1
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Herlah B, Pavlin M, Perdih A. Molecular choreography: Unveiling the dynamic landscape of type IIA DNA topoisomerases before T-segment passage through all-atom simulations. Int J Biol Macromol 2024; 269:131991. [PMID: 38714283 DOI: 10.1016/j.ijbiomac.2024.131991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 04/09/2024] [Accepted: 04/28/2024] [Indexed: 05/09/2024]
Abstract
Type IIA DNA topoisomerases are molecular nanomachines responsible for controlling topological states of DNA molecules. Here, we explore the dynamic landscape of yeast topoisomerase IIA during key stages of its catalytic cycle, focusing in particular on the events preceding the passage of the T-segment. To this end, we generated six configurations of fully catalytic yeast topo IIA, strategically inserted a T-segment into the N-gate in relevant configurations, and performed all-atom simulations. The essential motion of topo IIA protein dimer was characterized by rotational gyrating-like movement together with sliding motion within the DNA-gate. Both appear to be inherent properties of the enzyme and an inbuilt feature that allows passage of the T-segment through the cleaved G-segment. Coupled dynamics of the N-gate and DNA-gate residues may be particularly important for controlled and smooth passage of the T-segment and consequently the prevention of DNA double-strand breaks. QTK loop residue Lys367, which interacts with ATP and ADP molecules, is involved in regulating the size and stability of the N-gate. The unveiled features of the simulated configurations provide insights into the catalytic cycle of type IIA topoisomerases and elucidate the molecular choreography governing their ability to modulate the topological states of DNA topology.
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Affiliation(s)
- Barbara Herlah
- Theory Department, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia
| | - Matic Pavlin
- Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Andrej Perdih
- Theory Department, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia.
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2
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Hildebrand EM, Polovnikov K, Dekker B, Liu Y, Lafontaine DL, Fox AN, Li Y, Venev SV, Mirny LA, Dekker J. Mitotic chromosomes are self-entangled and disentangle through a topoisomerase-II-dependent two-stage exit from mitosis. Mol Cell 2024; 84:1422-1441.e14. [PMID: 38521067 DOI: 10.1016/j.molcel.2024.02.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 10/23/2023] [Accepted: 02/24/2024] [Indexed: 03/25/2024]
Abstract
The topological state of chromosomes determines their mechanical properties, dynamics, and function. Recent work indicated that interphase chromosomes are largely free of entanglements. Here, we use Hi-C, polymer simulations, and multi-contact 3C and find that, by contrast, mitotic chromosomes are self-entangled. We explore how a mitotic self-entangled state is converted into an unentangled interphase state during mitotic exit. Most mitotic entanglements are removed during anaphase/telophase, with remaining ones removed during early G1, in a topoisomerase-II-dependent process. Polymer models suggest a two-stage disentanglement pathway: first, decondensation of mitotic chromosomes with remaining condensin loops produces entropic forces that bias topoisomerase II activity toward decatenation. At the second stage, the loops are released, and the formation of new entanglements is prevented by lower topoisomerase II activity, allowing the establishment of unentangled and territorial G1 chromosomes. When mitotic entanglements are not removed in experiments and models, a normal interphase state cannot be acquired.
