chromosomes, indicating high levels of methylation, especially at retrotransposon sequences. 5-mC signals were absent in the centromeric and telomeric regions, as well as in subtelomeric blocks of constitutive heterochromatin, in each of the taxa studied. Pericentromeric domains were methylated, however, there was a certain level of polymorphism in these areas, as was the case with the nucleolus organizer region. Sequence methylation within the region of the heterochromatin intercalary bands were also demonstrated to be heterogenous. Unexpectedly, there was a lack of methylation in rye subtelomeres, indicating that heterochromatin is a very diverse fraction of chromatin, and its epigenetic regulation or potential influence on adjacent regions can be more complex than has conventionally been thought. Like telomeres and centromeres, subtelomeric heterochromatin can has a specific role, and the absence of 5-mC is required to maintain the heterochromatin state.
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Affiliation(s)
- Anna Kalinka
- Institute of Biology, University of Szczecin, Szczecin, Poland
- Molecular Biology and Biotechnology Center, University of Szczecin, Szczecin, Poland
- * E-mail:
| | - Magdalena Achrem
- Institute of Biology, University of Szczecin, Szczecin, Poland
- Molecular Biology and Biotechnology Center, University of Szczecin, Szczecin, Poland
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10
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Nuclear Envelope Proteins Modulating the Heterochromatin Formation and Functions in Fission Yeast. Cells 2020; 9:cells9081908. [PMID: 32824370 PMCID: PMC7464478 DOI: 10.3390/cells9081908] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/14/2020] [Accepted: 08/15/2020] [Indexed: 12/16/2022] Open
Abstract
The nuclear envelope (NE) consists of the inner and outer nuclear membranes (INM and ONM), and the nuclear pore complex (NPC), which penetrates the double membrane. ONM continues with the endoplasmic reticulum (ER). INM and NPC can interact with chromatin to regulate the genetic activities of the chromosome. Studies in the fission yeast Schizosaccharomyces pombe have contributed to understanding the molecular mechanisms underlying heterochromatin formation by the RNAi-mediated and histone deacetylase machineries. Recent studies have demonstrated that NE proteins modulate heterochromatin formation and functions through interactions with heterochromatic regions, including the pericentromeric and the sub-telomeric regions. In this review, we first introduce the molecular mechanisms underlying the heterochromatin formation and functions in fission yeast, and then summarize the NE proteins that play a role in anchoring heterochromatic regions and in modulating heterochromatin formation and functions, highlighting roles for a conserved INM protein, Lem2.
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11
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NAP1-RELATED PROTEIN1 and 2 negatively regulate H2A.Z abundance in chromatin in Arabidopsis. Nat Commun 2020; 11:2887. [PMID: 32513971 PMCID: PMC7280298 DOI: 10.1038/s41467-020-16691-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 05/20/2020] [Indexed: 12/22/2022] Open
Abstract
In eukaryotes, DNA wraps around histones to form nucleosomes, which are compacted into chromatin. DNA-templated processes, including transcription, require chromatin disassembly and reassembly mediated by histone chaperones. Additionally, distinct histone variants can replace core histones to regulate chromatin structure and function. Although replacement of H2A with the evolutionarily conserved H2A.Z via the SWR1 histone chaperone complex has been extensively studied, in plants little is known about how a reduction of H2A.Z levels can be achieved. Here, we show that NRP proteins cause a decrease of H2A.Z-containing nucleosomes in Arabidopsis under standard growing conditions. nrp1-1 nrp2-2 double mutants show an over-accumulation of H2A.Z genome-wide, especially at heterochromatic regions normally H2A.Z-depleted in wild-type plants. Our work suggests that NRP proteins regulate gene expression by counteracting SWR1, thereby preventing excessive accumulation of H2A.Z. The histone variant H2A.Z is deposited by the SWR1 complex to replace H2A in Arabidopsis, but the mechanism of H2A.Z removal is unclear. Here, the authors show that NRP proteins can regulate gene expression by counteracting SWR1 and prevent excessive accumulation of H2A.Z.
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12
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Hocher A, Taddei A. Subtelomeres as Specialized Chromatin Domains. Bioessays 2020; 42:e1900205. [PMID: 32181520 DOI: 10.1002/bies.201900205] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 02/19/2020] [Indexed: 12/26/2022]
Abstract
Specificities associated with chromosomal linearity are not restricted to telomeres. Here, recent results obtained on fission and budding yeast are summarized and an attempt is made to define subtelomeres using chromatin features extending beyond the heterochromatin emanating from telomeres. Subtelomeres, the chromosome domains adjacent to telomeres, differ from the rest of the genome by their gene content, rapid evolution, and chromatin features that together contribute to organism adaptation. However, current definitions of subtelomeres are generally based on synteny and are largely gene-centered. Taking into consideration both the peculiar gene content and dynamics as well as the chromatin properties of those domains, it is discussed how chromatin features can contribute to subtelomeric properties and functions, and play a pivotal role in the emergence of subtelomeres.
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Affiliation(s)
- Antoine Hocher
- MRC London Institute of Medical Sciences (LMS), Du Cane Road, London, W12 0NN, UK.,Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Angela Taddei
- Institut Curie, PSL Research University, CNRS, UMR3664, Paris, F-75005, France.,Sorbonne Université, UPMC University Paris 06, CNRS, UMR3664, Paris, F-75005, France
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13
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Murawska M, Schauer T, Matsuda A, Wilson MD, Pysik T, Wojcik F, Muir TW, Hiraoka Y, Straub T, Ladurner AG. The Chaperone FACT and Histone H2B Ubiquitination Maintain S. pombe Genome Architecture through Genic and Subtelomeric Functions. Mol Cell 2020; 77:501-513.e7. [PMID: 31837996 PMCID: PMC7007867 DOI: 10.1016/j.molcel.2019.11.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 10/01/2019] [Accepted: 11/15/2019] [Indexed: 12/31/2022]
Abstract
The histone chaperone FACT and histone H2B ubiquitination (H2Bub) facilitate RNA polymerase II (Pol II) passage through chromatin, yet it is not clear how they cooperate mechanistically. We used genomics, genetic, biochemical, and microscopic approaches to dissect their interplay in Schizosaccharomyces pombe. We show that FACT and H2Bub globally repress antisense transcripts near the 5' end of genes and inside gene bodies, respectively. The accumulation of these transcripts is accompanied by changes at genic nucleosomes and Pol II redistribution. H2Bub is required for FACT activity in genic regions. In the H2Bub mutant, FACT binding to chromatin is altered and its association with histones is stabilized, which leads to the reduction of genic nucleosomes. Interestingly, FACT depletion globally restores nucleosomes in the H2Bub mutant. Moreover, in the absence of Pob3, the FACT Spt16 subunit controls the 3' end of genes. Furthermore, FACT maintains nucleosomes in subtelomeric regions, which is crucial for their compaction.
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Affiliation(s)
- Magdalena Murawska
- Biomedical Center, Physiological Chemistry, Ludwig-Maximilians-University of Munich, 82152 Planegg-Martinsried, Germany
| | - Tamas Schauer
- Biomedical Center, Bioinformatics Unit, Ludwig-Maximilians-University of Munich, 82152 Planegg-Martinsried, Germany
| | - Atsushi Matsuda
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan; Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan
| | - Marcus D Wilson
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Mayfield Road, Edinburgh EH9 3JR, UK
| | - Thomas Pysik
- Biomedical Center, Physiological Chemistry, Ludwig-Maximilians-University of Munich, 82152 Planegg-Martinsried, Germany
| | - Felix Wojcik
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Tom W Muir
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Yasushi Hiraoka
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan; Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan
| | - Tobias Straub
- Biomedical Center, Bioinformatics Unit, Ludwig-Maximilians-University of Munich, 82152 Planegg-Martinsried, Germany
| | - Andreas G Ladurner
- Biomedical Center, Physiological Chemistry, Ludwig-Maximilians-University of Munich, 82152 Planegg-Martinsried, Germany.
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14
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Kwapisz M, Morillon A. Subtelomeric Transcription and its Regulation. J Mol Biol 2020; 432:4199-4219. [PMID: 32035903 PMCID: PMC7374410 DOI: 10.1016/j.jmb.2020.01.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 01/14/2020] [Accepted: 01/14/2020] [Indexed: 12/13/2022]
Abstract
The subtelomeres, highly heterogeneous repeated sequences neighboring telomeres, are transcribed into coding and noncoding RNAs in a variety of organisms. Telomereproximal subtelomeric regions produce non-coding transcripts i.e., ARRET, αARRET, subTERRA, and TERRA, which function in telomere maintenance. The role and molecular mechanisms of the majority of subtelomeric transcripts remain unknown. This review depicts the current knowledge and puts into perspective the results obtained in different models from yeasts to humans.
