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Hibino K, Sakai Y, Tamura S, Takagi M, Minami K, Natsume T, Shimazoe MA, Kanemaki MT, Imamoto N, Maeshima K. Single-nucleosome imaging unveils that condensins and nucleosome-nucleosome interactions differentially constrain chromatin to organize mitotic chromosomes. Nat Commun 2024; 15:7152. [PMID: 39169041 PMCID: PMC11339268 DOI: 10.1038/s41467-024-51454-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 08/08/2024] [Indexed: 08/23/2024] Open
Abstract
For accurate mitotic cell division, replicated chromatin must be assembled into chromosomes and faithfully segregated into daughter cells. While protein factors like condensin play key roles in this process, it is unclear how chromosome assembly proceeds as molecular events of nucleosomes in living cells and how condensins act on nucleosomes to organize chromosomes. To approach these questions, we investigate nucleosome behavior during mitosis of living human cells using single-nucleosome tracking, combined with rapid-protein depletion technology and computational modeling. Our results show that local nucleosome motion becomes increasingly constrained during mitotic chromosome assembly, which is functionally distinct from condensed apoptotic chromatin. Condensins act as molecular crosslinkers, locally constraining nucleosomes to organize chromosomes. Additionally, nucleosome-nucleosome interactions via histone tails constrain and compact whole chromosomes. Our findings elucidate the physical nature of the chromosome assembly process during mitosis.
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Affiliation(s)
- Kayo Hibino
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, Japan
| | - Yuji Sakai
- Graduate School of Nanobioscience, Yokohama City University, Yokohama, Kanagawa, Japan
- Department of Biosystems Science, Institute for Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Sachiko Tamura
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Masatoshi Takagi
- Cellular Dynamics Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
- Laboratory for Cell Function Dynamics, RIKEN Center for Brain Science, Wako, Saitama, Japan
| | - Katsuhiko Minami
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, Japan
| | - Toyoaki Natsume
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, Japan
- Molecular Cell Engineering Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
- Research Center for Genome & Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Masa A Shimazoe
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, Japan
| | - Masato T Kanemaki
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, Japan
- Molecular Cell Engineering Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
- Department of Biological Science, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Naoko Imamoto
- Cellular Dynamics Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
- Graduate School of Medical Safety Management, Jikei University of Health Care Sciences, Osaka, Japan
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan.
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, Japan.
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2
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Câmara AS, Kubalová I, Schubert V. Helical chromonema coiling is conserved in eukaryotes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:1284-1300. [PMID: 37840457 DOI: 10.1111/tpj.16484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 09/07/2023] [Accepted: 09/13/2023] [Indexed: 10/17/2023]
Abstract
Efficient chromatin condensation is required to transport chromosomes during mitosis and meiosis, forming daughter cells. While it is well accepted that these processes follow fundamental rules, there has been a controversial debate for more than 140 years on whether the higher-order chromatin organization in chromosomes is evolutionarily conserved. Here, we summarize historical and recent investigations based on classical and modern methods. In particular, classical light microscopy observations based on living, fixed, and treated chromosomes covering a wide range of plant and animal species, and even in single-cell eukaryotes suggest that the chromatids of large chromosomes are formed by a coiled chromatin thread, named the chromonema. More recently, these findings were confirmed by electron and super-resolution microscopy, oligo-FISH, molecular interaction data, and polymer simulation. Altogether, we describe common and divergent features of coiled chromonemata in different species. We hypothesize that chromonema coiling in large chromosomes is a fundamental feature established early during the evolution of eukaryotes to handle increasing genome sizes.
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Affiliation(s)
- Amanda Souza Câmara
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, D-06466, Seeland, Germany
| | - Ivona Kubalová
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, D-06466, Seeland, Germany
| | - Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, D-06466, Seeland, Germany
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3
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Golov AK, Gavrilov AA. Cohesin-Dependent Loop Extrusion: Molecular Mechanics and Role in Cell Physiology. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:601-625. [PMID: 38831499 DOI: 10.1134/s0006297924040023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 12/29/2023] [Accepted: 02/15/2024] [Indexed: 06/05/2024]
Abstract
The most prominent representatives of multisubunit SMC complexes, cohesin and condensin, are best known as structural components of mitotic chromosomes. It turned out that these complexes, as well as their bacterial homologues, are molecular motors, the ATP-dependent movement of these complexes along DNA threads leads to the formation of DNA loops. In recent years, we have witnessed an avalanche-like accumulation of data on the process of SMC dependent DNA looping, also known as loop extrusion. This review briefly summarizes the current understanding of the place and role of cohesin-dependent extrusion in cell physiology and presents a number of models describing the potential molecular mechanism of extrusion in a most compelling way. We conclude the review with a discussion of how the capacity of cohesin to extrude DNA loops may be mechanistically linked to its involvement in sister chromatid cohesion.
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Affiliation(s)
- Arkadiy K Golov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
- Technion - Israel Institute of Technology, Haifa, 3525433, Israel
| | - Alexey A Gavrilov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
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4
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Abstract
Many cellular processes require large-scale rearrangements of chromatin structure. Structural maintenance of chromosomes (SMC) protein complexes are molecular machines that can provide structure to chromatin. These complexes can connect DNA elements in cis, walk along DNA, build and processively enlarge DNA loops and connect DNA molecules in trans to hold together the sister chromatids. These DNA-shaping abilities place SMC complexes at the heart of many DNA-based processes, including chromosome segregation in mitosis, transcription control and DNA replication, repair and recombination. In this Review, we discuss the latest insights into how SMC complexes such as cohesin, condensin and the SMC5-SMC6 complex shape DNA to direct these fundamental chromosomal processes. We also consider how SMC complexes, by building chromatin loops, can counteract the natural tendency of alike chromatin regions to cluster. SMC complexes thus control nuclear organization by participating in a molecular tug of war that determines the architecture of our genome.
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Affiliation(s)
- Claire Hoencamp
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Benjamin D Rowland
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
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5
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Batty P, Langer CCH, Takács Z, Tang W, Blaukopf C, Peters J, Gerlich DW. Cohesin-mediated DNA loop extrusion resolves sister chromatids in G2 phase. EMBO J 2023; 42:e113475. [PMID: 37357575 PMCID: PMC10425840 DOI: 10.15252/embj.2023113475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 05/26/2023] [Accepted: 06/14/2023] [Indexed: 06/27/2023] Open
Abstract
Genetic information is stored in linear DNA molecules, which are highly folded inside cells. DNA replication along the folded template path yields two sister chromatids that initially occupy the same nuclear region in an intertwined arrangement. Dividing cells must disentangle and condense the sister chromatids into separate bodies such that a microtubule-based spindle can move them to opposite poles. While the spindle-mediated transport of sister chromatids has been studied in detail, the chromosome-intrinsic mechanics presegregating sister chromatids have remained elusive. Here, we show that human sister chromatids resolve extensively already during interphase, in a process dependent on the loop-extruding activity of cohesin, but not that of condensins. Increasing cohesin's looping capability increases sister DNA resolution in interphase nuclei to an extent normally seen only during mitosis, despite the presence of abundant arm cohesion. That cohesin can resolve sister chromatids so extensively in the absence of mitosis-specific activities indicates that DNA loop extrusion is a generic mechanism for segregating replicated genomes, shared across different Structural Maintenance of Chromosomes (SMC) protein complexes in all kingdoms of life.
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Affiliation(s)
- Paul Batty
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD ProgramDoctoral School of the University of Vienna and Medical University of ViennaViennaAustria
| | - Christoph CH Langer
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)Vienna BioCenter (VBC)ViennaAustria
| | - Zsuzsanna Takács
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)Vienna BioCenter (VBC)ViennaAustria
| | - Wen Tang
- Research Institute of Molecular Pathology (IMP)Vienna BioCenter (VBC)ViennaAustria
| | - Claudia Blaukopf
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)Vienna BioCenter (VBC)ViennaAustria
| | - Jan‐Michael Peters
- Research Institute of Molecular Pathology (IMP)Vienna BioCenter (VBC)ViennaAustria
| | - Daniel W Gerlich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)Vienna BioCenter (VBC)ViennaAustria
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Bleiler M, Cyr A, Wright DL, Giardina C. Incorporation of 53BP1 into phase-separated bodies in cancer cells during aberrant mitosis. J Cell Sci 2023; 136:jcs260027. [PMID: 36606487 PMCID: PMC10112977 DOI: 10.1242/jcs.260027] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 11/25/2022] [Indexed: 01/07/2023] Open
Abstract
53BP1 (also known as TP53BP1) is a key mediator of the non-homologous end joining (NHEJ) DNA repair pathway, which is the primary repair pathway in interphase cells. However, the mitotic functions of 53BP1 are less well understood. Here, we describe 53BP1 mitotic stress bodies (MSBs) formed in cancer cell lines in response to delayed mitosis. These bodies displayed liquid-liquid phase separation characteristics, were close to centromeres, and included lamin A/C and the DNA repair protein RIF1. After release from mitotic arrest, 53BP1 MSBs decreased in number and moved away from the chromatin. Using GFP fusion constructs, we found that the 53BP1 oligomerization domain region was required for MSB formation, and that inclusion of the 53BP1 N terminus increased MSB size. Exogenous expression of 53BP1 did not increase MSB size or number but did increase levels of MSB-free 53BP1. This was associated with slower mitotic progression, elevated levels of DNA damage and increased apoptosis, which is consistent with MSBs suppressing a mitotic surveillance by 53BP1 through sequestration. The 53BP1 MSBs, which were also found spontaneously in a subset of normally dividing cancer cells but not in non-transformed cells (ARPE-19), might facilitate the survival of cancer cells following aberrant mitoses. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Marina Bleiler
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Aiyana Cyr
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Dennis L. Wright
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT 06269, USA
| | - Charles Giardina
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
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7
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Regulation of the mitotic chromosome folding machines. Biochem J 2022; 479:2153-2173. [PMID: 36268993 DOI: 10.1042/bcj20210140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 09/30/2022] [Accepted: 10/03/2022] [Indexed: 11/17/2022]
Abstract
Over the last several years enormous progress has been made in identifying the molecular machines, including condensins and topoisomerases that fold mitotic chromosomes. The discovery that condensins generate chromatin loops through loop extrusion has revolutionized, and energized, the field of chromosome folding. To understand how these machines fold chromosomes with the appropriate dimensions, while disentangling sister chromatids, it needs to be determined how they are regulated and deployed. Here, we outline the current understanding of how these machines and factors are regulated through cell cycle dependent expression, chromatin localization, activation and inactivation through post-translational modifications, and through associations with each other, with other factors and with the chromatin template itself. There are still many open questions about how condensins and topoisomerases are regulated but given the pace of progress in the chromosome folding field, it seems likely that many of these will be answered in the years ahead.
