1
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Etherington GJ, Wu PS, Oliferenko S, Uhlmann F, Nieduszynski CA. Telomere-to-telomere Schizosaccharomyces japonicus genome assembly reveals hitherto unknown genome features. Yeast 2024; 41:73-86. [PMID: 38451028 DOI: 10.1002/yea.3912] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 10/27/2023] [Accepted: 11/10/2023] [Indexed: 03/08/2024] Open
Abstract
Schizosaccharomyces japonicus belongs to the single-genus class Schizosaccharomycetes, otherwise known as "fission yeasts." As part of a composite model system with its widely studied S. pombe sister species, S. japonicus has provided critical insights into the workings and the evolution of cell biological mechanisms. Furthermore, its divergent biology makes S. japonicus a valuable model organism in its own right. However, the currently available genome assembly contains gaps and has been unable to resolve centromeres and other repeat-rich chromosomal regions. Here we present a telomere-to-telomere long-read genome assembly of the S. japonicus genome. This includes the three megabase-length chromosomes, with centromeres hundreds of kilobases long, rich in 5S ribosomal RNA genes, transfer RNA genes, long terminal repeats, and short repeats. We identify a gene-sparse region on chromosome 2 that resembles a 331 kb centromeric duplication. We revise the genome size of S. japonicus to at least 16.6 Mb and possibly up to 18.12 Mb, at least 30% larger than previous estimates. Our whole genome assembly will support the growing S. japonicus research community and facilitate research in new directions, including centromere and DNA repeat evolution, and yeast comparative genomics.
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Affiliation(s)
| | | | - Snezhana Oliferenko
- The Francis Crick Institute, London, UK
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London, UK
| | - Frank Uhlmann
- The Francis Crick Institute, London, UK
- Cell Biology Centre, Institute of Innovative Research, Tokyo Institute of Technology, Kanagawa, Japan
| | - Conrad A Nieduszynski
- The Earlham Institute, Norwich, UK
- School of Biological Sciences, University of East Anglia, Norwich, UK
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2
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Cranz-Mileva S, Reilly E, Chalhoub N, Patel R, Atanassova T, Cao W, Ellison C, Zaratiegui M. Transposon Removal Reveals Their Adaptive Fitness Contribution. Genome Biol Evol 2024; 16:evae010. [PMID: 38245838 PMCID: PMC10836971 DOI: 10.1093/gbe/evae010] [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: 08/15/2023] [Revised: 01/04/2024] [Accepted: 01/12/2024] [Indexed: 01/22/2024] Open
Abstract
Transposable elements are molecular parasites that persist in their host genome by generating new copies to outpace natural selection. Transposable elements exert a large influence on host genome evolution, in some cases providing adaptive changes. Here we measure the fitness effect of the transposable element insertions in the fission yeast Schizosaccharomyces pombe type strain by removing all insertions of its only native transposable element family, the long terminal repeat retrotransposon Tf2. We show that Tf2 elements provide a positive fitness contribution to its host. Tf2 ablation results in changes to the regulation of a mitochondrial gene and, consistently, the fitness effect are sensitive to growth conditions. We propose that Tf2 influences host fitness in a directed manner by dynamically rewiring the transcriptional response to metabolic stress.
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Affiliation(s)
- Susanne Cranz-Mileva
- Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Eve Reilly
- Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Noor Chalhoub
- Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Rohan Patel
- Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Tania Atanassova
- Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Weihuan Cao
- Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Christopher Ellison
- Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Mikel Zaratiegui
- Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
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3
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Vega M, Barrios R, Fraile R, de Castro Cogle K, Castillo D, Anglada R, Casals F, Ayté J, Lowy-Gallego E, Hidalgo E. Topoisomerase 1 facilitates nucleosome reassembly at stress genes during recovery. Nucleic Acids Res 2023; 51:12161-12173. [PMID: 37956308 PMCID: PMC10711424 DOI: 10.1093/nar/gkad1066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 10/19/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023] Open
Abstract
Chromatin remodeling is essential to allow full development of alternative gene expression programs in response to environmental changes. In fission yeast, oxidative stress triggers massive transcriptional changes including the activation of hundreds of genes, with the participation of histone modifying complexes and chromatin remodelers. DNA transcription is associated to alterations in DNA topology, and DNA topoisomerases facilitate elongation along gene bodies. Here, we test whether the DNA topoisomerase Top1 participates in the RNA polymerase II-dependent activation of the cellular response to oxidative stress. Cells lacking Top1 are resistant to H2O2 stress. The transcriptome of Δtop1 strain was not greatly affected in the absence of stress, but activation of the anti-stress gene expression program was more sustained than in wild-type cells. Top1 associated to stress open reading frames. While the nucleosomes of stress genes are partially and transiently evicted during stress, the chromatin configuration remains open for longer times in cells lacking Top1, facilitating RNA polymerase II progression. We propose that, by removing DNA tension arising from transcription, Top1 facilitates nucleosome reassembly and works in synergy with the chromatin remodeler Hrp1 as opposing forces to transcription and to Snf22 / Hrp3 opening remodelers.