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Affiliation(s)
- Erica M Hildebrand
- Department of Systems Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | | | - Bastiaan Dekker
- Department of Systems Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Yu Liu
- Department of Systems Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA; Nuclear Dynamics and Cancer Program, Cancer Epigenetics Institute, Fox Chase Cancer Center, Temple Health, Philadelphia, PA 19111, USA
| | - Denis L Lafontaine
- Department of Systems Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - A Nicole Fox
- Department of Systems Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Ying Li
- Department of Systems Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Sergey V Venev
- Department of Systems Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Leonid A Mirny
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Job Dekker
- Department of Systems Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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3
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El Yakoubi W, Akera T. Condensin dysfunction is a reproductive isolating barrier in mice. Nature 2023; 623:347-355. [PMID: 37914934 DOI: 10.1038/s41586-023-06700-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 10/02/2023] [Indexed: 11/03/2023]
Abstract
Reproductive isolation occurs when the genomes of two populations accumulate genetic incompatibilities that prevent interbreeding1,2. Understanding of hybrid incompatibility at the cell biology level is limited, particularly in the case of hybrid female sterility3. Here we find that species divergence in condensin regulation and centromere organization between two mouse species, Mus musculus domesticus and Mus spretus, drives chromosome decondensation and mis-segregation in their F1 hybrid oocytes, reducing female fertility. The decondensation in hybrid oocytes was especially prominent at pericentromeric major satellites, which are highly abundant at M. m. domesticus centromeres4-6, leading to species-specific chromosome mis-segregation and egg aneuploidy. Consistent with the condensation defects, a chromosome structure protein complex, condensin II7,8, was reduced on hybrid oocyte chromosomes. We find that the condensin II subunit NCAPG2 was specifically reduced in the nucleus in prophase and that overexpressing NCAPG2 rescued both the decondensation and egg aneuploidy phenotypes. In addition to the overall reduction in condensin II on chromosomes, major satellites further reduced condensin II levels locally, explaining why this region is particularly prone to decondensation. Together, this study provides cell biological insights into hybrid incompatibility in female meiosis and demonstrates that condensin misregulation and pericentromeric satellite expansion can establish a reproductive isolating barrier in mammals.
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Affiliation(s)
- Warif El Yakoubi
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Takashi Akera
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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4
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Yamamoto T, Kinoshita K, Hirano T. Elasticity control of entangled chromosomes: Crosstalk between condensin complexes and nucleosomes. Biophys J 2023; 122:3869-3881. [PMID: 37571823 PMCID: PMC10560673 DOI: 10.1016/j.bpj.2023.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 07/18/2023] [Accepted: 08/08/2023] [Indexed: 08/13/2023] Open
Abstract
Condensin-mediated loop extrusion is now considered as the main driving force of mitotic chromosome assembly. Recent experiments have shown, however, that a class of mutant condensin complexes deficient in loop extrusion can assemble chromosome-like structures in Xenopus egg extracts, although these structures are somewhat different from those assembled by wild-type condensin complexes. In the absence of topoisomerase II (topo II), the mutant condensin complexes produce an unusual round-shaped structure termed a bean, which consists of a DNA-dense central core surrounded by a DNA-sparse halo. The mutant condensin complexes accumulate in the core, whereas histones are more concentrated in the halo than in the core. We consider that this peculiar structure serves as a model system to study how DNA entanglements, nucleosomes, and condensin functionally crosstalk with each other. To gain insight into how the bean structure is formed, here we construct a theoretical model. Our theory predicts that the core is formed by attractive interactions between mutant condensin complexes, whereas the halo is stabilized by the energy reduction through the selective accumulation of nucleosomes. The formation of the halo increases the elastic free energy due to the DNA entanglement in the core, but the latter free energy is compensated by condensin complexes that suppress the assembly of nucleosomes.
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Affiliation(s)
- Tetsuya Yamamoto
- Institute for Chemical Reaction Design and Discovery (ICReDD), Hokkaido University, Sapporo, Hokkaido, Japan.
| | | | - Tatsuya Hirano
- Chromosome Dynamics Laboratory, RIKEN, Wako, Saitama, Japan
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5
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Abstract
Many cellular processes require large-scale rearrangements of chromatin structure. Structural maintenance of chromosomes (SMC) protein complexes are molecular machines that can provide structure to chromatin. These complexes can connect DNA elements in cis, walk along DNA, build and processively enlarge DNA loops and connect DNA molecules in trans to hold together the sister chromatids. These DNA-shaping abilities place SMC complexes at the heart of many DNA-based processes, including chromosome segregation in mitosis, transcription control and DNA replication, repair and recombination. In this Review, we discuss the latest insights into how SMC complexes such as cohesin, condensin and the SMC5-SMC6 complex shape DNA to direct these fundamental chromosomal processes. We also consider how SMC complexes, by building chromatin loops, can counteract the natural tendency of alike chromatin regions to cluster. SMC complexes thus control nuclear organization by participating in a molecular tug of war that determines the architecture of our genome.