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8
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CDK activity sensors: genetically encoded ratiometric biosensors for live analysis of the cell cycle. Biochem Soc Trans 2022; 50:1081-1090. [PMID: 35674434 PMCID: PMC9661961 DOI: 10.1042/bst20211131] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/09/2022] [Accepted: 05/18/2022] [Indexed: 01/04/2023]
Abstract
Cyclin-dependent kinase (CDK) sensors have facilitated investigations of the cell cycle in living cells. These genetically encoded fluorescent biosensors change their subcellular location upon activation of CDKs. Activation is primarily regulated by their association with cyclins, which in turn trigger cell-cycle progression. In the absence of CDK activity, cells exit the cell cycle and become quiescent, a key step in stem cell maintenance and cancer cell dormancy. The evolutionary conservation of CDKs has allowed for the rapid development of CDK activity sensors for cell lines and several research organisms, including nematodes, fish, and flies. CDK activity sensors are utilized for their ability to visualize the exact moment of cell-cycle commitment. This has provided a breakthrough in understanding the proliferation-quiescence decision. Further adoption of these biosensors will usher in new discoveries focused on the cell-cycle regulation of development, ageing, and cancer.
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9
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Sister chromatid-sensitive Hi-C to map the conformation of replicated genomes. Nat Protoc 2022; 17:1486-1517. [PMID: 35478248 DOI: 10.1038/s41596-022-00687-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 01/19/2022] [Indexed: 12/23/2022]
Abstract
Chromosome conformation capture (Hi-C) techniques map the 3D organization of entire genomes. How sister chromatids fold in replicated chromosomes, however, cannot be determined with conventional Hi-C because of the identical DNA sequences of sister chromatids. Here, we present a protocol for sister chromatid-sensitive Hi-C (scsHi-C) that enables the distinction of DNA contacts within individual sister chromatids (cis sister contacts) from those between sister chromatids (trans sister contacts), thereby allowing investigation of the organization of replicated genomes. scsHi-C is based on live-cell labeling of nascent DNA by the synthetic nucleoside 4-thio-thymidine (4sT), which incorporates into a distinct DNA strand on each sister chromatid because of semi-conservative DNA replication. After purification of genomic DNA and in situ Hi-C library preparation, 4sT is chemically converted into 5-methyl-cytosine in the presence of OsO4/NH4Cl to introduce T-to-C signature point mutations on 4sT-labeled DNA. The Hi-C library is then sequenced, and ligated fragments are assigned to sister chromatids on the basis of strand orientation and the presence of signature mutations. The ensemble of scsHi-C contacts thereby represents genome-wide contact probabilities within and across sister chromatids. scsHi-C can be completed in 2 weeks, has been successfully applied in HeLa cells and can potentially be established for any cell type that allows proper cell cycle synchronization and incorporation of sufficient amounts of 4sT. The genome-wide maps of replicated chromosomes detected by scsHi-C enable investigation of the molecular mechanisms shaping sister chromatid topologies and the relevance of sister chromatid conformation in crucial processes like DNA repair, mitotic chromosome formation and potentially other biological processes.
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10
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Roca J, Dyson S, Segura J, Valdés A, Martínez-García B. Keeping intracellular DNA untangled: A new role for condensin? Bioessays 2021; 44:e2100187. [PMID: 34761394 DOI: 10.1002/bies.202100187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 12/25/2022]
Abstract
The DNA-passage activity of topoisomerase II accidentally produces DNA knots and interlinks within and between chromatin fibers. Fortunately, these unwanted DNA entanglements are actively removed by some mechanism. Here we present an outline on DNA knot formation and discuss recent studies that have investigated how intracellular DNA knots are removed. First, although topoisomerase II is able to minimize DNA entanglements in vitro to below equilibrium values, it is unclear whether such capacity performs equally in vivo in chromatinized DNA. Second, DNA supercoiling could bias topoisomerase II to untangle the DNA. However, experimental evidence indicates that transcriptional supercoiling of intracellular DNA boosts knot formation. Last, cohesin and condensin could tighten DNA entanglements via DNA loop extrusion (LE) and force their dissolution by topoisomerase II. Recent observations indicate that condensin activity promotes the removal of DNA knots during interphase and mitosis. This activity might facilitate the spatial organization and dynamics of chromatin.
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Affiliation(s)
- Joaquim Roca
- Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona, Spain
| | - Silvia Dyson
- Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona, Spain
| | - Joana Segura
- Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona, Spain
| | - Antonio Valdés
- Julius Maximilian University of Würzburg, Würzburg, Germany
| | - Belén Martínez-García
- Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona, Spain
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11
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Vernizzi L, Lehner CF. Bivalent individualization during chromosome territory formation in Drosophila spermatocytes by controlled condensin II protein activity and additional force generators. PLoS Genet 2021; 17:e1009870. [PMID: 34669718 PMCID: PMC8559962 DOI: 10.1371/journal.pgen.1009870] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 11/01/2021] [Accepted: 10/11/2021] [Indexed: 12/12/2022] Open
Abstract
Reduction of genome ploidy from diploid to haploid necessitates stable pairing of homologous chromosomes into bivalents before the start of the first meiotic division. Importantly, this chromosome pairing must avoid interlocking of non-homologous chromosomes. In spermatocytes of Drosophila melanogaster, where homolog pairing does not involve synaptonemal complex formation and crossovers, associations between non-homologous chromosomes are broken up by chromosome territory formation in early spermatocytes. Extensive non-homologous associations arise from the coalescence of the large blocks of pericentromeric heterochromatin into a chromocenter and from centromere clustering. Nevertheless, during territory formation, bivalents are moved apart into spatially separate subnuclear regions. The condensin II subunits, Cap-D3 and Cap-H2, have been implicated, but the remarkable separation of bivalents during interphase might require more than just condensin II. For further characterization of this process, we have applied time-lapse imaging using fluorescent markers of centromeres, telomeres and DNA satellites in pericentromeric heterochromatin. We describe the dynamics of the disruption of centromere clusters and the chromocenter in normal spermatocytes. Mutations in Cap-D3 and Cap-H2 abolish chromocenter disruption, resulting in excessive chromosome missegregation during M I. Chromocenter persistence in the mutants is not mediated by the special system, which conjoins homologs in compensation for the absence of crossovers in Drosophila spermatocytes. However, overexpression of Cap-H2 precluded conjunction between autosomal homologs, resulting in random segregation of univalents. Interestingly, Cap-D3 and Cap-H2 mutant spermatocytes displayed conspicuous stretching of the chromocenter, as well as occasional chromocenter disruption, suggesting that territory formation might involve forces unrelated to condensin II. While the molecular basis of these forces remains to be clarified, they are not destroyed by inhibitors of F actin and microtubules. Our results indicate that condensin II activity promotes chromosome territory formation in co-operation with additional force generators and that careful co-ordination with alternative homolog conjunction is crucial.
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Affiliation(s)
- Luisa Vernizzi
- Department of Molecular Life Science (DMLS), University of Zurich, Zurich, Switzerland
| | - Christian F. Lehner
- Department of Molecular Life Science (DMLS), University of Zurich, Zurich, Switzerland
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12
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Choppakatla P, Dekker B, Cutts EE, Vannini A, Dekker J, Funabiki H. Linker histone H1.8 inhibits chromatin binding of condensins and DNA topoisomerase II to tune chromosome length and individualization. eLife 2021; 10:e68918. [PMID: 34406118 PMCID: PMC8416026 DOI: 10.7554/elife.68918] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 08/13/2021] [Indexed: 12/14/2022] Open
Abstract
DNA loop extrusion by condensins and decatenation by DNA topoisomerase II (topo II) are thought to drive mitotic chromosome compaction and individualization. Here, we reveal that the linker histone H1.8 antagonizes condensins and topo II to shape mitotic chromosome organization. In vitro chromatin reconstitution experiments demonstrate that H1.8 inhibits binding of condensins and topo II to nucleosome arrays. Accordingly, H1.8 depletion in Xenopus egg extracts increased condensins and topo II levels on mitotic chromatin. Chromosome morphology and Hi-C analyses suggest that H1.8 depletion makes chromosomes thinner and longer through shortening the average loop size and reducing the DNA amount in each layer of mitotic loops. Furthermore, excess loading of condensins and topo II to chromosomes by H1.8 depletion causes hyper-chromosome individualization and dispersion. We propose that condensins and topo II are essential for chromosome individualization, but their functions are tuned by the linker histone to keep chromosomes together until anaphase.
