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Golov AK, Gavrilov AA. Cohesin-Dependent Loop Extrusion: Molecular Mechanics and Role in Cell Physiology. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:601-625. [PMID: 38831499 DOI: 10.1134/s0006297924040023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 12/29/2023] [Accepted: 02/15/2024] [Indexed: 06/05/2024]
Abstract
The most prominent representatives of multisubunit SMC complexes, cohesin and condensin, are best known as structural components of mitotic chromosomes. It turned out that these complexes, as well as their bacterial homologues, are molecular motors, the ATP-dependent movement of these complexes along DNA threads leads to the formation of DNA loops. In recent years, we have witnessed an avalanche-like accumulation of data on the process of SMC dependent DNA looping, also known as loop extrusion. This review briefly summarizes the current understanding of the place and role of cohesin-dependent extrusion in cell physiology and presents a number of models describing the potential molecular mechanism of extrusion in a most compelling way. We conclude the review with a discussion of how the capacity of cohesin to extrude DNA loops may be mechanistically linked to its involvement in sister chromatid cohesion.
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Affiliation(s)
- Arkadiy K Golov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
- Technion - Israel Institute of Technology, Haifa, 3525433, Israel
| | - Alexey A Gavrilov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
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2
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Kim J, Wang H, Ercan S. Cohesin mediated loop extrusion from active enhancers form chromatin jets in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.18.558239. [PMID: 37786717 PMCID: PMC10541618 DOI: 10.1101/2023.09.18.558239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
In mammals, cohesin and CTCF organize the 3D genome into topologically associated domains (TADs) to regulate communication between cis-regulatory elements. However, many organisms, including S. cerevisiae , C. elegans , and A. thaliana lack CTCF. Here, we use C. elegans as a model to investigate the function of cohesin in 3D genome organization in an animal without CTCF. We use auxin-inducible degradation to acutely deplete SMC-3 or its negative regulator WAPL-1 from somatic cells. Using Hi-C data, we identify a cohesin-dependent 3D genome organization feature called chromatin jets (aka fountains). These are population average reflections of DNA loops that are ∼20-40 kb in scale and often cover a few transcribed genes. The jets emerge from NIPBL occupied segments, and the trajectory of the jets coincides with cohesin binding. Cohesin translocation from jet origins depends on a fully intact complex and is extended upon WAPL-1 depletion. Hi-C results support the idea that cohesin is preferentially loaded at NIPBL occupied sites and loop extrudes in an effectively two-sided manner. The location of putative loading sites coincide with active enhancers and the strength of chromatin jet pattern correlates with transcription. Hi-C analyses upon WAPL-1 depletion reveal unequal loop extrusion processivity on each side and stalling due to cohesin molecules colliding. Compared to mammalian systems, average processivity of C. elegans cohesin is ∼10-fold shorter and NIPBL binding does not depend on cohesin. We conclude that the processivity of cohesin scales with genome size; and regardless of CTCF presence, preferential loading of cohesin at enhancers is a conserved mechanism of genome organization that regulates the interaction of gene regulatory elements in 3D.
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3
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Moon KW, Ryu JK. Current working models of SMC-driven DNA-loop extrusion. Biochem Soc Trans 2023; 51:1801-1810. [PMID: 37767565 DOI: 10.1042/bst20220898] [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: 06/17/2023] [Revised: 09/17/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023]
Abstract
Structural maintenance of chromosome (SMC) proteins play a key roles in the chromosome organization by condensing two meters of DNA into cell-sized structures considered as the SMC protein extrudes DNA loop. Recent sequencing-based high-throughput chromosome conformation capture technique (Hi-C) and single-molecule experiments have provided direct evidence of DNA-loop extrusion. However, the molecular mechanism by which SMCs extrude a DNA loop is still under debate. Here, we review DNA-loop extrusion studies with single-molecule assays and introduce recent structural studies of how the ATP-hydrolysis cycle is coupled to the conformational changes of SMCs for DNA-loop extrusion. In addition, we explain the conservation of the DNA-binding sites that are vital for dynamic DNA-loop extrusion by comparing Cryo-EM structures of SMC complexes. Based on this information, we compare and discuss four compelling working models that explain how the SMC complex extrudes a DNA loop.
