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Abstract
Protein complexes built of structural maintenance of chromosomes (SMC) and kleisin subunits, including cohesin, condensin and the Smc5/6 complex, are master organizers of genome architecture in all kingdoms of life. How these large ring-shaped molecular machines use the energy of ATP hydrolysis to change the topology of chromatin fibers has remained a central unresolved question of chromosome biology. A currently emerging concept suggests that the common principle that underlies the essential functions of SMC protein complexes in the control of gene expression, chromosome segregation or DNA damage repair is their ability to expand DNA into large loop structures. Here, we review the current knowledge about the biochemical and structural properties of SMC protein complexes that might enable them to extrude DNA loops and compare their action to other motor proteins and nucleic acid translocases. We evaluate the currently predominant models of active loop extrusion and propose a detailed version of a 'scrunching' model, which reconciles much of the available mechanistic data and provides an elegant explanation for how SMC protein complexes fulfill an array of seemingly diverse tasks during the organization of genomes.
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52
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Garcia-Luis J, Lazar-Stefanita L, Gutierrez-Escribano P, Thierry A, Cournac A, García A, González S, Sánchez M, Jarmuz A, Montoya A, Dore M, Kramer H, Karimi MM, Antequera F, Koszul R, Aragon L. FACT mediates cohesin function on chromatin. Nat Struct Mol Biol 2019; 26:970-979. [PMID: 31582854 PMCID: PMC6779571 DOI: 10.1038/s41594-019-0307-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 08/21/2019] [Indexed: 11/09/2022]
Abstract
Cohesin is a regulator of genome architecture with roles in sister chromatid cohesion and chromosome compaction. The recruitment and mobility of cohesin complexes on DNA is restricted by nucleosomes. Here, we show that the role of cohesin in chromosome organization requires the histone chaperone FACT ('facilitates chromatin transcription') in Saccharomyces cerevisiae. We find that FACT interacts directly with cohesin, and is dynamically required for its localization on chromatin. Depletion of FACT in metaphase cells prevents cohesin accumulation at pericentric regions and causes reduced binding on chromosome arms. Using the Hi-C technique, we show that cohesin-dependent TAD (topological associated domain)-like structures in G1 and metaphase chromosomes are reduced in the absence of FACT. Sister chromatid cohesion is intact in FACT-depleted cells, although chromosome segregation failure is observed. Our data show that FACT contributes to the formation of cohesin-dependent TADs, thus uncovering a new role for this complex in nuclear organization during interphase and mitotic chromosome folding.
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Affiliation(s)
- Jonay Garcia-Luis
- Cell Cycle Group, MRC London Institute of Medical Sciences (LMS), London, UK
| | - Luciana Lazar-Stefanita
- Institut Pasteur, Department of Genomes and Genetics, Unité Régulation Spatiale des Génomes, Paris, France
| | | | - Agnes Thierry
- Institut Pasteur, Department of Genomes and Genetics, Unité Régulation Spatiale des Génomes, Paris, France
| | - Axel Cournac
- Institut Pasteur, Department of Genomes and Genetics, Unité Régulation Spatiale des Génomes, Paris, France
| | - Alicia García
- Instituto de Biología Funcional y Genómica (IBFG), CSIC/Universidad de Salamanca, Salamanca, Spain
| | - Sara González
- Instituto de Biología Funcional y Genómica (IBFG), CSIC/Universidad de Salamanca, Salamanca, Spain
| | - Mar Sánchez
- Instituto de Biología Funcional y Genómica (IBFG), CSIC/Universidad de Salamanca, Salamanca, Spain
| | - Adam Jarmuz
- Cell Cycle Group, MRC London Institute of Medical Sciences (LMS), London, UK
| | - Alex Montoya
- Biological Mass Spectrometry and Proteomics Facility, MRC London Institute of Medical Sciences (LMS), London, UK
| | - Marian Dore
- Bioinformatics Facility, MRC London Institute of Medical Sciences (LMS), London, UK
| | - Holger Kramer
- Biological Mass Spectrometry and Proteomics Facility, MRC London Institute of Medical Sciences (LMS), London, UK
| | - Mohammad M Karimi
- Bioinformatics Facility, MRC London Institute of Medical Sciences (LMS), London, UK
| | - Francisco Antequera
- Instituto de Biología Funcional y Genómica (IBFG), CSIC/Universidad de Salamanca, Salamanca, Spain
| | - Romain Koszul
- Institut Pasteur, Department of Genomes and Genetics, Unité Régulation Spatiale des Génomes, Paris, France.
| | - Luis Aragon
- Cell Cycle Group, MRC London Institute of Medical Sciences (LMS), London, UK.
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53
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Large-scale chromatin organisation in interphase, mitosis and meiosis. Biochem J 2019; 476:2141-2156. [DOI: 10.1042/bcj20180512] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 01/17/2023]
Abstract
AbstractThe spatial configuration of chromatin is fundamental to ensure any given cell can fulfil its functional duties, from gene expression to specialised cellular division. Significant technological innovations have facilitated further insights into the structure, function and regulation of three-dimensional chromatin organisation. To date, the vast majority of investigations into chromatin organisation have been conducted in interphase and mitotic cells leaving meiotic chromatin relatively unexplored. In combination, cytological and genome-wide contact frequency analyses in mammalian germ cells have recently demonstrated that large-scale chromatin structures in meiotic prophase I are reminiscent of the sequential loop arrays found in mitotic cells, although interphase-like segmentation of transcriptionally active and inactive regions are also evident along the length of chromosomes. Here, we discuss the similarities and differences of such large-scale chromatin architecture, between interphase, mitotic and meiotic cells, as well as their functional relevance and the proposed modulatory mechanisms which underlie them.
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54
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Interplay between Phosphatases and the Anaphase-Promoting Complex/Cyclosome in Mitosis. Cells 2019; 8:cells8080814. [PMID: 31382469 PMCID: PMC6721574 DOI: 10.3390/cells8080814] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 07/25/2019] [Accepted: 08/01/2019] [Indexed: 12/14/2022] Open
Abstract
Accurate division of cells into two daughters is a process that is vital to propagation of life. Protein phosphorylation and selective degradation have emerged as two important mechanisms safeguarding the delicate choreography of mitosis. Protein phosphatases catalyze dephosphorylation of thousands of sites on proteins, steering the cells through establishment of the mitotic phase and exit from it. A large E3 ubiquitin ligase, the anaphase-promoting complex/cyclosome (APC/C) becomes active during latter stages of mitosis through G1 and marks hundreds of proteins for destruction. Recent studies have revealed the complex interregulation between these two classes of enzymes. In this review, we highlight the direct and indirect mechanisms by which phosphatases and the APC/C mutually influence each other to ensure accurate spatiotemporal and orderly progression through mitosis, with a particular focus on recent insights and conceptual advances.
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55
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Talbert PB, Meers MP, Henikoff S. Old cogs, new tricks: the evolution of gene expression in a chromatin context. Nat Rev Genet 2019; 20:283-297. [PMID: 30886348 DOI: 10.1038/s41576-019-0105-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Sophisticated gene-regulatory mechanisms probably evolved in prokaryotes billions of years before the emergence of modern eukaryotes, which inherited the same basic enzymatic machineries. However, the epigenomic landscapes of eukaryotes are dominated by nucleosomes, which have acquired roles in genome packaging, mitotic condensation and silencing parasitic genomic elements. Although the molecular mechanisms by which nucleosomes are displaced and modified have been described, just how transcription factors, histone variants and modifications and chromatin regulators act on nucleosomes to regulate transcription is the subject of considerable ongoing study. We explore the extent to which these transcriptional regulatory components function in the context of the evolutionarily ancient role of chromatin as a barrier to processes acting on DNA and how chromatin proteins have diversified to carry out evolutionarily recent functions that accompanied the emergence of differentiation and development in multicellular eukaryotes.