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Affiliation(s)
- Montserrat Vega
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona 08003, Spain
| | - Rubén Barrios
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona 08003, Spain
| | - Rodrigo Fraile
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona 08003, Spain
| | | | | | - Roger Anglada
- Genomics Core Facility, Universitat Pompeu Fabra, Barcelona 08003, Spain
| | - Ferran Casals
- Genomics Core Facility, Universitat Pompeu Fabra, Barcelona 08003, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona 08003, Spain
| | - Ernesto Lowy-Gallego
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona 08003, Spain
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4
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Colin L, Reyes C, Berthezene J, Maestroni L, Modolo L, Toselli E, Chanard N, Schaak S, Cuvier O, Gachet Y, Coulon S, Bernard P, Tournier S. Condensin positioning at telomeres by shelterin proteins drives sister-telomere disjunction in anaphase. eLife 2023; 12:RP89812. [PMID: 37988290 PMCID: PMC10662949 DOI: 10.7554/elife.89812] [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] [Indexed: 11/23/2023] Open
Abstract
The localization of condensin along chromosomes is crucial for their accurate segregation in anaphase. Condensin is enriched at telomeres but how and for what purpose had remained elusive. Here, we show that fission yeast condensin accumulates at telomere repeats through the balancing acts of Taz1, a core component of the shelterin complex that ensures telomeric functions, and Mit1, a nucleosome remodeler associated with shelterin. We further show that condensin takes part in sister-telomere separation in anaphase, and that this event can be uncoupled from the prior separation of chromosome arms, implying a telomere-specific separation mechanism. Consistent with a cis-acting process, increasing or decreasing condensin occupancy specifically at telomeres modifies accordingly the efficiency of their separation in anaphase. Genetic evidence suggests that condensin promotes sister-telomere separation by counteracting cohesin. Thus, our results reveal a shelterin-based mechanism that enriches condensin at telomeres to drive in cis their separation during mitosis.
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Affiliation(s)
- Léonard Colin
- CNRS - Laboratory of Biology and Modelling of the CellLyonFrance
- ENS de Lyon, Université Lyon, site Jacques MonodLyonFrance
| | - Celine Reyes
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPSToulouseFrance
| | - Julien Berthezene
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPSToulouseFrance
| | - Laetitia Maestroni
- CNRS, INSERM, Aix Marseille Université, Institut Paoli-Calmettes, CRCM, Equipe labellisée par la Ligue Nationale contre le CancerMarseilleFrance
| | - Laurent Modolo
- CNRS - Laboratory of Biology and Modelling of the CellLyonFrance
- ENS de Lyon, Université Lyon, site Jacques MonodLyonFrance
| | - Esther Toselli
- CNRS - Laboratory of Biology and Modelling of the CellLyonFrance
- ENS de Lyon, Université Lyon, site Jacques MonodLyonFrance
| | - Nicolas Chanard
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPSToulouseFrance
- CBI, MCD-UMR5077, CNRS, Chromatin Dynamics TeamToulouseFrance
| | - Stephane Schaak
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPSToulouseFrance
- CBI, MCD-UMR5077, CNRS, Chromatin Dynamics TeamToulouseFrance
| | - Olivier Cuvier
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPSToulouseFrance
- CBI, MCD-UMR5077, CNRS, Chromatin Dynamics TeamToulouseFrance
| | - Yannick Gachet
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPSToulouseFrance
| | - Stephane Coulon
- CNRS, INSERM, Aix Marseille Université, Institut Paoli-Calmettes, CRCM, Equipe labellisée par la Ligue Nationale contre le CancerMarseilleFrance
| | - Pascal Bernard
- CNRS - Laboratory of Biology and Modelling of the CellLyonFrance
- ENS de Lyon, Université Lyon, site Jacques MonodLyonFrance
| | - Sylvie Tournier
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPSToulouseFrance
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5
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Meier CS, Pagni M, Richard S, Mühlethaler K, Almeida JMGCF, Nevez G, Cushion MT, Calderón EJ, Hauser PM. Fungal antigenic variation using mosaicism and reassortment of subtelomeric genes' repertoires. Nat Commun 2023; 14:7026. [PMID: 37919276 PMCID: PMC10622565 DOI: 10.1038/s41467-023-42685-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 10/18/2023] [Indexed: 11/04/2023] Open
Abstract