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Affiliation(s)
- Kyoung-Wook Moon
- Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Je-Kyung Ryu
- Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
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4
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Lelkes E, Jemelková J, Holá M, Štefanovie B, Kolesár P, Vágnerová R, Dvořák Tomaštíková E, Pecinka A, Angelis KJ, Paleček JJ. Characterization of the conserved features of the NSE6 subunit of the Physcomitrium patens SMC5/6 complex. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 115:1084-1099. [PMID: 37191775 DOI: 10.1111/tpj.16282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 05/06/2023] [Accepted: 05/10/2023] [Indexed: 05/17/2023]
Abstract
Structural maintenance of chromosomes (SMC) complexes are molecular machines ensuring chromatin organization at higher levels. They play direct roles in cohesion, condensation, replication, transcription, and DNA repair. Their cores are composed of long-armed SMC, kleisin, and kleisin-associated subunits. Additional factors, like NSE6 within SMC5/6, bind to SMC core complexes and regulate their activities. In the human HsNSE6/SLF2, we recently identified a new CANIN domain. Here we tracked down its sequence homology to lower plants, selected the bryophyte Physcomitrium patens, and analyzed PpNSE6 protein-protein interactions to explore its conservation in detail. We identified a previously unrecognized core sequence motif conserved from yeasts to humans within the NSE6 CANIN domain. This motif mediates the interaction between NSE6 and its NSE5 partner in yeasts and plants. In addition, the CANIN domain and its preceding PpNSE6 sequences bind both PpSMC5 and PpSMC6 arms. Interestingly, we mapped the PpNSE6-binding site at the PpSMC5 arm right next to the PpNSE2-binding surface. The position of NSE6 at SMC arms suggests its role in the regulation of SMC5/6 dynamics. Consistent with the regulatory role of NSE6 subunits, Ppnse6 mutant lines were viable and sensitive to the DNA-damaging drug bleomycin and lost a large portion of rDNA copies. These moss mutants also exhibited reduced growth and developmental aberrations. Altogether, our data showed the conserved function of the NSE6 subunit and architecture of the SMC5/6 complex across species.
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Affiliation(s)
- Edit Lelkes
- National Center for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Jitka Jemelková
- National Center for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Marcela Holá
- Institute of Experimental Botany, Czech Academy of Sciences, Na Karlovce 1, 16000, Prague, Czech Republic
| | - Barbora Štefanovie
- National Center for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Peter Kolesár
- National Center for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Radka Vágnerová
- Institute of Experimental Botany, Czech Academy of Sciences, Na Karlovce 1, 16000, Prague, Czech Republic
| | - Eva Dvořák Tomaštíková
- Centre of Plant Structural and Functional Genomics, Institute of Experimental Botany, Czech Academy of Sciences, Šlechtitelů 31, 77900, Olomouc, Czech Republic
| | - Ales Pecinka
- Centre of Plant Structural and Functional Genomics, Institute of Experimental Botany, Czech Academy of Sciences, Šlechtitelů 31, 77900, Olomouc, Czech Republic
| | - Karel J Angelis
- Institute of Experimental Botany, Czech Academy of Sciences, Na Karlovce 1, 16000, Prague, Czech Republic
| | - Jan J Paleček
- National Center for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
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Huang YF, Liu L, Wang F, Yuan XW, Chen HC, Liu ZF. High-Resolution 3D Genome Map of Brucella Chromosomes in Exponential and Stationary Phases. Microbiol Spectr 2023; 11:e0429022. [PMID: 36847551 PMCID: PMC10100373 DOI: 10.1128/spectrum.04290-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/02/2023] [Indexed: 03/01/2023] Open
Abstract
The three-dimensional (3D) genome structure of an organism or cell is highly relevant to its biological activities, but the availability of 3D genome information for bacteria, especially intracellular pathogens, is still limited. Here, we used Hi-C (high-throughput chromosome conformation capture) technology to determine the 3D chromosome structures of exponential- and stationary-phase Brucella melitensis at a 1-kb resolution. We observed that the contact heat maps of the two B. melitensis chromosomes contain a prominent diagonal and a secondary diagonal. Then, 79 chromatin interaction domains (CIDs) were detected at an optical density at 600 nm (OD600) of 0.4 (exponential phase), with the longest CID being 106 kb and the shortest being 12 kb. Moreover, we obtained 49,363 