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Affiliation(s)
- Paul B Talbert
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Michael P Meers
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Steven Henikoff
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.
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56
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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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57
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Molecular Dynamics Simulations of Condensin-Mediated Mitotic Chromosome Assembly. Methods Mol Biol 2019. [PMID: 31147926 DOI: 10.1007/978-1-4939-9520-2_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Molecular dynamics simulation is a powerful tool used in modern molecular modeling, which enables a deeper comprehension of the physical behavior of atoms and molecules at a micro level. In this study, we simulated mitotic chromosome assembly mediated by condensins, a class of large protein complexes containing a pair of structural maintenance of chromosomes (SMC) subunits that are central to this process. In this chapter, we present the construction of a coarse-grained physical model of chromosomal DNA fibers and condensin molecules, and monitoring of the function of condensins in mitotic chromosome assembly, using computer-based molecular dynamics simulation. We explain how our model of chromosomes and condensins may be simulated using a package of molecular dynamics simulation. Procedures involved in calculating the observables of dynamics are described, together with an example of the simulation results.
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58
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French BT, Straight AF. The Power of Xenopus Egg Extract for Reconstitution of Centromere and Kinetochore Function. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2019; 56:59-84. [PMID: 28840233 DOI: 10.1007/978-3-319-58592-5_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Faithful transmission of genetic information during cell division requires attachment of chromosomes to the mitotic spindle via the kinetochore. In vitro reconstitution studies are beginning to uncover how the kinetochore is assembled upon the underlying centromere, how the kinetochore couples chromosome movement to microtubule dynamics, and how cells ensure the site of kinetochore assembly is maintained from one generation to the next. Here we give special emphasis to advances made in Xenopus egg extract, which provides a unique, biochemically tractable in vitro system that affords the complexity of cytoplasm and nucleoplasm to permit reconstitution of the dynamic, cell cycle-regulated functions of the centromere and kinetochore.
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Affiliation(s)
- Bradley T French
- Department of Biochemistry, Stanford University, 279 Campus Drive, Beckman 409, Stanford, CA, 94305, USA
| | - Aaron F Straight
- Department of Biochemistry, Stanford University, 279 Campus Drive, Beckman 409, Stanford, CA, 94305, USA.
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59
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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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60
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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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61
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Baxter J, Oliver AW, Schalbetter SA. Are SMC Complexes Loop Extruding Factors? Linking Theory With Fact. Bioessays 2018; 41:e1800182. [PMID: 30506702 DOI: 10.1002/bies.201800182] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/05/2018] [Indexed: 01/24/2023]
Abstract
The extreme length of chromosomal DNA requires organizing mechanisms to both promote functional genetic interactions and ensure faithful chromosome segregation when cells divide. Microscopy and genome-wide contact frequency analyses indicate that intra-chromosomal looping of DNA is a primary pathway of chromosomal organization during all stages of the cell cycle. DNA loop extrusion has emerged as a unifying model for how chromosome loops are formed in cis in different genomic contexts and cell cycle stages. The highly conserved family of SMC complexes have been found to be required for DNA cis-looping and have been suggested to be the enzymatic core of loop extruding machines. Here, the current body of evidence available for the in vivo and in vitro action of SMC complexes is discussed and compared to the predictions made by the loop extrusion model. How SMC complexes may differentially act on chromatin to generate DNA loops and how they could work to generate the dynamic and functionally appropriate organization of DNA in cells is explored.
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Affiliation(s)
- Jonathan Baxter
- Genome Damage and Stability Centre, Science Park Road, University of Sussex, Falmer, Brighton, East Sussex BN1 9RQ, UK
| | - Antony W Oliver
- Genome Damage and Stability Centre, Science Park Road, University of Sussex, Falmer, Brighton, East Sussex BN1 9RQ, UK
| | - Stephanie A Schalbetter
- Genome Damage and Stability Centre, Science Park Road, University of Sussex, Falmer, Brighton, East Sussex BN1 9RQ, UK
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62
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Soeda S, Yamada-Nomoto K, Michiue T, Ohsugi M. RSK-MASTL Pathway Delays Meiotic Exit in Mouse Zygotes to Ensure Paternal Chromosome Stability. Dev Cell 2018; 47:363-376.e5. [DOI: 10.1016/j.devcel.2018.09.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 06/25/2018] [Accepted: 09/09/2018] [Indexed: 11/30/2022]
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63
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The histone chaperone NAP1L3 is required for haematopoietic stem cell maintenance and differentiation. Sci Rep 2018; 8:11202. [PMID: 30046127 PMCID: PMC6060140 DOI: 10.1038/s41598-018-29518-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 07/12/2018] [Indexed: 01/04/2023] Open
Abstract
Nucleosome assembly proteins (NAPs) are histone chaperones with an important role in chromatin structure and epigenetic regulation of gene expression. We find that high gene expression levels of mouse Nap1l3 are restricted to haematopoietic stem cells (HSCs) in mice. Importantly, with shRNA or CRISPR-Cas9 mediated loss of function of mouse Nap1l3 and with overexpression of the gene, the number of colony-forming cells and myeloid progenitor cells in vitro are reduced. This manifests as a striking decrease in the number of HSCs, which reduces their reconstituting activities in vivo. Downregulation of human NAP1L3 in umbilical cord blood (UCB) HSCs impairs the maintenance and proliferation of HSCs both in vitro and in vivo. NAP1L3 downregulation in UCB HSCs causes an arrest in the G0 phase of cell cycle progression and induces gene expression signatures that significantly correlate with downregulation of gene sets involved in cell cycle regulation, including E2F and MYC target genes. Moreover, we demonstrate that HOXA3 and HOXA5 genes are markedly upregulated when NAP1L3 is suppressed in UCB HSCs. Taken together, our findings establish an important role for NAP1L3 in HSC homeostasis and haematopoietic differentiation.
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64
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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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65
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Sakai Y, Mochizuki A, Kinoshita K, Hirano T, Tachikawa M. Modeling the functions of condensin in chromosome shaping and segregation. PLoS Comput Biol 2018; 14:e1006152. [PMID: 29912867 PMCID: PMC6005465 DOI: 10.1371/journal.pcbi.1006152] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 04/24/2018] [Indexed: 11/18/2022] Open
Abstract
The mechanistic details underlying the assembly of rod-shaped chromosomes during mitosis and how they segregate from each other to act as individually mobile units remain largely unknown. Here, we construct a coarse-grained physical model of chromosomal DNA and condensins, a class of large protein complexes that plays key roles in these processes. We assume that condensins have two molecular activities: consecutive loop formation in DNA and inter-condensin attractions. Our simulation demonstrates that both of these activities and their balancing acts are essential for the efficient shaping and segregation of mitotic chromosomes. Our results also demonstrate that the shaping and segregation processes are strongly correlated, implying their mechanistic coupling during mitotic chromosome assembly. Our results highlight the functional importance of inter-condensin attractions in chromosome shaping and segregation. Immediately before a cell divides, chromosomal DNA in a eukaryotic cell is packaged into a discrete set of rod-shaped chromosomes. This process, known as mitotic chromosome assembly or condensation, secures the faithful segregation of genetic information into daughter cells. Central to this mechanistically complex process is a class of protein complexes known as condensins. However, how condensins support the assembly and segregation of mitotic chromosomes at a mechanistic level remains elusive. Here we construct a coarse-grained physical model of chromosomal DNA fibers and condensin molecules, and study how condensins work in the mitotic chromosome assembly using computer simulations. Our results show that two activities of condensins, formation of consecutive loops in chromosomal DNA fibers and inter-condensin attractions, are necessary for both the shaping and segregation of mitotic chromosomes, and balancing acts of these activities help to coordinate the efficient progress of the processes. Importantly, chromosome shaping and segregation in our results are strongly correlated, implying that they are controlled by the same underlying mechanism mediated by condensins.