Surface antigenic variation is crucial for major pathogens that infect humans. To escape the immune system, they exploit various mechanisms. Understanding these mechanisms is important to better prevent and fight the deadly diseases caused. Those used by the fungus Pneumocystis jirovecii that causes life-threatening pneumonia in immunocompromised individuals remain poorly understood. Here, though this fungus is currently not cultivable, our detailed analysis of the subtelomeric sequence motifs and genes encoding surface proteins suggests that the system involves the reassortment of the repertoire of ca. 80 non-expressed genes present in each strain, from which single genes are retrieved for mutually exclusive expression. Dispersion of the new repertoires, supposedly by healthy carrier individuals, appears very efficient because identical alleles are observed in patients from different countries. Our observations reveal a unique strategy of antigenic variation. They also highlight the possible role in genome rearrangements of small imperfect mirror sequences forming DNA triplexes.
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Affiliation(s)
- Caroline S Meier
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Marco Pagni
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Sophie Richard
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Konrad Mühlethaler
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - João M G C F Almeida
- UCIBIO, Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
| | - Gilles Nevez
- Laboratoire de Parasitologie et Mycologie, Hôpital de La Cavale Blanche, CHU de Brest, Brest, France
- Infections respiratoires fongiques (IFR), Université d'Angers, Université de Brest, Brest, France
| | - Melanie T Cushion
- Department of Internal Medicine, Division of Infectious Diseases, College of Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA
- Cincinnati VAMC, Medical Research Service, Cincinnati, OH, 45220, USA
| | - Enrique J Calderón
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocίo/Consejo Superior de Investigaciones Cientίficas/Universidad de Sevilla, Seville, Spain
- Centro de Investigación Biomédica en Red de Epidemiologίa y Salud Pública, Servicio de Medicina Interna, Hospital Universitario Virgen del Rocίo, Departamento de Medicina, Facultad de Medicina, Seville, Spain
| | - Philippe M Hauser
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
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6
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Kanoh J. Subtelomeres: hotspots of genome variation. Genes Genet Syst 2023; 98:155-160. [PMID: 37648502 DOI: 10.1266/ggs.23-00049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023] Open
Abstract
Eukaryotic cells contain multiple types of duplicated sequences. Typical examples are tandem repeat sequences including telomeres, centromeres, rDNA genes and transposable elements. Most of these sequences are unstable; thus, their copy numbers or sequences change rapidly in the course of evolution. In this review, I will describe roles of subtelomere regions, which are located adjacent to telomeres at chromosome ends, and recent discoveries about their sequence variation.
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Affiliation(s)
- Junko Kanoh
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo
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7
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Vaurs M, Naiman K, Bouabboune C, Rai S, Ptasińska K, Rives M, Matmati S, Carr AM, Géli V, Coulon S. Stn1-Ten1 and Taz1 independently promote replication of subtelomeric fragile sequences in fission yeast. Cell Rep 2023; 42:112537. [PMID: 37243596 DOI: 10.1016/j.celrep.2023.112537] [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: 09/15/2022] [Revised: 03/01/2023] [Accepted: 05/03/2023] [Indexed: 05/29/2023] Open
Abstract
Efficient replication of terminal DNA is crucial to maintain telomere stability. In fission yeast, Taz1 and the Stn1-Ten1 (ST) complex play prominent roles in DNA-ends replication. However, their function remains elusive. Here, we have analyzed genome-wide replication and show that ST does not affect genome-wide replication but is crucial for the efficient replication of a subtelomeric region called STE3-2. We further show that, when ST function is compromised, a homologous recombination (HR)-based fork restart mechanism becomes necessary for STE3-2 stability. While both Taz1 and Stn1 bind to STE3-2, we find that the STE3-2 replication function of ST is independent of Taz1 but relies on its association with the shelterin proteins Pot1-Tpz1-Poz1. Finally, we demonstrate that the firing of an origin normally inhibited by Rif1 can circumvent the replication defect of subtelomeres when ST function is compromised. Our results help illuminate why fission yeast telomeres are terminal fragile sites.