significant cis-interaction loci and 59,953 significant trans-interaction loci. Meanwhile, 82 CIDs of B. melitensis at an OD600 of 1.5 (stationary phase) were detected, with the longest CID being 94 kb and the shortest being 16 kb. In addition, 25,965 significant cis-interaction loci and 35,938 significant trans-interaction loci were obtained in this phase. Furthermore, we found that as the B. melitensis cells grew from the logarithmic to the plateau phase, the frequency of short-range interactions increased, while that of long-range interactions decreased. Finally, combined analysis of 3D genome and whole-genome transcriptome (RNA-seq) data revealed that the strength of short-range interactions in Chr1 is specifically and strongly correlated with gene expression. Overall, our study provides a global view of the chromatin interactions in the B. melitensis chromosomes, which will serve as a resource for further study of the spatial regulation of gene expression in Brucella. IMPORTANCE The spatial structure of chromatin plays important roles in normal cell functions and in the regulation of gene expression. Three-dimensional genome sequencing has been performed in many mammals and plants, but the availability of such data for bacteria, especially intracellular pathogens, is still limited. Approximately 10% of sequenced bacterial genomes contain more than one replicon. However, how multiple replicons are organized within bacterial cells, how they interact, and whether these interactions help to maintain or segregate these multipartite genomes are unresolved issues. Brucella is a Gram-negative, facultative intracellular, and zoonotic bacterium. Except for Brucella suis biovar 3, Brucella species have two chromosomes. Here, we applied Hi-C technology to determine the 3D genome structures of exponential- and stationary-phase Brucella melitensis chromosomes at a 1-kb resolution. Combined analysis of the 3D genome and RNA-seq data indicated that the strength of short-range interactions in B. melitensis Chr1 is specifically and strongly correlated with gene expression. Our study provides a resource to achieve a deeper understanding of the spatial regulation of gene expression in Brucella.
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Affiliation(s)
- Yong-Fang Huang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Lin Liu
- Wuhan Frasergen Bioinformatics Co., Ltd., Wuhan, Hubei, China
| | - Fei Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xin-Wei Yuan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Huan-Chun Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Zheng-Fei Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
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Mahrik L, Stefanovie B, Maresova A, Princova J, Kolesar P, Lelkes E, Faux C, Helmlinger D, Prevorovsky M, Palecek JJ. The SAGA histone acetyltransferase module targets SMC5/6 to specific genes. Epigenetics Chromatin 2023; 16:6. [PMID: 36793083 PMCID: PMC9933293 DOI: 10.1186/s13072-023-00480-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 02/02/2023] [Indexed: 02/17/2023] Open
Abstract
BACKGROUND Structural Maintenance of Chromosomes (SMC) complexes are molecular machines driving chromatin organization at higher levels. In eukaryotes, three SMC complexes (cohesin, condensin and SMC5/6) play key roles in cohesion, condensation, replication, transcription and DNA repair. Their physical binding to DNA requires accessible chromatin. RESULTS We performed a genetic screen in fission yeast to identify novel factors required for SMC5/6 binding to DNA. We identified 79 genes of which histone acetyltransferases (HATs) were the most represented. Genetic and phenotypic analyses suggested a particularly strong functional relationship between the SMC5/6 and SAGA complexes. Furthermore, several SMC5/6 subunits physically interacted with SAGA HAT module components Gcn5 and Ada2. As Gcn5-dependent acetylation facilitates the accessibility of chromatin to DNA-repair proteins, we first analysed the formation of DNA-damage-induced SMC5/6 foci in the Δgcn5 mutant. The SMC5/6 foci formed normally in Δgcn5, suggesting SAGA-independent SMC5/6 localization to DNA-damaged sites. Next, we used Nse4-FLAG chromatin-immunoprecipitation (ChIP-seq) analysis in unchallenged cells to assess SMC5/6 distribution. A significant portion of SMC5/6 accumulated within gene regions in wild-type cells, which was reduced in Δgcn5 and Δada2 mutants. The drop in SMC5/6 levels was also observed in gcn5-E191Q acetyltransferase-dead mutant. CONCLUSION Our data show genetic and physical interactions between SMC5/6 and SAGA complexes. The ChIP-seq analysis suggests that SAGA HAT module targets SMC5/6 to specific gene regions and facilitates their accessibility for SMC5/6 loading.