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Affiliation(s)
- Claire Hoencamp
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Benjamin D Rowland
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
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6
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Sundararajan S, Park H, Kawano S, Johansson M, Lama B, Saito-Fujita T, Saitoh N, Arnaoutov A, Dasso M, Wang Z, Keifenheim D, Clarke DJ, Azuma Y. Methylated histones on mitotic chromosomes promote topoisomerase IIα function for high fidelity chromosome segregation. iScience 2023; 26:106743. [PMID: 37197327 PMCID: PMC10183659 DOI: 10.1016/j.isci.2023.106743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/31/2022] [Accepted: 04/21/2023] [Indexed: 05/19/2023] Open
Abstract
DNA Topoisomerase IIα (TopoIIα) decatenates sister chromatids, allowing their segregation in mitosis. Without the TopoIIα Strand Passage Reaction (SPR), chromosome bridges and ultra-fine DNA bridges (UFBs) arise in anaphase. The TopoIIα C-terminal domain is dispensable for the SPR in vitro but essential for mitotic functions in vivo. Here, we present evidence that the Chromatin Tether (ChT) within the CTD interacts with specific methylated nucleosomes and is crucial for high-fidelity chromosome segregation. Mutation of individual αChT residues disrupts αChT-nucleosome interaction, induces loss of segregation fidelity and reduces association of TopoIIα with chromosomes. Specific methyltransferase inhibitors reducing histone H3 or H4 methylation decreased TopoIIα at centromeres and increased segregation errors. Methyltransferase inhibition did not further increase aberrant anaphases in the ChT mutants, indicating a functional connection. The evidence reveals novel cellular regulation whereby TopoIIα specifically interacts with methylated nucleosomes via the αChT to ensure high-fidelity chromosome segregation.
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Affiliation(s)
- Sanjana Sundararajan
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA
| | - Hyewon Park
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA
| | - Shinji Kawano
- Department of Biochemistry, Faculty of Science, Okayama University of Science, Okayama 700-0081, Japan
| | - Marnie Johansson
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Bunu Lama
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA
| | - Tomoko Saito-Fujita
- Division of Cancer Biology, The Cancer Institute of Japanese Foundation for Cancer Research, Tokyo 135-8550, Japan
| | - Noriko Saitoh
- Division of Cancer Biology, The Cancer Institute of Japanese Foundation for Cancer Research, Tokyo 135-8550, Japan
| | - Alexei Arnaoutov
- Division of Molecular and Cellular Biology, National Institute for Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-4480, USA
| | - Mary Dasso
- Division of Molecular and Cellular Biology, National Institute for Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-4480, USA
| | - Zhengqiang Wang
- Center for Drug Design, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA
| | - Daniel Keifenheim
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Duncan J. Clarke
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Yoshiaki Azuma
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA
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7
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Super-resolution microscopy reveals the number and distribution of topoisomerase IIα and CENH3 molecules within barley metaphase chromosomes. Chromosoma 2023; 132:19-29. [PMID: 36719450 PMCID: PMC9981516 DOI: 10.1007/s00412-023-00785-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 10/25/2022] [Accepted: 12/13/2022] [Indexed: 02/01/2023]
Abstract
Topoisomerase IIα (Topo IIα) and the centromere-specific histone H3 variant CENH3 are key proteins involved in chromatin condensation and centromere determination, respectively. Consequently, they are required for proper chromosome segregation during cell divisions. We combined two super-resolution techniques, structured illumination microscopy (SIM) to co-localize Topo IIα and CENH3, and photoactivated localization microscopy (PALM) to determine their molecule numbers in barley metaphase chromosomes. We detected a dispersed Topo IIα distribution along chromosome arms but an accumulation at centromeres, telomeres, and nucleolus-organizing regions. With a precision of 10-50 nm, we counted ~ 20,000-40,000 Topo IIα molecules per chromosome, 28% of them within the (peri)centromere. With similar precision, we identified ~13,500 CENH3 molecules per centromere where Topo IIα proteins and CENH3-containing chromatin intermingle. In short, we demonstrate PALM as a useful method to count and localize single molecules with high precision within chromosomes. The ultrastructural distribution and the detected amount of Topo IIα and CENH3 are instrumental for a better understanding of their functions during chromatin condensation and centromere determination.