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Affiliation(s)
- Mélina Vaurs
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Karel Naiman
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France; Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK
| | - Chaïnez Bouabboune
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Sudhir Rai
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Katarzyna Ptasińska
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK
| | - Marion Rives
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Samah Matmati
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Antony M Carr
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK
| | - Vincent Géli
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France.
| | - Stéphane Coulon
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France.
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8
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Kuse R, Ishii K. Flexible Attachment and Detachment of Centromeres and Telomeres to and from Chromosomes. Biomolecules 2023; 13:1016. [PMID: 37371596 DOI: 10.3390/biom13061016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/15/2023] [Accepted: 06/18/2023] [Indexed: 06/29/2023] Open
Abstract
Accurate transmission of genomic information across multiple cell divisions and generations, without any losses or errors, is fundamental to all living organisms. To achieve this goal, eukaryotes devised chromosomes. Eukaryotic genomes are represented by multiple linear chromosomes in the nucleus, each carrying a centromere in the middle, a telomere at both ends, and multiple origins of replication along the chromosome arms. Although all three of these DNA elements are indispensable for chromosome function, centromeres and telomeres possess the potential to detach from the original chromosome and attach to new chromosomal positions, as evident from the events of telomere fusion, centromere inactivation, telomere healing, and neocentromere formation. These events seem to occur spontaneously in nature but have not yet been elucidated clearly, because they are relatively infrequent and sometimes detrimental. To address this issue, experimental setups have been developed using model organisms such as yeast. In this article, we review some of the key experiments that provide clues as to the extent to which these paradoxical and elusive features of chromosomally indispensable elements may become valuable in the natural context.
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Affiliation(s)
- Riku Kuse
- Laboratory of Chromosome Function and Regulation, Graduate School of Engineering, Kochi University of Technology, Kochi 782-8502, Japan
| | - Kojiro Ishii
- Laboratory of Chromosome Function and Regulation, Graduate School of Engineering, Kochi University of Technology, Kochi 782-8502, Japan
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9
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Kanoh J. Roles of Specialized Chromatin and DNA Structures at Subtelomeres in Schizosaccharomyces pombe. Biomolecules 2023; 13:biom13050810. [PMID: 37238680 DOI: 10.3390/biom13050810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/28/2023] [Accepted: 05/02/2023] [Indexed: 05/28/2023] Open
Abstract
Eukaryotes have linear chromosomes with domains called telomeres at both ends. The telomere DNA consists of a simple tandem repeat sequence, and multiple telomere-binding proteins including the shelterin complex maintain chromosome-end structures and regulate various biological reactions, such as protection of chromosome ends and control of telomere DNA length. On the other hand, subtelomeres, which are located adjacent to telomeres, contain a complex mosaic of multiple common segmental sequences and a variety of gene sequences. This review focused on roles of the subtelomeric chromatin and DNA structures in the fission yeast Schizosaccharomyces pombe. The fission yeast subtelomeres form three distinct chromatin structures; one is the shelterin complex, which is localized not only at the telomeres but also at the telomere-proximal regions of subtelomeres to form transcriptionally repressive chromatin structures. The others are heterochromatin and knob, which have repressive effects in gene expression, but the subtelomeres are equipped with a mechanism that prevents these condensed chromatin structures from invading adjacent euchromatin regions. On the other hand, recombination reactions within or near subtelomeric sequences allow chromosomes to be circularized, enabling cells to survive in telomere shortening. Furthermore, DNA structures of the subtelomeres are more variable than other chromosomal regions, which may have contributed to biological diversity and evolution while changing gene expression and chromatin structures.