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Affiliation(s)
- Pavan Choppakatla
- Laboratory of Chromosome and Cell Biology, The Rockefeller UniversityNew YorkUnited States
| | - Bastiaan Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical SchoolWorcesterUnited States
| | - Erin E Cutts
- Division of Structural Biology, The Institute of Cancer ResearchLondonUnited Kingdom
| | - Alessandro Vannini
- Division of Structural Biology, The Institute of Cancer ResearchLondonUnited Kingdom
- Fondazione Human Technopole, Structural Biology Research Centre, 20157MilanItaly
| | - Job Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical SchoolWorcesterUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Hironori Funabiki
- Laboratory of Chromosome and Cell Biology, The Rockefeller UniversityNew YorkUnited States
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13
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Sajid A, Lalani EN, Chen B, Hashimoto T, Griffin DK, Bhartiya A, Thompson G, Robinson IK, Yusuf M. Ultra-Structural Imaging Provides 3D Organization of 46 Chromosomes of a Human Lymphocyte Prophase Nucleus. Int J Mol Sci 2021; 22:ijms22115987. [PMID: 34206020 PMCID: PMC8198510 DOI: 10.3390/ijms22115987] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/21/2021] [Accepted: 05/23/2021] [Indexed: 11/18/2022] Open
Abstract
Three dimensional (3D) ultra-structural imaging is an important tool for unraveling the organizational structure of individual chromosomes at various stages of the cell cycle. Performing hitherto uninvestigated ultra-structural analysis of the human genome at prophase, we used serial block-face scanning electron microscopy (SBFSEM) to understand chromosomal architectural organization within 3D nuclear space. Acquired images allowed us to segment, reconstruct, and extract quantitative 3D structural information about the prophase nucleus and the preserved, intact individual chromosomes within it. Our data demonstrate that each chromosome can be identified with its homolog and classified into respective cytogenetic groups. Thereby, we present the first 3D karyotype built from the compact axial structure seen on the core of all prophase chromosomes. The chromosomes display parallel-aligned sister chromatids with familiar chromosome morphologies with no crossovers. Furthermore, the spatial positions of all 46 chromosomes revealed a pattern showing a gene density-based correlation and a neighborhood map of individual chromosomes based on their relative spatial positioning. A comprehensive picture of 3D chromosomal organization at the nanometer level in a single human lymphocyte cell is presented.
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Affiliation(s)
- Atiqa Sajid
- Centre for Regenerative Medicine and Stem Cell Research, Aga Khan University, Karachi 74800, Pakistan; (A.S.); (E.-N.L.)
| | - El-Nasir Lalani
- Centre for Regenerative Medicine and Stem Cell Research, Aga Khan University, Karachi 74800, Pakistan; (A.S.); (E.-N.L.)
| | - Bo Chen
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; (B.C.); (A.B.); (I.K.R.)
- School of Materials Science and Engineering, Tongji University, Shanghai 201804, China
- Key Laboratory of Performance Evolution and Control for Engineering Structures of the Ministry of Education, Tongji University, Shanghai 200092, China
| | - Teruo Hashimoto
- Department of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, UK; (T.H.); (G.T.)
| | | | - Archana Bhartiya
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; (B.C.); (A.B.); (I.K.R.)
| | - George Thompson
- Department of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, UK; (T.H.); (G.T.)
| | - Ian K. Robinson
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; (B.C.); (A.B.); (I.K.R.)
- Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Mohammed Yusuf
- Centre for Regenerative Medicine and Stem Cell Research, Aga Khan University, Karachi 74800, Pakistan; (A.S.); (E.-N.L.)
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; (B.C.); (A.B.); (I.K.R.)
- Correspondence:
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14
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McKie SJ, Neuman KC, Maxwell A. DNA topoisomerases: Advances in understanding of cellular roles and multi-protein complexes via structure-function analysis. Bioessays 2021; 43:e2000286. [PMID: 33480441 PMCID: PMC7614492 DOI: 10.1002/bies.202000286] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/06/2020] [Accepted: 12/17/2020] [Indexed: 12/15/2022]
Abstract
DNA topoisomerases, capable of manipulating DNA topology, are ubiquitous and indispensable for cellular survival due to the numerous roles they play during DNA metabolism. As we review here, current structural approaches have revealed unprecedented insights into the complex DNA-topoisomerase interaction and strand passage mechanism, helping to advance our understanding of their activities in vivo. This has been complemented by single-molecule techniques, which have facilitated the detailed dissection of the various topoisomerase reactions. Recent work has also revealed the importance of topoisomerase interactions with accessory proteins and other DNA-associated proteins, supporting the idea that they often function as part of multi-enzyme assemblies in vivo. In addition, novel topoisomerases have been identified and explored, such as topo VIII and Mini-A. These new findings are advancing our understanding of DNA-related processes and the vital functions topos fulfil, demonstrating their indispensability in virtually every aspect of DNA metabolism.
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Affiliation(s)
- Shannon J. McKie
- Department Biological Chemistry, John Innes Centre, Norwich, UK
- Laboratory of Single Molecule Biophysics, NHLBI, Bethesda, Maryland, USA
| | - Keir C. Neuman
- Laboratory of Single Molecule Biophysics, NHLBI, Bethesda, Maryland, USA
| | - Anthony Maxwell
- Department Biological Chemistry, John Innes Centre, Norwich, UK
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15
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Dyson S, Segura J, Martínez‐García B, Valdés A, Roca J. Condensin minimizes topoisomerase II-mediated entanglements of DNA in vivo. EMBO J 2021; 40:e105393. [PMID: 33155682 PMCID: PMC7780148 DOI: 10.15252/embj.2020105393] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 09/10/2020] [Accepted: 10/07/2020] [Indexed: 12/24/2022] Open
Abstract
The juxtaposition of intracellular DNA segments, together with the DNA-passage activity of topoisomerase II, leads to the formation of DNA knots and interlinks, which jeopardize chromatin structure and gene expression. Recent studies in budding yeast have shown that some mechanism minimizes the knotting probability of intracellular DNA. Here, we tested whether this is achieved via the intrinsic capacity of topoisomerase II for simplifying the equilibrium topology of DNA; or whether it is mediated by SMC (structural maintenance of chromosomes) protein complexes like condensin or cohesin, whose capacity to extrude DNA loops could enforce dissolution of DNA knots by topoisomerase II. We show that the low knotting probability of DNA does not depend on the simplification capacity of topoisomerase II nor on the activities of cohesin or Smc5/6 complexes. However, inactivation of condensin increases the occurrence of DNA knots throughout the cell cycle. These results suggest an in vivo role for the DNA loop extrusion activity of condensin and may explain why condensin disruption produces a variety of alterations in interphase chromatin, in addition to persistent sister chromatid interlinks in mitotic chromatin.
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Grants
- BFU2015-67007-P Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- PID2019-109482GB-I00 Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- BES-2016-077806 Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- BES-2012-061167 Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
- BES-2015-071597 Ministerio de Economía, Industria y Competitividad, Gobierno de España (MINECO)
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Affiliation(s)
- Sílvia Dyson
- Molecular Biology Institute of Barcelona (IBMB)Spanish National Research Council (CSIC)BarcelonaSpain
| | - Joana Segura
- Molecular Biology Institute of Barcelona (IBMB)Spanish National Research Council (CSIC)BarcelonaSpain
| | - Belén Martínez‐García
- Molecular Biology Institute of Barcelona (IBMB)Spanish National Research Council (CSIC)BarcelonaSpain
| | - Antonio Valdés
- Molecular Biology Institute of Barcelona (IBMB)Spanish National Research Council (CSIC)BarcelonaSpain
| | - Joaquim Roca
- Molecular Biology Institute of Barcelona (IBMB)Spanish National Research Council (CSIC)BarcelonaSpain
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16
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Mitter M, Gerlich DW. Mapping Sister Chromatid Conformation in Replicated Chromosomes. Trends Biochem Sci 2020; 46:169-170. [PMID: 33342665 DOI: 10.1016/j.tibs.2020.11.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 11/30/2020] [Indexed: 12/24/2022]
Affiliation(s)
- Michael Mitter
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Daniel W Gerlich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria.
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17
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Banigan EJ, Mirny LA. The interplay between asymmetric and symmetric DNA loop extrusion. eLife 2020; 9:e63528. [PMID: 33295869 PMCID: PMC7793625 DOI: 10.7554/elife.63528] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 11/30/2020] [Indexed: 12/30/2022] Open
Abstract
Chromosome compaction is essential for reliable transmission of genetic information. Experiments suggest that ∼1000-fold compaction is driven by condensin complexes that extrude chromatin loops, by progressively collecting chromatin fiber from one or both sides of the complex to form a growing loop. Theory indicates that symmetric two-sided loop extrusion can achieve such compaction, but recent single-molecule studies (Golfier et al., 2020) observed diverse dynamics of condensins that perform one-sided, symmetric two-sided, and asymmetric two-sided extrusion. We use simulations and theory to determine how these molecular properties lead to chromosome compaction. High compaction can be achieved if even a small fraction of condensins have two essential properties: a long residence time and the ability to perform two-sided (not necessarily symmetric) extrusion. In mixtures of condensins I and II, coupling two-sided extrusion and stable chromatin binding by condensin II promotes compaction. These results provide missing connections between single-molecule observations and chromosome-scale organization.
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Affiliation(s)
- Edward J Banigan
- Department of Physics and Institute for Medical Engineering and Science, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Leonid A Mirny
- Department of Physics and Institute for Medical Engineering and Science, Massachusetts Institute of TechnologyCambridgeUnited States
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18
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Detecting chromatin interactions between and along sister chromatids with SisterC. Nat Methods 2020; 17:1002-1009. [PMID: 32968250 PMCID: PMC7541687 DOI: 10.1038/s41592-020-0930-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 07/04/2020] [Accepted: 07/21/2020] [Indexed: 11/28/2022]
Abstract
Chromosome segregation requires both compaction and disentanglement of sister chromatids. We describe SisterC, a chromosome conformation capture assay that distinguishes interactions between and along identical sister chromatids. SisterC employs BrdU incorporation during S-phase to label newly replicated strands, followed by Hi-C and then the destruction of BrdU-containing strands by UV/Hoechst treatment. After sequencing of the remaining intact strands, this allows for assignment of Hi-C products as inter- and intra-sister interactions based on the strands that reads are mapped to. We performed SisterC on mitotic S. cerevisiae cells. We find precise alignment of sister chromatids at centromeres. Along arms, sister chromatids are less precisely aligned with inter-sister connections every ~35kb. Inter-sister interactions occur between cohesin binding sites that often are offset by 5 to 25kb. Along sister chromatids, cohesin forms loops of up to 50kb. SisterC allows study of the complex interplay between sister chromatid compaction and their segregation during mitosis.
