1
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Zhang F, Bechara S, Nowacki M. Structural maintenance of chromosomes (SMC) proteins are required for DNA elimination in Paramecium. Life Sci Alliance 2024; 7:e202302281. [PMID: 38056908 PMCID: PMC10700549 DOI: 10.26508/lsa.202302281] [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: 07/18/2023] [Revised: 11/22/2023] [Accepted: 11/22/2023] [Indexed: 12/08/2023] Open
Abstract
Chromosome (SMC) proteins are a large family of ATPases that play important roles in the organization and dynamics of chromatin. They are central regulators of chromosome dynamics and the core component of condensin. DNA elimination during zygotic somatic genome development is a characteristic feature of ciliated protozoa such as Paramecium This process occurs after meiosis, mitosis, karyogamy, and another mitosis, which result in the formation of a new germline and somatic nuclei. The series of nuclear divisions implies an important role of SMC proteins in Paramecium sexual development. The relationship between DNA elimination and SMC has not yet been described. Here, we applied RNA interference, genome sequencing, mRNA sequencing, immunofluorescence, and mass spectrometry to investigate the roles of SMC components in DNA elimination. Our results show that SMC4-2 is required for genome rearrangement, whereas SMC4-1 is not. Functional diversification of SMC4 in Paramecium led to a formation of two paralogues where SMC4-2 acquired a novel, development-specific function and differs from SMC4-1. Moreover, our study suggests a competitive relationship between these two proteins.
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Affiliation(s)
- Fukai Zhang
- https://ror.org/02k7v4d05 Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Sebastian Bechara
- https://ror.org/02k7v4d05 Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Mariusz Nowacki
- https://ror.org/02k7v4d05 Institute of Cell Biology, University of Bern, Bern, Switzerland
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2
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Tang M, Pobegalov G, Tanizawa H, Chen ZA, Rappsilber J, Molodtsov M, Noma KI, Uhlmann F. Establishment of dsDNA-dsDNA interactions by the condensin complex. Mol Cell 2023; 83:3787-3800.e9. [PMID: 37820734 PMCID: PMC10842940 DOI: 10.1016/j.molcel.2023.09.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/13/2023] [Accepted: 09/13/2023] [Indexed: 10/13/2023]
Abstract
Condensin is a structural maintenance of chromosomes (SMC) complex family member thought to build mitotic chromosomes by DNA loop extrusion. However, condensin variants unable to extrude loops, yet proficient in chromosome formation, were recently described. Here, we explore how condensin might alternatively build chromosomes. Using bulk biochemical and single-molecule experiments with purified fission yeast condensin, we observe that individual condensins sequentially and topologically entrap two double-stranded DNAs (dsDNAs). Condensin loading transitions through a state requiring DNA bending, as proposed for the related cohesin complex. While cohesin then favors the capture of a second single-stranded DNA (ssDNA), second dsDNA capture emerges as a defining feature of condensin. We provide complementary in vivo evidence for DNA-DNA capture in the form of condensin-dependent chromatin contacts within, as well as between, chromosomes. Our results support a "diffusion capture" model in which condensin acts in mitotic chromosome formation by sequential dsDNA-dsDNA capture.
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Affiliation(s)
- Minzhe Tang
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Georgii Pobegalov
- Mechanobiology and Biophysics Laboratory, The Francis Crick Institute, London NW1 1AT, UK; Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
| | - Hideki Tanizawa
- Division of Genome Biology, Institute for Genetic Medicine, Hokkaido University, Sapporo, Hokkaido 060-0815, Japan
| | - Zhuo A Chen
- Bioanalytics Unit, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany
| | - Juri Rappsilber
- Bioanalytics Unit, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany; Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Maxim Molodtsov
- Mechanobiology and Biophysics Laboratory, The Francis Crick Institute, London NW1 1AT, UK; Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
| | - Ken-Ichi Noma
- Division of Genome Biology, Institute for Genetic Medicine, Hokkaido University, Sapporo, Hokkaido 060-0815, Japan; Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK; Cell Biology Centre, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Kanagawa 226-0026, Japan.
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3
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Xu YJ, Bhadra S, Mahdi ATA, Dev K, Yurtsever I, Nakamura TM. Comprehensive mutational analysis of the checkpoint signaling function of Rpa1/Ssb1 in fission yeast. PLoS Genet 2023; 19:e1010691. [PMID: 37200372 DOI: 10.1371/journal.pgen.1010691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 05/31/2023] [Accepted: 04/24/2023] [Indexed: 05/20/2023] Open
Abstract
Replication protein A (RPA) is a heterotrimeric complex and the major single-strand DNA (ssDNA) binding protein in eukaryotes. It plays important roles in DNA replication, repair, recombination, telomere maintenance, and checkpoint signaling. Because RPA is essential for cell survival, understanding its checkpoint signaling function in cells has been challenging. Several RPA mutants have been reported previously in fission yeast. None of them, however, has a defined checkpoint defect. A separation-of-function mutant of RPA, if identified, would provide significant insights into the checkpoint initiation mechanisms. We have explored this possibility and carried out an extensive genetic screen for Rpa1/Ssb1, the large subunit of RPA in fission yeast, looking for mutants with defects in checkpoint signaling. This screen has identified twenty-five primary mutants that are sensitive to genotoxins. Among these mutants, two have been confirmed partially defective in checkpoint signaling primarily at the replication fork, not the DNA damage site. The remaining mutants are likely defective in other functions such as DNA repair or telomere maintenance. Our screened mutants, therefore, provide a valuable tool for future dissection of the multiple functions of RPA in fission yeast.
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Affiliation(s)
- Yong-Jie Xu
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, United States of America
| | - Sankhadip Bhadra
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, United States of America
| | - Alaa Taha A Mahdi
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, United States of America
| | - Kamal Dev
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, United States of America
| | - Ilknur Yurtsever
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, United States of America
| | - Toru M Nakamura
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois, United States of America
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4
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Xu YJ, Bhadra S, Mahdi ATA, Dev K, Yurtsever I, Nakamura TM. Comprehensive mutational analysis of the checkpoint signaling function of Rpa1/Ssb1 in fission yeast. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.06.531248. [PMID: 36945624 PMCID: PMC10028789 DOI: 10.1101/2023.03.06.531248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Replication protein A (RPA) is a heterotrimeric complex and the major single-strand DNA (ssDNA) binding protein in eukaryotes. It plays important roles in DNA replication, repair, recombination, telomere maintenance, and checkpoint signaling. Because RPA is essential for cell survival, understanding its checkpoint signaling function in cells has been challenging. Several RPA mutants have been reported previously in fission yeast. None of them, however, has a defined checkpoint defect. A separation-of-function mutant of RPA, if identified, would provide significant insights into the checkpoint initiation mechanisms. We have explored this possibility and carried out an extensive genetic screening for Rpa1/Ssb1, the large subunit of RPA in fission yeast, looking for mutants with defects in checkpoint signaling. This screen has identified twenty-five primary mutants that are sensitive to genotoxins. Among these mutants, two have been confirmed partially defective in checkpoint signaling primarily at the replication fork, not the DNA damage site. The remaining mutants are likely defective in other functions such as DNA repair or telomere maintenance. Our screened mutants, therefore, provide a valuable tool for future dissection of the multiple functions of RPA in fission yeast. AUTHOR SUMMARY Originally discovered as a protein required for replication of simian virus SV40 DNA, replication protein A is now known to function in DNA replication, repair, recombination, telomere maintenance, and checkpoint signaling in all eukaryotes. The protein is a complex of three subunits and the two larger ones are essential for cell growth. This essential function however complicates the studies in living cells, and for this reason, its checkpoint function remains to be fully understood. We have carried out an genetic screening of the largest subunit of this protein in fission yeast, aiming to find a non-lethal mutant that lacks the checkpoint function. This extensive screen has uncovered two mutants with a partial defect in checkpoint signaling when DNA replication is arrested. Surprisingly, although the two mutants also have a defect in DNA repair, their checkpoint signaling remains largely functional in the presence of DNA damage. We have also uncovered twenty-three mutants with defects in DNA repair or telomere maintenance, but not checkpoint signaling. Therefore, the non-lethal mutants uncovered by this study provide a valuable tool for dissecting the multiple functions of this biologically important protein in fission yeast.