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8
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Jeong J, Lee JH, Carcamo CC, Parker MW, Berger JM. DNA-Stimulated Liquid-Liquid phase separation by eukaryotic topoisomerase ii modulates catalytic function. eLife 2022; 11:e81786. [PMID: 36342377 PMCID: PMC9674351 DOI: 10.7554/elife.81786] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 11/06/2022] [Indexed: 11/09/2022] Open
Abstract
Type II topoisomerases modulate chromosome supercoiling, condensation, and catenation by moving one double-stranded DNA segment through a transient break in a second duplex. How DNA strands are chosen and selectively passed to yield appropriate topological outcomes - for example, decatenation vs. catenation - is poorly understood. Here, we show that at physiological enzyme concentrations, eukaryotic type IIA topoisomerases (topo IIs) readily coalesce into condensed bodies. DNA stimulates condensation and fluidizes these assemblies to impart liquid-like behavior. Condensation induces both budding yeast and human topo IIs to switch from DNA unlinking to active DNA catenation, and depends on an unstructured C-terminal region, the loss of which leads to high levels of knotting and reduced catenation. Our findings establish that local protein concentration and phase separation can regulate how topo II creates or dissolves DNA links, behaviors that can account for the varied roles of the enzyme in supporting transcription, replication, and chromosome compaction.
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Affiliation(s)
- Joshua Jeong
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Joyce H Lee
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Claudia C Carcamo
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Matthew W Parker
- Department of Biophysics, University of Texas Southwestern Medical CenterDallasUnited States
| | - James M Berger
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of MedicineBaltimoreUnited States
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9
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Regulation of the mitotic chromosome folding machines. Biochem J 2022; 479:2153-2173. [PMID: 36268993 DOI: 10.1042/bcj20210140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 09/30/2022] [Accepted: 10/03/2022] [Indexed: 11/17/2022]
Abstract
Over the last several years enormous progress has been made in identifying the molecular machines, including condensins and topoisomerases that fold mitotic chromosomes. The discovery that condensins generate chromatin loops through loop extrusion has revolutionized, and energized, the field of chromosome folding. To understand how these machines fold chromosomes with the appropriate dimensions, while disentangling sister chromatids, it needs to be determined how they are regulated and deployed. Here, we outline the current understanding of how these machines and factors are regulated through cell cycle dependent expression, chromatin localization, activation and inactivation through post-translational modifications, and through associations with each other, with other factors and with the chromatin template itself. There are still many open questions about how condensins and topoisomerases are regulated but given the pace of progress in the chromosome folding field, it seems likely that many of these will be answered in the years ahead.
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10
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Yoshida MM, Kinoshita K, Aizawa Y, Tane S, Yamashita D, Shintomi K, Hirano T. Molecular dissection of condensin II-mediated chromosome assembly using in vitro assays. eLife 2022; 11:78984. [PMID: 35983835 PMCID: PMC9433093 DOI: 10.7554/elife.78984] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 08/11/2022] [Indexed: 11/18/2022] Open
Abstract
In vertebrates, condensin I and condensin II cooperate to assemble rod-shaped chromosomes during mitosis. Although the mechanism of action and regulation of condensin I have been studied extensively, our corresponding knowledge of condensin II remains very limited. By introducing recombinant condensin II complexes into Xenopus egg extracts, we dissect the roles of its individual subunits in chromosome assembly. We find that one of two HEAT subunits, CAP-D3, plays a crucial role in condensin II-mediated assembly of chromosome axes, whereas the other HEAT subunit, CAP-G2, has a very strong negative impact on this process. The structural maintenance of chromosomes ATPase and the basic amino acid clusters of the kleisin subunit CAP-H2 are essential for this process. Deletion of the C-terminal tail of CAP-D3 increases the ability of condensin II to assemble chromosomes and further exposes a hidden function of CAP-G2 in the lateral compaction of chromosomes. Taken together, our results uncover a multilayered regulatory mechanism unique to condensin II, and provide profound implications for the evolution of condensin II.