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Affiliation(s)
- Junko Kanoh
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
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10
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Power ML, Foley NM, Jones G, Teeling EC. Taking flight: An ecological, evolutionary and genomic perspective on bat telomeres. Mol Ecol 2022; 31:6053-6068. [PMID: 34387012 DOI: 10.1111/mec.16117] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/21/2021] [Accepted: 08/03/2021] [Indexed: 01/31/2023]
Abstract
Over 20% of all living mammals are bats (order Chiroptera). Bats possess extraordinary adaptations including powered flight, laryngeal echolocation and a unique immune system that enables them to tolerate a diversity of viral infections without presenting clinical disease symptoms. They occupy multiple trophic niches and environments globally. Significant physiological and ecological diversity occurs across the order. Bats also exhibit extreme longevity given their body size with many species showing few signs of ageing. The molecular basis of this extended longevity has recently attracted attention. Telomere maintenance potentially underpins bats' extended healthspan, although functional studies are still required to validate the causative mechanisms. In this review, we detail the current knowledge on bat telomeres, telomerase expression, and how these relate to ecology, longevity and life-history strategies. Patterns of telomere shortening and telomerase expression vary across species, and comparative genomic analyses suggest that alternative telomere maintenance mechanisms evolved in the longest-lived bats. We discuss the unique challenges faced when working with populations of wild bats and highlight ways to advance the field including expanding long-term monitoring across species that display contrasting life-histories and occupy different environmental niches. We further review how new high quality, chromosome-level genome assemblies can enable us to uncover the molecular mechanisms governing telomere dynamics and how phylogenomic analyses can reveal the adaptive significance of telomere maintenance and variation in bats.
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Affiliation(s)
- Megan L Power
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Belfield, Ireland
| | - Nicole M Foley
- Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA
| | - Gareth Jones
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Emma C Teeling
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Belfield, Ireland
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11
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Melde RH, Bao K, Sharp NP. Recent insights into the evolution of mutation rates in yeast. Curr Opin Genet Dev 2022; 76:101953. [PMID: 35834945 PMCID: PMC9491374 DOI: 10.1016/j.gde.2022.101953] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 05/25/2022] [Accepted: 06/13/2022] [Indexed: 02/08/2023]
Abstract
Mutation is the origin of all genetic variation, good and bad. The mutation process can evolve in response to mutations, positive or negative selection, and genetic drift, but how these forces contribute to mutation-rate variation is an unsolved problem at the heart of genetics research. Mutations can be challenging to measure, but genome sequencing and other tools have allowed for the collection of larger and more detailed datasets, particularly in the yeast-model system. We review key hypotheses for the evolution of mutation rates and describe recent advances in understanding variation in mutational properties within and among yeast species. The multidimensional spectrum of mutations is increasingly recognized as holding valuable clues about how this important process evolves.
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Affiliation(s)
- Robert H Melde
- Department of Genetics, University of Wisconsin-Madison, USA.
| | - Kevin Bao
- Department of Genetics, University of Wisconsin-Madison, USA
| | - Nathaniel P Sharp
- Department of Genetics, University of Wisconsin-Madison, USA. https://twitter.com/@sharpnath
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12
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Gu X, Ye T, Zhang XR, Nie L, Wang H, Li W, Lu R, Fu C, Du LL, Zhou JQ. Single-chromosome fission yeast models reveal the configuration robustness of a functional genome. Cell Rep 2022; 40:111237. [PMID: 36001961 DOI: 10.1016/j.celrep.2022.111237] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 05/02/2022] [Accepted: 07/28/2022] [Indexed: 11/03/2022] Open
Abstract
In eukaryotic organisms, genetic information is usually carried on multiple chromosomes. Whether and how the number and configuration of chromosomes affect organismal fitness and speciation remain unclear. Here, we have successfully established several single-chromosome fission yeast Schizosaccharomyces pombe strains, in which the three natural chromosomes have been fused into one giant chromosome in different orders. Chromosome fusions accompanied by the deletions of telomeres and centromeres result in the loss of chromosomal interactions and a drastic change of global chromosome organization, but alter gene expression marginally. The single-chromosome strains display little defects in cell morphology, mitosis, genotoxin sensitivity, and meiosis. Crosses between a wild-type strain and a single-chromosome strain or between two single-chromosome strains with different fusion orders suffer defective meiosis and poor spore viability. We conclude that eukaryotic genomes are robust against dramatic chromosomal reconfiguration, and stochastic changes in chromosome number and genome organization during evolution underlie reproductive isolation and speciation.