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5
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Scherzer M, Giordano F, Ferran MS, Ström L. Recruitment of Scc2/4 to double-strand breaks depends on γH2A and DNA end resection. Life Sci Alliance 2022; 5:e202101244. [PMID: 35086935 PMCID: PMC8807874 DOI: 10.26508/lsa.202101244] [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: 09/24/2021] [Revised: 01/13/2022] [Accepted: 01/14/2022] [Indexed: 12/15/2022] Open
Abstract
Homologous recombination enables cells to overcome the threat of DNA double-strand breaks (DSBs), allowing for repair without the loss of genetic information. Central to the homologous recombination repair process is the de novo loading of cohesin around a DSB by its loader complex Scc2/4. Although cohesin's DSB accumulation has been explored in numerous studies, the prerequisites for Scc2/4 recruitment during the repair process are still elusive. To address this question, we combine chromatin immunoprecipitation-qPCR with a site-specific DSB in vivo, in Saccharomyces cerevisiae We find that Scc2 DSB recruitment relies on γH2A and Tel1, but as opposed to cohesin, not on Mec1. We further show that the binding of Scc2, which emanates from the break site, depends on and coincides with DNA end resection. Absence of chromatin remodeling at the DSB affects Scc2 binding and DNA end resection to a comparable degree, further indicating the latter to be a major driver for Scc2 recruitment. Our results shed light on the intricate DSB repair cascade leading to the recruitment of Scc2/4 and subsequent loading of cohesin.
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Affiliation(s)
- Martin Scherzer
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Fosco Giordano
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Maria Solé Ferran
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Lena Ström
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
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6
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He D, Guo Y, Cheng J, Wang Y. Chl1 coordinates with H3K9 methyltransferase Clr4 to reduce the accumulation of RNA-DNA hybrids and maintain genome stability. iScience 2022; 25:104313. [PMID: 35602970 PMCID: PMC9118164 DOI: 10.1016/j.isci.2022.104313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/30/2022] [Accepted: 04/22/2022] [Indexed: 11/28/2022] Open
Abstract
A genome-wide analysis in Schizosaccharomyces pombe indicated that double-deletion mutants of Chl1 and histone H3K9 methyltransferase complex factors are synthetically sick. Here, we show that loss of Chl1 increases the accumulation of RNA-DNA hybrids at pericentromeric dg and dh repeats in the absence of the H3K9 methyltransferase Clr4, which leads to genome instability, including more severe defects in chromosome segregation and increased chromatin accessibility. Localization of Chl1 at pericentromeric regions depends on a subunit of replication protein A (RPA), Ssb1. In wild-type (WT) cells, transcriptionally repressed heterochromatin prevents the formation of RNA-DNA hybrids. When Clr4 is deleted, dg and dh repeats are highly transcribed. Then Ssb1 associates with the displaced single-stranded DNA (ssDNA) and recruits Chl1 to resolve the RNA-DNA hybrids. Together, our data suggest that Chl1 coordinates with Clr4 to eliminate RNA-DNA hybrids, which contributes to the maintenance of genome integrity. Double mutant of Chl1 and Chl1 leads to the accumulation of RNA-DNA hybrids RNA-DNA hybrids at pericentromeric regions affect genome stability and cell viability Ssb1 recruits Chl1 to unwind RNA-DNA hybrids in the absence of Clr4
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Affiliation(s)
- Deyun He
- College of Biological Sciences, China Agricultural University, Beijing, 100193, China
- College of Bioengineering, Key Laboratory of Shandong Microbial Engineering, State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, Shandong 250353, China
| | - Yazhen Guo
- College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jinkui Cheng
- College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yu Wang
- College of Biological Sciences, China Agricultural University, Beijing, 100193, China
- Corresponding author
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7
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Lancaster L, Patel H, Kelly G, Uhlmann F. A role for condensin in mediating transcriptional adaptation to environmental stimuli. Life Sci Alliance 2021; 4:e202000961. [PMID: 34083394 PMCID: PMC8200293 DOI: 10.26508/lsa.202000961] [Citation(s) in RCA: 2] [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: 11/17/2020] [Revised: 05/21/2021] [Accepted: 05/21/2021] [Indexed: 01/04/2023] Open
Abstract
Nuclear organisation shapes gene regulation; however, the principles by which three-dimensional genome architecture influences gene transcription are incompletely understood. Condensin is a key architectural chromatin constituent, best known for its role in mitotic chromosome condensation. Yet at least a subset of condensin is bound to DNA throughout the cell cycle. Studies in various organisms have reported roles for condensin in transcriptional regulation, but no unifying mechanism has emerged. Here, we use rapid conditional condensin depletion in the budding yeast Saccharomyces cerevisiae to study its role in transcriptional regulation. We observe a large number of small gene expression changes, enriched at genes located close to condensin-binding sites, consistent with a possible local effect of condensin on gene expression. Furthermore, nascent RNA sequencing reveals that transcriptional down-regulation in response to environmental stimuli, in particular to heat shock, is subdued without condensin. Our results underscore the multitude by which an architectural chromosome constituent can affect gene regulation and suggest that condensin facilitates transcriptional reprogramming as part of adaptation to environmental changes.
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Affiliation(s)
- Lucy Lancaster
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK
| | - Harshil Patel
- Bioinformatics and Biostatistics Science Technology Platform, The Francis Crick Institute, London, UK
| | - Gavin Kelly
- Bioinformatics and Biostatistics Science Technology Platform, The Francis Crick Institute, London, UK
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK
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8
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Henrikus SS, Costa A. Towards a Structural Mechanism for Sister Chromatid Cohesion Establishment at the Eukaryotic Replication Fork. BIOLOGY 2021; 10:466. [PMID: 34073213 PMCID: PMC8229022 DOI: 10.3390/biology10060466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 12/23/2022]
Abstract
Cohesion between replicated chromosomes is essential for chromatin dynamics and equal segregation of duplicated genetic material. In the G1 phase, the ring-shaped cohesin complex is loaded onto duplex DNA, enriching at replication start sites, or "origins". During the same phase of the cell cycle, and also at the origin sites, two MCM helicases are loaded as symmetric double hexamers around duplex DNA. During the S phase, and through the action of replication factors, cohesin switches from encircling one parental duplex DNA to topologically enclosing the two duplicated DNA filaments, which are known as sister chromatids. Despite its vital importance, the structural mechanism leading to sister chromatid cohesion establishment at the replication fork is mostly elusive. Here we review the current understanding of the molecular interactions between the replication machinery and cohesin, which support sister chromatid cohesion establishment and cohesin function. In particular, we discuss how cryo-EM is shedding light on the mechanisms of DNA replication and cohesin loading processes. We further expound how frontier cryo-EM approaches, combined with biochemistry and single-molecule fluorescence assays, can lead to understanding the molecular basis of sister chromatid cohesion establishment at the replication fork.
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Affiliation(s)
| | - Alessandro Costa
- Macromolecular Machines Laboratory, The Francis Crick Institute, London NW1 1AT, UK;
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9
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Kim KD. Potential roles of condensin in genome organization and beyond in fission yeast. J Microbiol 2021; 59:449-459. [PMID: 33877578 DOI: 10.1007/s12275-021-1039-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 11/24/2022]
Abstract
The genome is highly organized hierarchically by the function of structural maintenance of chromosomes (SMC) complex proteins such as condensin and cohesin from bacteria to humans. Although the roles of SMC complex proteins have been well characterized, their specialized roles in nuclear processes remain unclear. Condensin and cohesin have distinct binding sites and mediate long-range and short-range genomic associations, respectively, to form cell cycle-specific genome organization. Condensin can be recruited to highly expressed genes as well as dispersed repeat genetic elements, such as Pol III-transcribed genes, LTR retrotransposon, and rDNA repeat. In particular, mitotic transcription factors Ace2 and Ams2 recruit condensin to their target genes, forming centromeric clustering during mitosis. Condensin is potentially involved in various chromosomal processes such as the mobility of chromosomes, chromosome territories, DNA reannealing, and transcription factories. The current knowledge of condensin in fission yeast summarized in this review can help us understand how condensin mediates genome organization and participates in chromosomal processes in other organisms.
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Affiliation(s)
- Kyoung-Dong Kim
- Department of Systems Biotechnology, Chung-Ang University, Anseong, 17546, Republic of Korea.