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Affiliation(s)
| | | | - Yuuki Aizawa
- Chromosome Dynamics Laboratory, RIKEN, Wako, Japan
| | - Shoji Tane
- Chromosome Dynamics Laboratory, RIKEN, Wako, Japan
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11
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Shintomi K. Making Mitotic Chromosomes in a Test Tube. EPIGENOMES 2022; 6:epigenomes6030020. [PMID: 35893016 PMCID: PMC9326633 DOI: 10.3390/epigenomes6030020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 07/18/2022] [Accepted: 07/18/2022] [Indexed: 02/01/2023] Open
Abstract
Mitotic chromosome assembly is an essential preparatory step for accurate transmission of the genome during cell division. During the past decades, biochemical approaches have uncovered the molecular basis of mitotic chromosomes. For example, by using cell-free assays of frog egg extracts, the condensin I complex central for the chromosome assembly process was first identified, and its functions have been intensively studied. A list of chromosome-associated proteins has been almost completed, and it is now possible to reconstitute structures resembling mitotic chromosomes with a limited number of purified factors. In this review, I introduce how far we have come in understanding the mechanism of chromosome assembly using cell-free assays and reconstitution assays, and I discuss their potential applications to solve open questions.
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Affiliation(s)
- Keishi Shintomi
- Chromosome Dynamics Laboratory, RIKEN, Wako 351-0198, Saitama, Japan
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12
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Yamamoto T, Schiessel H. Loop extrusion driven volume phase transition of entangled chromosomes. Biophys J 2022; 121:2742-2750. [PMID: 35706364 DOI: 10.1016/j.bpj.2022.06.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/26/2022] [Accepted: 06/09/2022] [Indexed: 11/24/2022] Open
Abstract
Experiments on reconstituted chromosomes have revealed that mitotic chromosomes are assembled even without nucleosomes. When topoisomerase II (topo II) is depleted from such reconstituted chromosomes, these chromosomes are not disentangled and form "sparklers," where DNA and linker histone are condensed in the core and condensin is localized at the periphery. To understand the mechanism of the assembly of sparklers, we here take into account the loop extrusion by condensin in an extension of the theory of entangled polymer gels. The loop extrusion stiffens an entangled DNA network because DNA segments in the elastically effective chains are translocated to loops, which are elastically ineffective. Our theory predicts that the loop extrusion by condensin drives the volume phase transition that collapses a swollen entangled DNA gel because the stiffening of the network destabilizes the swollen phase. This may be an important piece to understand the mechanism of the assembly of mitotic chromosomes.
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Affiliation(s)
- Tetsuya Yamamoto
- Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo, Japan.
| | - Helmut Schiessel
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany
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13
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Meijering AEC, Sarlós K, Nielsen CF, Witt H, Harju J, Kerklingh E, Haasnoot GH, Bizard AH, Heller I, Broedersz CP, Liu Y, Peterman EJG, Hickson ID, Wuite GJL. Nonlinear mechanics of human mitotic chromosomes. Nature 2022; 605:545-550. [PMID: 35508652 PMCID: PMC9117150 DOI: 10.1038/s41586-022-04666-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 03/21/2022] [Indexed: 12/26/2022]
Abstract
In preparation for mitotic cell division, the nuclear DNA of human cells is compacted into individualized, X-shaped chromosomes1. This metamorphosis is driven mainly by the combined action of condensins and topoisomerase IIα (TOP2A)2,3, and has been observed using microscopy for over a century. Nevertheless, very little is known about the structural organization of a mitotic chromosome. Here we introduce a workflow to interrogate the organization of human chromosomes based on optical trapping and manipulation. This allows high-resolution force measurements and fluorescence visualization of native metaphase chromosomes to be conducted under tightly controlled experimental conditions. We have used this method to extensively characterize chromosome mechanics and structure. Notably, we find that under increasing mechanical load, chromosomes exhibit nonlinear stiffening behaviour, distinct from that predicted by classical polymer models4. To explain this anomalous stiffening, we introduce a hierarchical worm-like chain model that describes the chromosome as a heterogeneous assembly of nonlinear worm-like chains. Moreover, through inducible degradation of TOP2A5 specifically in mitosis, we provide evidence that TOP2A has a role in the preservation of chromosome compaction. The methods described here open the door to a wide array of investigations into the structure and dynamics of both normal and disease-associated chromosomes.