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Affiliation(s)
- Xin Gu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tiantian Ye
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiao-Ran Zhang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Lingyun Nie
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Huan Wang
- Frasergen Bioinformatics, Wuhan, China
| | - Wei Li
- Frasergen Bioinformatics, Wuhan, China
| | - Rui Lu
- Frasergen Bioinformatics, Wuhan, China
| | - Chuanhai Fu
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Li-Lin Du
- National Institute of Biological Sciences, Beijing 102206, China.
| | - Jin-Qiu Zhou
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of the Chinese Academy of Sciences, Hangzhou 310024, China.
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13
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Lysak MA. Celebrating Mendel, McClintock, and Darlington: On end-to-end chromosome fusions and nested chromosome fusions. THE PLANT CELL 2022; 34:2475-2491. [PMID: 35441689 PMCID: PMC9252491 DOI: 10.1093/plcell/koac116] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 04/13/2022] [Indexed: 05/04/2023]
Abstract
The evolution of eukaryotic genomes is accompanied by fluctuations in chromosome number, reflecting cycles of chromosome number increase (polyploidy and centric fissions) and decrease (chromosome fusions). Although all chromosome fusions result from DNA recombination between two or more nonhomologous chromosomes, several mechanisms of descending dysploidy are exploited by eukaryotes to reduce their chromosome number. Genome sequencing and comparative genomics have accelerated the identification of inter-genome chromosome collinearity and gross chromosomal rearrangements and have shown that end-to-end chromosome fusions (EEFs) and nested chromosome fusions (NCFs) may have played a more important role in the evolution of eukaryotic karyotypes than previously thought. The present review aims to summarize the limited knowledge on the origin, frequency, and evolutionary implications of EEF and NCF events in eukaryotes and especially in land plants. The interactions between nonhomologous chromosomes in interphase nuclei and chromosome (mis)pairing during meiosis are examined for their potential importance in the origin of EEFs and NCFs. The remaining open questions that need to be addressed are discussed.
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Affiliation(s)
- Martin A Lysak
- CEITEC—Central European Institute of Technology, Masaryk University, Brno, CZ-625 00, Czech Republic
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14
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Wang S, Wang C, Feng X, Zhao J, Deng P, Wang Y, Zhang H, Liu X, Li T, Chen C, Wang B, Ji W. Molecular cytogenetics and development of St-chromosome-specific molecular markers of novel stripe rust resistant wheat-Thinopyrum intermedium and wheat-Thinopyrum ponticum substitution lines. BMC PLANT BIOLOGY 2022; 22:111. [PMID: 35279089 PMCID: PMC8917741 DOI: 10.1186/s12870-022-03496-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 02/24/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Owing to their excellent resistance to abiotic and biotic stress, Thinopyrum intermedium (2n = 6x = 42, JJJsJsStSt) and Th. ponticum (2n = 10x = 70) are both widely utilized in wheat germplasm innovation programs. Disomic substitution lines (DSLs) carrying one pair of alien chromosomes are valuable bridge materials for transmission of novel genes, fluorescence in situ hybridization (FISH) karyotype construction and specific molecular marker development. RESULTS Six wheat-Thinopyrum DSLs derived from crosses between Abbondanza nullisomic lines (2n = 40) and two octoploid Trititrigia lines (2n = 8x = 56), were characterized by sequential FISH-genome in situ hybridization (GISH), multicolor GISH (mc-GISH), and an analysis of the wheat 15 K SNP array combined with molecular marker selection. ES-9 (DS2St (2A)) and ES-10 (DS3St (3D)) are wheat-Th. ponticum DSLs, while ES-23 (DS2St (2A)), ES-24 (DS3St (3D)), ES-25(DS2St (2B)), and ES-26 (DS2St (2D)) are wheat-Th. intermedium DSLs. ES-9, ES-23, ES-25 and ES-26 conferred high thousand-kernel weight and stripe rust resistance at adult stages, while ES-10 and ES-24 were highly resistant to stripe rust at all stages. Furthermore, cytological analysis showed that the alien chromosomes belonging to the same homoeologous group (2 or 3) derived from different donors carried the same FISH karyotype and could form a bivalent. Based on specific-locus amplified fragment sequencing (SLAF-seq), two 2St-chromosome-specific markers (PTH-005 and PTH-013) and two 3St-chromosome-specific markers (PTH-113 and PTH-135) were developed. CONCLUSIONS The six wheat-Thinopyrum DSLs conferring stripe rust resistance can be used as bridging parents for transmission of valuable resistance genes. The utility of PTH-113 and PTH-135 in a BC1F2 population showed that the newly developed markers could be useful tools for efficient identification of St chromosomes in a common wheat background.