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10
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Rivosecchi J, Jost D, Vachez L, Gautier FD, Bernard P, Vanoosthuyse V. RNA polymerase backtracking results in the accumulation of fission yeast condensin at active genes. Life Sci Alliance 2021; 4:4/6/e202101046. [PMID: 33771877 PMCID: PMC8046420 DOI: 10.26508/lsa.202101046] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/04/2021] [Accepted: 03/07/2021] [Indexed: 12/23/2022] Open
Abstract
Using both experiments and mathematical modelling, the authors show that RNA polymerase backtracking contributes to the accumulation of condensin in the termination zone of active genes. The mechanisms leading to the accumulation of the SMC complexes condensins around specific transcription units remain unclear. Observations made in bacteria suggested that RNA polymerases (RNAPs) constitute an obstacle to SMC translocation, particularly when RNAP and SMC travel in opposite directions. Here we show in fission yeast that gene termini harbour intrinsic condensin-accumulating features whatever the orientation of transcription, which we attribute to the frequent backtracking of RNAP at gene ends. Consistent with this, to relocate backtracked RNAP2 from gene termini to gene bodies was sufficient to cancel the accumulation of condensin at gene ends and to redistribute it evenly within transcription units, indicating that RNAP backtracking may play a key role in positioning condensin. Formalization of this hypothesis in a mathematical model suggests that the inclusion of a sub-population of RNAP with longer dwell-times is essential to fully recapitulate the distribution profiles of condensin around active genes. Taken together, our data strengthen the idea that dense arrays of proteins tightly bound to DNA alter the distribution of condensin on chromosomes.
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Affiliation(s)
- Julieta Rivosecchi
- Laboratoire de Biologie et Modélisation de la Cellule, Université de Lyon, École Normale Supérieure de Lyon, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 5239, Lyon, France
| | - Daniel Jost
- Laboratoire de Biologie et Modélisation de la Cellule, Université de Lyon, École Normale Supérieure de Lyon, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 5239, Lyon, France
| | - Laetitia Vachez
- Laboratoire de Biologie et Modélisation de la Cellule, Université de Lyon, École Normale Supérieure de Lyon, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 5239, Lyon, France
| | - François Dr Gautier
- Laboratoire de Biologie et Modélisation de la Cellule, Université de Lyon, École Normale Supérieure de Lyon, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 5239, Lyon, France
| | - Pascal Bernard
- Laboratoire de Biologie et Modélisation de la Cellule, Université de Lyon, École Normale Supérieure de Lyon, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 5239, Lyon, France
| | - Vincent Vanoosthuyse
- Laboratoire de Biologie et Modélisation de la Cellule, Université de Lyon, École Normale Supérieure de Lyon, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 5239, Lyon, France
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11
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Kakui Y, Barrington C, Barry DJ, Gerguri T, Fu X, Bates PA, Khatri BS, Uhlmann F. Fission yeast condensin contributes to interphase chromatin organization and prevents transcription-coupled DNA damage. Genome Biol 2020; 21:272. [PMID: 33153481 PMCID: PMC7643427 DOI: 10.1186/s13059-020-02183-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 10/19/2020] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Structural maintenance of chromosomes (SMC) complexes are central organizers of chromatin architecture throughout the cell cycle. The SMC family member condensin is best known for establishing long-range chromatin interactions in mitosis. These compact chromatin and create mechanically stable chromosomes. How condensin contributes to chromatin organization in interphase is less well understood. RESULTS Here, we use efficient conditional depletion of fission yeast condensin to determine its contribution to interphase chromatin organization. We deplete condensin in G2-arrested cells to preempt confounding effects from cell cycle progression without condensin. Genome-wide chromatin interaction mapping, using Hi-C, reveals condensin-mediated chromatin interactions in interphase that are qualitatively similar to those observed in mitosis, but quantitatively far less prevalent. Despite their low abundance, chromatin mobility tracking shows that condensin markedly confines interphase chromatin movements. Without condensin, chromatin behaves as an unconstrained Rouse polymer with excluded volume, while condensin constrains its mobility. Unexpectedly, we find that condensin is required during interphase to prevent ongoing transcription from eliciting a DNA damage response. CONCLUSIONS In addition to establishing mitotic chromosome architecture, condensin-mediated long-range chromatin interactions contribute to shaping chromatin organization in interphase. The resulting structure confines chromatin mobility and protects the genome from transcription-induced DNA damage. This adds to the important roles of condensin in maintaining chromosome stability.
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Affiliation(s)
- Yasutaka Kakui
- Chromosome Segregation Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
- Waseda Institute for Advanced Study, Waseda University, 1-21-1, Nishiwaseda, Shinjuku-ku, Tokyo, 169-0051, Japan.
| | - Christopher Barrington
- Bioinformatics & Biostatistics Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - David J Barry
- Advanced Light Microscopy Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Tereza Gerguri
- Biomolecular Modelling Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Xiao Fu
- Biomolecular Modelling Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Paul A Bates
- Biomolecular Modelling Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Bhavin S Khatri
- Chromosome Segregation Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, SL5 7PY, UK
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
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12
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Minchell NE, Keszthelyi A, Baxter J. Cohesin Causes Replicative DNA Damage by Trapping DNA Topological Stress. Mol Cell 2020; 78:739-751.e8. [PMID: 32259483 PMCID: PMC7242899 DOI: 10.1016/j.molcel.2020.03.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 02/12/2020] [Accepted: 03/09/2020] [Indexed: 12/25/2022]
Abstract
DNA topological stress inhibits DNA replication fork (RF) progression and contributes to DNA replication stress. In Saccharomyces cerevisiae, we demonstrate that centromeric DNA and the rDNA array are especially vulnerable to DNA topological stress during replication. The activity of the SMC complexes cohesin and condensin are linked to both the generation and repair of DNA topological-stress-linked damage in these regions. At cohesin-enriched centromeres, cohesin activity causes the accumulation of DNA damage, RF rotation, and pre-catenation, confirming that cohesin-dependent DNA topological stress impacts on normal replication progression. In contrast, at the rDNA, cohesin and condensin activity inhibit the repair of damage caused by DNA topological stress. We propose that, as well as generally acting to ensure faithful genetic inheritance, SMCs can disrupt genome stability by trapping DNA topological stress.
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Affiliation(s)
- Nicola Elizabeth Minchell
- Genome Damage and Stability Centre, School of Life Sciences, Science Park Road, University of Sussex, Falmer, Brighton, East Sussex BN1 9RQ, UK
| | - Andrea Keszthelyi
- Genome Damage and Stability Centre, School of Life Sciences, Science Park Road, University of Sussex, Falmer, Brighton, East Sussex BN1 9RQ, UK
| | - Jonathan Baxter
- Genome Damage and Stability Centre, School of Life Sciences, Science Park Road, University of Sussex, Falmer, Brighton, East Sussex BN1 9RQ, UK.
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13
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El Dika M. New insights into the regulation of DNA-Protein Crosslink Repair by the Aspartic Protease Ddi1 in yeast. DNA Repair (Amst) 2020; 90:102854. [PMID: 32330640 DOI: 10.1016/j.dnarep.2020.102854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 04/07/2020] [Indexed: 11/19/2022]
Affiliation(s)
- Mohammed El Dika
- Institut Curie, PSL Research University, CNRS, UMR3348, Orsay, France; Paris Sud University, Paris-Saclay University, CNRS, UMR3348, Orsay, France.
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14
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Nakazawa N, Arakawa O, Yanagida M. Condensin locates at transcriptional termination sites in mitosis, possibly releasing mitotic transcripts. Open Biol 2019; 9:190125. [PMID: 31615333 PMCID: PMC6833218 DOI: 10.1098/rsob.190125] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Condensin is an essential component of chromosome dynamics, including mitotic chromosome condensation and segregation, DNA repair, and development. Genome-wide localization of condensin is known to correlate with transcriptional activity. The functional relationship between condensin accumulation and transcription sites remains unclear, however. By constructing the auxin-inducible degron strain of condensin, herein we demonstrate that condensin does not affect transcription itself. Instead, RNA processing at transcriptional termination appears to define condensin accumulation sites during mitosis, in the fission yeast Schizosaccharomyces pombe. Combining the auxin-degron strain with the nda3 β-tubulin cold-sensitive (cs) mutant enabled us to inactivate condensin in mitotically arrested cells, without releasing the cells into anaphase. Transcriptional activation and termination were not affected by condensin's degron-mediated depletion, at heat-shock inducible genes or mitotically activated genes. On the other hand, condensin accumulation sites shifted approximately 500 bp downstream in the auxin-degron of 5′-3′ exoribonuclease Dhp1, in which transcripts became aberrantly elongated, suggesting that condensin accumulates at transcriptionally terminated DNA regions. Growth defects in mutant strains of 3′-processing ribonuclease and polyA cleavage factors were additive in condensin temperature-sensitive (ts) mutants. Considering condensin's in vitro activity to form double-stranded DNAs from unwound, single-stranded DNAs or DNA-RNA hybrids, condensin-mediated processing of mitotic transcripts at the 3′-end may be a prerequisite for faithful chromosome segregation.