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Affiliation(s)
- Anna E C Meijering
- Department of Physics and Astronomy and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Kata Sarlós
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Christian F Nielsen
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Hannes Witt
- Department of Physics and Astronomy and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Janni Harju
- Department of Physics and Astronomy and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Emma Kerklingh
- Department of Physics and Astronomy and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Guus H Haasnoot
- Department of Physics and Astronomy and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Anna H Bizard
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Iddo Heller
- Department of Physics and Astronomy and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Chase P Broedersz
- Department of Physics and Astronomy and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
| | - Ying Liu
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Erwin J G Peterman
- Department of Physics and Astronomy and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Ian D Hickson
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.
| | - Gijs J L Wuite
- Department of Physics and Astronomy and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
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14
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Haase J, Chen R, Parker WM, Bonner MK, Jenkins LM, Kelly AE. The TFIIH complex is required to establish and maintain mitotic chromosome structure. eLife 2022; 11:75475. [PMID: 35293859 PMCID: PMC8956287 DOI: 10.7554/elife.75475] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 03/15/2022] [Indexed: 11/13/2022] Open
Abstract
Condensins compact chromosomes to promote their equal segregation during mitosis, but the mechanism of condensin engagement with and action on chromatin is incompletely understood. Here, we show that the general transcription factor TFIIH complex is continuously required to establish and maintain a compacted chromosome structure in transcriptionally silent Xenopus egg extracts. Inhibiting the DNA-dependent ATPase activity of the TFIIH complex subunit XPB rapidly and reversibly induces a complete loss of chromosome structure and prevents the enrichment of condensins I and II, but not topoisomerase II, on chromatin. In addition, inhibiting TFIIH prevents condensation of both mouse and Xenopus nuclei in Xenopus egg extracts, which suggests an evolutionarily conserved mechanism of TFIIH action. Reducing nucleosome density through partial histone depletion restores chromosome structure and condensin enrichment in the absence of TFIIH activity. We propose that the TFIIH complex promotes mitotic chromosome condensation by dynamically altering the chromatin environment to facilitate condensin loading and condensin-dependent loop extrusion.
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Affiliation(s)
- Julian Haase
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, United States
| | - Richard Chen
- Graduate School of Biomedical Sciences, The University of Texas Southwestern Medical Center, Dallas, United States
| | - Wesley M Parker
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, United States
| | - Mary Kate Bonner
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, United States
| | - Lisa M Jenkins
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, United States
| | - Alexander E Kelly
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, United States
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15
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Kinoshita K, Tsubota Y, Tane S, Aizawa Y, Sakata R, Takeuchi K, Shintomi K, Nishiyama T, Hirano T. A loop extrusion-independent mechanism contributes to condensin I-mediated chromosome shaping. J Cell Biol 2022; 221:212966. [PMID: 35045152 PMCID: PMC8932526 DOI: 10.1083/jcb.202109016] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/16/2021] [Accepted: 12/23/2021] [Indexed: 12/14/2022] Open
Abstract
Condensin I is a five-subunit protein complex that is central to mitotic chromosome assembly in eukaryotic cells. Despite recent progress, its molecular mechanisms of action remain to be fully elucidated. By using Xenopus egg extracts as a functional assay, we find that condensin I complexes harboring mutations in its kleisin subunit CAP-H produce chromosomes with confined axes in the presence of topoisomerase IIα (topo IIα) and highly compact structures (termed “beans”) with condensin-positive central cores in its absence. The bean phenotype depends on the SMC ATPase cycle and can be reversed by subsequent addition of topo IIα. The HEAT repeat subunit CAP-D2, but not CAP-G, is essential for the bean formation. Notably, loop extrusion activities of the mutant complexes cannot explain the chromosomal defects they exhibit in Xenopus egg extracts, implying that a loop extrusion–independent mechanism contributes to condensin I–mediated chromosome assembly and shaping. We provide evidence that condensin–condensin interactions underlie these processes.