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Affiliation(s)
- Siwen Wang
- College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Changyou Wang
- College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
- Shaanxi Research Station of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture, Yangling, 712100 Shaanxi China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, 712100 Shaanxi China
| | - Xianbo Feng
- College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Jixin Zhao
- College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
- Shaanxi Research Station of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture, Yangling, 712100 Shaanxi China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, 712100 Shaanxi China
| | - Pingchuan Deng
- College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
- Shaanxi Research Station of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture, Yangling, 712100 Shaanxi China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, 712100 Shaanxi China
| | - Yajuan Wang
- College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
- Shaanxi Research Station of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture, Yangling, 712100 Shaanxi China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, 712100 Shaanxi China
| | - Hong Zhang
- College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
- Shaanxi Research Station of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture, Yangling, 712100 Shaanxi China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, 712100 Shaanxi China
| | - Xinlun Liu
- College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
- Shaanxi Research Station of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture, Yangling, 712100 Shaanxi China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, 712100 Shaanxi China
| | - Tingdong Li
- College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
- Shaanxi Research Station of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture, Yangling, 712100 Shaanxi China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, 712100 Shaanxi China
| | - Chunhuan Chen
- College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
- Shaanxi Research Station of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture, Yangling, 712100 Shaanxi China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, 712100 Shaanxi China
| | - Baotong Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, 712100 Shaanxi China
- College of Plant Protection, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Wanquan Ji
- College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
- Shaanxi Research Station of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture, Yangling, 712100 Shaanxi China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, 712100 Shaanxi China
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15
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Yamamoto I, Nakaoka H, Takikawa M, Tashiro S, Kanoh J, Miyoshi T, Ishikawa F. Fission yeast Stn1 maintains stability of repetitive DNA at subtelomere and ribosomal DNA regions. Nucleic Acids Res 2021; 49:10465-10476. [PMID: 34520548 PMCID: PMC8501966 DOI: 10.1093/nar/gkab767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 08/03/2021] [Accepted: 08/31/2021] [Indexed: 11/14/2022] Open
Abstract
Telomere binding protein Stn1 forms the CST (Cdc13/CTC1-STN1-TEN1) complex in budding yeast and mammals. Likewise, fission yeast Stn1 and Ten1 form a complex indispensable for telomere protection. We have previously reported that stn1-1, a high-temperature sensitive mutant, rapidly loses telomere DNA at the restrictive temperature due to frequent failure of replication fork progression at telomeres and subtelomeres, both containing repetitive sequences. It is unclear, however, whether Stn1 is required for maintaining other repetitive DNAs such as ribosomal DNA. In this study, we have demonstrated that stn1-1 cells, even when grown at the permissive temperature, exhibited dynamic rearrangements in the telomere-proximal regions of subtelomere and ribosomal DNA repeats. Furthermore, Rad52 and γH2A accumulation was observed at ribosomal DNA repeats in the stn1-1 mutant. The phenotypes exhibited by the stn1-1 allele were largely suppressed in the absence of Reb1, a replication fork barrier-forming protein, suggesting that Stn1 is involved in the maintenance of the arrested replication forks. Collectively, we propose that Stn1 maintains the stability of repetitive DNAs at subtelomeres and rDNA regions.
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Affiliation(s)
- Io Yamamoto
- Laboratory of Cell Cycle Regulation, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8501, Japan.,Department of Stress Response, Radiation Biology Center, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8501, Japan
| | - Hidenori Nakaoka
- Laboratory of Cell Cycle Regulation, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8501, Japan.,Department of Stress Response, Radiation Biology Center, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8501, Japan
| | - Masahiro Takikawa
- Laboratory of Cell Cycle Regulation, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8501, Japan
| | - Sanki Tashiro
- Laboratory of Cell Cycle Regulation, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8501, Japan.,Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
| | - Junko Kanoh
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan.,Department of Life Sciences, Graduate School of Arts and Sciences, the University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Tomoichiro Miyoshi
- Laboratory of Cell Cycle Regulation, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8501, Japan.,Department of Stress Response, Radiation Biology Center, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8501, Japan
| | - Fuyuki Ishikawa
- Laboratory of Cell Cycle Regulation, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8501, Japan.,Department of Stress Response, Radiation Biology Center, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8501, Japan
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16
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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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