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Affiliation(s)
- Norihiko Nakazawa
- Okinawa Institute of Science and Technology Graduate University, G0 Cell Unit, Onna-son, Okinawa 904-0495, Japan
| | - Orie Arakawa
- Okinawa Institute of Science and Technology Graduate University, G0 Cell Unit, Onna-son, Okinawa 904-0495, Japan
| | - Mitsuhiro Yanagida
- Okinawa Institute of Science and Technology Graduate University, G0 Cell Unit, Onna-son, Okinawa 904-0495, Japan
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15
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Kawakami H, Muraoka R, Ohashi E, Kawabata K, Kanamoto S, Chichibu T, Tsurimoto T, Katayama T. Specific basic patch-dependent multimerization of Saccharomyces cerevisiae ORC on single-stranded DNA promotes ATP hydrolysis. Genes Cells 2019; 24:608-618. [PMID: 31233675 DOI: 10.1111/gtc.12710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/12/2019] [Accepted: 06/18/2019] [Indexed: 11/26/2022]
Abstract
Replication initiation at specific genomic loci dictates precise duplication and inheritance of genetic information. In eukaryotic cells, ATP-bound origin recognition complexes (ORCs) stably bind to double-stranded (ds) DNA origins to recruit the replicative helicase onto the origin DNA. To achieve these processes, an essential region of the origin DNA must be recognized by the eukaryotic origin sensor (EOS) basic patch within the disordered domain of the largest ORC subunit, Orc1. Although ORC also binds single-stranded (ss) DNA in an EOS-independent manner, it is unknown whether EOS regulates ORC on ssDNA. We found that, in budding yeast, ORC multimerizes on ssDNA in vitro independently of adenine nucleotides. We also found that the ORC multimers form in an EOS-dependent manner and stimulate the ORC ATPase activity. An analysis of genomics data supported the idea that ORC-ssDNA binding occurs in vivo at specific genomic loci outside of replication origins. These results suggest that EOS function is differentiated by ORC-bound ssDNA, which promotes ORC self-assembly and ATP hydrolysis. These mechanisms could modulate ORC activity at specific genomic loci and could be conserved among eukaryotes.
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Affiliation(s)
- Hironori Kawakami
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Ryuya Muraoka
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Eiji Ohashi
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Kenta Kawabata
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Shota Kanamoto
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Takeaki Chichibu
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Toshiki Tsurimoto
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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16
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Isolation of Fission Yeast Condensin Temperature-Sensitive Mutants with Single Amino Acid Substitutions Targeted to Hinge Domain. G3-GENES GENOMES GENETICS 2019; 9:1777-1783. [PMID: 30914423 PMCID: PMC6505169 DOI: 10.1534/g3.119.400156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Essential genes cannot be deleted from the genome; therefore, temperature-sensitive (ts) mutants and cold-sensitive (cs) mutants are very useful to discover functions of essential genes in model organisms such as Schizosaccharomyces pombe and Saccharomyces cerevisiae. To isolate ts/cs mutants for essential genes of interest, error-prone mutagenesis (or random mutagenesis) coupled with in vitro selection has been widely used. However, this method often introduces multiple silent mutations, in addition to the mutation responsible for ts/cs, with the result that one cannot discern which mutation is responsible for the ts/cs phenotype. In addition, the location of the responsible mutation introduced is random, whereas it is preferable to isolate ts/cs mutants with single amino acid substitutions, located in a targeted motif or domain of the protein of interest. To solve these problems, we have developed a method to isolate ts/cs mutants with single amino acid substitutions in targeted regions using site-directed mutagenesis. This method takes advantage of the empirical fact that single amino acid substitutions (L/S -> P or G/A -> E/D) often cause ts or cs. Application of the method to condensin and cohesin hinge domains was successful: ∼20% of the selected single amino acid substitutions turned out to be ts or cs. This method is versatile in fission yeast and is expected to be broadly applicable to isolate ts/cs mutants with single amino acid substitutions in targeted regions of essential genes. 11 condensin hinge ts mutants were isolated using the method and their responsible mutations are broadly distributed in hinge domain. Characterization of these mutants will be very helpful to understand the function of hinge domain.
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17
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Baxter J, Oliver AW, Schalbetter SA. Are SMC Complexes Loop Extruding Factors? Linking Theory With Fact. Bioessays 2018; 41:e1800182. [PMID: 30506702 DOI: 10.1002/bies.201800182] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/05/2018] [Indexed: 01/24/2023]
Abstract
The extreme length of chromosomal DNA requires organizing mechanisms to both promote functional genetic interactions and ensure faithful chromosome segregation when cells divide. Microscopy and genome-wide contact frequency analyses indicate that intra-chromosomal looping of DNA is a primary pathway of chromosomal organization during all stages of the cell cycle. DNA loop extrusion has emerged as a unifying model for how chromosome loops are formed in cis in different genomic contexts and cell cycle stages. The highly conserved family of SMC complexes have been found to be required for DNA cis-looping and have been suggested to be the enzymatic core of loop extruding machines. Here, the current body of evidence available for the in vivo and in vitro action of SMC complexes is discussed and compared to the predictions made by the loop extrusion model. How SMC complexes may differentially act on chromatin to generate DNA loops and how they could work to generate the dynamic and functionally appropriate organization of DNA in cells is explored.
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Affiliation(s)
- Jonathan Baxter
- Genome Damage and Stability Centre, Science Park Road, University of Sussex, Falmer, Brighton, East Sussex BN1 9RQ, UK
| | - Antony W Oliver
- Genome Damage and Stability Centre, Science Park Road, University of Sussex, Falmer, Brighton, East Sussex BN1 9RQ, UK
| | - Stephanie A Schalbetter
- Genome Damage and Stability Centre, Science Park Road, University of Sussex, Falmer, Brighton, East Sussex BN1 9RQ, UK
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18
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Condensin action and compaction. Curr Genet 2018; 65:407-415. [PMID: 30361853 DOI: 10.1007/s00294-018-0899-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 10/18/2018] [Accepted: 10/20/2018] [Indexed: 12/20/2022]
Abstract
Condensin is a multi-subunit protein complex that belongs to the family of structural maintenance of chromosomes (SMC) complexes. Condensins regulate chromosome structure in a wide range of processes including chromosome segregation, gene regulation, DNA repair and recombination. Recent research defined the structural features and molecular activities of condensins, but it is unclear how these activities are connected to the multitude of phenotypes and functions attributed to condensins. In this review, we briefly discuss the different molecular mechanisms by which condensins may regulate global chromosome compaction, organization of topologically associated domains, clustering of specific loci such as tRNA genes, rDNA segregation, and gene regulation.
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19
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Murayama Y, Samora CP, Kurokawa Y, Iwasaki H, Uhlmann F. Establishment of DNA-DNA Interactions by the Cohesin Ring. Cell 2018; 172:465-477.e15. [PMID: 29358048 PMCID: PMC5786502 DOI: 10.1016/j.cell.2017.12.021] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 10/12/2017] [Accepted: 12/16/2017] [Indexed: 01/14/2023]
Abstract
The ring-shaped structural maintenance of chromosome (SMC) complexes are multi-subunit ATPases that topologically encircle DNA. SMC rings make vital contributions to numerous chromosomal functions, including mitotic chromosome condensation, sister chromatid cohesion, DNA repair, and transcriptional regulation. They are thought to do so by establishing interactions between more than one DNA. Here, we demonstrate DNA-DNA tethering by the purified fission yeast cohesin complex. DNA-bound cohesin efficiently and topologically captures a second DNA, but only if that is single-stranded DNA (ssDNA). Like initial double-stranded DNA (dsDNA) embrace, second ssDNA capture is ATP-dependent, and it strictly requires the cohesin loader complex. Second-ssDNA capture is relatively labile but is converted into stable dsDNA-dsDNA cohesion through DNA synthesis. Our study illustrates second-DNA capture by an SMC complex and provides a molecular model for the establishment of sister chromatid cohesion.