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Affiliation(s)
| | - Yuko Tsubota
- Division of Biological Sciences, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Shoji Tane
- Chromosome Dynamics Laboratory, RIKEN, Wako, Saitama, Japan
| | - Yuuki Aizawa
- Chromosome Dynamics Laboratory, RIKEN, Wako, Saitama, Japan
| | - Ryota Sakata
- Division of Biological Sciences, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Kozo Takeuchi
- Chromosome Dynamics Laboratory, RIKEN, Wako, Saitama, Japan
| | | | - Tomoko Nishiyama
- Division of Biological Sciences, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Tatsuya Hirano
- Chromosome Dynamics Laboratory, RIKEN, Wako, Saitama, Japan
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Morovicz AP, Mazloumi Gavgani F, Jacobsen RG, Skuseth Slinning M, Turcu DC, Lewis AE. Phosphoinositide 3-kinase signalling in the nucleolus. Adv Biol Regul 2021; 83:100843. [PMID: 34920983 DOI: 10.1016/j.jbior.2021.100843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 11/20/2021] [Indexed: 12/26/2022]
Abstract
The phosphoinositide 3-kinase (PI3K) signalling pathway plays key roles in many cellular processes and is altered in many diseases. The function and mode of action of the pathway have mostly been elucidated in the cytoplasm. However, many of the components of the PI3K pathway are also present in the nucleus at specific sub-nuclear sites including nuclear speckles, nuclear lipid islets and the nucleolus. Nucleoli are membrane-less subnuclear structures where ribosome biogenesis occurs. Processes leading to ribosome biogenesis are tightly regulated to maintain protein translation capacity of cells. This review focuses on nucleolar PI3K signalling and how it regulates rRNA synthesis, as well as on the identification of downstream phosphatidylinositol (3,4,5)trisphosphate effector proteins.
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Affiliation(s)
| | | | - Rhîan G Jacobsen
- Department of Biological Sciences, University of Bergen, 5008, Bergen, Norway
| | | | - Diana C Turcu
- Department of Biological Sciences, University of Bergen, 5008, Bergen, Norway
| | - Aurélia E Lewis
- Department of Biological Sciences, University of Bergen, 5008, Bergen, Norway.
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17
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Choppakatla P, Dekker B, Cutts EE, Vannini A, Dekker J, Funabiki H. Linker histone H1.8 inhibits chromatin binding of condensins and DNA topoisomerase II to tune chromosome length and individualization. eLife 2021; 10:e68918. [PMID: 34406118 PMCID: PMC8416026 DOI: 10.7554/elife.68918] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 08/13/2021] [Indexed: 12/14/2022] Open
Abstract
DNA loop extrusion by condensins and decatenation by DNA topoisomerase II (topo II) are thought to drive mitotic chromosome compaction and individualization. Here, we reveal that the linker histone H1.8 antagonizes condensins and topo II to shape mitotic chromosome organization. In vitro chromatin reconstitution experiments demonstrate that H1.8 inhibits binding of condensins and topo II to nucleosome arrays. Accordingly, H1.8 depletion in Xenopus egg extracts increased condensins and topo II levels on mitotic chromatin. Chromosome morphology and Hi-C analyses suggest that H1.8 depletion makes chromosomes thinner and longer through shortening the average loop size and reducing the DNA amount in each layer of mitotic loops. Furthermore, excess loading of condensins and topo II to chromosomes by H1.8 depletion causes hyper-chromosome individualization and dispersion. We propose that condensins and topo II are essential for chromosome individualization, but their functions are tuned by the linker histone to keep chromosomes together until anaphase.
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Affiliation(s)
- Pavan Choppakatla
- Laboratory of Chromosome and Cell Biology, The Rockefeller UniversityNew YorkUnited States
| | - Bastiaan Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical SchoolWorcesterUnited States
| | - Erin E Cutts
- Division of Structural Biology, The Institute of Cancer ResearchLondonUnited Kingdom
| | - Alessandro Vannini
- Division of Structural Biology, The Institute of Cancer ResearchLondonUnited Kingdom
- Fondazione Human Technopole, Structural Biology Research Centre, 20157MilanItaly
| | - Job Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical SchoolWorcesterUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Hironori Funabiki
- Laboratory of Chromosome and Cell Biology, The Rockefeller UniversityNew YorkUnited States
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