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Affiliation(s)
- Yuji Sakai
- iTHES Research Group, RIKEN, Wako, Japan.,Theoretical Biology Laboratory, RIKEN, Wako, Japan.,Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Atsushi Mochizuki
- iTHES Research Group, RIKEN, Wako, Japan.,Theoretical Biology Laboratory, RIKEN, Wako, Japan.,iTHEMS Program, RIKEN, Wako, Japan.,CREST, JST 4-1-8 Honcho, Kawaguchi, Japan
| | | | | | - Masashi Tachikawa
- iTHES Research Group, RIKEN, Wako, Japan.,Theoretical Biology Laboratory, RIKEN, Wako, Japan.,iTHEMS Program, RIKEN, Wako, Japan
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66
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Yamaguchi K, Hada M, Fukuda Y, Inoue E, Makino Y, Katou Y, Shirahige K, Okada Y. Re-evaluating the Localization of Sperm-Retained Histones Revealed the Modification-Dependent Accumulation in Specific Genome Regions. Cell Rep 2018; 23:3920-3932. [DOI: 10.1016/j.celrep.2018.05.094] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/18/2018] [Accepted: 05/30/2018] [Indexed: 11/24/2022] Open
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67
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Abstract
The mitotic chromosome, which is composed of a pair of sister chromatids, is a large macromolecular assembly that ensures faithful transmission of genetic information into daughter cells. Despite its fundamental importance, how a nucleosome fiber is folded and assembled into a large-scale chromatid structure remains poorly understood. To address this question, we have established a biochemically tractable system in which mitotic chromatids can be reconstituted in vitro by mixing a simple substrate (sperm nucleus) and a limited number of purified factors. The minimum set of required factors includes core histones, three histone chaperones, topoisomerase II, and condensin I. In this article, we describe a set of protocols for the preparation of key reagents and the setup of reconstitution reactions. We believe that this classical approach of biochemical reconstitution will be of great help to dissect the mechanisms of action of individual factors during mitotic chromatid assembly and to assess the contribution of nucleosome dynamics to this process from a fresh angle. © 2018 by John Wiley & Sons, Inc.
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68
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Gligoris TG. Chromosome Biology: The Smc-Kleisin Enzymology Finally Comes of Age. Curr Biol 2018; 28:R612-R614. [PMID: 29787727 DOI: 10.1016/j.cub.2018.03.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Cohesin and condensin are Smc-kleisin complexes responsible for shaping our chromosomes. Despite extensive genetic and genomic information available on their function, their biochemistry has been hard to study. Two recent studies finally bring exciting new insights into their enzymology.
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69
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Schiklenk C, Petrova B, Kschonsak M, Hassler M, Klein C, Gibson TJ, Haering CH. Control of mitotic chromosome condensation by the fission yeast transcription factor Zas1. J Cell Biol 2018; 217:2383-2401. [PMID: 29735745 PMCID: PMC6028546 DOI: 10.1083/jcb.201711097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 03/28/2018] [Accepted: 04/17/2018] [Indexed: 01/05/2023] Open
Abstract
How chromosomes compact into rod-shaped structures is a longstanding unresolved question of cell biology. Schiklenk et al. identify the transcription factor Zas1 as a central regulator of mitotic chromosome condensation in fission yeast and show that it uses a conserved transactivation domain–based mechanism to control gene expression. Although the formation of rod-shaped chromosomes is vital for the correct segregation of eukaryotic genomes during cell divisions, the molecular mechanisms that control the chromosome condensation process have remained largely unknown. Here, we identify the C2H2 zinc-finger transcription factor Zas1 as a key regulator of mitotic condensation dynamics in a quantitative live-cell microscopy screen of the fission yeast Schizosaccharomyces pombe. By binding to specific DNA target sequences in their promoter regions, Zas1 controls expression of the Cnd1 subunit of the condensin protein complex and several other target genes, whose combined misregulation in zas1 mutants results in defects in chromosome condensation and segregation. Genetic and biochemical analysis reveals an evolutionarily conserved transactivation domain motif in Zas1 that is pivotal to its function in gene regulation. Our results suggest that this motif, together with the Zas1 C-terminal helical domain to which it binds, creates a cis/trans switch module for transcriptional regulation of genes that control chromosome condensation.
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Affiliation(s)
- Christoph Schiklenk
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Boryana Petrova
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Marc Kschonsak
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Markus Hassler
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Carlo Klein
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Toby J Gibson
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Christian H Haering
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany .,Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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70
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Takagi M, Ono T, Natsume T, Sakamoto C, Nakao M, Saitoh N, Kanemaki MT, Hirano T, Imamoto N. Ki-67 and condensins support the integrity of mitotic chromosomes through distinct mechanisms. J Cell Sci 2018; 131:jcs.212092. [PMID: 29487178 DOI: 10.1242/jcs.212092] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 02/15/2018] [Indexed: 12/11/2022] Open
Abstract
Although condensins play essential roles in mitotic chromosome assembly, Ki-67 (also known as MKI67), a protein localizing to the periphery of mitotic chromosomes, had also been shown to make a contribution to the process. To examine their respective roles, we generated a set of HCT116-based cell lines expressing Ki-67 and/or condensin subunits that were fused with an auxin-inducible degron for their conditional degradation. Both the localization and the dynamic behavior of Ki-67 on mitotic chromosomes were not largely affected upon depletion of condensin subunits, and vice versa. When both Ki-67 and SMC2 (a core subunit of condensins) were depleted, ball-like chromosome clusters with no sign of discernible thread-like structures were observed. This severe defective phenotype was distinct from that observed in cells depleted of either Ki-67 or SMC2 alone. Our results show that Ki-67 and condensins, which localize to the external surface and the central axis of mitotic chromosomes, respectively, have independent yet cooperative functions in supporting the structural integrity of mitotic chromosomes.
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Affiliation(s)
| | - Takao Ono
- Chromosome Dynamics Laboratory, RIKEN, Wako 351-0198, Japan
| | - Toyoaki Natsume
- Division of Molecular Cell Engineering, NIG, Mishima 411-8540, Japan
| | - Chiyomi Sakamoto
- Department of Medical Cell Biology, IMEG, Kumamoto University, Kumamoto 860-0811, Japan
| | - Mitsuyoshi Nakao
- Department of Medical Cell Biology, IMEG, Kumamoto University, Kumamoto 860-0811, Japan
| | - Noriko Saitoh
- Department of Medical Cell Biology, IMEG, Kumamoto University, Kumamoto 860-0811, Japan.,Department of Cancer Biology, The Cancer Institute of JFCR, Tokyo 135-8550, Japan
| | - Masato T Kanemaki
- Division of Molecular Cell Engineering, NIG, Mishima 411-8540, Japan
| | - Tatsuya Hirano
- Chromosome Dynamics Laboratory, RIKEN, Wako 351-0198, Japan
| | - Naoko Imamoto
- Cellular Dynamics Laboratory, RIKEN, Wako 351-0198, Japan
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71
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Wang HZ, Yang SH, Li GY, Cao X. Subunits of human condensins are potential therapeutic targets for cancers. Cell Div 2018; 13:2. [PMID: 29467813 PMCID: PMC5819170 DOI: 10.1186/s13008-018-0035-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 02/05/2018] [Indexed: 11/16/2022] Open
Abstract
The main role of condensins is to regulate chromosome condensation and segregation during cell cycles. Recently, it has been suggested in the literatures that subunits of condensin I and condensin II are involved in some human cancers. This paper will first briefly discuss discoveries of human condensins, their components and structures, and their multiple cellular functions. This will be followed by reviews of most recent studies on subunits of human condensins and their dysregulations or mutations in human cancers. It can be concluded that many of these subunits have potentials to be novel targets for cancer therapies. However, hCAP-D2, a subunit of human condensin I, has not been directly documented to be associated with any human cancers to date. This review hypothesizes that hCAP-D2 can also be a potential therapeutic target for human cancers, and therefore that all subunits of human condensins are potential therapeutic targets for human cancers.