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Affiliation(s)
- Marta Kwapisz
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, France
| | - Antonin Morillon
- ncRNA, Epigenetic and Genome Fluidity, CNRS UMR 3244, Sorbonne Université, PSL University, Institut Curie, Centre de Recherche, 26 rue d'Ulm, 75248, Paris, France.
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15
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Yamada S, Kugou K, Ding DQ, Fujita Y, Hiraoka Y, Murakami H, Ohta K, Yamada T. The histone variant H2A.Z promotes initiation of meiotic recombination in fission yeast. Nucleic Acids Res 2019; 46:609-620. [PMID: 29145618 PMCID: PMC5778600 DOI: 10.1093/nar/gkx1110] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 10/25/2017] [Indexed: 01/13/2023] Open
Abstract
Meiotic recombination is initiated by programmed formation of DNA double strand breaks (DSBs), which are mainly formed at recombination hotspots. Meiotic DSBs require multiple proteins including the conserved protein Spo11 and its cofactors, and are influenced by chromatin structure. For example, local chromatin around hotspots directly impacts DSB formation. Moreover, DSB is proposed to occur in a higher-order chromatin architecture termed 'axis-loop', in which many loops protrude from cohesin-enriched axis. However, still much remains unknown about how meiotic DSBs are generated in chromatin. Here, we show that the conserved histone H2A variant H2A.Z promotes meiotic DSB formation in fission yeast. Detailed investigation revealed that H2A.Z is neither enriched around hotspots nor axis sites, and that transcript levels of DSB-promoting factors were maintained without H2A.Z. Moreover, H2A.Z appeared to be dispensable for chromatin binding of meiotic cohesin. Instead, in H2A.Z-lacking mutants, multiple proteins involved in DSB formation, such as the fission yeast Spo11 homolog and its regulators, were less associated with chromatin. Remarkably, nuclei were more compact in the absence of H2A.Z. Based on these, we propose that fission yeast H2A.Z promotes meiotic DSB formation partly through modulating chromosome architecture to enhance interaction between DSB-related proteins and cohesin-loaded chromatin.
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Affiliation(s)
- Shintaro Yamada
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
| | - Kazuto Kugou
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
| | - Da-Qiao Ding
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
| | - Yurika Fujita
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
| | - Yasushi Hiraoka
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan.,Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
| | - Hiroshi Murakami
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, Tokyo 112-8551, Japan
| | - Kunihiro Ohta
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
| | - Takatomi Yamada
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, Tokyo 112-8551, Japan
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16
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Giaimo BD, Ferrante F, Herchenröther A, Hake SB, Borggrefe T. The histone variant H2A.Z in gene regulation. Epigenetics Chromatin 2019; 12:37. [PMID: 31200754 PMCID: PMC6570943 DOI: 10.1186/s13072-019-0274-9] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 04/23/2019] [Indexed: 01/04/2023] Open
Abstract
The histone variant H2A.Z is involved in several processes such as transcriptional control, DNA repair, regulation of centromeric heterochromatin and, not surprisingly, is implicated in diseases such as cancer. Here, we review the recent developments on H2A.Z focusing on its role in transcriptional activation and repression. H2A.Z, as a replication-independent histone, has been studied in several model organisms and inducible mammalian model systems. Its loading machinery and several modifying enzymes have been recently identified, and some of the long-standing discrepancies in transcriptional activation and/or repression are about to be resolved. The buffering functions of H2A.Z, as supported by genome-wide localization and analyzed in several dynamic systems, are an excellent example of transcriptional control. Posttranslational modifications such as acetylation and ubiquitination of H2A.Z, as well as its specific binding partners, are in our view central players in the control of gene expression. Understanding the key-mechanisms in either turnover or stabilization of H2A.Z-containing nucleosomes as well as defining the H2A.Z interactome will pave the way for therapeutic applications in the future.
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Affiliation(s)
| | - Francesca Ferrante
- Institute of Biochemistry, University of Giessen, Friedrichstrasse 24, 35392, Giessen, Germany
| | - Andreas Herchenröther
- Institute for Genetics, University of Giessen, Heinrich-Buff-Ring 58-62, 35392, Giessen, Germany
| | - Sandra B Hake
- Institute for Genetics, University of Giessen, Heinrich-Buff-Ring 58-62, 35392, Giessen, Germany
| | - Tilman Borggrefe
- Institute of Biochemistry, University of Giessen, Friedrichstrasse 24, 35392, Giessen, Germany.
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17
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The histone chaperone NAP1L3 is required for haematopoietic stem cell maintenance and differentiation. Sci Rep 2018; 8:11202. [PMID: 30046127 PMCID: PMC6060140 DOI: 10.1038/s41598-018-29518-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 07/12/2018] [Indexed: 01/04/2023] Open
Abstract
Nucleosome assembly proteins (NAPs) are histone chaperones with an important role in chromatin structure and epigenetic regulation of gene expression. We find that high gene expression levels of mouse Nap1l3 are restricted to haematopoietic stem cells (HSCs) in mice. Importantly, with shRNA or CRISPR-Cas9 mediated loss of function of mouse Nap1l3 and with overexpression of the gene, the number of colony-forming cells and myeloid progenitor cells in vitro are reduced. This manifests as a striking decrease in the number of HSCs, which reduces their reconstituting activities in vivo. Downregulation of human NAP1L3 in umbilical cord blood (UCB) HSCs impairs the maintenance and proliferation of HSCs both in vitro and in vivo. NAP1L3 downregulation in UCB HSCs causes an arrest in the G0 phase of cell cycle progression and induces gene expression signatures that significantly correlate with downregulation of gene sets involved in cell cycle regulation, including E2F and MYC target genes. Moreover, we demonstrate that HOXA3 and HOXA5 genes are markedly upregulated when NAP1L3 is suppressed in UCB HSCs. Taken together, our findings establish an important role for NAP1L3 in HSC homeostasis and haematopoietic differentiation.
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18
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Seo HD, Kwon CS, Lee D. The 19S proteasome regulates subtelomere silencing and facultative heterochromatin formation in fission yeast. Curr Genet 2017; 64:741-752. [PMID: 29214404 DOI: 10.1007/s00294-017-0792-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/14/2017] [Accepted: 11/27/2017] [Indexed: 12/27/2022]
Abstract
Accumulating evidence shows that non-proteolytic functions of the proteasome are as crucial as its well-known proteolytic function in regulating cellular activities. In our recent work, we showed that the 19S proteasome mediates the heterochromatin spreading of centromeric heterochromatin in non-proteolytic manner. However, the involvement of the proteasome in other heterochromatin regions remained largely unknown. In the present study, we investigated the non-proteolytic role of the 19S proteasome in subtelomere and facultative heterochromatin regions. Using the non-proteolytic mutant, rpt4-1, we show that the 19S proteasome is involved in regulating subtelomere silencing and facultative heterochromatin formation in fission yeast. In addition to this proteasome-related regulation, we also observed a distinct pathway that regulates subtelomere silencing and facultative heterochromatin formation through the Paf1 complex subunit, Leo1. Our comparison of the two pathways revealed a new group of heterochromatin domains that are regulated exclusively by the proteasome pathway. Taken together, our findings reveal that the proteasome is involved in the global regulation of facultative and constitutive heterochromatin.
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Affiliation(s)
- Hogyu David Seo
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea
| | - Chang Seob Kwon
- Department of Chemistry and Biology, Korea Science Academy of KAIST, Busan, 47162, South Korea
| | - Daeyoup Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea.
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19
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Tashiro S, Nishihara Y, Kugou K, Ohta K, Kanoh J. Subtelomeres constitute a safeguard for gene expression and chromosome homeostasis. Nucleic Acids Res 2017; 45:10333-10349. [PMID: 28981863 PMCID: PMC5737222 DOI: 10.1093/nar/gkx780] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 08/28/2017] [Indexed: 12/19/2022] Open
Abstract
The subtelomere, a telomere-adjacent chromosomal domain, contains species-specific homologous DNA sequences, in addition to various genes. However, the functions of subtelomeres, particularly subtelomeric homologous (SH) sequences, remain elusive. Here, we report the first comprehensive analyses of the cellular functions of SH sequences in the fission yeast, Schizosaccharomyces pombe. Complete removal of SH sequences from the genome revealed that they are dispensable for mitosis, meiosis and telomere length control. However, when telomeres are lost, SH sequences prevent deleterious inter-chromosomal end fusion by facilitating intra-chromosomal circularization. Surprisingly, SH-deleted cells sometimes survive telomere loss through inter-chromosomal end fusions via homologous loci such as LTRs, accompanied by centromere inactivation of either chromosome. Moreover, SH sequences function as a buffer region against the spreading of subtelomeric heterochromatin into the neighboring gene-rich regions. Furthermore, we found a nucleosome-free region at the subtelomeric border, which may be a second barrier that blocks heterochromatin spreading into the subtelomere-adjacent euchromatin. Thus, our results demonstrate multiple defense functions of subtelomeres in chromosome homeostasis and gene expression.