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Affiliation(s)
- L Mahrik
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlarska 2, 61137, Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - B Stefanovie
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlarska 2, 61137, Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - A Maresova
- Department of Cell Biology, Faculty of Science, Charles University, Vinicna 7, 12800, Prague, Czech Republic
| | - J Princova
- Department of Cell Biology, Faculty of Science, Charles University, Vinicna 7, 12800, Prague, Czech Republic
| | - P Kolesar
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlarska 2, 61137, Brno, Czech Republic
| | - E Lelkes
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlarska 2, 61137, Brno, Czech Republic
| | - C Faux
- Centre de Recherche en Biologie Cellulaire de Montpellier, University of Montpellier, CNRS, 1919 Route de Mende, 34293, Montpellier Cedex 05, France
| | - D Helmlinger
- Centre de Recherche en Biologie Cellulaire de Montpellier, University of Montpellier, CNRS, 1919 Route de Mende, 34293, Montpellier Cedex 05, France
| | - M Prevorovsky
- Department of Cell Biology, Faculty of Science, Charles University, Vinicna 7, 12800, Prague, Czech Republic.
| | - J J Palecek
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlarska 2, 61137, Brno, Czech Republic.
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic.
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic.
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7
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Roberts DM. A new role for monomeric ParA/Soj in chromosome dynamics in Bacillus subtilis. Microbiologyopen 2023; 12:e1344. [PMID: 36825885 PMCID: PMC9841721 DOI: 10.1002/mbo3.1344] [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: 12/02/2022] [Revised: 01/10/2023] [Accepted: 01/10/2023] [Indexed: 01/17/2023] Open
Abstract
ParABS (Soj-Spo0J) systems were initially implicated in plasmid and chromosome segregation in bacteria. However, it is now increasingly understood that they play multiple roles in cell cycle events in Bacillus subtilis, and possibly other bacteria. In a recent study, monomeric forms of ParA/Soj have been implicated in regulating aspects of chromosome dynamics during B. subtilis sporulation. In this commentary, I will discuss the known roles of ParABS systems, explore why sporulation is a valuable model for studying these proteins, and the new insights into the role of monomeric ParA/Soj. Finally, I will touch upon some of the future work that remains.
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8
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Balaji AK, Saha S, Deshpande S, Poola D, Sengupta K. Nuclear envelope, chromatin organizers, histones, and DNA: The many achilles heels exploited across cancers. Front Cell Dev Biol 2022; 10:1068347. [PMID: 36589746 PMCID: PMC9800887 DOI: 10.3389/fcell.2022.1068347] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022] Open
Abstract
In eukaryotic cells, the genome is organized in the form of chromatin composed of DNA and histones that organize and regulate gene expression. The dysregulation of chromatin remodeling, including the aberrant incorporation of histone variants and their consequent post-translational modifications, is prevalent across cancers. Additionally, nuclear envelope proteins are often deregulated in cancers, which impacts the 3D organization of the genome. Altered nuclear morphology, genome organization, and gene expression are defining features of cancers. With advances in single-cell sequencing, imaging technologies, and high-end data mining approaches, we are now at the forefront of designing appropriate small molecules to selectively inhibit the growth and proliferation of cancer cells in a genome- and epigenome-specific manner. Here, we review recent advances and the emerging significance of aberrations in nuclear envelope proteins, histone variants, and oncohistones in deregulating chromatin organization and gene expression in oncogenesis.