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Affiliation(s)
- Hong-Zhen Wang
- 1School of Life Sciences, Jilin Normal University, Siping, 136000 P. R. China.,2Key Laboratory for Molecular Enzymology and Engineering of The Ministry of Education, School of Life Sciences, Jilin University, Changchun, 130012 P. R. China.,3Department of Chemical and Biological Engineering, University of Ottawa, Ottawa, K1N 6N5 Canada
| | - Si-Han Yang
- 1School of Life Sciences, Jilin Normal University, Siping, 136000 P. R. China
| | - Gui-Ying Li
- 2Key Laboratory for Molecular Enzymology and Engineering of The Ministry of Education, School of Life Sciences, Jilin University, Changchun, 130012 P. R. China
| | - Xudong Cao
- 3Department of Chemical and Biological Engineering, University of Ottawa, Ottawa, K1N 6N5 Canada
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72
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Onikubo T, Shechter D. Chaperone-mediated chromatin assembly and transcriptional regulation in Xenopus laevis. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2018; 60:271-276. [PMID: 27759155 DOI: 10.1387/ijdb.130188ds] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Chromatin is the complex of DNA and histone proteins that is the physiological form of the eukaryotic genome. Chromatin is generally repressive for transcription, especially so during early metazoan development when maternal factors are explicitly in control of new zygotic gene expression. In the important model organism Xenopus laevis, maturing oocytes are transcriptionally active with reduced rates of chromatin assembly, while laid eggs and fertilized embryos have robust rates of chromatin assembly and are transcriptionally repressed. As the DNA-to-cytoplasmic ratio decreases approaching the mid-blastula transition (MBT) and the onset of zygotic genome activation (ZGA), the chromatin assembly process changes with the concomitant reduction in maternal chromatin components. Chromatin assembly is mediated in part by histone chaperones that store maternal histones and release them into new zygotic chromatin. Here, we review literature on chromatin and transcription in frog embryos and cell-free extracts and highlight key insights demonstrating the roles of maternal and zygotic histone deposition and their relationship with transcriptional regulation. We explore the central historical and recent literature on the use of Xenopus embryos and the key contributions provided by experiments in cell-free oocyte and egg extracts for the interplay between histone chaperones, chromatin assembly, and transcriptional regulation. Ongoing and future studies in Xenopus cell free extracts will likely contribute essential new insights into the interplay between chromatin assembly and transcriptional regulation.
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Affiliation(s)
- Takashi Onikubo
- Department of Biochemistry. Albert Einstein College of Medicine, Bronx, NY, USA
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73
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Ramos F, Leonard J, Clemente-Blanco A, Aragón L. Cdc14 and Chromosome Condensation: Evaluation of the Recruitment of Condensin to Genomic Regions. Methods Mol Biol 2018; 1505:229-243. [PMID: 27826868 DOI: 10.1007/978-1-4939-6502-1_17] [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] [Indexed: 02/24/2023]
Abstract
Chromosome condensation is an essential morphological event required for successful DNA segregation during mitosis. The high level of genome compaction achieved during this process is attained by the evolutionary conserved condensin complex. Recently, several lines of evidences have demonstrated that the mitotic phosphatase Cdc14 is required to ensure condensin loading onto chromosomes. To date several approaches have been used in order to characterize condensin activity and regulation, however these techniques are time-consuming and require complex equipment. In this chapter we described an easy and reliable protocol to analyze Cdc14-dependent condensin loading onto specific genomic DNA regions by using a chromatin immunoprecipitation (ChIP) technique.
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Affiliation(s)
- Facundo Ramos
- Cell Cycle and Genome Stability Group, Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca (USAL), C/ Zacarías González 2, Salamanca, 37007, Spain
| | - Joanne Leonard
- Cell Cycle Group, Medical Research Council, Clinical Sciences Centre, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Andrés Clemente-Blanco
- Cell Cycle and Genome Stability Group, Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca (USAL), C/ Zacarías González 2, Salamanca, 37007, Spain
| | - Luis Aragón
- Cell Cycle Group, Medical Research Council, Clinical Sciences Centre, Imperial College London, Du Cane Road, London, W12 0NN, UK.
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74
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Warren C, Matsui T, Karp JM, Onikubo T, Cahill S, Brenowitz M, Cowburn D, Girvin M, Shechter D. Dynamic intramolecular regulation of the histone chaperone nucleoplasmin controls histone binding and release. Nat Commun 2017; 8:2215. [PMID: 29263320 PMCID: PMC5738438 DOI: 10.1038/s41467-017-02308-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/17/2017] [Indexed: 12/21/2022] Open
Abstract
Nucleoplasmin (Npm) is a highly conserved histone chaperone responsible for the maternal storage and zygotic release of histones H2A/H2B. Npm contains a pentameric N-terminal core domain and an intrinsically disordered C-terminal tail domain. Though intrinsically disordered regions are common among histone chaperones, their roles in histone binding and chaperoning remain unclear. Using an NMR-based approach, here we demonstrate that the Xenopus laevis Npm tail domain controls the binding of histones at its largest acidic stretch (A2) via direct competition with both the C-terminal basic stretch and basic nuclear localization signal. NMR and small-angle X-ray scattering (SAXS) structural analyses allowed us to construct models of both the tail domain and the pentameric complex. Functional analyses demonstrate that these competitive intramolecular interactions negatively regulate Npm histone chaperone activity in vitro. Together these data establish a potentially generalizable mechanism of histone chaperone regulation via dynamic and specific intramolecular shielding of histone interaction sites.
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Affiliation(s)
- Christopher Warren
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10461, USA
| | - Tsutomu Matsui
- Department of Chemistry, Stanford University, Stanford Synchrotron Radiation Lightsource, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Jerome M Karp
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10461, USA
| | - Takashi Onikubo
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10461, USA
- Laboratory of Biochemistry and Molecular Biology, Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Sean Cahill
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10461, USA
| | - Michael Brenowitz
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10461, USA
| | - David Cowburn
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10461, USA
| | - Mark Girvin
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10461, USA
| | - David Shechter
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10461, USA.
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75
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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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76
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Eeftens J, Dekker C. Catching DNA with hoops—biophysical approaches to clarify the mechanism of SMC proteins. Nat Struct Mol Biol 2017; 24:1012-1020. [DOI: 10.1038/nsmb.3507] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/18/2017] [Indexed: 12/11/2022]
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77
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Shintomi K, Hirano T. Mitotic Chromosome Assembly In Vitro: Functional Cross Talk between Nucleosomes and Condensins. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2017; 82:157-164. [PMID: 29118204 DOI: 10.1101/sqb.2017.82.033639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The mitotic chromosome is a macromolecular assembly that ensures error-free transmission of the genome during cell division. It has long been a big mystery how long stretches of DNA might be folded into rod-shaped chromosomes or how such an elaborate process might be accomplished at a mechanistic level. Cell-free extracts made from frog eggs offer a unique opportunity to address these questions by enabling mitotic chromosomes to be assembled in a test tube. Moreover, the core part of the chromosome assembly reaction can now be reconstituted with a limited number of purified factors. A combination of these in vitro assays makes it possible not only to prepare a complete list of proteins required for chromosome assembly but also to dissect functions of individual proteins and their cooperation with unparalleled clarity. Emerging lines of evidence underscore the paramount importance of condensins in building mitotic chromosomes and shed new light on the functional cross talk between nucleosomes and condensins in this process.