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Affiliation(s)
- Sanki Tashiro
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yuki Nishihara
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kazuto Kugou
- Department of Life Sciences, University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Kunihiro Ohta
- Department of Life Sciences, University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Junko Kanoh
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
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20
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The Ino80 complex mediates epigenetic centromere propagation via active removal of histone H3. Nat Commun 2017; 8:529. [PMID: 28904333 PMCID: PMC5597579 DOI: 10.1038/s41467-017-00704-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 07/19/2017] [Indexed: 12/25/2022] Open
Abstract
The centromere is the chromosomal locus at which the kinetochore is assembled to direct chromosome segregation. The histone H3 variant, centromere protein A (CENP-A), is known to epigenetically mark active centromeres, but the mechanism by which CENP-A propagates at the centromere, replacing histone H3, remains poorly understood. Using fission yeast, here we show that the Ino80 adenosine triphosphate (ATP)-dependent chromatin-remodeling complex, which removes histone H3-containing nucleosomes from associated chromatin, promotes CENP-ACnp1 chromatin assembly at the centromere in a redundant manner with another chromatin-remodeling factor Chd1Hrp1. CENP-ACnp1 chromatin actively recruits the Ino80 complex to centromeres to elicit eviction of histone H3-containing nucleosomes. Artificial targeting of Ino80 subunits to a non-centromeric DNA sequence placed in a native centromere enhances the spreading of CENP-ACnp1 chromatin into the non-centromeric DNA. Based on these results, we propose that CENP-ACnp1 chromatin employs the Ino80 complex to mediate the replacement of histone H3 with CENP-ACnp1, and thereby reinforces itself. The histone variant CENP-A marks active centromeres and replaces H3 at centromeres through a poorly understood mechanism. Here, the authors provide evidence that the chromatin remodeller Ino80 promotes CENP-A chromatin assembly at the centromere in fission yeast.
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21
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Yadav RK, Jablonowski CM, Fernandez AG, Lowe BR, Henry RA, Finkelstein D, Barnum KJ, Pidoux AL, Kuo YM, Huang J, O’Connell MJ, Andrews AJ, Onar-Thomas A, Allshire RC, Partridge JF. Histone H3G34R mutation causes replication stress, homologous recombination defects and genomic instability in S. pombe. eLife 2017; 6:e27406. [PMID: 28718400 PMCID: PMC5515577 DOI: 10.7554/elife.27406] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 06/20/2017] [Indexed: 12/12/2022] Open
Abstract
Recurrent somatic mutations of H3F3A in aggressive pediatric high-grade gliomas generate K27M or G34R/V mutant histone H3.3. H3.3-G34R/V mutants are common in tumors with mutations in p53 and ATRX, an H3.3-specific chromatin remodeler. To gain insight into the role of H3-G34R, we generated fission yeast that express only the mutant histone H3. H3-G34R specifically reduces H3K36 tri-methylation and H3K36 acetylation, and mutants show partial transcriptional overlap with set2 deletions. H3-G34R mutants exhibit genomic instability and increased replication stress, including slowed replication fork restart, although DNA replication checkpoints are functional. H3-G34R mutants are defective for DNA damage repair by homologous recombination (HR), and have altered HR protein dynamics in both damaged and untreated cells. These data suggest H3-G34R slows resolution of HR-mediated repair and that unresolved replication intermediates impair chromosome segregation. This analysis of H3-G34R mutant fission yeast provides mechanistic insight into how G34R mutation may promote genomic instability in glioma.
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Affiliation(s)
- Rajesh K Yadav
- Department of Pathology, St. Jude Children’s Research Hospital, Memphis, United States
| | - Carolyn M Jablonowski
- Department of Pathology, St. Jude Children’s Research Hospital, Memphis, United States
| | - Alfonso G Fernandez
- Department of Pathology, St. Jude Children’s Research Hospital, Memphis, United States
| | - Brandon R Lowe
- Department of Pathology, St. Jude Children’s Research Hospital, Memphis, United States
| | - Ryan A Henry
- Department of Cancer Biology, Fox Chase Cancer Center, Philadelphia, United States
| | - David Finkelstein
- Department of Bioinformatics, St. Jude Children’s Research Hospital, Memphis, United States
| | - Kevin J Barnum
- Department of Oncological Sciences and Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Alison L Pidoux
- Wellcome Trust School for Biological Sciences, University of Edinburgh, Edinburgh, Scotland
| | - Yin-Ming Kuo
- Department of Cancer Biology, Fox Chase Cancer Center, Philadelphia, United States
| | - Jie Huang
- Department of Biostatistics, St. Jude Children’s Research Hospital, Memphis, United States
| | - Matthew J O’Connell
- Department of Oncological Sciences and Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Andrew J Andrews
- Department of Cancer Biology, Fox Chase Cancer Center, Philadelphia, United States
| | - Arzu Onar-Thomas
- Department of Biostatistics, St. Jude Children’s Research Hospital, Memphis, United States
| | - Robin C Allshire
- Wellcome Trust School for Biological Sciences, University of Edinburgh, Edinburgh, Scotland
| | - Janet F Partridge
- Department of Pathology, St. Jude Children’s Research Hospital, Memphis, United States
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22
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Matsuda A, Asakawa H, Haraguchi T, Hiraoka Y. Spatial organization of the Schizosaccharomyces pombe genome within the nucleus. Yeast 2016; 34:55-66. [PMID: 27766670 DOI: 10.1002/yea.3217] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 10/06/2016] [Accepted: 10/13/2016] [Indexed: 12/14/2022] Open
Abstract
The fission yeast Schizosaccharomyces pombe is a useful experimental system for studying the organization of chromosomes within the cell nucleus. S. pombe has a small genome that is organized into three chromosomes. The small size of the genome and the small number of chromosomes are advantageous for cytological and genome-wide studies of chromosomes; however, the small size of the nucleus impedes microscopic observations owing to limits in spatial resolution during imaging. Recent advances in microscopy, such as super-resolution microscopy, have greatly expanded the use of S. pombe as a model organism in a wide range of studies. In addition, biochemical studies, such as chromatin immunoprecipitation and chromosome conformation capture, have provided complementary approaches. Here, we review the spatial organization of the S. pombe genome as determined by a combination of cytological and biochemical studies. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Atsushi Matsuda
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Haruhiko Asakawa
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
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23
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Verrier L, Taglini F, Barrales RR, Webb S, Urano T, Braun S, Bayne EH. Global regulation of heterochromatin spreading by Leo1. Open Biol 2016; 5:rsob.150045. [PMID: 25972440 PMCID: PMC4450266 DOI: 10.1098/rsob.150045] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Heterochromatin plays important roles in eukaryotic genome regulation. However, the repressive nature of heterochromatin combined with its propensity to self-propagate necessitates robust mechanisms to contain heterochromatin within defined boundaries and thus prevent silencing of expressed genes. Here we show that loss of the PAF complex (PAFc) component Leo1 compromises chromatin boundaries, resulting in invasion of heterochromatin into flanking euchromatin domains. Similar effects are seen upon deletion of other PAFc components, but not other factors with related functions in transcription-associated chromatin modification, indicating a specific role for PAFc in heterochromatin regulation. Loss of Leo1 results in reduced levels of H4K16 acetylation at boundary regions, while tethering of the H4K16 acetyltransferase Mst1 to boundary chromatin suppresses heterochromatin spreading in leo1Δ cells, suggesting that Leo1 antagonises heterochromatin spreading by promoting H4K16 acetylation. Our findings reveal a previously undescribed role for PAFc in regulating global heterochromatin distribution.
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Affiliation(s)
- Laure Verrier
- Institute of Cell Biology, University of Edinburgh, Edinburgh, UK
| | | | - Ramon R Barrales
- Butenandt Institute of Physiological Chemistry, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Shaun Webb
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Takeshi Urano
- Department of Biochemistry, Faculty of Medicine, Shimane University, Izumo, Japan
| | - Sigurd Braun
- Butenandt Institute of Physiological Chemistry, Ludwig-Maximilians-Universität München, Munich, Germany
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24
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Shugoshin forms a specialized chromatin domain at subtelomeres that regulates transcription and replication timing. Nat Commun 2016; 7:10393. [PMID: 26804021 PMCID: PMC4737732 DOI: 10.1038/ncomms10393] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 12/07/2015] [Indexed: 01/11/2023] Open
Abstract
A chromosome is composed of structurally and functionally distinct domains. However, the molecular mechanisms underlying the formation of chromatin structure and the function of subtelomeres, the telomere-adjacent regions, remain obscure. Here we report the roles of the conserved centromeric protein Shugoshin 2 (Sgo2) in defining chromatin structure and functions of the subtelomeres in the fission yeast Schizosaccharomyces pombe. We show that Sgo2 localizes at the subtelomeres preferentially during G2 phase and is essential for the formation of a highly condensed subtelomeric chromatin body 'knob'. Furthermore, the absence of Sgo2 leads to the derepression of the subtelomeric genes and premature DNA replication at the subtelomeric late origins. Thus, the subtelomeric specialized chromatin domain organized by Sgo2 represses both transcription and replication to ensure proper gene expression and replication timing.