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Affiliation(s)
- Yasuto Murayama
- Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
| | - Catarina P Samora
- Chromosome Segregation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Yumiko Kurokawa
- Education Academy of Computational Life Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Hiroshi Iwasaki
- Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Frank Uhlmann
- Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan; Chromosome Segregation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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20
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Murayama Y. DNA entry, exit and second DNA capture by cohesin: insights from biochemical experiments. Nucleus 2018; 9:492-502. [PMID: 30205748 PMCID: PMC6244732 DOI: 10.1080/19491034.2018.1516486] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/28/2018] [Accepted: 08/16/2018] [Indexed: 12/23/2022] Open
Abstract
Cohesin is a ring-shaped, multi-subunit ATPase assembly that is fundamental to the spatiotemporal organization of chromosomes. The ring establishes a variety of chromosomal structures including sister chromatid cohesion and chromatin loops. At the core of the ring is a pair of highly conserved SMC (Structural Maintenance of Chromosomes) proteins, which are closed by the flexible kleisin subunit. In common with other essential SMC complexes including condensin and the SMC5-6 complex, cohesin encircles DNA inside its cavity, with the aid of HEAT (Huntingtin, elongation factor 3, protein phosphatase 2A and TOR) repeat auxiliary proteins. Through this topological embrace, cohesin is thought to establish a series of intra- and interchromosomal interactions by tethering more than one DNA molecule. Recent progress in biochemical reconstitution of cohesin provides molecular insights into how this ring complex topologically binds and mediates DNA-DNA interactions. Here, I review these studies and discuss how cohesin mediates such chromosome interactions.
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Affiliation(s)
- Yasuto Murayama
- Chromosome Biochemistry Laboratory, Center for Frontier Research, National Institute of Genetics, Mishima, Shizuoka, Japan
- Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Mishima, Shizuoka, Japan
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21
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Condensin, master organizer of the genome. Chromosome Res 2017; 25:61-76. [PMID: 28181049 DOI: 10.1007/s10577-017-9553-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/19/2016] [Accepted: 01/23/2017] [Indexed: 02/06/2023]
Abstract
A fundamental requirement in nature is for a cell to correctly package and divide its replicated genome. Condensin is a mechanical multisubunit complex critical to this process. Condensin uses ATP to power conformational changes in DNA to enable to correct DNA compaction, organization, and segregation of DNA from the simplest bacteria to humans. The highly conserved nature of the condensin complex and the structural similarities it shares with the related cohesin complex have provided important clues as to how it functions in cells. The fundamental requirement for condensin in mitosis and meiosis is well established, yet the precise mechanism of action is still an open question. Mutation or removal of condensin subunits across a range of species disrupts orderly chromosome condensation leading to errors in chromosome segregation and likely death of the cell. There are divergences in function across species for condensin. Once considered to function solely in mitosis and meiosis, an accumulating body of evidence suggests that condensin has key roles in also regulating the interphase genome. This review will examine how condensin organizes our genomes, explain where and how it binds the genome at a mechanical level, and highlight controversies and future directions as the complex continues to fascinate and baffle biologists.
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22
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The loading of condensin in the context of chromatin. Curr Genet 2016; 63:577-589. [PMID: 27909798 DOI: 10.1007/s00294-016-0669-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 11/24/2016] [Accepted: 11/25/2016] [Indexed: 12/23/2022]
Abstract
The packaging of DNA into chromosomes is a ubiquitous process that enables living organisms to structure and transmit their genome accurately through cell divisions. In the three kingdoms of life, the architecture and dynamics of chromosomes rely upon ring-shaped SMC (Structural Maintenance of Chromosomes) condensin complexes. To understand how condensin rings organize chromosomes, it is essential to decipher how they associate with chromatin filaments. Here, we use recent evidence to discuss the role played by nucleosomes and transcription factors in the loading of condensin at transcribed genes. We propose a model whereby cis-acting features nestled in the promoters of active genes synergistically attract condensin rings and promote their association with DNA.
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23
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Zhang T, Si-Hoe SL, Hudson DF, Surana U. Condensin recruitment to chromatin is inhibited by Chk2 kinase in response to DNA damage. Cell Cycle 2016; 15:3454-3470. [PMID: 27792460 DOI: 10.1080/15384101.2016.1249075] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The DNA damage checkpoint, when activated in response to genotoxic damage during S phase, arrests cells in G2 phase of the cell cycle. ATM, ATR, Chk1 and Chk2 kinases are the main effectors of this checkpoint pathway. The checkpoint kinases prevent the onset of mitosis by eliciting well characterized inhibitory phosphorylation of Cdk1. Since Cdk1 is required for the recruitment of condensin, it is thought that upon DNA damage the checkpoint also indirectly blocks chromosome condensation via Cdk1 inhibition. Here we report that the G2 damage checkpoint prevents stable recruitment of the chromosome-packaging-machinery components condensin complex I and II onto the chromatin even in the presence of an active Cdk1. DNA damage-induced inhibition of condensin subunit recruitment is mediated specifically by the Chk2 kinase, implying that the condensin complexes are targeted by the checkpoint in response to DNA damage, independently of Cdk1 inactivation. Thus, the G2 checkpoint directly prevents stable recruitment of condensin complexes to actively prevent chromosome compaction during G2 arrest, presumably to ensure efficient repair of the genomic damage.
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Affiliation(s)
- Tao Zhang
- a Institute of Molecular and Cell Biology, Agency for Science Technology and Research , Singapore.,b Murdoch Childrens Research Institute, Royal Children's Hospital , Melbourne , Australia.,c Department of Pediatrics , University of Melbourne, Royal Children's Hospital , Melbourne , Australia
| | - San Ling Si-Hoe
- a Institute of Molecular and Cell Biology, Agency for Science Technology and Research , Singapore
| | - Damien F Hudson
- b Murdoch Childrens Research Institute, Royal Children's Hospital , Melbourne , Australia.,c Department of Pediatrics , University of Melbourne, Royal Children's Hospital , Melbourne , Australia
| | - Uttam Surana
- a Institute of Molecular and Cell Biology, Agency for Science Technology and Research , Singapore.,d Department of Pharmacology , National University of Singapore , Singapore.,e Bioprocessing Technology Institute, Agency for Science Technology and Research , Singapore
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24
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Uchiyama S, Fukui K. Condensin in Chromatid Cohesion and Segregation. Cytogenet Genome Res 2016; 147:212-6. [PMID: 26998746 DOI: 10.1159/000444868] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2015] [Indexed: 11/19/2022] Open
Abstract
After replication of genomic DNA during the S phase, 2 chromatids hold together longitudinally. When cells enter mitosis, the paired sister chromatids start to condense and then segregate into individual chromatids except for the centromeric region. Upon attachment of microtubules to the kinetochore, subsequent pulling of the 2 sister chromatids by the spindles towards opposite poles results in 2 completely separated chromatids. Besides more than 100 kinds of kinetochore proteins, several key proteins such as cohesin, separase, shugoshin, and condensin contribute to chromatid cohesion and segregation. Among these proteins, condensin, a protein complex composed of 5 subunits discovered 2 decades ago, has been extensively studied in terms of the maintenance of chromosome morphology as its major function. Recent studies on condensin uncovered its role in chromatid cohesion and segregation, which will be reviewed in this article.
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Affiliation(s)
- Susumu Uchiyama
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Osaka, Japan
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25
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Abstract
Condensins are large protein complexes that play a central role in chromosome organization and segregation in the three domains of life. They display highly characteristic, rod-shaped structures with SMC (structural maintenance of chromosomes) ATPases as their core subunits and organize large-scale chromosome structure through active mechanisms. Most eukaryotic species have two distinct condensin complexes whose balanced usage is adapted flexibly to different organisms and cell types. Studies of bacterial condensins provide deep insights into the fundamental mechanisms of chromosome segregation. This Review surveys both conserved features and rich variations of condensin-based chromosome organization and discusses their evolutionary implications.
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Affiliation(s)
- Tatsuya Hirano
- Chromosome Dynamics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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26
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Uchiyama S, Kawahara K, Hosokawa Y, Fukakusa S, Oki H, Nakamura S, Kojima Y, Noda M, Takino R, Miyahara Y, Maruno T, Kobayashi Y, Ohkubo T, Fukui K. Structural Basis for Dimer Formation of Human Condensin Structural Maintenance of Chromosome Proteins and Its Implications for Single-stranded DNA Recognition. J Biol Chem 2015; 290:29461-77. [PMID: 26491021 PMCID: PMC4705948 DOI: 10.1074/jbc.m115.670794] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/17/2015] [Indexed: 11/06/2022] Open
Abstract
Eukaryotic structural maintenance of chromosome proteins (SMC) are major components of cohesin and condensins that regulate chromosome structure and dynamics during cell cycle. We here determine the crystal structure of human condensin SMC hinge heterodimer with ~30 residues of coiled coils. The structure, in conjunction with the hydrogen exchange mass spectrometry analyses, revealed the structural basis for the specific heterodimer formation of eukaryotic SMC and that the coiled coils from two different hinges protrude in the same direction, providing a unique binding surface conducive for binding to single-stranded DNA. The characteristic hydrogen exchange profiles of peptides constituted regions especially across the hinge-hinge dimerization interface, further suggesting the structural alterations upon single-stranded DNA binding and the presence of a half-opened state of hinge heterodimer. This structural change potentially relates to the DNA loading mechanism of SMC, in which the hinge domain functions as an entrance gate as previously proposed for cohesin. Our results, however, indicated that this is not the case for condensins based on the fact that the coiled coils are still interacting with each other, even when DNA binding induces structural changes in the hinge region, suggesting the functional differences of SMC hinge domain between condensins and cohesin in DNA recognition.