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Affiliation(s)
- Keishi Shintomi
- Chromosome Dynamics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Tatsuya Hirano
- Chromosome Dynamics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
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78
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Oligomerization and ATP stimulate condensin-mediated DNA compaction. Sci Rep 2017; 7:14279. [PMID: 29079757 PMCID: PMC5660149 DOI: 10.1038/s41598-017-14701-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 10/16/2017] [Indexed: 11/09/2022] Open
Abstract
Large-scale chromatin remodeling during mitosis is catalyzed by a heteropentameric enzyme known as condensin. The DNA-organizing mechanism of condensin depends on the energy of ATP hydrolysis but how this activity specifically promotes proper compaction and segregation of chromosomes during mitosis remains poorly understood. Purification of budding yeast condensin reveals that it occurs not only in the classical heteropentameric "monomer" form, but that it also adopts much larger configurations consistent with oligomerization. We use a single-DNA magnetic tweezers assay to study compaction of DNA by yeast condensin, with the result that only the multimer shows ATP-enhanced DNA-compaction. The compaction reaction involves step-like events of 200 nm (600 bp) size and is strongly suppressed by forces above 1 pN, consistent with a loop-capture mechanism for initial binding and compaction. The compaction reactions are largely insensitive to DNA torsional stress. Our results suggest a physiological role for oligomerized condensin in driving gradual chromatin compaction by step-like and slow "creeping" dynamics consistent with a loop-extrusion mechanism.
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79
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Affiliation(s)
- Yasutaka Kakui
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
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80
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Albritton SE, Ercan S. Caenorhabditis elegans Dosage Compensation: Insights into Condensin-Mediated Gene Regulation. Trends Genet 2017; 34:41-53. [PMID: 29037439 DOI: 10.1016/j.tig.2017.09.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/19/2017] [Accepted: 09/25/2017] [Indexed: 01/05/2023]
Abstract
Recent work demonstrating the role of chromosome organization in transcriptional regulation has sparked substantial interest in the molecular mechanisms that control chromosome structure. Condensin, an evolutionarily conserved multisubunit protein complex, is essential for chromosome condensation during cell division and functions in regulating gene expression during interphase. In Caenorhabditis elegans, a specialized condensin forms the core of the dosage compensation complex (DCC), which specifically binds to and represses transcription from the hermaphrodite X chromosomes. DCC serves as a clear paradigm for addressing how condensins target large chromosomal domains and how they function to regulate chromosome structure and transcription. Here, we discuss recent research on C. elegans DCC in the context of canonical condensin mechanisms as have been studied in various organisms.
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Affiliation(s)
- Sarah Elizabeth Albritton
- Department of Biology, Center for Genomics and Systems Biology, New York University, New York, NY 10003, USA
| | - Sevinç Ercan
- Department of Biology, Center for Genomics and Systems Biology, New York University, New York, NY 10003, USA.
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81
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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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82
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Zhiteneva A, Bonfiglio JJ, Makarov A, Colby T, Vagnarelli P, Schirmer EC, Matic I, Earnshaw WC. Mitotic post-translational modifications of histones promote chromatin compaction in vitro. Open Biol 2017; 7:170076. [PMID: 28903997 PMCID: PMC5627050 DOI: 10.1098/rsob.170076] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 07/27/2017] [Indexed: 02/01/2023] Open
Abstract
How eukaryotic chromosomes are compacted during mitosis has been a leading question in cell biology since the nineteenth century. Non-histone proteins such as condensin complexes contribute to chromosome shaping, but appear not to be necessary for mitotic chromatin compaction. Histone modifications are known to affect chromatin structure. As histones undergo major changes in their post-translational modifications during mitotic entry, we speculated that the spectrum of cell-cycle-specific histone modifications might contribute to chromosome compaction during mitosis. To test this hypothesis, we isolated core histones from interphase and mitotic cells and reconstituted chromatin with them. We used mass spectrometry to show that key post-translational modifications remained intact during our isolation procedure. Light, atomic force and transmission electron microscopy analysis showed that chromatin assembled from mitotic histones has a much greater tendency to aggregate than chromatin assembled from interphase histones, even under low magnesium conditions where interphase chromatin remains as separate beads-on-a-string structures. These observations are consistent with the hypothesis that mitotic chromosome formation is a two-stage process with changes in the spectrum of histone post-translational modifications driving mitotic chromatin compaction, while the action of non-histone proteins such as condensin may then shape the condensed chromosomes into their classic mitotic morphology.
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Affiliation(s)
- Alisa Zhiteneva
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Juan Jose Bonfiglio
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, Cologne 50931, Germany
| | - Alexandr Makarov
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Thomas Colby
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, Cologne 50931, Germany
| | - Paola Vagnarelli
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
- Institute of Environment, Health and Society, Department of Life Sciences, Brunel University London, Heinz Wolff Building, Uxbridge UB8 3PH, UK
| | - Eric C Schirmer
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Ivan Matic
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, Cologne 50931, Germany
| | - William C Earnshaw
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
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83
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Ono T, Sakamoto C, Nakao M, Saitoh N, Hirano T. Condensin II plays an essential role in reversible assembly of mitotic chromosomes in situ. Mol Biol Cell 2017; 28:2875-2886. [PMID: 28835373 PMCID: PMC5638589 DOI: 10.1091/mbc.e17-04-0252] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 08/15/2017] [Accepted: 08/16/2017] [Indexed: 01/31/2023] Open
Abstract
A modified protocol for inducing reversible assembly of mitotic chromosomes in situ is developed. As judged by this assay, which is combined with quantitative morphological analyses using a supervised machine-learning algorithm, condensin II plays a crucial role in both the recovery of chromatin shapes and the reorganization of chromosome axes. Condensins I and II are multisubunit complexes that play a central role in mitotic chromosome assembly. Although both complexes become concentrated along the axial region of each chromatid by metaphase, it remains unclear exactly how such axes might assemble and contribute to chromosome shaping. To address these questions from a physico-chemical point of view, we have established a set of two-step protocols for inducing reversible assembly of chromosome structure in situ, namely within a whole cell. In this assay, mitotic chromosomes are first expanded in a hypotonic buffer containing a Mg2+-chelating agent and then converted into different shapes in a NaCl concentration-dependent manner. Both chromatin and condensin-positive chromosome axes are converted into near-original shapes at 100 mM NaCl. This assay combined with small interfering RNA depletion demonstrates that the recovery of chromatin shapes and the reorganization of axes are highly sensitive to depletion of condensin II but less sensitive to depletion of condensin I or topoisomerase IIα. Furthermore, quantitative morphological analyses using the machine-learning algorithm wndchrm support the notion that chromosome shaping is tightly coupled to the reorganization of condensin II-based axes. We propose that condensin II makes a primary contribution to mitotic chromosome architecture and maintenance in human cells.
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Affiliation(s)
- Takao Ono
- Chromosome Dynamics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Chiyomi Sakamoto
- Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto 860-0811, Japan
| | - Mitsuyoshi Nakao
- Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto 860-0811, Japan
| | - Noriko Saitoh
- Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto 860-0811, Japan
| | - Tatsuya Hirano
- Chromosome Dynamics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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84
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Warren C, Shechter D. Fly Fishing for Histones: Catch and Release by Histone Chaperone Intrinsically Disordered Regions and Acidic Stretches. J Mol Biol 2017; 429:2401-2426. [PMID: 28610839 DOI: 10.1016/j.jmb.2017.06.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 06/05/2017] [Accepted: 06/06/2017] [Indexed: 01/21/2023]
Abstract
Chromatin is the complex of eukaryotic DNA and proteins required for the efficient compaction of the nearly 2-meter-long human genome into a roughly 10-micron-diameter cell nucleus. The fundamental repeating unit of chromatin is the nucleosome: 147bp of DNA wrapped about an octamer of histone proteins. Nucleosomes are stable enough to organize the genome yet must be dynamically displaced and reassembled to allow access to the underlying DNA for transcription, replication, and DNA damage repair. Histone chaperones are a non-catalytic group of proteins that are central to the processes of nucleosome assembly and disassembly and thus the fluidity of the ever-changing chromatin landscape. Histone chaperones are responsible for binding the highly basic histone proteins, shielding them from non-specific interactions, facilitating their deposition onto DNA, and aiding in their eviction from DNA. Although most histone chaperones perform these common functions, recent structural studies of many different histone chaperones reveal that there are few commonalities in their folds. Importantly, sequence-based predictions show that histone chaperones are highly enriched in intrinsically disordered regions (IDRs) and acidic stretches. In this review, we focus on the molecular mechanisms underpinning histone binding, selectivity, and regulation of these highly dynamic protein regions. We highlight new evidence suggesting that IDRs are often critical for histone chaperone function and play key roles in chromatin assembly and disassembly pathways.