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25
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Escape from Mitotic Arrest: An Unexpected Connection Between Microtubule Dynamics and Epigenetic Regulation of Centromeric Chromatin in Schizosaccharomyces pombe. Genetics 2015; 201:1467-78. [PMID: 26510788 DOI: 10.1534/genetics.115.181792] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/23/2015] [Indexed: 01/02/2023] Open
Abstract
Accurate chromosome segregation is necessary to ensure genomic integrity. Segregation depends on the proper functioning of the centromere, kinetochore, and mitotic spindle microtubules and is monitored by the spindle assembly checkpoint (SAC). In the fission yeast Schizosaccharomyces pombe, defects in Dis1, a microtubule-associated protein that influences microtubule dynamics, lead to mitotic arrest as a result of an active SAC and consequent failure to grow at low temperature. In a mutant dis1 background (dis1-288), loss of function of Msc1, a fission yeast homolog of the KDM5 family of proteins, suppresses the growth defect and promotes normal mitosis. Genetic analysis implicates a histone deacetylase (HDAC)-linked pathway in suppression because HDAC mutants clr6-1, clr3∆, and sir2∆, though not hos2∆, also promote normal mitosis in the dis1-288 mutant. Suppression of the dis phenotype through loss of msc1 function requires the spindle checkpoint protein Mad2 and is limited by the presence of the heterochromatin-associated HP1 protein homolog Swi6. We speculate that alterations in histone acetylation promote a centromeric chromatin environment that compensates for compromised dis1 function by allowing for successful kinetochore-microtubule interactions that can satisfy the SAC. In cells arrested in mitosis by mutation of dis1, loss of function of epigenetic determinants such as Msc1 or specific HDACs can promote cell survival. Because the KDM5 family of proteins has been implicated in human cancers, an appreciation of the potential role of this family of proteins in chromosome segregation is warranted.
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26
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Matsuda A, Chikashige Y, Ding DQ, Ohtsuki C, Mori C, Asakawa H, Kimura H, Haraguchi T, Hiraoka Y. Highly condensed chromatins are formed adjacent to subtelomeric and decondensed silent chromatin in fission yeast. Nat Commun 2015; 6:7753. [PMID: 26205977 PMCID: PMC4525289 DOI: 10.1038/ncomms8753] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 06/08/2015] [Indexed: 11/09/2022] Open
Abstract
It is generally believed that silent chromatin is condensed and transcriptionally active chromatin is decondensed. However, little is known about the relationship between the condensation levels and gene expression. Here we report the condensation levels of interphase chromatin in the fission yeast Schizosaccharomyces pombe examined by super-resolution fluorescence microscopy. Unexpectedly, silent chromatin is less condensed than the euchromatin. Furthermore, the telomeric silent regions are flanked by highly condensed chromatin bodies, or 'knobs'. Knob regions span ∼50 kb of sequence devoid of methylated histones. Knob condensation is independent of HP1 homologue Swi6 and other gene silencing factors. Disruption of methylation at lysine 36 of histone H3 (H3K36) eliminates knob formation and gene repression at the subtelomeric and adjacent knob regions. Thus, epigenetic marks at H3K36 play crucial roles in the formation of a unique chromatin structure and in gene regulation at those regions in S. pombe.
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Affiliation(s)
- Atsushi Matsuda
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2, Iwaoka, Iwaoka-cho, Kobe 651-2492, Japan
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan
| | - Yuji Chikashige
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2, Iwaoka, Iwaoka-cho, Kobe 651-2492, Japan
| | - Da-Qiao Ding
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2, Iwaoka, Iwaoka-cho, Kobe 651-2492, Japan
| | - Chizuru Ohtsuki
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan
| | - Chie Mori
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2, Iwaoka, Iwaoka-cho, Kobe 651-2492, Japan
| | - Haruhiko Asakawa
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan
| | - Hiroshi Kimura
- Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-B, Nagatsuda, Yokohama 226-8501, Japan
| | - Tokuko Haraguchi
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2, Iwaoka, Iwaoka-cho, Kobe 651-2492, Japan
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan
| | - Yasushi Hiraoka
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2, Iwaoka, Iwaoka-cho, Kobe 651-2492, Japan
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan
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Allshire RC, Ekwall K. Epigenetic Regulation of Chromatin States in Schizosaccharomyces pombe. Cold Spring Harb Perspect Biol 2015; 7:a018770. [PMID: 26134317 DOI: 10.1101/cshperspect.a018770] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This article discusses the advances made in epigenetic research using the model organism fission yeast Schizosaccharomyces pombe. S. pombe has been used for epigenetic research since the discovery of position effect variegation (PEV). This is a phenomenon in which a transgene inserted within heterochromatin is variably expressed, but can be stably inherited in subsequent cell generations. PEV occurs at centromeres, telomeres, ribosomal DNA (rDNA) loci, and mating-type regions of S. pombe chromosomes. Heterochromatin assembly in these regions requires enzymes that modify histones and the RNA interference (RNAi) machinery. One of the key histone-modifying enzymes is the lysine methyltransferase Clr4, which methylates histone H3 on lysine 9 (H3K9), a classic hallmark of heterochromatin. The kinetochore is assembled on specialized chromatin in which histone H3 is replaced by the variant CENP-A. Studies in fission yeast have contributed to our understanding of the establishment and maintenance of CENP-A chromatin and the epigenetic activation and inactivation of centromeres.
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Affiliation(s)
- Robin C Allshire
- Wellcome Trust Centre for Cell Biology, The University of Edinburgh, Edinburgh EH9 3JR, Scotland, United Kingdom
| | - Karl Ekwall
- Department of Biosciences and Nutrition, Karolinska Institutet, Center for Biosciences, NOVUM, S-141 83, Huddinge, Sweden
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Steglich B, Strålfors A, Khorosjutina O, Persson J, Smialowska A, Javerzat JP, Ekwall K. The Fun30 chromatin remodeler Fft3 controls nuclear organization and chromatin structure of insulators and subtelomeres in fission yeast. PLoS Genet 2015; 11:e1005101. [PMID: 25798942 PMCID: PMC4370569 DOI: 10.1371/journal.pgen.1005101] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 02/25/2015] [Indexed: 12/21/2022] Open
Abstract
In eukaryotic cells, local chromatin structure and chromatin organization in the nucleus both influence transcriptional regulation. At the local level, the Fun30 chromatin remodeler Fft3 is essential for maintaining proper chromatin structure at centromeres and subtelomeres in fission yeast. Using genome-wide mapping and live cell imaging, we show that this role is linked to controlling nuclear organization of its targets. In fft3∆ cells, subtelomeres lose their association with the LEM domain protein Man1 at the nuclear periphery and move to the interior of the nucleus. Furthermore, genes in these domains are upregulated and active chromatin marks increase. Fft3 is also enriched at retrotransposon-derived long terminal repeat (LTR) elements and at tRNA genes. In cells lacking Fft3, these sites lose their peripheral positioning and show reduced nucleosome occupancy. We propose that Fft3 has a global role in mediating association between specific chromatin domains and the nuclear envelope. In the genome of eukaryotic cells, domains of active and repressive chromatin alternate along the chromosome arms. Insulator elements are necessary to shield these different environments from each other. In the fission yeast Schizosaccharomyces pombe, the chromatin remodeler Fft3 is required to maintain the repressed subtelomeric chromatin. Here we show that Fft3 maintains nucleosome structure of insulator elements at the subtelomeric borders. We also observe that subtelomeres and insulator elements move away from the nuclear envelope in cells lacking Fft3. The nuclear periphery is known to harbor repressive chromatin in many eukaryotes and has been implied in insulator function. Our results suggest that chromatin remodeling through Fft3 is required to maintain proper chromatin structure and nuclear organization of insulator elements.