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19
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Chu L, Liang Z, Mukhina M, Fisher J, Vincenten N, Zhang Z, Hutchinson J, Zickler D, Kleckner N. The 3D Topography of Mitotic Chromosomes. Mol Cell 2020; 79:902-916.e6. [PMID: 32768407 DOI: 10.1016/j.molcel.2020.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/16/2020] [Accepted: 07/06/2020] [Indexed: 01/08/2023]
Abstract
A long-standing conundrum is how mitotic chromosomes can compact, as required for clean separation to daughter cells, while maintaining close parallel alignment of sister chromatids. Pursuit of this question, by high resolution 3D fluorescence imaging of living and fixed mammalian cells, has led to three discoveries. First, we show that the structural axes of separated sister chromatids are linked by evenly spaced "mini-axis" bridges. Second, when chromosomes first emerge as discrete units, at prophase, they are organized as co-oriented sister linear loop arrays emanating from a conjoined axis. We show that this same basic organization persists throughout mitosis, without helical coiling. Third, from prophase onward, chromosomes are deformed into sequential arrays of half-helical segments of alternating handedness (perversions), accompanied by correlated kinks. These arrays fluctuate dynamically over <15 s timescales. Together these discoveries redefine the foundation for thinking about the evolution of mitotic chromosomes as they prepare for anaphase segregation.
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Affiliation(s)
- Lingluo Chu
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Zhangyi Liang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Maria Mukhina
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Jay Fisher
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA; Redbud Labs, Research Triangle, NC 27709, USA
| | - Nadine Vincenten
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Zheng Zhang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA; CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, People's Republic of China
| | - John Hutchinson
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Denise Zickler
- University Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif sur Yvette, France
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.
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20
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Topoisomerase IIα is essential for maintenance of mitotic chromosome structure. Proc Natl Acad Sci U S A 2020; 117:12131-12142. [PMID: 32414923 DOI: 10.1073/pnas.2001760117] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Topoisomerase IIα (TOP2A) is a core component of mitotic chromosomes and important for establishing mitotic chromosome condensation. The primary roles of TOP2A in mitosis have been difficult to decipher due to its multiple functions across the cell cycle. To more precisely understand the role of TOP2A in mitosis, we used the auxin-inducible degron (AID) system to rapidly degrade the protein at different stages of the human cell cycle. Removal of TOP2A prior to mitosis does not affect prophase timing or the initiation of chromosome condensation. Instead, it prevents chromatin condensation in prometaphase, extends the length of prometaphase, and ultimately causes cells to exit mitosis without chromosome segregation occurring. Surprisingly, we find that removal of TOP2A from cells arrested in prometaphase or metaphase cause dramatic loss of compacted mitotic chromosome structure and conclude that TOP2A is crucial for maintenance of mitotic chromosomes. Treatments with drugs used to poison/inhibit TOP2A function, such as etoposide and ICRF-193, do not phenocopy the effects on chromosome structure of TOP2A degradation by AID. Our data point to a role for TOP2A as a structural chromosome maintenance enzyme locking in condensation states once sufficient compaction is achieved.
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21
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Abstract
Until recently, our understanding of chromosome organization in higher eukaryotic cells has been based on analyses of large-scale, low-resolution changes in chromosomes structure. More recently, CRISPR-Cas9 technologies have allowed us to "zoom in" and visualize specific chromosome regions in live cells so that we can begin to examine in detail the dynamics of chromosome organization in individual cells. In this review, we discuss traditional methods of chromosome locus visualization and look at how CRISPR-Cas9 gene-targeting methodologies have helped improve their application. We also describe recent developments of the CRISPR-Cas9 technology that enable visualization of specific chromosome regions without the requirement for complex genetic manipulation.
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Affiliation(s)
- John K Eykelenboom
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee , Dundee, UK
| | - Tomoyuki U Tanaka
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee , Dundee, UK
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22
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Banigan EJ, van den Berg AA, Brandão HB, Marko JF, Mirny LA. Chromosome organization by one-sided and two-sided loop extrusion. eLife 2020; 9:e53558. [PMID: 32250245 PMCID: PMC7295573 DOI: 10.7554/elife.53558] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 04/03/2020] [Indexed: 12/19/2022] Open
Abstract
SMC complexes, such as condensin or cohesin, organize chromatin throughout the cell cycle by a process known as loop extrusion. SMC complexes reel in DNA, extruding and progressively growing DNA loops. Modeling assuming two-sided loop extrusion reproduces key features of chromatin organization across different organisms. In vitro single-molecule experiments confirmed that yeast condensins extrude loops, however, they remain anchored to their loading sites and extrude loops in a 'one-sided' manner. We therefore simulate one-sided loop extrusion to investigate whether 'one-sided' complexes can compact mitotic chromosomes, organize interphase domains, and juxtapose bacterial chromosomal arms, as can be done by 'two-sided' loop extruders. While one-sided loop extrusion cannot reproduce these phenomena, variants can recapitulate in vivo observations. We predict that SMC complexes in vivo constitute effectively two-sided motors or exhibit biased loading and propose relevant experiments. Our work suggests that loop extrusion is a viable general mechanism of chromatin organization.
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Affiliation(s)
- Edward J Banigan
- Institute for Medical Engineering & Science, Massachusetts Institute of TechnologyCambridgeUnited States
- Department of Physics, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Aafke A van den Berg
- Institute for Medical Engineering & Science, Massachusetts Institute of TechnologyCambridgeUnited States
- Department of Physics, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Hugo B Brandão
- Harvard Graduate Program in Biophysics, Harvard UniversityCambridgeUnited States
| | - John F Marko
- Departments of Molecular Biosciences and Physics & Astronomy, Northwestern UniversityEvanstonUnited States
| | - Leonid A Mirny
- Institute for Medical Engineering & Science, Massachusetts Institute of TechnologyCambridgeUnited States
- Department of Physics, Massachusetts Institute of TechnologyCambridgeUnited States
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23
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Abstract
Effective maintenance and stability of our genomes is essential for normal cell division, tissue homeostasis, and cellular and organismal fitness. The processes of chromosome replication and segregation require continual surveillance to insure fidelity. Accurate and efficient repair of DNA damage preserves genome integrity, which if lost can lead to multiple diseases, including cancer. Poly(ADP-ribose) a dynamic and reversible posttranslational modification and the enzymes that catalyze it (PARP1, PARP2, tankyrase 1, and tankyrase 2) function to maintain genome stability through diverse mechanisms. Here we review the role of these enzymes and the modification in genome repair, replication, and resolution in human cells.
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Affiliation(s)
- Kameron Azarm
- Department of Pathology, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, New York 10016, USA
| | - Susan Smith
- Department of Pathology, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, New York 10016, USA
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24
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Daban JR. Supramolecular multilayer organization of chromosomes: possible functional roles of planar chromatin in gene expression and DNA replication and repair. FEBS Lett 2020; 594:395-411. [PMID: 31879954 DOI: 10.1002/1873-3468.13724] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 11/25/2019] [Accepted: 12/12/2019] [Indexed: 01/16/2023]
Abstract
Experimental evidence indicates that the chromatin filament is self-organized into a multilayer planar structure that is densely stacked in metaphase and unstacked in interphase. This chromatin organization is unexpected, but it is shown that diverse supramolecular assemblies, including dinoflagellate chromosomes, are multilayered. The mechanical strength of planar chromatin protects the genome integrity, even when double-strand breaks are produced. Here, it is hypothesized that the chromatin filament in the loops and topologically associating domains is folded within the thin layers of the multilaminar chromosomes. It is also proposed that multilayer chromatin has two states: inactive when layers are stacked and active when layers are unstacked. Importantly, the well-defined topology of planar chromatin may facilitate DNA replication without entanglements and DNA repair by homologous recombination.
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Affiliation(s)
- Joan-Ramon Daban
- Departament de Bioquímica i Biologia Molecular, Facultat de Biociències, Universitat Autònoma de Barcelona, Spain
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25
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Movafagh A, Abadi A, Mazloumi Z, Kolahi A, Sheikhpour M, Rezaei-Tavirani M, Moradi A, Ahadi M, Aghamaleki F, Safavi N, Heidary M, Zamani M, Rad S, Entezari M, Hashemi M. Comparison and frequency of cell cultured in 48-h and 72-h mitotically treated with phytohemagglutinin-M: Both promise for normal and cancer cells. CLINICAL CANCER INVESTIGATION JOURNAL 2020. [DOI: 10.4103/ccij.ccij_6_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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26
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Elbatsh AMO, Kim E, Eeftens JM, Raaijmakers JA, van der Weide RH, García-Nieto A, Bravo S, Ganji M, Uit de Bos J, Teunissen H, Medema RH, de Wit E, Haering CH, Dekker C, Rowland BD. Distinct Roles for Condensin's Two ATPase Sites in Chromosome Condensation. Mol Cell 2019; 76:724-737.e5. [PMID: 31629658 PMCID: PMC6900782 DOI: 10.1016/j.molcel.2019.09.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 07/17/2019] [Accepted: 09/13/2019] [Indexed: 01/19/2023]
Abstract
Condensin is a conserved SMC complex that uses its ATPase machinery to structure genomes, but how it does so is largely unknown. We show that condensin's ATPase has a dual role in chromosome condensation. Mutation of one ATPase site impairs condensation, while mutating the second site results in hyperactive condensin that compacts DNA faster than wild-type, both in vivo and in vitro. Whereas one site drives loop formation, the second site is involved in the formation of more stable higher-order Z loop structures. Using hyperactive condensin I, we reveal that condensin II is not intrinsically needed for the shortening of mitotic chromosomes. Condensin II rather is required for a straight chromosomal axis and enables faithful chromosome segregation by counteracting the formation of ultrafine DNA bridges. SMC complexes with distinct roles for each ATPase site likely reflect a universal principle that enables these molecular machines to intricately control chromosome architecture.