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Affiliation(s)
- Christopher Warren
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - David Shechter
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
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85
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Okada Y, Yamaguchi K. Epigenetic modifications and reprogramming in paternal pronucleus: sperm, preimplantation embryo, and beyond. Cell Mol Life Sci 2017; 74:1957-1967. [PMID: 28050628 PMCID: PMC11107594 DOI: 10.1007/s00018-016-2447-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 12/08/2016] [Accepted: 12/19/2016] [Indexed: 12/13/2022]
Abstract
Pronuclear/zygotic stage is the very first stage of life. In this period, paternal pronucleus undergoes massive chromatin remodeling called "paternal reprogramming" including protamine-histone replacement and subsequent acquisition of epigenetic modifications. Although these consecutive events are required for the initiation of maternal-zygotic transition, the precise role of paternal reprogramming and its effect on subsequent embryonic development has been largely unknown to date. Recently, various new techniques, especially next-generation sequencing (NGS) and RNAi microinjection contribute to unveil the epigenetic transition from both paternal and maternal to early preimplantation embryos, suggesting not only the simple transcriptional regulation by transcription factors but also dynamic structural alteration of chromatin to initiate the wave of zygotic gene transcription. This review summarizes such recent progress for understanding the epigenetic transition in sperm and preimplantation embryos, and further argue about its transgenerational effect.
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Affiliation(s)
- Yuki Okada
- Laboratory of Pathology and Development, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, 113-0032, Japan.
| | - Kosuke Yamaguchi
- Laboratory of Pathology and Development, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, 113-0032, Japan
- Graduate School of Art and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan
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86
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Sater AK, Moody SA. Using Xenopus to understand human disease and developmental disorders. Genesis 2017; 55. [PMID: 28095616 DOI: 10.1002/dvg.22997] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 11/14/2016] [Indexed: 02/03/2023]
Abstract
Model animals are crucial to biomedical research. Among the commonly used model animals, the amphibian, Xenopus, has had tremendous impact because of its unique experimental advantages, cost effectiveness, and close evolutionary relationship with mammals as a tetrapod. Over the past 50 years, the use of Xenopus has made possible many fundamental contributions to biomedicine, and it is a cornerstone of research in cell biology, developmental biology, evolutionary biology, immunology, molecular biology, neurobiology, and physiology. The prospects for Xenopus as an experimental system are excellent: Xenopus is uniquely well-suited for many contemporary approaches used to study fundamental biological and disease mechanisms. Moreover, recent advances in high throughput DNA sequencing, genome editing, proteomics, and pharmacological screening are easily applicable in Xenopus, enabling rapid functional genomics and human disease modeling at a systems level.
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Affiliation(s)
- Amy K Sater
- Department of Biology and Biochemistry, University of Houston, Houston, Texas
| | - Sally A Moody
- Department of Anatomy and Regenerative Biology, George Washington University School of Medicine and Health Sciences, Washington, District of Columbia
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87
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Shintomi K, Inoue F, Watanabe H, Ohsumi K, Ohsugi M, Hirano T. Mitotic chromosome assembly despite nucleosome depletion in Xenopus egg extracts. Science 2017; 356:1284-1287. [PMID: 28522692 DOI: 10.1126/science.aam9702] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 05/08/2017] [Indexed: 12/23/2022]
Abstract
The nucleosome is the fundamental structural unit of eukaryotic chromatin. During mitosis, duplicated nucleosome fibers are organized into a pair of rod-shaped structures (chromatids) within a mitotic chromosome. However, it remains unclear whether nucleosome assembly is indeed an essential prerequisite for mitotic chromosome assembly. We combined mouse sperm nuclei and Xenopus cell-free egg extracts depleted of the histone chaperone Asf1 and found that chromatid-like structures could be assembled even in the near absence of nucleosomes. The resultant "nucleosome-depleted" chromatids contained discrete central axes positive for condensins, although they were more fragile than normal nucleosome-containing chromatids. Combinatorial depletion experiments underscored the central importance of condensins in mitotic chromosome assembly, which sheds light on their functional cross-talk with nucleosomes in this process.
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Affiliation(s)
- Keishi Shintomi
- Chromosome Dynamics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Fukashi Inoue
- Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan.,TAK-Circulator Corporation, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hiroshi Watanabe
- Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Keita Ohsumi
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Miho Ohsugi
- Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Tatsuya Hirano
- Chromosome Dynamics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.
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88
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Golloshi R, Sanders JT, McCord RP. Genome organization during the cell cycle: unity in division. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2017; 9. [PMID: 28510289 DOI: 10.1002/wsbm.1389] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/12/2017] [Accepted: 03/14/2017] [Indexed: 12/11/2022]
Abstract
During the cell cycle, the genome must undergo dramatic changes in structure, from a decondensed, yet highly organized interphase structure to a condensed, generic mitotic chromosome and then back again. For faithful cell division, the genome must be replicated and chromosomes and sister chromatids physically segregated from one another. Throughout these processes, there is feedback and tension between the information-storing role and the physical properties of chromosomes. With a combination of recent techniques in fluorescence microscopy, chromosome conformation capture (Hi-C), biophysical experiments, and computational modeling, we can now attribute mechanisms to many long-observed features of chromosome structure changes during cell division. Apparent conflicts that arise when integrating the concepts from these different proposed mechanisms emphasize that orchestrating chromosome organization during cell division requires a complex system of factors rather than a simple pathway. Cell division is both essential for and threatening to proper genome organization. As interphase three-dimensional (3D) genome structure is quite static at a global level, cell division provides an important window of opportunity to make substantial changes in 3D genome organization in daughter cells, allowing for proper differentiation and development. Mistakes in the process of chromosome condensation or rebuilding the structure after mitosis can lead to diseases such as cancer, premature aging, and neurodegeneration. WIREs Syst Biol Med 2017, 9:e1389. doi: 10.1002/wsbm.1389 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Rosela Golloshi
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
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89
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Syrjänen JL, Heller I, Candelli A, Davies OR, Peterman EJG, Wuite GJL, Pellegrini L. Single-molecule observation of DNA compaction by meiotic protein SYCP3. eLife 2017; 6. [PMID: 28287952 PMCID: PMC5348128 DOI: 10.7554/elife.22582] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 03/04/2017] [Indexed: 12/14/2022] Open
Abstract
In a previous paper (Syrjänen et al., 2014), we reported the first structural characterisation of a synaptonemal complex (SC) protein, SYCP3, which led us to propose a model for its role in chromosome compaction during meiosis. As a component of the SC lateral element, SYCP3 has a critical role in defining the specific chromosome architecture required for correct meiotic progression. In the model, the reported compaction of chromosomal DNA caused by SYCP3 would result from its ability to bridge distant sites on a DNA molecule with the DNA-binding domains located at each end of its strut-like structure. Here, we describe a single-molecule assay based on optical tweezers, fluorescence microscopy and microfluidics that, in combination with bulk biochemical data, provides direct visual evidence for our proposed mechanism of SYCP3-mediated chromosome organisation. DOI:http://dx.doi.org/10.7554/eLife.22582.001
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Affiliation(s)
- Johanna L Syrjänen
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Iddo Heller
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Andrea Candelli
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Owen R Davies
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Erwin J G Peterman
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Gijs J L Wuite
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Luca Pellegrini
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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90
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Kinoshita K, Hirano T. Dynamic organization of mitotic chromosomes. Curr Opin Cell Biol 2017; 46:46-53. [PMID: 28214612 DOI: 10.1016/j.ceb.2017.01.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 01/30/2017] [Indexed: 12/19/2022]
Abstract
The assembly of rod-shaped chromosomes during mitosis is an essential prerequisite for faithful segregation of genetic information into daughter cells. Despite the long history of chromosome research, it is only recently that we have acquired powerful approaches and crucial tools that help to unlock the secret of this seemingly complex process. In particular, in vitro assays, mammalian genetics, Hi-C analyses and computer simulations have provided valuable information during the past two years. These studies are now beginning to elucidate how the core components of mitotic chromosomes, namely, histones, topoisomerase IIα and condensins, cooperate with each other to convert very long stretches of DNA into rod-shaped chromosomes.