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Affiliation(s)
- Babett Steglich
- Department of Biosciences and Nutrition; Center for Innovative Medicine, Karolinska Institutet, Novum Building, Huddinge, Sweden
| | - Annelie Strålfors
- Department of Biosciences and Nutrition; Center for Innovative Medicine, Karolinska Institutet, Novum Building, Huddinge, Sweden
| | - Olga Khorosjutina
- Department of Biosciences and Nutrition; Center for Innovative Medicine, Karolinska Institutet, Novum Building, Huddinge, Sweden
| | - Jenna Persson
- Department of Biosciences and Nutrition; Center for Innovative Medicine, Karolinska Institutet, Novum Building, Huddinge, Sweden
| | - Agata Smialowska
- Department of Biosciences and Nutrition; Center for Innovative Medicine, Karolinska Institutet, Novum Building, Huddinge, Sweden
| | - Jean-Paul Javerzat
- Univ. Bordeaux, Institut de Biochimie et Génétique Cellulaires, UMR 5095, Bordeaux, France
- CNRS, Institut de Biochimie et Génétique Cellulaires, UMR 5095, Bordeaux, France
| | - Karl Ekwall
- Department of Biosciences and Nutrition; Center for Innovative Medicine, Karolinska Institutet, Novum Building, Huddinge, Sweden
- * E-mail:
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Abstract
Histones package and compact DNA by assembling into nucleosome core particles. Most histones are synthesized at S phase for rapid deposition behind replication forks. In addition, the replacement of histones deposited during S phase by variants that can be deposited independently of replication provide the most fundamental level of chromatin differentiation. Alternative mechanisms for depositing different variants can potentially establish and maintain epigenetic states. Variants have also evolved crucial roles in chromosome segregation, transcriptional regulation, DNA repair, and other processes. Investigations into the evolution, structure, and metabolism of histone variants provide a foundation for understanding the participation of chromatin in important cellular processes and in epigenetic memory.
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Affiliation(s)
- Steven Henikoff
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024
| | - M Mitchell Smith
- Department of Microbiology, University of Virginia, Charlottesville, Virginia 22908
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30
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Nucleosome positioning in yeasts: methods, maps, and mechanisms. Chromosoma 2014; 124:131-51. [PMID: 25529773 DOI: 10.1007/s00412-014-0501-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 01/23/2023]
Abstract
Eukaryotic nuclear DNA is packaged into nucleosomes. During the past decade, genome-wide nucleosome mapping across species revealed the high degree of order in nucleosome positioning. There is a conserved stereotypical nucleosome organization around transcription start sites (TSSs) with a nucleosome-depleted region (NDR) upstream of the TSS and a TSS-aligned regular array of evenly spaced nucleosomes downstream over the gene body. As nucleosomes largely impede access to DNA and thereby provide an important level of genome regulation, it is of general interest to understand the mechanisms generating nucleosome positioning and especially the stereotypical NDR-array pattern. We focus here on the most advanced models, unicellular yeasts, and review the progress in mapping nucleosomes and which nucleosome positioning mechanisms are discussed. There are four mechanistic aspects: How are NDRs generated? How are individual nucleosomes positioned, especially those flanking the NDRs? How are nucleosomes evenly spaced leading to regular arrays? How are regular arrays aligned at TSSs? The main candidates for nucleosome positioning determinants are intrinsic DNA binding preferences of the histone octamer, specific DNA binding factors, nucleosome remodeling enzymes, transcription, and statistical positioning. We summarize the state of the art in an integrative model where nucleosomes are positioned by a combination of all these candidate determinants. We highlight the predominance of active mechanisms involving nucleosome remodeling enzymes which may be recruited by DNA binding factors and the transcription machinery. While this mechanistic framework emerged clearly during recent years, the involved factors and their mechanisms are still poorly understood and require future efforts combining in vivo and in vitro approaches.
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'Memory and molecular turnover,' 30 years after inception. Epigenetics Chromatin 2014; 7:37. [PMID: 25525471 PMCID: PMC4269865 DOI: 10.1186/1756-8935-7-37] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 11/28/2014] [Indexed: 12/28/2022] Open
Abstract
In 1984 Sir Francis Crick hypothesized that memory is recorded in the brain as reversible modifications to DNA and protein, but acknowledged that most biomolecules turn over too rapidly to account for long-term memories. To accommodate this possible paradox he modeled an enzymatic mechanism to maintain modifications on hemi-modified multimeric symmetrical molecules. While studies on the turnover of chromatin modifications that may be involved in memory are in their infancy, an exploration of his model in the light of modern epigenetics produced somewhat surprising results. The molecular turnover rates for two classes of chromatin modifications believed to record and store durable memories were approximated from experiments using diverse approaches and were found to be remarkably short. The half-lives of DNA cytosine methylation and post-translationally modified nucleosomal histones are measured in hours and minutes, respectively, for a subset of sites on chromatin controlling gene expression. It appears likely that the turnover of DNA methylation in the brain and in neurons, in particular, is even more rapid than in other cell types and organs, perhaps accommodating neuronal plasticity, learning, and memory. The machinery responsible for the rapid turnover of DNA methylation and nucleosomal histone modifications is highly complex, partially redundant, and appears to act in a sequence specific manner. Molecular symmetry plays an important part in maintaining site-specific turnover, but its particular role in memory maintenance is unknown. Elucidating Crick’s paradox, the contradiction between rapid molecular turnover of modified biomolecules and long-term memory storage, appears fundamental to understanding cognitive function and neurodegenerative disease.
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32
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Clément-Ziza M, Marsellach FX, Codlin S, Papadakis MA, Reinhardt S, Rodríguez-López M, Martin S, Marguerat S, Schmidt A, Lee E, Workman CT, Bähler J, Beyer A. Natural genetic variation impacts expression levels of coding, non-coding, and antisense transcripts in fission yeast. Mol Syst Biol 2014; 10:764. [PMID: 25432776 PMCID: PMC4299605 DOI: 10.15252/msb.20145123] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Our current understanding of how natural genetic variation affects gene expression beyond
well-annotated coding genes is still limited. The use of deep sequencing technologies for the study
of expression quantitative trait loci (eQTLs) has the potential to close this gap. Here, we
generated the first recombinant strain library for fission yeast and conducted an RNA-seq-based QTL
study of the coding, non-coding, and antisense transcriptomes. We show that the frequency of distal
effects (trans-eQTLs) greatly exceeds the number of local effects
(cis-eQTLs) and that non-coding RNAs are as likely to be affected by eQTLs as
protein-coding RNAs. We identified a genetic variation of swc5 that modifies the
levels of 871 RNAs, with effects on both sense and antisense transcription, and show that this
effect most likely goes through a compromised deposition of the histone variant H2A.Z. The strains,
methods, and datasets generated here provide a rich resource for future studies.
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Affiliation(s)
- Mathieu Clément-Ziza
- Biotechnology Centre, Technische Universität Dresden, Dresden, Germany Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Francesc X Marsellach
- Department of Genetics, Evolution & Environment and UCL Genetics Institute, University College London, London, UK
| | - Sandra Codlin
- Department of Genetics, Evolution & Environment and UCL Genetics Institute, University College London, London, UK
| | - Manos A Papadakis
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Susanne Reinhardt
- Biotechnology Centre, Technische Universität Dresden, Dresden, Germany
| | - María Rodríguez-López
- Department of Genetics, Evolution & Environment and UCL Genetics Institute, University College London, London, UK
| | - Stuart Martin
- Department of Genetics, Evolution & Environment and UCL Genetics Institute, University College London, London, UK
| | - Samuel Marguerat
- Department of Genetics, Evolution & Environment and UCL Genetics Institute, University College London, London, UK
| | | | - Eunhye Lee
- Department of Genetics, Evolution & Environment and UCL Genetics Institute, University College London, London, UK
| | - Christopher T Workman
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Jürg Bähler
- Department of Genetics, Evolution & Environment and UCL Genetics Institute, University College London, London, UK
| | - Andreas Beyer
- Biotechnology Centre, Technische Universität Dresden, Dresden, Germany Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany
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33
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Abenza JF, Chessel A, Raynaud WG, Carazo-Salas RE. Dynamics of cell shape inheritance in fission yeast. PLoS One 2014; 9:e106959. [PMID: 25210736 PMCID: PMC4161360 DOI: 10.1371/journal.pone.0106959] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 08/01/2014] [Indexed: 01/24/2023] Open
Abstract
Every cell has a characteristic shape key to its fate and function. That shape is not only the product of genetic design and of the physical and biochemical environment, but it is also subject to inheritance. However, the nature and contribution of cell shape inheritance to morphogenetic control is mostly ignored. Here, we investigate morphogenetic inheritance in the cylindrically-shaped fission yeast Schizosaccharomyces pombe. Focusing on sixteen different ‘curved’ mutants - a class of mutants which often fail to grow axially straight – we quantitatively characterize their dynamics of cell shape inheritance throughout generations. We show that mutants of similar machineries display similar dynamics of cell shape inheritance, and exploit this feature to show that persistent axial cell growth in S. pombe is secured by multiple, separable molecular pathways. Finally, we find that one of those pathways corresponds to the swc2-swr1-vps71 SWR1/SRCAP chromatin remodelling complex, which acts additively to the known mal3-tip1-mto1-mto2 microtubule and tea1-tea2-tea4-pom1 polarity machineries.