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Affiliation(s)
- Ahmed M O Elbatsh
- Division of Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Eugene Kim
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Jorine M Eeftens
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Jonne A Raaijmakers
- Division of Cell Biology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Robin H van der Weide
- Division of Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Alberto García-Nieto
- Division of Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Sol Bravo
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Mahipal Ganji
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Jelmi Uit de Bos
- Division of Cell Biology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Hans Teunissen
- Division of Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - René H Medema
- Division of Cell Biology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Elzo de Wit
- Division of Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Christian H Haering
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands.
| | - Benjamin D Rowland
- Division of Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands.
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27
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Cell Cycle-Dependent Control and Roles of DNA Topoisomerase II. Genes (Basel) 2019; 10:genes10110859. [PMID: 31671531 PMCID: PMC6896119 DOI: 10.3390/genes10110859] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 10/25/2019] [Accepted: 10/28/2019] [Indexed: 12/13/2022] Open
Abstract
Type II topoisomerases are ubiquitous enzymes in all branches of life that can alter DNA superhelicity and unlink double-stranded DNA segments during processes such as replication and transcription. In cells, type II topoisomerases are particularly useful for their ability to disentangle newly-replicated sister chromosomes. Growing lines of evidence indicate that eukaryotic topoisomerase II (topo II) activity is monitored and regulated throughout the cell cycle. Here, we discuss the various roles of topo II throughout the cell cycle, as well as mechanisms that have been found to govern and/or respond to topo II function and dysfunction. Knowledge of how topo II activity is controlled during cell cycle progression is important for understanding how its misregulation can contribute to genetic instability and how modulatory pathways may be exploited to advance chemotherapeutic development.
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28
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Batty P, Gerlich DW. Mitotic Chromosome Mechanics: How Cells Segregate Their Genome. Trends Cell Biol 2019; 29:717-726. [PMID: 31230958 DOI: 10.1016/j.tcb.2019.05.007] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 05/23/2019] [Accepted: 05/23/2019] [Indexed: 01/09/2023]
Abstract
During mitosis, replicated chromosomes segregate such that each daughter cell receives one copy of the genome. Faithful mechanical transport during mitosis requires that chromosomes undergo extensive structural changes as the cell cycle progresses, resulting in the formation of compact, cylindrical bodies. Such structural changes encompass a range of different activities, including longitudinal condensation of the chromosome axis, global chromatin compaction, resolution of sister chromatids, and individualisation of chromosomes into separate bodies. After mitosis, chromosomes undergo further reorganisation to rebuild interphase cell nuclei. Here we review the requirements for mitotic chromosomes to successfully transmit genetic information to daughter cells and the biophysical principles that underpin such requirements.
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Affiliation(s)
- Paul Batty
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Daniel W Gerlich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), 1030 Vienna, Austria.
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29
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Mirkovic M, Oliveira RA. Centromeric Cohesin: Molecular Glue and Much More. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2019; 56:485-513. [PMID: 28840250 DOI: 10.1007/978-3-319-58592-5_20] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Sister chromatid cohesion, mediated by the cohesin complex, is a prerequisite for faithful chromosome segregation during mitosis. Premature release of sister chromatid cohesion leads to random segregation of the genetic material and consequent aneuploidy. Multiple regulatory mechanisms ensure proper timing for cohesion establishment, concomitant with DNA replication, and cohesion release during the subsequent mitosis. Here we summarize the most important phases of the cohesin cycle and the coordination of cohesion release with the progression through mitosis. We further discuss recent evidence that has revealed additional functions for centromeric localization of cohesin in the fidelity of mitosis in metazoans. Beyond its well-established role as "molecular glue", centromeric cohesin complexes are now emerging as a scaffold for multiple fundamental processes during mitosis, including the formation of correct chromosome and kinetochore architecture, force balance with the mitotic spindle, and the association with key molecules that regulate mitotic fidelity, particularly at the chromosomal inner centromere. Centromeric chromatin may be thus seen as a dynamic place where cohesin ensures mitotic fidelity by multiple means.
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Affiliation(s)
- Mihailo Mirkovic
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 2780-156, Oeiras, Portugal
| | - Raquel A Oliveira
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 2780-156, Oeiras, Portugal.
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30
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Eykelenboom JK, Gierliński M, Yue Z, Hegarat N, Pollard H, Fukagawa T, Hochegger H, Tanaka TU. Live imaging of marked chromosome regions reveals their dynamic resolution and compaction in mitosis. J Cell Biol 2019; 218:1531-1552. [PMID: 30858191 PMCID: PMC6504890 DOI: 10.1083/jcb.201807125] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 12/19/2018] [Accepted: 02/05/2019] [Indexed: 01/27/2023] Open
Abstract
When human cells enter mitosis, chromosomes undergo substantial changes in their organization to resolve sister chromatids and compact chromosomes. To comprehend the timing and coordination of these events, we need to evaluate the progression of both sister chromatid resolution and chromosome compaction in one assay. Here we achieved this by analyzing changes in configuration of marked chromosome regions over time, with high spatial and temporal resolution. This assay showed that sister chromatids cycle between nonresolved and partially resolved states with an interval of a few minutes during G2 phase before completing full resolution in prophase. Cohesins and WAPL antagonistically regulate sister chromatid resolution in late G2 and prophase while local enrichment of cohesin on chromosomes prevents precocious sister chromatid resolution. Moreover, our assay allowed quantitative evaluation of condensin II and I activities, which differentially promote sister chromatid resolution and chromosome compaction, respectively. Our assay reveals novel aspects of dynamics in mitotic chromosome resolution and compaction that were previously obscure in global chromosome assays.
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Affiliation(s)
- John K Eykelenboom
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
| | - Marek Gierliński
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
- Data Analysis Group, School of Life Sciences, University of Dundee, Dundee, UK
| | - Zuojun Yue
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
| | - Nadia Hegarat
- Genome Damage and Stability Centre, University of Sussex, Brighton, UK
| | - Hilary Pollard
- Genome Damage and Stability Centre, University of Sussex, Brighton, UK
| | - Tatsuo Fukagawa
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Helfrid Hochegger
- Genome Damage and Stability Centre, University of Sussex, Brighton, UK
| | - Tomoyuki U Tanaka
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
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31
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Takahashi M, Hirota T. Folding the genome into mitotic chromosomes. Curr Opin Cell Biol 2019; 60:19-26. [PMID: 30999230 DOI: 10.1016/j.ceb.2019.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 03/02/2019] [Accepted: 03/06/2019] [Indexed: 10/27/2022]
Abstract
How linear DNA molecules are packaged into compact cylindrical chromosomes in preparation for cell division has remained one of the central outstanding questions in cell biology. Condensin is a highly conserved protein complex that universally determines large-scale DNA geometry during mitotic chromosome assembly. A wide range of recently developed approaches, including super resolution microscopy, single molecule imaging, Hi-C analyses and computational modeling, have profoundly changed how we view mitotic chromosomes. This review highlights recent discoveries on chromosome architecture and condensin function.
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Affiliation(s)
- Motoko Takahashi
- Division of Experimental Pathology, Cancer Institute of the Japanese Foundation for Cancer Research (JFCR), Tokyo, Japan
| | - Toru Hirota
- Division of Experimental Pathology, Cancer Institute of the Japanese Foundation for Cancer Research (JFCR), Tokyo, Japan.
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32
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Resolution of human ribosomal DNA occurs in anaphase, dependent on tankyrase 1, condensin II, and topoisomerase IIα. Genes Dev 2019; 33:276-281. [PMID: 30804226 PMCID: PMC6411013 DOI: 10.1101/gad.321836.118] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 01/07/2019] [Indexed: 11/25/2022]
Abstract
In this paper by Daniloski et al., the authors investigated the timing and mechanism of the resolution of the ribosomal DNA (rDNA) repeats during chromosome segregation in human cells. They found that resolution of human rDNA occurs in anaphase after the bulk of the genome, dependent on tankyrase 1, condensin II, and topoisomerase II. Formation of individualized sister chromatids is essential for their accurate segregation. In budding yeast, while most of the genome segregates at the metaphase to anaphase transition, resolution of the ribosomal DNA (rDNA) repeats is delayed. The timing and mechanism in human cells is unknown. Here we show that resolution of human rDNA occurs in anaphase after the bulk of the genome, dependent on tankyrase 1, condensin II, and topoisomerase IIα. Defective resolution leads to rDNA bridges, rDNA damage, and aneuploidy of an rDNA-containing acrocentric chromosome. Thus, temporal regulation of rDNA segregation is conserved between yeast and man and is essential for genome integrity.
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33
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Oomen ME, Hansen AS, Liu Y, Darzacq X, Dekker J. CTCF sites display cell cycle-dependent dynamics in factor binding and nucleosome positioning. Genome Res 2019; 29:236-249. [PMID: 30655336 PMCID: PMC6360813 DOI: 10.1101/gr.241547.118] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 11/15/2018] [Indexed: 12/28/2022]
Abstract
CCCTC-binding factor (CTCF) plays a key role in the formation of topologically associating domains (TADs) and loops in interphase. During mitosis TADs are absent, but how TAD formation is dynamically controlled during the cell cycle is not known. Several contradicting observations have been made regarding CTCF binding to mitotic chromatin using both genomics- and microscopy-based techniques. Here, we have used four different assays to address this debate. First, using 5C, we confirmed that TADs and CTCF loops are readily detected in interphase, but absent during prometaphase. Second, ATAC-seq analysis showed that CTCF sites display greatly reduced accessibility and lose the CTCF footprint in prometaphase, suggesting loss of CTCF binding and rearrangement of the nucleosomal array around the binding motif. In contrast, transcription start sites remain accessible in prometaphase, although adjacent nucleosomes can also become repositioned and occupy at least a subset of start sites during mitosis. Third, loss of site-specific CTCF binding was directly demonstrated using CUT&RUN. Histone modifications and histone variants are maintained in mitosis, suggesting a role in bookmarking of active CTCF sites. Finally, live-cell imaging, fluorescence recovery after photobleaching, and single molecule tracking showed that almost all CTCF chromatin binding is lost in prometaphase. Combined, our results demonstrate loss of CTCF binding to CTCF sites during prometaphase and rearrangement of the chromatin landscape around CTCF motifs. This, combined with loss of cohesin, would contribute to the observed loss of TADs and CTCF loops during mitosis and reveals that CTCF sites, key architectural cis-elements, display cell cycle stage–dependent dynamics in factor binding and nucleosome positioning.