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Affiliation(s)
- Kazuhisa Kinoshita
- Chromosome Dynamics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Tatsuya Hirano
- Chromosome Dynamics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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91
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Affiliation(s)
- Dana Branzei
- a IFOM, the FIRC Institute of Molecular Oncology , Milan , Italy
| | - Andrea Ciliberto
- a IFOM, the FIRC Institute of Molecular Oncology , Milan , Italy
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92
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van Wely KHM, Mora Gallardo C, Vann KR, Kutateladze TG. Epigenetic countermarks in mitotic chromosome condensation. Nucleus 2017; 8:144-149. [PMID: 28045584 PMCID: PMC5403135 DOI: 10.1080/19491034.2016.1276144] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mitosis in metazoans is characterized by abundant phosphorylation of histone H3 and involves the recruitment of condensin complexes to chromatin. The relationship between the 2 phenomena and their respective contributions to chromosome condensation in vivo remain poorly understood. Recent studies have shown that H3T3 phosphorylation decreases binding of histone readers to methylated H3K4 in vitro and is essential to displace the corresponding proteins from mitotic chromatin in vivo. Together with previous observations, these data provide further evidence for a role of mitotic histone H3 phosphorylation in blocking transcriptional programs or preserving the ‘memory’ PTMs. Mitotic protein exclusion can also have a role in depopulating the chromatin template for subsequent condensin loading. H3 phosphorylation thus serves as an integral step in the condensation of chromosome arms.
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Affiliation(s)
- Karel H M van Wely
- a Department of Immunology and Oncology , Centro Nacional de Biotecnología/CSIC , Madrid , Spain
| | - Carmen Mora Gallardo
- a Department of Immunology and Oncology , Centro Nacional de Biotecnología/CSIC , Madrid , Spain
| | - Kendra R Vann
- b Department of Pharmacology , University of Colorado School of Medicine , Aurora , CO , USA
| | - Tatiana G Kutateladze
- b Department of Pharmacology , University of Colorado School of Medicine , Aurora , CO , USA
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93
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Tung SY, Wang SH, Lee SP, Tsai SP, Shen HH, Chen FJ, Wu YY, Hsiao SP, Liou GG. Modulations of SIR-nucleosome interactions of reconstructed yeast silent pre-heterochromatin by O-acetyl-ADP-ribose and magnesium. Mol Biol Cell 2016; 28:381-386. [PMID: 27932495 PMCID: PMC5341722 DOI: 10.1091/mbc.e16-06-0359] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 11/22/2016] [Accepted: 11/29/2016] [Indexed: 12/25/2022] Open
Abstract
In vitro–assembled filaments are confirmed as SIR-nucleosome pre-heterochromatin, and AAR acts as a modulator for their formation. Not only is magnesium present in the environmental buffer, but it also is chelated by the SIR-nucleosome pre-heterochromatin to promote its condensation. Yeast silent heterochromatin provides an excellent model with which to study epigenetic inheritance. Previously we developed an in vitro assembly system to demonstrate the formation of filament structures with requirements that mirror yeast epigenetic gene silencing in vivo. However, the properties of these filaments were not investigated in detail. Here we show that the assembly system requires Sir2, Sir3, Sir4, nucleosomes, and O-acetyl-ADP-ribose. We also demonstrate that all Sir proteins and nucleosomes are components of these filaments to prove that they are SIR-nucleosome filaments. Furthermore, we show that the individual localization patterns of Sir proteins on the SIR-nucleosome filament reflect those patterns on telomeres in vivo. In addition, we reveal that magnesium exists in the SIR-nucleosome filament, with a role similar to that for chromatin condensation. These results suggest that a small number of proteins and molecules are sufficient to mediate the formation of a minimal yeast silent pre-heterochromatin in vitro.
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Affiliation(s)
- Shu-Yun Tung
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
| | - Sue-Hong Wang
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung 402, Taiwan
| | - Sue-Ping Lee
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
| | - Shu-Ping Tsai
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
| | - Hsiao-Hsuian Shen
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli 350, Taiwan
| | - Feng-Jung Chen
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli 350, Taiwan
| | - Yu-Yi Wu
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli 350, Taiwan
| | - Sheng-Pin Hsiao
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli 350, Taiwan
| | - Gunn-Guang Liou
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan .,Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli 350, Taiwan.,Guang EM Laboratory, New Taipei 242, Taiwan
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94
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The loading of condensin in the context of chromatin. Curr Genet 2016; 63:577-589. [PMID: 27909798 DOI: 10.1007/s00294-016-0669-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 11/24/2016] [Accepted: 11/25/2016] [Indexed: 12/23/2022]
Abstract
The packaging of DNA into chromosomes is a ubiquitous process that enables living organisms to structure and transmit their genome accurately through cell divisions. In the three kingdoms of life, the architecture and dynamics of chromosomes rely upon ring-shaped SMC (Structural Maintenance of Chromosomes) condensin complexes. To understand how condensin rings organize chromosomes, it is essential to decipher how they associate with chromatin filaments. Here, we use recent evidence to discuss the role played by nucleosomes and transcription factors in the loading of condensin at transcribed genes. We propose a model whereby cis-acting features nestled in the promoters of active genes synergistically attract condensin rings and promote their association with DNA.
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95
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Kagami Y, Yoshida K. The functional role for condensin in the regulation of chromosomal organization during the cell cycle. Cell Mol Life Sci 2016; 73:4591-4598. [PMID: 27402120 PMCID: PMC11108269 DOI: 10.1007/s00018-016-2305-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/24/2016] [Accepted: 07/06/2016] [Indexed: 12/23/2022]
Abstract
In all organisms, the control of cell cycle progression is a fundamental process that is essential for cell growth, development, and survival. Through each cell cycle phase, the regulation of chromatin organization is essential for natural cell proliferation and maintaining cellular homeostasis. During mitosis, the chromatin morphology is dramatically changed to have a "thread-like" shape and the condensed chromosomes are segregated equally into two daughter cells. Disruption of the mitotic chromosome architecture physically impedes chromosomal behaviors, such as chromosome alignment and chromosome segregation; therefore, the proper mitotic chromosome structure is required to maintain chromosomal stability. Accumulating evidence has demonstrated that mitotic chromosome condensation is induced by condensin complexes. Moreover, recent studies have shown that condensin also modulates interphase chromatin and regulates gene expression. This review mainly focuses on the molecular mechanisms that condensin uses to exert its functions during the cell cycle progression. Moreover, we discuss the condensin-mediated chromosomal organization in cancer cells.
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Affiliation(s)
- Yuya Kagami
- Department of Biochemistry, Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo, 105-8461, Japan
| | - Kiyotsugu Yoshida
- Department of Biochemistry, Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo, 105-8461, Japan.