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Guo Y, Al-Jibury E, Garcia-Millan R, Ntagiantas K, King JWD, Nash AJ, Galjart N, Lenhard B, Rueckert D, Fisher AG, Pruessner G, Merkenschlager M. Chromatin jets define the properties of cohesin-driven in vivo loop extrusion. Mol Cell 2022; 82:3769-3780.e5. [PMID: 36182691 DOI: 10.1016/j.molcel.2022.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 07/26/2022] [Accepted: 09/01/2022] [Indexed: 01/01/2023]
Abstract
Complex genomes show intricate organization in three-dimensional (3D) nuclear space. Current models posit that cohesin extrudes loops to form self-interacting domains delimited by the DNA binding protein CTCF. Here, we describe and quantitatively characterize cohesin-propelled, jet-like chromatin contacts as landmarks of loop extrusion in quiescent mammalian lymphocytes. Experimental observations and polymer simulations indicate that narrow origins of loop extrusion favor jet formation. Unless constrained by CTCF, jets propagate symmetrically for 1-2 Mb, providing an estimate for the range of in vivo loop extrusion. Asymmetric CTCF binding deflects the angle of jet propagation as experimental evidence that cohesin-mediated loop extrusion can switch from bi- to unidirectional and is controlled independently in both directions. These data offer new insights into the physiological behavior of in vivo cohesin-mediated loop extrusion and further our understanding of the principles that underlie genome organization.
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Affiliation(s)
- Ya Guo
- MRC London Institute of Medical Sciences, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London W12 0NN, UK; Sheng Yushou Center of Cell Biology and Immunology, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; WLA Laboratories, Shanghai 201203, China
| | - Ediem Al-Jibury
- MRC London Institute of Medical Sciences, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London W12 0NN, UK; Department of Computing, Imperial College London, London SW7 2RH, UK
| | - Rosalba Garcia-Millan
- Department of Mathematics, Imperial College London, London SW7 2RH, UK; Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, UK; St John's College, University of Cambridge, Cambridge CB2 1TP, UK
| | | | - James W D King
- MRC London Institute of Medical Sciences, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London W12 0NN, UK
| | - Alex J Nash
- MRC London Institute of Medical Sciences, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London W12 0NN, UK
| | - Niels Galjart
- Department of Cell Biology, Erasmus University Medical Center, 3015 GD Rotterdam, the Netherlands
| | - Boris Lenhard
- MRC London Institute of Medical Sciences, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London W12 0NN, UK; Sars International Centre for Marine Molecular Biology, University of Bergen, 5008 Bergen, Norway
| | - Daniel Rueckert
- Department of Computing, Imperial College London, London SW7 2RH, UK; Chair for AI in Healthcare and Medicine, Technical University of Munich, 81675 Munich, Germany
| | - Amanda G Fisher
- MRC London Institute of Medical Sciences, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London W12 0NN, UK
| | - Gunnar Pruessner
- Department of Mathematics, Imperial College London, London SW7 2RH, UK.
| | - Matthias Merkenschlager
- MRC London Institute of Medical Sciences, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London W12 0NN, UK.
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10
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Roberts DM, Anchimiuk A, Kloosterman TG, Murray H, Wu LJ, Gruber S, Errington J. Chromosome remodelling by SMC/Condensin in B. subtilis is regulated by monomeric Soj/ParA during growth and sporulation. Proc Natl Acad Sci U S A 2022; 119:e2204042119. [PMID: 36206370 PMCID: PMC9564211 DOI: 10.1073/pnas.2204042119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 09/09/2022] [Indexed: 11/18/2022] Open
Abstract
SMC complexes, loaded at ParB-parS sites, are key mediators of chromosome organization in bacteria. ParA/Soj proteins interact with ParB/Spo0J in a pathway involving adenosine triphosphate (ATP)-dependent dimerization and DNA binding, facilitating chromosome segregation in bacteria. In Bacillus subtilis, ParA/Soj also regulates DNA replication initiation and along with ParB/Spo0J is involved in cell cycle changes during endospore formation. The first morphological stage in sporulation is the formation of an elongated chromosome structure called an axial filament. Here, we show that a major redistribution of SMC complexes drives axial filament formation in a process regulated by ParA/Soj. Furthermore, and unexpectedly, this regulation is dependent on monomeric forms of ParA/Soj that cannot bind DNA or hydrolyze ATP. These results reveal additional roles for ParA/Soj proteins in the regulation of SMC dynamics in bacteria and yet further complexity in the web of interactions involving chromosome replication, segregation and organization, controlled by ParAB and SMC.