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Affiliation(s)
- Marlies E Oomen
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Anders S Hansen
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of Excellence, University of California, Berkeley, California 94720, USA
| | - Yu Liu
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of Excellence, University of California, Berkeley, California 94720, USA
| | - Job Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.,Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
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34
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Yan N, He Y, Wen H, Lai F, Yin D, Cui H. A Suzuki-Miyaura method for labelling proliferating cells containing incorporated BrdU. Analyst 2019; 143:1224-1233. [PMID: 29431786 DOI: 10.1039/c7an01934c] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The 5-bromo-2'-deoxyuridine (BrdU) incorporation cell proliferation assay is the most commonly used method for assessing DNA replication. The current detection of BrdU in cells relies on antibody immunostaining, but has various limitations including low antibody specificity and poor tissue penetration. In this study, we utilised a Suzuki-Miyaura reaction to develop a chemical method to label cellular BrdU with fluorescent boronic acid probes. The coupling conditions were optimised for complex cellular environments, and the key observation was the need to use oxygen scavengers and zerovalent palladium to prevent side reactions and increase the rate of coupling. The reliability and specificity of the BrdU Suzuki-Miyaura labelling method were verified under various biological conditions. The applicability of the BrdU Suzuki-Miyaura labelling methodology was also investigated, and we show that labelling cellular BrdU is highly sensitive and reliable, which is comparable to the ideal performance of BrdU immunostaining. Moreover, the Suzuki-Miyaura reaction protocol provides high BrdU recognition specificity. Taken together, the BrdU Suzuki-Miyaura labelling protocol provides an attractive alternative to the more traditional cell proliferation assay.
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Affiliation(s)
- Ning Yan
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, 100050, China.
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35
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Konishi M, Shindo N, Komiya M, Tanaka K, Itoh T, Hirota T. Quantitative analyses of the metaphase-to-anaphase transition reveal differential kinetic regulation for securin and cyclin B1. Biomed Res 2018; 39:75-85. [PMID: 29669986 DOI: 10.2220/biomedres.39.75] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Separation of sister chromatids is a drastic and irreversible step in the cell cycle. The key biochemistry behind this event is the proteolysis mediated by the ubiquitin ligase called the anaphase promoting complex, or APC/C. Securin and cyclin B1 are the two established substrates for APC/C whose degradation releases separase and inactivates cyclin B1-dependent kinase 1 (cdk1), respectively, at the metaphase-to-anaphase transition. In this study, we have combined biochemical quantifications with mathematical simulations to characterize the kinetic regulation of securin and cyclin B1, in the cytoplasmic and chromosomal compartments, and found that they are differentially distributed and degraded with different rates. Modeling their interaction with separase predicted that activation timing of separase well coincides with the decline of securin-separase concentration in the cytoplasm. Notably, it also coincides with the peak of cyclin B1-separase level on chromosomes, which appeared crucial to coordinate the timing for separase activation and cdk1 inhibition. We have also conducted phosphoproteomic analysis and identified Ki67 as a chromosomal cdk1 substrate whose dephosphorylation is facilitated by cyclin B1-separase interaction in anaphase.
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Affiliation(s)
- Makoto Konishi
- Division of Experimental Pathology, Cancer Institute of the Japanese Foundation for Cancer Research (JFCR).,Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology
| | - Norihisa Shindo
- Division of Experimental Pathology, Cancer Institute of the Japanese Foundation for Cancer Research (JFCR)
| | - Masataka Komiya
- Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology
| | - Kozo Tanaka
- Department of Molecular Oncology, Institute of Development, Aging and Cancer, Tohoku University
| | - Takehiko Itoh
- Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology
| | - Toru Hirota
- Division of Experimental Pathology, Cancer Institute of the Japanese Foundation for Cancer Research (JFCR)
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36
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Arifulin EA, Musinova YR, Vassetzky YS, Sheval EV. Mobility of Nuclear Components and Genome Functioning. BIOCHEMISTRY (MOSCOW) 2018; 83:690-700. [PMID: 30195325 DOI: 10.1134/s0006297918060068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cell nucleus is characterized by strong compartmentalization of structural components in its three-dimensional space. Certain genomic functions are accompanied by changes in the localization of chromatin loci and nuclear bodies. Here we review recent data on the mobility of nuclear components and the role of this mobility in genome functioning.
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Affiliation(s)
- E A Arifulin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
| | - Y R Musinova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.,LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, Villejuif, 94805, France.,Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Y S Vassetzky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.,LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, Villejuif, 94805, France.,Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, 119334, Russia.,UMR8126, CNRS, Université Paris-Sud, Institut de Cancérologie Gustave Roussy, Villejuif, 94805, France
| | - E V Sheval
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.,LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, Villejuif, 94805, France
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37
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Walther N, Hossain MJ, Politi AZ, Koch B, Kueblbeck M, Ødegård-Fougner Ø, Lampe M, Ellenberg J. A quantitative map of human Condensins provides new insights into mitotic chromosome architecture. J Cell Biol 2018; 217:2309-2328. [PMID: 29632028 PMCID: PMC6028534 DOI: 10.1083/jcb.201801048] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/09/2018] [Accepted: 03/13/2018] [Indexed: 12/29/2022] Open
Abstract
The two Condensin complexes in human cells are essential for mitotic chromosome structure. We used homozygous genome editing to fluorescently tag Condensin I and II subunits and mapped their absolute abundance, spacing, and dynamic localization during mitosis by fluorescence correlation spectroscopy (FSC)-calibrated live-cell imaging and superresolution microscopy. Although ∼35,000 Condensin II complexes are stably bound to chromosomes throughout mitosis, ∼195,000 Condensin I complexes dynamically bind in two steps: prometaphase and early anaphase. The two Condensins rarely colocalize at the chromatid axis, where Condensin II is centrally confined, but Condensin I reaches ∼50% of the chromatid diameter from its center. Based on our comprehensive quantitative data, we propose a three-step hierarchical loop model of mitotic chromosome compaction: Condensin II initially fixes loops of a maximum size of ∼450 kb at the chromatid axis, whose size is then reduced by Condensin I binding to ∼90 kb in prometaphase and ∼70 kb in anaphase, achieving maximum chromosome compaction upon sister chromatid segregation.
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Affiliation(s)
- Nike Walther
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - M Julius Hossain
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Antonio Z Politi
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Birgit Koch
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Moritz Kueblbeck
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Øyvind Ødegård-Fougner
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Marko Lampe
- Advanced Light Microscopy Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jan Ellenberg
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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38
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Stanyte R, Nuebler J, Blaukopf C, Hoefler R, Stocsits R, Peters JM, Gerlich DW. Dynamics of sister chromatid resolution during cell cycle progression. J Cell Biol 2018; 217:1985-2004. [PMID: 29695489 PMCID: PMC5987726 DOI: 10.1083/jcb.201801157] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/16/2018] [Accepted: 04/11/2018] [Indexed: 01/04/2023] Open
Abstract
Faithful genome transmission in dividing cells requires that the two copies of each chromosome's DNA package into separate but physically linked sister chromatids. The linkage between sister chromatids is mediated by cohesin, yet where sister chromatids are linked and how they resolve during cell cycle progression has remained unclear. In this study, we investigated sister chromatid organization in live human cells using dCas9-mEGFP labeling of endogenous genomic loci. We detected substantial sister locus separation during G2 phase irrespective of the proximity to cohesin enrichment sites. Almost all sister loci separated within a few hours after their respective replication and then rapidly equilibrated their average distances within dynamic chromatin polymers. Our findings explain why the topology of sister chromatid resolution in G2 largely reflects the DNA replication program. Furthermore, these data suggest that cohesin enrichment sites are not persistent cohesive sites in human cells. Rather, cohesion might occur at variable genomic positions within the cell population.
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Affiliation(s)
- Rugile Stanyte
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Johannes Nuebler
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA
| | - Claudia Blaukopf
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Rudolf Hoefler
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Roman Stocsits
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Daniel W Gerlich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
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39
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Takahashi M, Hirota T. Dynamics of sister chromatids through the cell cycle: Together and apart. J Cell Biol 2018; 217:1887-1889. [PMID: 29764905 PMCID: PMC5987729 DOI: 10.1083/jcb.201804091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Takahashi and Hirota preview work from Stanyte et al. examining the behavior of sister chromatids and their resolution as the cell cycle progresses. When and how sister chromatid resolution occurs after DNA replication is a fundamental question. Stanyte et al. (2018. J. Cell Biol.https://doi.org/10.1083/jcb.201801157) used CRISPR/Cas9 technology to label and track genomic loci in live cells throughout the cell cycle, shedding light on how replication is linked to mitotic sister chromatid organization.
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Affiliation(s)
- Motoko Takahashi
- Division of Experimental Pathology, Cancer Institute of the Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Toru Hirota
- Division of Experimental Pathology, Cancer Institute of the Japanese Foundation for Cancer Research, Tokyo, Japan
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40
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Morales C, Losada A. Establishing and dissolving cohesion during the vertebrate cell cycle. Curr Opin Cell Biol 2018; 52:51-57. [PMID: 29433064 DOI: 10.1016/j.ceb.2018.01.010] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 01/18/2018] [Accepted: 01/29/2018] [Indexed: 01/28/2023]
Abstract
Replicated chromatids are held together from the time they emerge from the replication fork until their separation in anaphase. This process, known as cohesion, promotes faithful DNA repair by homologous recombination in interphase and ensures accurate chromosome segregation in mitosis. Identification of cohesin thirty years ago solved a long-standing question about the nature of the linkage keeping together the sister chromatids. Cohesin is an evolutionarily conserved complex composed of a heterodimer of the Structural Maintenance of Chromosomes (SMC) family of ATPases, Smc1 and Smc3, the kleisin subunit Rad21 and a Huntingtin/EF3/PP2A/Tor1 (HEAT) repeat domain-containing subunit named SA/STAG. In addition to mediating cohesion, cohesin plays a major role in genome organization. Cohesin functions rely on the ability of the complex to entrap DNA topologically and in a dynamic manner. Establishment of cohesion during S phase requires coordination with the DNA replication machinery and restricts the dynamic behaviour of at least a fraction of cohesin. Dissolution of cohesion in subsequent mitosis is regulated by multiple mechanisms that ensure that daughter cells receive the correct number of intact chromosomes. We here review recent progress on our understanding of how these processes are regulated in somatic vertebrate cells.