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Affiliation(s)
- Juan F. Abenza
- The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom
- * E-mail: (JFA); (REC-S)
| | - Anatole Chessel
- The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom
| | - William G. Raynaud
- The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom
| | - Rafael E. Carazo-Salas
- The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom
- * E-mail: (JFA); (REC-S)
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34
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Boyarchuk E, Filipescu D, Vassias I, Cantaloube S, Almouzni G. The histone variant composition of centromeres is controlled by the pericentric heterochromatin state during the cell cycle. J Cell Sci 2014; 127:3347-59. [PMID: 24906798 DOI: 10.1242/jcs.148189] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Correct chromosome segregation requires a unique chromatin environment at centromeres and in their vicinity. Here, we address how the deposition of canonical H2A and H2A.Z histone variants is controlled at pericentric heterochromatin (PHC). Whereas in euchromatin newly synthesized H2A and H2A.Z are deposited throughout the cell cycle, we reveal two discrete waves of deposition at PHC - during mid to late S phase in a replication-dependent manner for H2A and during G1 phase for H2A.Z. This G1 cell cycle restriction is lost when heterochromatin features are altered, leading to the accumulation of H2A.Z at the domain. Interestingly, compromising PHC integrity also impacts upon neighboring centric chromatin, increasing the amount of centromeric CENP-A without changing the timing of its deposition. We conclude that the higher-order chromatin structure at the pericentric domain influences dynamics at the nucleosomal level within centromeric chromatin. The two different modes of rearrangement of the PHC during the cell cycle provide distinct opportunities to replenish one or the other H2A variant, highlighting PHC integrity as a potential signal to regulate the deposition timing and stoichiometry of histone variants at the centromere.
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Affiliation(s)
- Ekaterina Boyarchuk
- Institut Curie, Centre de Recherche, Paris, 75248 France CNRS, UMR3664, Paris, 75248 France Equipe Labellisée Ligue contre le Cancer, UMR3664, Paris, 75248 France UPMC, UMR3664, Paris, 75248 France Sorbonne University, PSL, 75006 Paris, France
| | - Dan Filipescu
- Institut Curie, Centre de Recherche, Paris, 75248 France CNRS, UMR3664, Paris, 75248 France Equipe Labellisée Ligue contre le Cancer, UMR3664, Paris, 75248 France UPMC, UMR3664, Paris, 75248 France Sorbonne University, PSL, 75006 Paris, France
| | - Isabelle Vassias
- Institut Curie, Centre de Recherche, Paris, 75248 France CNRS, UMR3664, Paris, 75248 France Equipe Labellisée Ligue contre le Cancer, UMR3664, Paris, 75248 France UPMC, UMR3664, Paris, 75248 France Sorbonne University, PSL, 75006 Paris, France
| | - Sylvain Cantaloube
- Institut Curie, Centre de Recherche, Paris, 75248 France CNRS, UMR3664, Paris, 75248 France Equipe Labellisée Ligue contre le Cancer, UMR3664, Paris, 75248 France UPMC, UMR3664, Paris, 75248 France Sorbonne University, PSL, 75006 Paris, France
| | - Geneviève Almouzni
- Institut Curie, Centre de Recherche, Paris, 75248 France CNRS, UMR3664, Paris, 75248 France Equipe Labellisée Ligue contre le Cancer, UMR3664, Paris, 75248 France UPMC, UMR3664, Paris, 75248 France Sorbonne University, PSL, 75006 Paris, France
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35
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Soboleva TA, Nekrasov M, Ryan DP, Tremethick DJ. Histone variants at the transcription start-site. Trends Genet 2014; 30:199-209. [DOI: 10.1016/j.tig.2014.03.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 03/23/2014] [Accepted: 03/24/2014] [Indexed: 01/30/2023]
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36
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Billon P, Côté J. Precise deposition of histone H2A.Z in chromatin for genome expression and maintenance. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1819:290-302. [PMID: 24459731 DOI: 10.1016/j.bbagrm.2011.10.004] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Histone variant H2A.Z is essential in higher eukaryotes and has different functions in the cell. Several studies indicate that H2A.Z is found at specific loci in the genome such as regulatory-gene regions, where it poises genes for transcription. Itsdeposition creates chromatin regions with particular structural characteristics which could favor rapid transcription activation. This review focuses on the highly regulated mechanism of H2A.Z deposition in chromatin which is essential for genome integrity. Chaperones escort H2A.Z to large ATP-dependent chromatin remodeling enzymes which are responsible for its deposition/eviction. Over the last ten years, biochemical, genetic and genomic studies helped us understand the precise role of these complexes in this process. It hasbeen suggested that a cooperation occurs between histone acetyltransferase and chromatin remodeling activities to incorporate H2A.Z in chromatin. Its regulated deposition near centromeres and telomeres also shows its implication in chromosomal structure integrity and parallels a role in DNA damage response. Thedynamics of H2A.Z deposition/eviction at specific loci was shown to be critical for genome expression andmaintenance, thus cell fate. Altogether, recent findings reassert the importance of the regulated depositionof this histone variant. This article is part of a Special Issue entitled: Histone chaperones and Chromatin assembly.
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37
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Wang J, Tadeo X, Hou H, Tu PG, Thompson J, Yates JR, Jia S. Epe1 recruits BET family bromodomain protein Bdf2 to establish heterochromatin boundaries. Genes Dev 2013; 27:1886-902. [PMID: 24013502 PMCID: PMC3778242 DOI: 10.1101/gad.221010.113] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Heterochromatin spreading leads to gene silencing, and boundary elements constrain such spreading. IRC inverted repeats are required for boundary function at centromeric heterochromatin in fission yeast. Jia and colleagues now identify BET family homolog Bdf2 as required for heterochromatin boundary function at IRCs. Bdf2 interacts with boundary protein Epe1, recognizes acetylated histone H4 tails, and antagonizes Sir2-mediated deacetylation of histone H4K16. This study illustrates a mechanism for establishing chromosome boundaries through recruitment of a factor that protects euchromatic histone modifications. Heterochromatin spreading leads to the silencing of genes within its path, and boundary elements have evolved to constrain such spreading. In fission yeast, heterochromatin at centromeres I and III is flanked by inverted repeats termed IRCs, which are required for proper boundary functions. However, the mechanisms by which IRCs prevent heterochromatin spreading are unknown. Here, we identified Bdf2, which is homologous to the mammalian bromodomain and extraterminal (BET) family double bromodomain proteins involved in diverse types of cancers, as a factor required for proper boundary function at IRCs. Bdf2 is enriched at IRCs through its interaction with the boundary protein Epe1. The bromodomains of Bdf2 recognize acetylated histone H4 tails and antagonize Sir2-mediated deacetylation of histone H4K16. Furthermore, abolishing H4K16 acetylation (H4K16ac) with an H4K16R mutation promotes heterochromatin spreading, and mimicking H4K16ac by an H4K16Q mutation blocks heterochromatin spreading at IRCs. Our results thus illustrate a mechanism of establishing chromosome boundaries at specific sites through the recruitment of a factor that protects euchromatic histone modifications. They also reveal a previously unappreciated function of H4K16ac in cooperation with H3K9 methylation to regulate heterochromatin spreading.
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Affiliation(s)
- Jiyong Wang
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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38
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Epigenetically induced paucity of histone H2A.Z stabilizes fission-yeast ectopic centromeres. Nat Struct Mol Biol 2013; 20:1397-406. [PMID: 24186062 DOI: 10.1038/nsmb.2697] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 09/16/2013] [Indexed: 11/08/2022]
Abstract
In most eukaryotes, centromeres are epigenetically defined by nucleosomes that contain the histone H3 variant centromere protein A (CENP-A). Specific targeting of the CENP-A-loading chaperone to the centromere is vital for stable centromere propagation; however, the existence of ectopic centromeres (neocentromeres) indicates that this chaperone can function in different chromatin environments. The mechanism responsible for accommodating the CENP-A chaperone at noncentromeric regions is poorly understood. Here, we report the identification of transient, immature neocentromeres in Schizosaccharomyces pombe that show reduced association with the CENP-A chaperone Scm3, owing to persistence of the histone H2A variant H2A.Z. After the acquisition of adjacent heterochromatin or relocation of the immature neocentromeres to subtelomeric regions, H2A.Z was depleted and Scm3 was replenished, thus leading to subsequent stabilization of the neocentromeres. These findings provide new insights into histone variant-mediated epigenetic control of neocentromere establishment.