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Affiliation(s)
- David M. Roberts
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, United Kingdom
| | - Anna Anchimiuk
- Department of Fundamental Microbiology, University of Lausanne, Bâtiment Biophore, 015 Lausanne, Switzerland
| | - Tomas G. Kloosterman
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, United Kingdom
| | - Heath Murray
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, United Kingdom
| | - Ling Juan Wu
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, United Kingdom
| | - Stephan Gruber
- Department of Fundamental Microbiology, University of Lausanne, Bâtiment Biophore, 015 Lausanne, Switzerland
| | - Jeff Errington
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, United Kingdom
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11
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Kim J, Jimenez DS, Ragipani B, Zhang B, Street LA, Kramer M, Albritton SE, Winterkorn LH, Morao AK, Ercan S. Condensin DC loads and spreads from recruitment sites to create loop-anchored TADs in C. elegans. eLife 2022; 11:68745. [PMID: 36331876 PMCID: PMC9635877 DOI: 10.7554/elife.68745] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 10/23/2022] [Indexed: 11/06/2022] Open
Abstract
Condensins are molecular motors that compact DNA via linear translocation. In Caenorhabditis elegans, the X-chromosome harbors a specialized condensin that participates in dosage compensation (DC). Condensin DC is recruited to and spreads from a small number of recruitment elements on the X-chromosome (rex) and is required for the formation of topologically associating domains (TADs). We take advantage of autosomes that are largely devoid of condensin DC and TADs to address how rex sites and condensin DC give rise to the formation of TADs. When an autosome and X-chromosome are physically fused, despite the spreading of condensin DC into the autosome, no TAD was created. Insertion of a strong rex on the X-chromosome results in the TAD boundary formation regardless of sequence orientation. When the same rex is inserted on an autosome, despite condensin DC recruitment, there was no spreading or features of a TAD. On the other hand, when a 'super rex' composed of six rex sites or three separate rex sites are inserted on an autosome, recruitment and spreading of condensin DC led to the formation of TADs. Therefore, recruitment to and spreading from rex sites are necessary and sufficient for recapitulating loop-anchored TADs observed on the X-chromosome. Together our data suggest a model in which rex sites are both loading sites and bidirectional barriers for condensin DC, a one-sided loop-extruder with movable inactive anchor.
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Affiliation(s)
- Jun Kim
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - David S Jimenez
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - Bhavana Ragipani
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - Bo Zhang
- UCSF HSWSan FranciscoUnited States
| | - Lena A Street
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - Maxwell Kramer
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - Sarah E Albritton
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - Lara H Winterkorn
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - Ana K Morao
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - Sevinc Ercan
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
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12
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Ryu JK, Rah SH, Janissen R, Kerssemakers JWJ, Bonato A, Michieletto D, Dekker C. Condensin extrudes DNA loops in steps up to hundreds of base pairs that are generated by ATP binding events. Nucleic Acids Res 2021; 50:820-832. [PMID: 34951453 PMCID: PMC8789078 DOI: 10.1093/nar/gkab1268] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 10/22/2021] [Accepted: 12/09/2021] [Indexed: 12/28/2022] Open
Abstract
The condensin SMC protein complex organizes chromosomal structure by extruding loops of DNA. Its ATP-dependent motor mechanism remains unclear but likely involves steps associated with large conformational changes within the ∼50 nm protein complex. Here, using high-resolution magnetic tweezers, we resolve single steps in the loop extrusion process by individual yeast condensins. The measured median step sizes range between 20–40 nm at forces of 1.0–0.2 pN, respectively, comparable with the holocomplex size. These large steps show that, strikingly, condensin typically reels in DNA in very sizeable amounts with ∼200 bp on average per single extrusion step at low force, and occasionally even much larger, exceeding 500 bp per step. Using Molecular Dynamics simulations, we demonstrate that this is due to the structural flexibility of the DNA polymer at these low forces. Using ATP-binding-impaired and ATP-hydrolysis-deficient mutants, we find that ATP binding is the primary step-generating stage underlying DNA loop extrusion. We discuss our findings in terms of a scrunching model where a stepwise DNA loop extrusion is generated by an ATP-binding-induced engagement of the hinge and the globular domain of the SMC complex.