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96
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Moriwaki T, Goshima G. Five factors can reconstitute all three phases of microtubule polymerization dynamics. J Cell Biol 2016; 215:357-368. [PMID: 27799364 PMCID: PMC5100292 DOI: 10.1083/jcb.201604118] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 09/23/2016] [Indexed: 12/15/2022] Open
Abstract
Cytoplasmic microtubules (MTs) undergo growth, shrinkage, and pausing. However, how MT polymerization cycles are produced and spatiotemporally regulated at a molecular level is unclear, as the entire cycle has not been recapitulated in vitro with defined components. In this study, we reconstituted dynamic MT plus end behavior involving all three phases by mixing tubulin with five Drosophila melanogaster proteins (EB1, XMAP215Msps, Sentin, kinesin-13Klp10A, and CLASPMast/Orbit). When singly mixed with tubulin, CLASPMast/Orbit strongly inhibited MT catastrophe and reduced the growth rate. However, in the presence of the other four factors, CLASPMast/Orbit acted as an inducer of pausing. The mitotic kinase Plk1Polo modulated the activity of CLASPMast/Orbit and kinesin-13Klp10A and increased the dynamic instability of MTs, reminiscent of mitotic cells. These results suggest that five conserved proteins constitute the core factors for creating dynamic MTs in cells and that Plk1-dependent phosphorylation is a crucial event for switching from the interphase to mitotic mode.
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Affiliation(s)
- Takashi Moriwaki
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
- Marine Biological Laboratory, Woods Hole, MA 02543
| | - Gohta Goshima
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
- Marine Biological Laboratory, Woods Hole, MA 02543
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97
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Hoa NN, Shimizu T, Zhou ZW, Wang ZQ, Deshpande RA, Paull TT, Akter S, Tsuda M, Furuta R, Tsutsui K, Takeda S, Sasanuma H. Mre11 Is Essential for the Removal of Lethal Topoisomerase 2 Covalent Cleavage Complexes. Mol Cell 2016; 64:580-592. [PMID: 27814490 DOI: 10.1016/j.molcel.2016.10.011] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 07/22/2016] [Accepted: 10/05/2016] [Indexed: 12/12/2022]
Abstract
The Mre11/Rad50/Nbs1 complex initiates double-strand break repair by homologous recombination (HR). Loss of Mre11 or its nuclease activity in mouse cells is known to cause genome aberrations and cellular senescence, although the molecular basis for this phenotype is not clear. To identify the origin of these defects, we characterized Mre11-deficient (MRE11-/-) and nuclease-deficient Mre11 (MRE11-/H129N) chicken DT40 and human lymphoblast cell lines. These cells exhibit increased spontaneous chromosomal DSBs and extreme sensitivity to topoisomerase 2 poisons. The defects in Mre11 compromise the repair of etoposide-induced Top2-DNA covalent complexes, and MRE11-/- and MRE11-/H129N cells accumulate high levels of Top2 covalent conjugates even in the absence of exogenous damage. We demonstrate that both the genome instability and mortality of MRE11-/- and MRE11-/H129N cells are significantly reversed by overexpression of Tdp2, an enzyme that eliminates covalent Top2 conjugates; thus, the essential role of Mre11 nuclease activity is likely to remove these lesions.
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Affiliation(s)
- Nguyen Ngoc Hoa
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
| | - Tsubasa Shimizu
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
| | - Zhong Wei Zhou
- Leibniz Institute for Age Research-Fritz Lipmann Institute, Beutenbergstrasse 11, 07745 Jena, Germany
| | - Zhao-Qi Wang
- Leibniz Institute for Age Research-Fritz Lipmann Institute, Beutenbergstrasse 11, 07745 Jena, Germany
| | - Rajashree A Deshpande
- Howard Hughes Medical Institute, Department of Molecular Biosciences, and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Tanya T Paull
- Howard Hughes Medical Institute, Department of Molecular Biosciences, and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Salma Akter
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
| | - Masataka Tsuda
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
| | - Ryohei Furuta
- Department of Neurogenomics, Graduate School of Medicine, Dentistry and Pharmaceutical Science, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan
| | - Ken Tsutsui
- Department of Neurogenomics, Graduate School of Medicine, Dentistry and Pharmaceutical Science, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan
| | - Shunichi Takeda
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hiroyuki Sasanuma
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan.
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98
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Zhang T, Si-Hoe SL, Hudson DF, Surana U. Condensin recruitment to chromatin is inhibited by Chk2 kinase in response to DNA damage. Cell Cycle 2016; 15:3454-3470. [PMID: 27792460 DOI: 10.1080/15384101.2016.1249075] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The DNA damage checkpoint, when activated in response to genotoxic damage during S phase, arrests cells in G2 phase of the cell cycle. ATM, ATR, Chk1 and Chk2 kinases are the main effectors of this checkpoint pathway. The checkpoint kinases prevent the onset of mitosis by eliciting well characterized inhibitory phosphorylation of Cdk1. Since Cdk1 is required for the recruitment of condensin, it is thought that upon DNA damage the checkpoint also indirectly blocks chromosome condensation via Cdk1 inhibition. Here we report that the G2 damage checkpoint prevents stable recruitment of the chromosome-packaging-machinery components condensin complex I and II onto the chromatin even in the presence of an active Cdk1. DNA damage-induced inhibition of condensin subunit recruitment is mediated specifically by the Chk2 kinase, implying that the condensin complexes are targeted by the checkpoint in response to DNA damage, independently of Cdk1 inactivation. Thus, the G2 checkpoint directly prevents stable recruitment of condensin complexes to actively prevent chromosome compaction during G2 arrest, presumably to ensure efficient repair of the genomic damage.
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Affiliation(s)
- Tao Zhang
- a Institute of Molecular and Cell Biology, Agency for Science Technology and Research , Singapore.,b Murdoch Childrens Research Institute, Royal Children's Hospital , Melbourne , Australia.,c Department of Pediatrics , University of Melbourne, Royal Children's Hospital , Melbourne , Australia
| | - San Ling Si-Hoe
- a Institute of Molecular and Cell Biology, Agency for Science Technology and Research , Singapore
| | - Damien F Hudson
- b Murdoch Childrens Research Institute, Royal Children's Hospital , Melbourne , Australia.,c Department of Pediatrics , University of Melbourne, Royal Children's Hospital , Melbourne , Australia
| | - Uttam Surana
- a Institute of Molecular and Cell Biology, Agency for Science Technology and Research , Singapore.,d Department of Pharmacology , National University of Singapore , Singapore.,e Bioprocessing Technology Institute, Agency for Science Technology and Research , Singapore
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99
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Pommier Y, Sun Y, Huang SYN, Nitiss JL. Roles of eukaryotic topoisomerases in transcription, replication and genomic stability. Nat Rev Mol Cell Biol 2016; 17:703-721. [DOI: 10.1038/nrm.2016.111] [Citation(s) in RCA: 540] [Impact Index Per Article: 67.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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100
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Takahashi M, Wakai T, Hirota T. Condensin I-mediated mitotic chromosome assembly requires association with chromokinesin KIF4A. Genes Dev 2016; 30:1931-6. [PMID: 27633014 PMCID: PMC5066236 DOI: 10.1101/gad.282855.116] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/08/2016] [Indexed: 12/15/2022]
Abstract
In this study, Takahashi et al. investigated the role of chromokinesin KIF4A in condensin complexes. They found that KIF4A associates with condensin I but not with condensin II during mitosis, providing new insight into the regulation of condensin I and mitotic chromsome organization. The chromokinesin KIF4A has been implicated in shaping mitotic chromosomes, but its functional relationship to condensin complexes remains controversial. Here, we found that, in mitosis, KIF4A associates with condensin I but not with condensin II. Mutational analyses indicated that the enrichment of condensin I to chromosomal axes depends on its association with KIF4A in a way that likely involves its motor activity. Remarkably, this interaction is required for condensin I to confer physiological properties to chromosomes. These observations provide an insight into how condensin I is enriched at chromosomal axes and underscore the significance of axial structure in organizing mitotic chromosomes.
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Affiliation(s)
- Motoko Takahashi
- Cancer Institute of the Japanese Foundation for Cancer Research (JFCR), Tokyo 135-8550, Japan; Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8112, Japan
| | - Toshifumi Wakai
- Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8112, Japan
| | - Toru Hirota
- Cancer Institute of the Japanese Foundation for Cancer Research (JFCR), Tokyo 135-8550, Japan
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