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Affiliation(s)
- Carmen Morales
- Chromosome Dynamics Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Ana Losada
- Chromosome Dynamics Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
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41
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Samejima K, Booth DG, Ogawa H, Paulson JR, Xie L, Watson CA, Platani M, Kanemaki MT, Earnshaw WC. Functional analysis after rapid degradation of condensins and 3D-EM reveals chromatin volume is uncoupled from chromosome architecture in mitosis. J Cell Sci 2018; 131:jcs.210187. [PMID: 29361541 PMCID: PMC5868952 DOI: 10.1242/jcs.210187] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 01/15/2018] [Indexed: 01/01/2023] Open
Abstract
The requirement for condensin in chromosome formation in somatic cells remains unclear, as imperfectly condensed chromosomes do form in cells depleted of condensin by conventional methodologies. In order to dissect the roles of condensin at different stages of vertebrate mitosis, we have established a versatile cellular system that combines auxin-mediated rapid degradation with chemical genetics to obtain near-synchronous mitotic entry of chicken DT40 cells in the presence and absence of condensin. We analyzed the outcome by live- and fixed-cell microscopy methods, including serial block face scanning electron microscopy with digital reconstruction. Following rapid depletion of condensin, chromosomal defects were much more obvious than those seen after a slow depletion of condensin. The total mitotic chromatin volume was similar to that in control cells, but a single mass of mitotic chromosomes was clustered at one side of a bent mitotic spindle. Cultures arrest at prometaphase, eventually exiting mitosis without segregating chromosomes. Experiments where the auxin concentration was titrated showed that different condensin levels are required for anaphase chromosome segregation and formation of a normal chromosome architecture. This article has an associated First Person interview with the first author of the paper. Summary: Rapid condensin depletion reveals that different condensin levels are required for mitotic chromosome architecture and segregation. Condensin is not required for chromatin volume compaction during mitosis.
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Affiliation(s)
- Kumiko Samejima
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
| | - Daniel G Booth
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
| | - Hiromi Ogawa
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
| | - James R Paulson
- Department of Chemistry, University of Wisconsin-Oshkosh, 800 Algoma Blvd, Oshkosh, WI 54901, USA
| | - Linfeng Xie
- Department of Chemistry, University of Wisconsin-Oshkosh, 800 Algoma Blvd, Oshkosh, WI 54901, USA
| | - Cara A Watson
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
| | - Melpomeni Platani
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
| | - Masato T Kanemaki
- Division of Molecular Cell Engineering, National Institute of Genetics, ROIS, and Department of Genetics, SOKENDAI, Yata 1111, Mishima, Shizuoka 411-8540, Japan
| | - William C Earnshaw
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
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42
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The deubiquitylase USP15 regulates topoisomerase II alpha to maintain genome integrity. Oncogene 2018; 37:2326-2342. [PMID: 29429988 PMCID: PMC5916918 DOI: 10.1038/s41388-017-0092-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 10/25/2017] [Accepted: 11/24/2017] [Indexed: 02/04/2023]
Abstract
Ubiquitin-specific protease 15 (USP15) is a widely expressed deubiquitylase that has been implicated in diverse cellular processes in cancer. Here we identify topoisomerase II (TOP2A) as a novel protein that is regulated by USP15. TOP2A accumulates during G2 and functions to decatenate intertwined sister chromatids at prophase, ensuring the replicated genome can be accurately divided into daughter cells at anaphase. We show that USP15 is required for TOP2A accumulation, and that USP15 depletion leads to the formation of anaphase chromosome bridges. These bridges fail to decatenate, and at mitotic exit form micronuclei that are indicative of genome instability. We also describe the cell cycle-dependent behaviour for two major isoforms of USP15, which differ by a short serine-rich insertion that is retained in isoform-1 but not in isoform-2. Although USP15 is predominantly cytoplasmic in interphase, we show that both isoforms move into the nucleus at prophase, but that isoform-1 is phosphorylated on its unique S229 residue at mitotic entry. The micronuclei phenotype we observe on USP15 depletion can be rescued by either USP15 isoform and requires USP15 catalytic activity. Importantly, however, an S229D phospho-mimetic mutant of USP15 isoform-1 cannot rescue either the micronuclei phenotype, or accumulation of TOP2A. Thus, S229 phosphorylation selectively abrogates this role of USP15 in maintaining genome integrity in an isoform-specific manner. Finally, we show that USP15 isoform-1 is preferentially upregulated in a panel of non-small cell lung cancer cell lines, and propose that isoform imbalance may contribute to genome instability in cancer. Our data provide the first example of isoform-specific deubiquitylase phospho-regulation and reveal a novel role for USP15 in guarding genome integrity.
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43
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Gibcus JH, Samejima K, Goloborodko A, Samejima I, Naumova N, Nuebler J, Kanemaki MT, Xie L, Paulson JR, Earnshaw WC, Mirny LA, Dekker J. A pathway for mitotic chromosome formation. Science 2018; 359:eaao6135. [PMID: 29348367 PMCID: PMC5924687 DOI: 10.1126/science.aao6135] [Citation(s) in RCA: 419] [Impact Index Per Article: 69.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 01/09/2018] [Indexed: 12/23/2022]
Abstract
Mitotic chromosomes fold as compact arrays of chromatin loops. To identify the pathway of mitotic chromosome formation, we combined imaging and Hi-C analysis of synchronous DT40 cell cultures with polymer simulations. Here we show that in prophase, the interphase organization is rapidly lost in a condensin-dependent manner, and arrays of consecutive 60-kilobase (kb) loops are formed. During prometaphase, ~80-kb inner loops are nested within ~400-kb outer loops. The loop array acquires a helical arrangement with consecutive loops emanating from a central "spiral staircase" condensin scaffold. The size of helical turns progressively increases to ~12 megabases during prometaphase. Acute depletion of condensin I or II shows that nested loops form by differential action of the two condensins, whereas condensin II is required for helical winding.
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Affiliation(s)
- Johan H Gibcus
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605, USA
| | - Kumiko Samejima
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
| | - Anton Goloborodko
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Itaru Samejima
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
| | - Natalia Naumova
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605, USA
| | - Johannes Nuebler
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Masato T Kanemaki
- Division of Molecular Cell Engineering, National Institute of Genetics, Research Organization of Information and Systems, and Department of Genetics, SOKENDAI, Yata 1111, Mishima, Shizuoka 411-8540, Japan
| | - Linfeng Xie
- Department of Chemistry, University of Wisconsin Oshkosh, 800 Algoma Boulevard, Oshkosh, WI 54901, USA
| | - James R Paulson
- Department of Chemistry, University of Wisconsin Oshkosh, 800 Algoma Boulevard, Oshkosh, WI 54901, USA
| | - William C Earnshaw
- Wellcome Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK.
| | - Leonid A Mirny
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Job Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605, USA.
- Howard Hughes Medical Institute, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605, USA
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44
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Wu X, Li Z, Shen Y. The small molecule CS1 inhibits mitosis and sister chromatid resolution in HeLa cells. Biochim Biophys Acta Gen Subj 2018; 1862:1134-1147. [PMID: 29410075 DOI: 10.1016/j.bbagen.2018.01.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 12/01/2017] [Accepted: 01/18/2018] [Indexed: 01/03/2023]
Abstract
BACKGROUND Mitosis, the most dramatic event in the cell cycle, involves the reorganization of virtually all cellular components. Antimitotic agents are useful for dissecting the mechanism of this reorganization. Previously, we found that the small molecule CS1 accumulates cells in G2/M phase [1], but the mechanism of its action remains unknown. METHODS Cell cycle analysis, live cell imaging and nuclear staining were used. Chromosomal morphology was detected by chromosome spreading. The effects of CS1 on microtubules were confirmed by tubulin polymerization, colchicine tubulin-binding, cellular tubulin polymerization and immunofluorescence assays and by analysis of microtubule dynamics and molecular modeling. Histone phosphoproteomics was performed using mass spectrometry. Cell signaling cascades were analyzed using immunofluorescence, immunoprecipitation, immunoblotting, siRNA knockdown and chemical inhibition of specific proteins. RESULTS The small molecule CS1 was shown to be an antimitotic agent. CS1 potently inhibited microtubule polymerization via interaction with the colchicine-binding pocket of tubulin in vitro and inhibited the formation of the spindle apparatus by reducing the bulk of growing microtubules in HeLa cells, which led to activation of the spindle assembly checkpoint (SAC) and mitotic arrest of HeLa cells. Compared with colchicine, CS1 impaired the progression of sister chromatid resolution independent of cohesin dissociation, and this was reversed by the removal of CS1. Additionally, CS1 induced unique histone phosphorylation patterns distinct from those induced by colchicine. CONCLUSIONS AND SIGNIFICANCE CS1 is a unique antimitotic small molecule and a powerful tool with unprecedented value over colchicine that makes it possible to specifically and conditionally perturb mitotic progression.
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Affiliation(s)
- Xingkang Wu
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, No. 44 West Wenhua Road, Jinan, Shandong 250012, PR China
| | - Zhenyu Li
- Department of Pharmacy, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, PR China
| | - Yuemao Shen
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, No. 44 West Wenhua Road, Jinan, Shandong 250012, PR China; State Key Laboratory of Microbial Technology, Shandong University, No. 27 South Shanda Road, Jinan, Shandong 250100, PR China.