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39
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Steglich B, Sazer S, Ekwall K. Transcriptional regulation at the yeast nuclear envelope. Nucleus 2013; 4:379-89. [PMID: 24021962 DOI: 10.4161/nucl.26394] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The spatial organization of the genome inside the nucleus affects many nuclear processes, such as DNA replication, DNA repair, and gene transcription. In metazoans, the nuclear periphery harbors mainly repressed genes that associate with the nuclear lamina. This review discusses how peripheral positioning is connected to transcriptional regulation in yeasts. Tethering of reporter genes to the nuclear envelope was found to result in transcriptional silencing. Similarly, repression of the silent mating type loci and subtelomeric genes is influenced by their position close to the nuclear envelope. In contrast, active genes are bound by nucleoporins and inducible genes associate with the nuclear pore complex upon activation. Taken together, these results portray the nuclear envelope as a platform for transcriptional regulation, both through activation at nuclear pores and silencing at the nuclear envelope.
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Affiliation(s)
- Babett Steglich
- Department of Biosciences and Nutrition; Center for Biosciences; Karolinska Institutet; Huddinge, Sweden; Verna and Marrs McLean Department of Biochemistry and Molecular Biology; Baylor College of Medicine; Houston, TX USA; Department of Molecular and Cellular Biology; Baylor College of Medicine; Houston, TX USA
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40
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Abstract
Chromatin acts as an organizer and indexer of genomic DNA and is a highly dynamic and regulated structure with properties directly related to its constituent parts. Histone variants are abundant components of chromatin that replace canonical histones in a subset of nucleosomes, thereby altering nucleosomal characteristics. The present review focuses on the H2A variant histones, summarizing current knowledge of how H2A variants can introduce chemical and functional heterogeneity into chromatin, the positions that nucleosomes containing H2A variants occupy in eukaryotic genomes, and the regulation of these localization patterns.
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Petter M, Selvarajah SA, Lee CC, Chin WH, Gupta AP, Bozdech Z, Brown GV, Duffy MF. H2A.Z and H2B.Z double-variant nucleosomes define intergenic regions and dynamically occupy var gene promoters in the malaria parasite Plasmodium falciparum. Mol Microbiol 2013; 87:1167-82. [PMID: 23373537 DOI: 10.1111/mmi.12154] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2013] [Indexed: 12/15/2022]
Abstract
Histone variants are important components of eukaryotic chromatin and can alter chromatin structure to confer specialized functions. H2B variant histones are rare in nature but have evolved independently in the phyla Apicomplexa and Trypanasomatida. Here, we investigate the apicomplexan-specific Plasmodium falciparum histone variant Pf H2B.Z and show that within nucleosomes Pf H2B.Z dimerizes with the H2A variant Pf H2A.Z and that Pf H2B.Z and Pf H2A.Z occupancy correlates in the subset of genes examined. These double-variant nucleosomes also carry common markers of euchromatin like H3K4me3 and histone acetylation. Pf H2B.Z levels are elevated in intergenic regions across the genome, except in the var multigene family, where Pf H2A.Z/Pf H2B.Z double-variant nucleosomes are only enriched in the promoter of the single active var copy and this enrichment is developmentally regulated. Importantly, this pattern seems to be specific for var genes and does not apply to other heterochromatic gene families involved in red blood cell invasion which are also subject to clonal expression. Thus, Pf H2A.Z/Pf H2B.Z double-variant nucleosomes appear to have a highly specific function in the regulation of P. falciparum virulence.
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Affiliation(s)
- Michaela Petter
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia.
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42
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Steglich B, Filion GJ, van Steensel B, Ekwall K. The inner nuclear membrane proteins Man1 and Ima1 link to two different types of chromatin at the nuclear periphery in S. pombe. Nucleus 2012; 3:77-87. [PMID: 22156748 DOI: 10.4161/nucl.18825] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Metazoan chromatin at the nuclear periphery is generally characterized by lowly expressed genes and repressive chromatin marks and presents a sub-compartment with properties distinct from the nuclear interior. To test whether the S. pombe nuclear periphery behaves similarly, we used DNA adenine methyltransferase identification (DamID) to map the target loci of two inner nuclear membrane proteins, Ima1 and Man1. We found that peripheral chromatin shows low levels of RNA-Polymerase II and nucleosome occupancy, both characteristic of repressed chromatin regions. Consistently, lowly expressed genes preferentially associate with the periphery and highly expressed genes are depleted from it. When looking at peripheral intergenic regions (IGRs), we found that divergent IGRs are enriched compared with convergent IGRs, indicating that transcription preferentially points away from the periphery rather than toward it. Interestingly, we found that Ima1 and Man1 have common, but also separate target regions in the genome. Ima1-interacting loci were enriched for the RNAi components Dcr1 and Rdp1. This agrees with previous findings that Dcr1 is localized at the nuclear periphery. In contrast, Man1 target loci were bound by the heterochromatin protein Swi6, especially at subtelomeric regions. Subtelomeric chromatin was shown to form a unique chromatin type lacking both repressive and active chromatin features and containing low levels of the histone variant H2A.Z. Thus, we find that the fission yeast nuclear periphery shows similar properties to those of metazoan cells, despite the absence of a nuclear lamina. Our results point to a role of nuclear membrane proteins in organizing chromatin domains and loops.
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Affiliation(s)
- Babett Steglich
- Center for Biosciences, Department of Biosciences and Nutrition, Karolinska Institute, Huddinge, Sweden
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Pointner J, Persson J, Prasad P, Norman-Axelsson U, Strålfors A, Khorosjutina O, Krietenstein N, Svensson JP, Ekwall K, Korber P. CHD1 remodelers regulate nucleosome spacing in vitro and align nucleosomal arrays over gene coding regions in S. pombe. EMBO J 2012; 31:4388-403. [PMID: 23103765 DOI: 10.1038/emboj.2012.289] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 09/28/2012] [Indexed: 11/09/2022] Open
Abstract
Nucleosome positioning governs access to eukaryotic genomes. Many genes show a stereotypic organisation at their 5'end: a nucleosome free region just upstream of the transcription start site (TSS) followed by a regular nucleosomal array over the coding region. The determinants for this pattern are unclear, but nucleosome remodelers are likely critical. Here we study the role of remodelers in global nucleosome positioning in S. pombe and the corresponding changes in expression. We find a striking evolutionary shift in remodeler usage between budding and fission yeast. The S. pombe RSC complex does not seem to be involved in nucleosome positioning, despite its prominent role in S. cerevisiae. While S. pombe lacks ISWI-type remodelers, it has two CHD1-type ATPases, Hrp1 and Hrp3. We demonstrate nucleosome spacing activity for Hrp1 and Hrp3 in vitro, and that together they are essential for linking regular genic arrays to most TSSs in vivo. Impaired arrays in the absence of either or both remodelers may lead to increased cryptic antisense transcription, but overall gene expression levels are only mildly affected.
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Affiliation(s)
- Julia Pointner
- Adolf-Butenandt-Institut, University of Munich, Munich, Germany
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44
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Braun S, Madhani HD. Shaping the landscape: mechanistic consequences of ubiquitin modification of chromatin. EMBO Rep 2012; 13:619-30. [PMID: 22688965 DOI: 10.1038/embor.2012.78] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 05/22/2012] [Indexed: 12/15/2022] Open
Abstract
The organization of eukaryotic chromosomes into transcriptionally active euchromatin and repressed heterochromatin requires mechanisms that establish, maintain and distinguish these canonical chromatin domains. Post-translational modifications are fundamental in these processes. Monoubiquitylation of histones was discovered more than three decades ago, but its precise function has been enigmatic until recently. It is now appreciated that the spectrum of chromatin ubiquitylation is not restricted to monoubiquitylation of histones, but includes degradatory ubiquitylation of histones, histone-modifying enzymes and non-histone chromatin factors. These occur in a spatially and temporally controlled manner. In this review, we summarize our understanding of these mechanisms with a particular emphasis on how ubiquitylation shapes the physical landscape of chromatin.
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Affiliation(s)
- Sigurd Braun
- Department of Biochemistry & Biophysics, University of California, 600 16th Street, San Francisco, California 94158 2200, USA.