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Affiliation(s)
- Susumu Uchiyama
- From the Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- the Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama Myodaiji, Okazaki 444-8787, Japan
| | - Kazuki Kawahara
- the Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan, and
| | - Yuki Hosokawa
- the Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan, and
| | - Shunsuke Fukakusa
- the Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan, and
| | - Hiroya Oki
- the Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan, and
| | - Shota Nakamura
- the Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yukiko Kojima
- the Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan, and
| | - Masanori Noda
- From the Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Rie Takino
- From the Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yuya Miyahara
- From the Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takahiro Maruno
- From the Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yuji Kobayashi
- From the Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tadayasu Ohkubo
- the Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan, and
| | - Kiichi Fukui
- From the Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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27
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Condensin targets and reduces unwound DNA structures associated with transcription in mitotic chromosome condensation. Nat Commun 2015. [PMID: 26204128 PMCID: PMC4525155 DOI: 10.1038/ncomms8815] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Chromosome condensation is a hallmark of mitosis in eukaryotes and is a prerequisite for faithful segregation of genetic material to daughter cells. Here we show that condensin, which is essential for assembling condensed chromosomes, helps to preclude the detrimental effects of gene transcription on mitotic condensation. ChIP-seq profiling reveals that the fission yeast condensin preferentially binds to active protein-coding genes in a transcription-dependent manner during mitosis. Pharmacological and genetic attenuation of transcription largely rescue bulk chromosome segregation defects observed in condensin mutants. We also demonstrate that condensin is associated with and reduces unwound DNA segments generated by transcription, providing a direct link between an in vitro activity of condensin and its in vivo function. The human condensin isoform condensin I also binds to unwound DNA regions at the transcription start sites of active genes, implying that our findings uncover a fundamental feature of condensin complexes. Chromosome condensation is a prerequisite for faithful segregation of chromosomes to daughter cells. Here, the authors show that the condensin complex binds to protein-coding genes in a transcription-dependent manner during condensation, and reduces unwound DNA segments generated by transcription.
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28
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Akai Y, Kanai R, Nakazawa N, Ebe M, Toyoshima C, Yanagida M. ATPase-dependent auto-phosphorylation of the open condensin hinge diminishes DNA binding. Open Biol 2015; 4:rsob.140193. [PMID: 25520186 PMCID: PMC4281712 DOI: 10.1098/rsob.140193] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Condensin, which contains two structural maintenance of chromosome (SMC) subunits and three regulatory non-SMC subunits, is essential for many chromosomal functions, including mitotic chromosome condensation and segregation. The ATPase domain of the SMC subunit comprises two termini connected by a long helical domain that is interrupted by a central hinge. The role of the ATPase domain has remained elusive. Here we report that the condensin SMC subunit of the fission yeast Schizosaccharomyces pombe is phosphorylated in a manner that requires the presence of the intact SMC ATPase Walker motif. Principal phosphorylation sites reside in the conserved, glycine-rich stretch at the hinge interface surrounded by the highly basic DNA-binding patch. Phosphorylation reduces affinity for DNA. Consistently, phosphomimetic mutants produce severe mitotic phenotypes. Structural evidence suggests that prior opening (though slight) of the hinge is necessary for phosphorylation, which is implicated in condensin's dissociation from and its progression along DNA.
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Affiliation(s)
- Yuko Akai
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Ryuta Kanai
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo 113-0032, Japan
| | - Norihiko Nakazawa
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Masahiro Ebe
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Chikashi Toyoshima
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo 113-0032, Japan
| | - Mitsuhiro Yanagida
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
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29
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Roy MA, Dhanaraman T, D'Amours D. The Smc5-Smc6 heterodimer associates with DNA through several independent binding domains. Sci Rep 2015; 5:9797. [PMID: 25984708 PMCID: PMC4434891 DOI: 10.1038/srep09797] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 03/20/2015] [Indexed: 12/12/2022] Open
Abstract
The Smc5-6 complex is required for the maintenance of genome integrity through its
functions in DNA repair and chromosome biogenesis. However, the specific mode of
action of Smc5 and Smc6 in these processes remains largely unknown. We previously
showed that individual components of the Smc5-Smc6 complex bind strongly to DNA as
monomers, despite the absence of a canonical DNA-binding domain (DBD) in these
proteins. How heterodimerization of Smc5-6 affects its binding to DNA, and which
parts of the SMC molecules confer DNA-binding activity is not known at present. To
address this knowledge gap, we characterized the functional domains of the Smc5-6
heterodimer and identify two DBDs in each SMC molecule. The first DBD is located
within the SMC hinge region and its adjacent coiled-coil arms, while the second is
found in the conserved ATPase head domain. These DBDs can independently recapitulate
the substrate preference of the full-length Smc5 and Smc6 proteins. We also show
that heterodimerization of full-length proteins specifically increases the affinity
of the resulting complex for double-stranded DNA substrates. Collectively, our
findings provide critical insights into the structural requirements for effective
binding of the Smc5-6 complex to DNA repair substrates in vitro and in live
cells.
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Affiliation(s)
- Marc-André Roy
- Institute for Research in Immunology and Cancer, and Département de Pathologie et biologie cellulaire, Université de Montréal P.O. Box 6128, Succursale Centre-Ville Montréal, QC, H3C 3J7, Canada
| | - Thillaivillalan Dhanaraman
- Institute for Research in Immunology and Cancer, and Département de Pathologie et biologie cellulaire, Université de Montréal P.O. Box 6128, Succursale Centre-Ville Montréal, QC, H3C 3J7, Canada
| | - Damien D'Amours
- Institute for Research in Immunology and Cancer, and Département de Pathologie et biologie cellulaire, Université de Montréal P.O. Box 6128, Succursale Centre-Ville Montréal, QC, H3C 3J7, Canada
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Nakazawa N, Sajiki K, Xu X, Villar-Briones A, Arakawa O, Yanagida M. RNA pol II transcript abundance controls condensin accumulation at mitotically up-regulated and heat-shock-inducible genes in fission yeast. Genes Cells 2015; 20:481-99. [PMID: 25847133 PMCID: PMC4471619 DOI: 10.1111/gtc.12239] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 02/24/2015] [Indexed: 12/31/2022]
Abstract
Condensin plays fundamental roles in chromosome dynamics. In this study, we determined the binding sites of condensin on fission yeast (Schizosaccharomyces pombe) chromosomes at the level of nucleotide sequences using chromatin immunoprecipitation (ChIP) and ChIP sequencing (ChIP-seq). We found that condensin binds to RNA polymerase I-, II- and III-transcribed genes during both mitosis and interphase, and we focused on pol II constitutive and inducible genes. Accumulation sites for condensin are distinct from those of cohesin and DNA topoisomerase II. Using cell cycle stage and heat-shock-inducible genes, we show that pol II-mediated transcripts cause condensin accumulation. First, condensin's enrichment on mitotically activated genes was abolished by deleting the sep1(+) gene that encodes an M-phase-specific forkhead transcription factor. Second, by raising the temperature, condensin accumulation was rapidly induced at heat-shock protein genes in interphase and even during mid-mitosis. In interphase, condensin accumulates preferentially during the postreplicative phase. Pol II-mediated transcription was neither repressed nor activated by condensin, as levels of transcripts per se did not change when mutant condensin failed to associate with chromosomal DNA. However, massive chromosome missegregation occurred, suggesting that abundant pol II transcription may require active condensin before proper chromosome segregation.