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Maeshima K, Matsuda T, Shindo Y, Imamura H, Tamura S, Imai R, Kawakami S, Nagashima R, Soga T, Noji H, Oka K, Nagai T. A Transient Rise in Free Mg 2+ Ions Released from ATP-Mg Hydrolysis Contributes to Mitotic Chromosome Condensation. Curr Biol 2018; 28:444-451.e6. [PMID: 29358072 DOI: 10.1016/j.cub.2017.12.035] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 12/12/2017] [Accepted: 12/18/2017] [Indexed: 01/01/2023]
Abstract
For cell division, negatively charged chromatin, in which nucleosome fibers (10 nm fibers) are irregularly folded [1-5], must be condensed into chromosomes and segregated. While condensin and other proteins are critical for organizing chromatin into the appropriate chromosome shape [6-17], free divalent cations such as Mg2+ and Ca2+, which condense chromatin or chromosomes in vitro [18-28], have long been considered important, especially for local condensation, because the nucleosome fiber has a net negative charge and is by itself stretched like "beads on a string" by electrostatic repulsion. For further folding, other positively charged factors are required to decrease the charge and repulsion [29]. However, technical limitations to measure intracellular free divalent cations, but not total cations [30], especially Mg2+, have prevented us from elucidating their function. Here, we developed a Förster resonance energy transfer (FRET)-based Mg2+ indicator that monitors free Mg2+ dynamics throughout the cell cycle. By combining this indicator with Ca2+ [31] and adenosine triphosphate (ATP) [32] indicators, we demonstrate that the levels of free Mg2+, but not Ca2+, increase during mitosis. The Mg2+ increase is coupled with a decrease in ATP, which is normally bound to Mg2+ in the cell [33]. ATP inhibited Mg2+-dependent chromatin condensation in vitro. Chelating Mg2+ induced mitotic cell arrest and chromosome decondensation, while ATP reduction had the opposite effect. Our results suggest that ATP-bound Mg2+ is released by ATP hydrolysis and contributes to mitotic chromosome condensation with increased rigidity, suggesting a novel regulatory mechanism for higher-order chromatin organization by the intracellular Mg2+-ATP balance.
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Affiliation(s)
- Kazuhiro Maeshima
- Structural Biology Center, National Institute of Genetics, and Department of Genetics, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan.
| | - Tomoki Matsuda
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Yutaka Shindo
- Department of Biosciences & Informatics, Keio University, Hiyoshi, Yokohama 223-8522, Japan
| | - Hiromi Imamura
- Department of Life Science, Kyoto University, Kyoto 606-8501, Japan
| | - Sachiko Tamura
- Structural Biology Center, National Institute of Genetics, and Department of Genetics, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
| | - Ryosuke Imai
- Structural Biology Center, National Institute of Genetics, and Department of Genetics, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
| | - Syoji Kawakami
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Ryosuke Nagashima
- Structural Biology Center, National Institute of Genetics, and Department of Genetics, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
| | - Tomoyoshi Soga
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0052, Japan
| | - Hiroyuki Noji
- Department of Applied Chemistry, The University of Tokyo, Tokyo 113-8656, Japan
| | - Kotaro Oka
- Department of Biosciences & Informatics, Keio University, Hiyoshi, Yokohama 223-8522, Japan
| | - Takeharu Nagai
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan.
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A Mild Aqueous Sonogashira Reaction as a Fluorescent Labeling Strategy for 5-Bromide-2'-Deoxyuridine. Molecules 2018; 23:molecules23010154. [PMID: 29329267 PMCID: PMC6017456 DOI: 10.3390/molecules23010154] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 01/08/2018] [Accepted: 01/11/2018] [Indexed: 12/31/2022] Open
Abstract
C5-modified uridines are a valuable class of nucleoside analogues, both as potent chemotherapy agents and through their use as the conjunction site in DNA labeling strategies. As an important C5-modified uridine, BrdU has been used in cell proliferation assays since the 1980s. Currently, the detection of BrdU relies on traditional immunostaining; however, this approach has its limitations. Thus, it is desirable, albeit difficult, to develop chemistry methods to fluorescently label BrdU in a cellular context. In the present study, we report our efforts toward developing a robust chemistry methodology for BrdU fluorescent labeling. The Sonogashira reaction was chosen as the key reaction, and various alkynyl groups (aliphatic or aryl) containing fluorescent dyes were synthesized to cross-couple with BrdU. Various bases and catalyst systems were screened to evaluate the optimum conditions. A mild aqueous Sonogashira reaction (K₂PdCl₄, S-Phos, n-Bu₄N⁺OH-, Sodium d-isoascorbate, EtOH/H₂O = 1:1, 37 °C, Ar) was obtained to enable high-yielding BrdU fluorescent labeling.
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Piskadlo E, Oliveira RA. A Topology-Centric View on Mitotic Chromosome Architecture. Int J Mol Sci 2017; 18:E2751. [PMID: 29258269 PMCID: PMC5751350 DOI: 10.3390/ijms18122751] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 02/04/2023] Open
Abstract
Mitotic chromosomes are long-known structures, but their internal organization and the exact process by which they are assembled are still a great mystery in biology. Topoisomerase II is crucial for various aspects of mitotic chromosome organization. The unique ability of this enzyme to untangle topologically intertwined DNA molecules (catenations) is of utmost importance for the resolution of sister chromatid intertwines. Although still controversial, topoisomerase II has also been proposed to directly contribute to chromosome compaction, possibly by promoting chromosome self-entanglements. These two functions raise a strong directionality issue towards topoisomerase II reactions that are able to disentangle sister DNA molecules (in trans) while compacting the same DNA molecule (in cis). Here, we review the current knowledge on topoisomerase II role specifically during mitosis, and the mechanisms that directly or indirectly regulate its activity to ensure faithful chromosome segregation. In particular, we discuss how the activity or directionality of this enzyme could be regulated by the SMC (structural maintenance of chromosomes) complexes, predominantly cohesin and condensin, throughout mitosis.
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Affiliation(s)
- Ewa Piskadlo
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal.
| | - Raquel A Oliveira
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal.
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Kakui Y, Rabinowitz A, Barry DJ, Uhlmann F. Condensin-mediated remodeling of the mitotic chromatin landscape in fission yeast. Nat Genet 2017; 49:1553-1557. [PMID: 28825727 PMCID: PMC5621628 DOI: 10.1038/ng.3938] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 07/27/2017] [Indexed: 12/12/2022]
Abstract
The eukaryotic genome consists of DNA molecules far longer than the cells that contain them. They reach their greatest compaction during chromosome condensation in mitosis. This process is aided by condensin, a structural maintenance of chromosomes (SMC) family member. The spatial organization of mitotic chromosomes and how condensin shapes chromatin architecture are not yet fully understood. Here we use chromosome conformation capture (Hi-C) to study mitotic chromosome condensation in the fission yeast Schizosaccharomyces pombe. This showed that the interphase landscape characterized by small chromatin domains is replaced by fewer but larger domains in mitosis. Condensin achieves this by setting up longer-range, intrachromosomal DNA interactions, which compact and individualize chromosomes. At the same time, local chromatin contacts are constrained by condensin, with profound implications for local chromatin function during mitosis. Our results highlight condensin as a major determinant that changes the chromatin landscape as cells prepare their genomes for cell division.
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Affiliation(s)
- Yasutaka Kakui
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK
| | - Adam Rabinowitz
- Bioinformatics Core, The Francis Crick Institute, London, UK
| | - David J Barry
- Advanced Light Microscopy Facility, The Francis Crick Institute, London, UK
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK
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49
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Kuznetsova MA, Chaban IA, Sheval EV. Visualization of chromosome condensation in plants with large chromosomes. BMC PLANT BIOLOGY 2017; 17:153. [PMID: 28899358 PMCID: PMC5596468 DOI: 10.1186/s12870-017-1102-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/07/2017] [Indexed: 05/13/2023]
Abstract
BACKGROUND Most data concerning chromosome organization have been acquired from studies of a small number of model organisms, the majority of which are mammals. In plants with large genomes, the chromosomes are significantly larger than the animal chromosomes that have been studied to date, and it is possible that chromosome condensation in such plants was modified during evolution. Here, we analyzed chromosome condensation and decondensation processes in order to find structural mechanisms that allowed for an increase in chromosome size. RESULTS We found that anaphase and telophase chromosomes of plants with large chromosomes (average 2C DNA content exceeded 0.8 pg per chromosome) contained chromatin-free cavities in their axial regions in contrast to well-characterized animal chromosomes, which have high chromatin density in the axial regions. Similar to animal chromosomes, two intermediates of chromatin folding were visible inside condensing (during prophase) and decondensing (during telophase) chromosomes of Nigella damascena: approximately 150 nm chromonemata and approximately 300 nm fibers. The spatial folding of the latter fibers occurs in a fundamentally different way than in animal chromosomes, which leads to the formation of chromosomes with axial chromatin-free cavities. CONCLUSION Different compaction topology, but not the number of compaction levels, allowed for the evolution of increased chromosome size in plants.
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Affiliation(s)
- Maria A Kuznetsova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992, Moscow, Russia
| | - Inna A Chaban
- All-Russian Research Institute of Agricultural Biotechnology, Timiryazevskaja 42, 127550, Moscow, Russia
| | - Eugene V Sheval
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992, Moscow, Russia.
- LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France.
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50
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Fenelon KD, Hopyan S. Structural components of nuclear integrity with gene regulatory potential. Curr Opin Cell Biol 2017. [PMID: 28641117 DOI: 10.1016/j.ceb.2017.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The nucleus is a mechanosensitive and load-bearing structure. Structural components of the nucleus interact to maintain nuclear integrity and have become subjects of exciting research that is relevant to cell and developmental biology. Here we outline the boundaries of what is known about key architectural elements within the nucleus and highlight their potential structural and transcriptional regulatory functions.
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Affiliation(s)
- Kelli D Fenelon
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, M5S 1A8, Canada
| | - Sevan Hopyan
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, M5S 1A8, Canada; Division of Orthopaedic Surgery, Hospital for Sick Children and University of Toronto, M5G 1X8, Canada.
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