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45
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Givens RM, Lai WKM, Rizzo JM, Bard JE, Mieczkowski PA, Leatherwood J, Huberman JA, Buck MJ. Chromatin architectures at fission yeast transcriptional promoters and replication origins. Nucleic Acids Res 2012; 40:7176-89. [PMID: 22573177 PMCID: PMC3424540 DOI: 10.1093/nar/gks351] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have used micrococcal nuclease (MNase) digestion followed by deep sequencing in order to obtain a higher resolution map than previously available of nucleosome positions in the fission yeast, Schizosaccharomyces pombe. Our data confirm an unusually short average nucleosome repeat length, ∼152 bp, in fission yeast and that transcriptional start sites (TSSs) are associated with nucleosome-depleted regions (NDRs), ordered nucleosome arrays downstream and less regularly spaced upstream nucleosomes. In addition, we found enrichments for associated function in four of eight groups of genes clustered according to chromatin configurations near TSSs. At replication origins, our data revealed asymmetric localization of pre-replication complex (pre-RC) proteins within large NDRs—a feature that is conserved in fission and budding yeast and is therefore likely to be conserved in other eukaryotic organisms.
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Affiliation(s)
- Robert M Givens
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
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Sadeghi L, Bonilla C, Strålfors A, Ekwall K, Svensson JP. Podbat: a novel genomic tool reveals Swr1-independent H2A.Z incorporation at gene coding sequences through epigenetic meta-analysis. PLoS Comput Biol 2011; 7:e1002163. [PMID: 21901086 PMCID: PMC3161910 DOI: 10.1371/journal.pcbi.1002163] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 05/26/2011] [Indexed: 11/19/2022] Open
Abstract
Epigenetic regulation consists of a multitude of different modifications that determine active and inactive states of chromatin. Conditions such as cell differentiation or exposure to environmental stress require concerted changes in gene expression. To interpret epigenomics data, a spectrum of different interconnected datasets is needed, ranging from the genome sequence and positions of histones, together with their modifications and variants, to the transcriptional output of genomic regions. Here we present a tool, Podbat (Positioning database and analysis tool), that incorporates data from various sources and allows detailed dissection of the entire range of chromatin modifications simultaneously. Podbat can be used to analyze, visualize, store and share epigenomics data. Among other functions, Podbat allows data-driven determination of genome regions of differential protein occupancy or RNA expression using Hidden Markov Models. Comparisons between datasets are facilitated to enable the study of the comprehensive chromatin modification system simultaneously, irrespective of data-generating technique. Any organism with a sequenced genome can be accommodated. We exemplify the power of Podbat by reanalyzing all to-date published genome-wide data for the histone variant H2A.Z in fission yeast together with other histone marks and also phenotypic response data from several sources. This meta-analysis led to the unexpected finding of H2A.Z incorporation in the coding regions of genes encoding proteins involved in the regulation of meiosis and genotoxic stress responses. This incorporation was partly independent of the H2A.Z-incorporating remodeller Swr1. We verified an Swr1-independent role for H2A.Z following genotoxic stress in vivo. Podbat is open source software freely downloadable from www.podbat.org, distributed under the GNU LGPL license. User manuals, test data and instructions are available at the website, as well as a repository for third party-developed plug-in modules. Podbat requires Java version 1.6 or higher.
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Affiliation(s)
- Laia Sadeghi
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Carolina Bonilla
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Annelie Strålfors
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Karl Ekwall
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - J. Peter Svensson
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
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Tada K, Susumu H, Sakuno T, Watanabe Y. Condensin association with histone H2A shapes mitotic chromosomes. Nature 2011; 474:477-83. [PMID: 21633354 DOI: 10.1038/nature10179] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Accepted: 05/11/2011] [Indexed: 02/07/2023]
Abstract
Chromosome structure is dynamically regulated during cell division, and this regulation is dependent, in part, on condensin. The localization of condensin at chromosome arms is crucial for chromosome partitioning during anaphase. Condensin is also enriched at kinetochores but its precise role and loading machinery remain unclear. Here we show that fission yeast (Schizosaccharomyces pombe) kinetochore proteins Pcs1 and Mde4--homologues of budding yeast (Saccharomyces cerevisiae) monopolin subunits and known to prevent merotelic kinetochore orientation--act as a condensin 'recruiter' at kinetochores, and that condensin itself may act to clamp microtubule binding sites during metaphase. In addition to the regional recruitment factors, overall condensin association with chromatin is governed by the chromosomal passenger kinase Aurora B. Aurora-B-dependent phosphorylation of condensin promotes its association with histone H2A and H2A.Z, which we identify as conserved chromatin 'receptors' of condensin. Condensin phosphorylation and its deposition onto chromosome arms reach a peak during anaphase, when Aurora B kinase relocates from centromeres to the spindle midzone, where the separating chromosome arms are positioned. Our results elucidate the molecular basis for the spatiotemporal regulation of mitotic chromosome architecture, which is crucial for chromosome partitioning.
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Affiliation(s)
- Kenji Tada
- Laboratory of Chromosome Dynamics, Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi, Tokyo 113-0032, Japan
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48
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Boyarchuk E, Montes de Oca R, Almouzni G. Cell cycle dynamics of histone variants at the centromere, a model for chromosomal landmarks. Curr Opin Cell Biol 2011; 23:266-76. [PMID: 21470840 DOI: 10.1016/j.ceb.2011.03.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 02/18/2011] [Accepted: 03/13/2011] [Indexed: 10/18/2022]
Abstract
Classical heterochromatin chromosomal landmarks, such as centromeres and telomeres, are characterized by specific chromatin signatures. Among these, the incorporation of histone variants has recently emerged as an important feature. Using the centromere as a paradigm, we consider the role of histone variant dynamics in locus-specific chromatin organization. We describe the distinct location and dynamics of CenH3, H3.3, and H2AZ at the centromere during the cell cycle. This leads us to present the current view concerning modes of incorporation at this chromosomal landmark. Finally, we highlight the importance of histone variants in the crosstalk between centric and pericentric domains for maintaining centromere identity.
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49
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Xiong L, Wang Y. Mapping Post-translational Modifications of Histones H2A, H2B and H4 in Schizosaccharomyces pombe. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2011; 301:159-165. [PMID: 21516229 PMCID: PMC3079223 DOI: 10.1016/j.ijms.2010.08.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Core histones are known to carry a variety of post-translational modifications (PTMs), including acetylation, phosphorylation, methylation and ubiquitination, which play important roles in the epigenetic control of gene expression. The nature and biological functions of these PTMs in histones from plants, animals and budding yeast have been extensively investigated. In contrast, the corresponding studies for fission yeast were mainly focused on histone H3. In the present study, we applied LC-nano-ESI-MS/MS, coupled with multiple protease digestion, to identify PTMs in histones H2A, H2B and H4 from Schizosaccharomyces pombe (S. pombe), the typical model organism of fission yeast. Various protease digestions provided high sequence coverage for PTM mapping, and accurate mass measurement of fragment ions allowed for unambiguous differentiation of acetylation from tri-methylation. Many modification sites conserved in other organisms were identified in S. pombe. In addition, some unique modification sites, including N-terminal acetylation in H2A and H2B as well as K123 acetylation in H2A.β, were observed. Our results provide a comprehensive picture of the PTMs of histones H2A, H2B and H4 in S. pombe, which serves as a foundation for future investigations on the regulation and functions of histone modifications in this important model organism.
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Affiliation(s)
| | - Yinsheng Wang
- To whom correspondence should be addressed: . Tel.: (951)827-2700; Fax: (951)827-4713
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50
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Strålfors A, Walfridsson J, Bhuiyan H, Ekwall K. The FUN30 chromatin remodeler, Fft3, protects centromeric and subtelomeric domains from euchromatin formation. PLoS Genet 2011; 7:e1001334. [PMID: 21437270 PMCID: PMC3060074 DOI: 10.1371/journal.pgen.1001334] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 02/11/2011] [Indexed: 11/18/2022] Open
Abstract
The chromosomes of eukaryotes are organized into structurally and functionally discrete domains. This implies the presence of insulator elements that separate adjacent domains, allowing them to maintain different chromatin structures. We show that the Fun30 chromatin remodeler, Fft3, is essential for maintaining a proper chromatin structure at centromeres and subtelomeres. Fft3 is localized to insulator elements and inhibits euchromatin assembly in silent chromatin domains. In its absence, euchromatic histone modifications and histone variants invade centromeres and subtelomeres, causing a mis-regulation of gene expression and severe chromosome segregation defects. Our data strongly suggest that Fft3 controls the identity of chromatin domains by protecting these regions from euchromatin assembly.
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Affiliation(s)
- Annelie Strålfors
- Department of Biosciences and Medical Nutrition, Center for Biosciences, Karolinska Institutet, Huddinge, Sweden
| | - Julian Walfridsson
- Department of Biosciences and Medical Nutrition, Center for Biosciences, Karolinska Institutet, Huddinge, Sweden
- University College Södertörn, Department of Life Sciences, Huddinge, Sweden
| | | | - Karl Ekwall
- Department of Biosciences and Medical Nutrition, Center for Biosciences, Karolinska Institutet, Huddinge, Sweden
- University College Södertörn, Department of Life Sciences, Huddinge, Sweden
- * E-mail:
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