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Affiliation(s)
- Norihiko Nakazawa
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, 904-0495, Japan
| | - Kenichi Sajiki
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, 904-0495, Japan
| | - Xingya Xu
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, 904-0495, Japan
| | - Alejandro Villar-Briones
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, 904-0495, Japan
| | - Orie Arakawa
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, 904-0495, Japan
| | - Mitsuhiro Yanagida
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, 904-0495, Japan
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31
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Xu X, Nakazawa N, Yanagida M. Condensin HEAT subunits required for DNA repair, kinetochore/centromere function and ploidy maintenance in fission yeast. PLoS One 2015; 10:e0119347. [PMID: 25764183 PMCID: PMC4357468 DOI: 10.1371/journal.pone.0119347] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/23/2015] [Indexed: 11/18/2022] Open
Abstract
Condensin, a central player in eukaryotic chromosomal dynamics, contains five evolutionarily-conserved subunits. Two SMC (structural maintenance of chromosomes) subunits contain ATPase, hinge, and coiled-coil domains. One non-SMC subunit is similar to bacterial kleisin, and two other non-SMC subunits contain HEAT (similar to armadillo) repeats. Here we report isolation and characterization of 21 fission yeast (Schizosaccharomyces pombe) mutants for three non-SMC subunits, created using error-prone mutagenesis that resulted in single-amino acid substitutions. Beside condensation, segregation, and DNA repair defects, similar to those observed in previously isolated SMC and cnd2 mutants, novel phenotypes were observed for mutants of HEAT-repeats containing Cnd1 and Cnd3 subunits. cnd3-L269P is hypersensitive to the microtubule poison, thiabendazole, revealing defects in kinetochore/centromere and spindle assembly checkpoints. Three cnd1 and three cnd3 mutants increased cell size and doubled DNA content, thereby eliminating the haploid state. Five of these mutations reside in helix B of HEAT repeats. Two non-SMC condensin subunits, Cnd1 and Cnd3, are thus implicated in ploidy maintenance.
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Affiliation(s)
- Xingya Xu
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, Japan
- Department of Genetics, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Norihiko Nakazawa
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, Japan
| | - Mitsuhiro Yanagida
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, Japan
- * E-mail:
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32
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Bernard P, Vanoosthuyse V. Does transcription play a role in creating a condensin binding site? Transcription 2015; 6:12-6. [PMID: 25634470 DOI: 10.1080/21541264.2015.1012980] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The highly conserved condensin complex is essential for the condensation and integrity of chromosomes through cell division. Published data argue that high levels of transcription contribute to specify some condensin-binding sites on chromosomes but the exact role of transcription in this process remains elusive. Here we discuss our recent data addressing the role of transcription in establishing a condensin-binding site.
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Affiliation(s)
- Pascal Bernard
- a CNRS, Université Lyon 01, UMR5239, LBMC; Ecole Normale Supérieure de Lyon , Lyon , France
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33
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Legros P, Malapert A, Niinuma S, Bernard P, Vanoosthuyse V. RNA processing factors Swd2.2 and Sen1 antagonize RNA Pol III-dependent transcription and the localization of condensin at Pol III genes. PLoS Genet 2014; 10:e1004794. [PMID: 25392932 PMCID: PMC4230746 DOI: 10.1371/journal.pgen.1004794] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 10/02/2014] [Indexed: 11/19/2022] Open
Abstract
Condensin-mediated chromosome condensation is essential for genome stability upon cell division. Genetic studies have indicated that the association of condensin with chromatin is intimately linked to gene transcription, but what transcription-associated feature(s) direct(s) the accumulation of condensin remains unclear. Here we show in fission yeast that condensin becomes strikingly enriched at RNA Pol III-transcribed genes when Swd2.2 and Sen1, two factors involved in the transcription process, are simultaneously deleted. Sen1 is an ATP-dependent helicase whose orthologue in Saccharomyces cerevisiae contributes both to terminate transcription of some RNA Pol II transcripts and to antagonize the formation of DNA:RNA hybrids in the genome. Using two independent mapping techniques, we show that DNA:RNA hybrids form in abundance at Pol III-transcribed genes in fission yeast but we demonstrate that they are unlikely to faciliate the recruitment of condensin. Instead, we show that Sen1 forms a stable and abundant complex with RNA Pol III and that Swd2.2 and Sen1 antagonize both the interaction of RNA Pol III with chromatin and RNA Pol III-dependent transcription. When Swd2.2 and Sen1 are lacking, the increased concentration of RNA Pol III and condensin at Pol III-transcribed genes is accompanied by the accumulation of topoisomerase I and II and by local nucleosome depletion, suggesting that Pol III-transcribed genes suffer topological stress. We provide evidence that this topological stress contributes to recruit and/or stabilize condensin at Pol III-transcribed genes in the absence of Swd2.2 and Sen1. Our data challenge the idea that a processive RNA polymerase hinders the binding of condensin and suggest that transcription-associated topological stress could in some circumstances facilitate the association of condensin. Failure to condense chromosomes prior to anaphase onset can lead to genome instability. The evolutionary-conserved condensin complex drives chromosome condensation, probably by changing the topology of chromatin around its binding sites. Condensin localizes to regions of high transcription, suggesting that some transcription-associated feature(s) direct its association with chromatin. Here we considered that transcription-dependent DNA:RNA hybrids or topological stress could be involved in recruiting condensin. Our data show that condensin is indeed enriched at regions accumulating DNA:RNA hybrids but that they are not involved in its recruitment. Rather, we identify a mutant combination where increased transcription by RNA Pol III is associated locally with stronger topological stress. Strikingly the localization of condensin is dramatically enhanced at the same loci and we show that topological stress contributes to this enhanced association. Our data strengthen the idea that transcription creates the environment necessary to recruit condensin in mitosis.
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Affiliation(s)
- Pénélope Legros
- CNRS, Université Lyon 01, UMR5239, LBMC; Ecole Normale Supérieure de Lyon, Lyon, France.
| | - Amélie Malapert
- CNRS, Université Lyon 01, UMR5239, LBMC; Ecole Normale Supérieure de Lyon, Lyon, France.
| | - Sho Niinuma
- CNRS, Université Lyon 01, UMR5239, LBMC; Ecole Normale Supérieure de Lyon, Lyon, France.
| | - Pascal Bernard
- CNRS, Université Lyon 01, UMR5239, LBMC; Ecole Normale Supérieure de Lyon, Lyon, France.
| | - Vincent Vanoosthuyse
- CNRS, Université Lyon 01, UMR5239, LBMC; Ecole Normale Supérieure de Lyon, Lyon, France.
- * E-mail:
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Yanagida M. The role of model organisms in the history of mitosis research. Cold Spring Harb Perspect Biol 2014; 6:a015768. [PMID: 25183827 DOI: 10.1101/cshperspect.a015768] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Mitosis is a cell-cycle stage during which condensed chromosomes migrate to the middle of the cell and segregate into two daughter nuclei before cytokinesis (cell division) with the aid of a dynamic mitotic spindle. The history of mitosis research is quite long, commencing well before the discovery of DNA as the repository of genetic information. However, great and rapid progress has been made since the introduction of recombinant DNA technology and discovery of universal cell-cycle control. A large number of conserved eukaryotic genes required for the progression from early to late mitotic stages have been discovered, confirming that DNA replication and mitosis are the two main events in the cell-division cycle. In this article, a historical overview of mitosis is given, emphasizing the importance of diverse model organisms that have been used to solve fundamental questions about mitosis.
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Affiliation(s)
- Mitsuhiro Yanagida
- Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0495, Japan
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35
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Li P, Jin H, Yu HG. Condensin suppresses recombination and regulates double-strand break processing at the repetitive ribosomal DNA array to ensure proper chromosome segregation during meiosis in budding yeast. Mol Biol Cell 2014; 25:2934-47. [PMID: 25103240 PMCID: PMC4230583 DOI: 10.1091/mbc.e14-05-0957] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Condensin undergoes a sequestration, release, and reloading cycle at the rDNA array in budding yeast meiosis. It regulates rDNA stability by suppressing double-strand break (DSB) formation and promoting DSB processing. During meiosis, homologues are linked by crossover, which is required for bipolar chromosome orientation before chromosome segregation at anaphase I. The repetitive ribosomal DNA (rDNA) array, however, undergoes little or no meiotic recombination. Hyperrecombination can cause chromosome missegregation and rDNA copy number instability. We report here that condensin, a conserved protein complex required for chromosome organization, regulates double-strand break (DSB) formation and repair at the rDNA gene cluster during meiosis in budding yeast. Condensin is highly enriched at the rDNA region during prophase I, released at the prophase I/metaphase I transition, and reassociates with rDNA before anaphase I onset. We show that condensin plays a dual role in maintaining rDNA stability: it suppresses the formation of Spo11-mediated rDNA breaks, and it promotes DSB processing to ensure proper chromosome segregation. Condensin is unnecessary for the export of rDNA breaks outside the nucleolus but required for timely repair of meiotic DSBs. Our work reveals that condensin coordinates meiotic recombination with chromosome segregation at the repetitive rDNA sequence, thereby maintaining genome integrity.
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Affiliation(s)
- Ping Li
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4370
| | - Hui Jin
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4370
| | - Hong-Guo Yu
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4370
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36
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Association of condensin with chromosomes depends on DNA binding by its HEAT-repeat subunits. Nat Struct Mol Biol 2014; 21:560-8. [DOI: 10.1038/nsmb.2831] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 04/24/2014] [Indexed: 02/07/2023]
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37
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Abstract
Mitotic chromosome condensation is a prerequisite for the accurate segregation of chromosomes during cell division, and the conserved condensin complex a central player of this process. However, how condensin binds chromatin and shapes mitotic chromosomes remain poorly understood. Recent genome-wide binding studies showing that in most species condensin is enriched near highly expressed genes suggest a conserved link between condensin occupancy and high transcription rates. To gain insight into the mechanisms of condensin binding and mitotic chromosome condensation, we searched for factors that collaborate with condensin through a synthetic lethal genetic screen in the fission yeast Schizosaccharomyces pombe. We isolated novel mutations affecting condensin, as well as mutations in four genes not previously implicated in mitotic chromosome condensation in fission yeast. These mutations cause chromosome segregation defects similar to those provoked by defects in condensation. We also identified a suppressor of the cut3-477 condensin mutation, which largely rescued chromosome segregation during anaphase. Remarkably, of the five genes identified in this study, four encode transcription co-factors. Our results therefore provide strong additional evidence for a functional connection between chromosome condensation and transcription.
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38
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Murakami-Tonami Y, Kishida S, Takeuchi I, Katou Y, Maris JM, Ichikawa H, Kondo Y, Sekido Y, Shirahige K, Murakami H, Kadomatsu K. Inactivation of SMC2 shows a synergistic lethal response in MYCN-amplified neuroblastoma cells. Cell Cycle 2014; 13:1115-31. [PMID: 24553121 PMCID: PMC4013162 DOI: 10.4161/cc.27983] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The condensin complex is required for chromosome condensation during mitosis; however, the role of this complex during interphase is unclear. Neuroblastoma is the most common extracranial solid tumor of childhood, and it is often lethal. In human neuroblastoma, MYCN gene amplification is correlated with poor prognosis. This study demonstrates that the gene encoding the condensin complex subunit SMC2 is transcriptionally regulated by MYCN. SMC2 also transcriptionally regulates DNA damage response genes in cooperation with MYCN. Downregulation of SMC2 induced DNA damage and showed a synergistic lethal response in MYCN-amplified/overexpression cells, leading to apoptosis in human neuroblastoma cells. Finally, this study found that patients bearing MYCN-amplified tumors showed improved survival when SMC2 expression was low. These results identify novel functions of SMC2 in DNA damage response, and we propose that SMC2 (or the condensin complex) is a novel molecular target for the treatment of MYCN-amplified neuroblastoma.
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Affiliation(s)
- Yuko Murakami-Tonami
- Department of Molecular Biology; Nagoya University Graduate School of Medicine; Nagoya, Japan
| | - Satoshi Kishida
- Department of Molecular Biology; Nagoya University Graduate School of Medicine; Nagoya, Japan
| | - Ichiro Takeuchi
- Department of Computer Science/Scientific and Engineering Simulation; Nagoya Institute of Technology; Nagoya, Japan
| | - Yuki Katou
- Laboratory of Genome Structure & Function; Institute of Molecular and Cellular Biosciences; The University of Tokyo; Tokyo, Japan
| | - John M Maris
- Department of Pediatrics and Center for Childhood Cancer Research; Children's Hospital of Philadelphia; University of Pennsylvania; Philadelphia, PA USA
| | | | - Yutaka Kondo
- Division of Molecular Oncology; Aichi Cancer Center Research Institute; Nagoya, Japan; Division of Epigenomics; Aichi Cancer Center Research Institute; Nagoya, Japan
| | - Yoshitaka Sekido
- Division of Molecular Oncology; Aichi Cancer Center Research Institute; Nagoya, Japan
| | - Katsuhiko Shirahige
- Laboratory of Genome Structure & Function; Institute of Molecular and Cellular Biosciences; The University of Tokyo; Tokyo, Japan
| | - Hiroshi Murakami
- Department of Biological Science; Faculty of Science and Engineering; Chuo University; Tokyo, Japan
| | - Kenji Kadomatsu
- Department of Molecular Biology; Nagoya University Graduate School of Medicine; Nagoya, Japan
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39
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Je EM, Yoo NJ, Lee SH. Mutational and expressional analysis of SMC2 gene in gastric and colorectal cancers with microsatellite instability. APMIS 2014; 122:499-504. [PMID: 24483990 DOI: 10.1111/apm.12193] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/05/2013] [Indexed: 12/21/2022]
Abstract
Structural maintenance of chromosomes 2 (SMC2) gene encodes condensin complexes that are required for proper chromosome segregation and maintenance of chromosomal stability. Although cells with defective chromosome segregation become aneuploid and are prone to harbor chromosome instability, pathologic implications of SMC2 gene alterations are largely unknown. In a public database, we found that SMC2 gene had mononucleotide repeats that could be mutated in cancers with microsatellite instability (MSI). In this study, we analyzed these repeats in 32 gastric cancers (GC) with high MSI (MSI-H), 59 GC with low MSI (MSI-L)/stable MSI (MSS), 43 colorectal cancers (CRC) with MSI-H and 60 CRC with MSI-L/MSS by single-strand conformation polymorphism (SSCP) and DNA sequencing. We also analyzed SMC2 protein expression in GC and CRC tissues using immunohistochemistry. We found SMC2 frameshift mutations in two GC and two CRC that would result in truncation of SMC2. The mutations were detected exclusively in MSI-H cancers, but not in MSI-L/MSS cancers. Loss of SMC2 expression was observed in 22% of GC and 25% of CRC. Of note, all of the cancers with SMC2 frameshift mutations displayed loss of SMC2 expression. Also, both GC and CRC with MSI-H had significantly higher incidences in SMC2 frameshift mutations and loss of SMC2 expression than those with MSI-L/MSS. Our data indicate that SMC2 gene is altered by both frameshift mutation and loss of expression in GC and CRC with MSI-H, and suggest that SMC2 gene alterations might be involved in pathogenesis of these cancers.
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Affiliation(s)
- Eun Mi Je
- Department of Pathology, College of Medicine, The Catholic University of Korea, Seoul, Korea
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40
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Wallace HA, Bosco G. Condensins and 3D Organization of the Interphase Nucleus. CURRENT GENETIC MEDICINE REPORTS 2013; 1:219-229. [PMID: 24563825 DOI: 10.1007/s40142-013-0024-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Condensins are conserved multi-subunit protein complexes that participate in eukaryotic genome organization. Well known for their role in mitotic chromosome condensation, condensins have recently emerged as integral components of diverse interphase processes. Recent evidence shows that condensins are involved in chromatin organization, gene expression, and DNA repair and indicates similarities between the interphase and mitotic functions of condensin. Recent work has enhanced our knowledge of how chromatin architecture is dynamically regulated by condensin to impact essential cellular processes.
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Affiliation(s)
- Heather A Wallace
- Department of Genetics, Geisel School of Medicine at Dartmouth, 609 Vail, HB 7400, Hanover, NH 03755, USA
| | - Giovanni Bosco
- Department of Genetics, Geisel School of Medicine at Dartmouth, 609 Vail, HB 7400, Hanover, NH 03755, USA
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41
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Piazza I, Haering CH, Rutkowska A. Condensin: crafting the chromosome landscape. Chromosoma 2013; 122:175-90. [DOI: 10.1007/s00412-013-0405-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 03/03/2013] [Accepted: 03/04/2013] [Indexed: 02/06/2023]
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42
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Abstract
Condensins are multisubunit protein complexes that play a fundamental role in the structural and functional organization of chromosomes in the three domains of life. Most eukaryotic species have two different types of condensin complexes, known as condensins I and II, that fulfill nonoverlapping functions and are subjected to differential regulation during mitosis and meiosis. Recent studies revealed that the two complexes contribute to a wide variety of interphase chromosome functions, such as gene regulation, recombination, and repair. Also emerging are their cell type- and tissue-specific functions and relevance to human disease. Biochemical and structural analyses of eukaryotic and bacterial condensins steadily uncover the mechanisms of action of this class of highly sophisticated molecular machines. Future studies on condensins will not only enhance our understanding of chromosome architecture and dynamics, but also help address a previously underappreciated yet profound set of questions in chromosome biology.
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Affiliation(s)
- Tatsuya Hirano
- Chromosome Dynamics Laboratory, RIKEN Advanced Science Institute, Wako, Saitama, Japan.
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43
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Open Biology's first few months. Open Biol 2012. [PMCID: PMC3352091 DOI: 10.1098/rsob.120027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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