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Affiliation(s)
- Je-Kyung Ryu
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Sang-Hyun Rah
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Richard Janissen
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Jacob W J Kerssemakers
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Andrea Bonato
- University of Edinburgh, SUPA, School of Physics and Astronomy, EH9 3FD, Edinburgh, UK
| | - Davide Michieletto
- University of Edinburgh, SUPA, School of Physics and Astronomy, EH9 3FD, Edinburgh, UK.,MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
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13
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Prince JP, Bolla JR, Fisher GLM, Mäkelä J, Fournier M, Robinson CV, Arciszewska LK, Sherratt DJ. Acyl carrier protein promotes MukBEF action in Escherichia coli chromosome organization-segregation. Nat Commun 2021; 12:6721. [PMID: 34795302 PMCID: PMC8602292 DOI: 10.1038/s41467-021-27107-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 11/02/2021] [Indexed: 11/22/2022] Open
Abstract
Structural Maintenance of Chromosomes (SMC) complexes act ubiquitously to compact DNA linearly, thereby facilitating chromosome organization-segregation. SMC proteins have a conserved architecture, with a dimerization hinge and an ATPase head domain separated by a long antiparallel intramolecular coiled-coil. Dimeric SMC proteins interact with essential accessory proteins, kleisins that bridge the two subunits of an SMC dimer, and HAWK/KITE proteins that interact with kleisins. The ATPase activity of the Escherichia coli SMC protein, MukB, which is essential for its in vivo function, requires its interaction with the dimeric kleisin, MukF that in turn interacts with the KITE protein, MukE. Here we demonstrate that, in addition, MukB interacts specifically with Acyl Carrier Protein (AcpP) that has essential functions in fatty acid synthesis. We characterize the AcpP interaction at the joint of the MukB coiled-coil and show that the interaction is necessary for MukB ATPase and for MukBEF function in vivo.
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Affiliation(s)
- Josh P. Prince
- grid.4991.50000 0004 1936 8948Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK ,grid.14105.310000000122478951Present Address: Meiosis Group, Medical Research Council London Institute of Medical Sciences, Du Cane Road, London, W12 0NN UK
| | - Jani R. Bolla
- grid.4991.50000 0004 1936 8948Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ UK ,The Kavli Institute for Nanoscience Discovery, South Parks Road, Oxford, OX1 3QU UK ,grid.4991.50000 0004 1936 8948Present Address: Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Gemma L. M. Fisher
- grid.4991.50000 0004 1936 8948Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK ,grid.14105.310000000122478951Present Address: DNA Motors Group, Medical Research Council London Institute of Medical Sciences, Du Cane Road, London, W12 0NN UK
| | - Jarno Mäkelä
- grid.4991.50000 0004 1936 8948Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK ,grid.168010.e0000000419368956Present Address: ChEM-H Institute, Stanford University, 290 Jane Stanford Way, Stanford, CA 94305 USA
| | - Marjorie Fournier
- grid.4991.50000 0004 1936 8948Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Carol V. Robinson
- grid.4991.50000 0004 1936 8948Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ UK ,The Kavli Institute for Nanoscience Discovery, South Parks Road, Oxford, OX1 3QU UK
| | - Lidia K. Arciszewska
- grid.4991.50000 0004 1936 8948Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - David J. Sherratt
- grid.4991.50000 0004 1936 8948Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
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14
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Kumar R, Bahng S, Marians KJ. The MukB-topoisomerase IV interaction mutually suppresses their catalytic activities. Nucleic Acids Res 2021; 50:2621-2634. [PMID: 34747485 PMCID: PMC8934648 DOI: 10.1093/nar/gkab1027] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 10/11/2021] [Accepted: 10/13/2021] [Indexed: 02/05/2023] Open
Abstract
The bacterial condensin MukB and the cellular chromosomal decatenase, topoisomerase IV interact and this interaction is required for proper condensation and topological ordering of the chromosome. Here, we show that Topo IV stimulates MukB DNA condensation by stabilizing loops in DNA: MukB alone can condense nicked plasmid DNA into a protein–DNA complex that has greater electrophoretic mobility than that of the DNA alone, but both MukB and Topo IV are required for a similar condensation of a linear DNA representing long stretches of the chromosome. Remarkably, we show that rather than MukB stimulating the decatenase activity of Topo IV, as has been argued previously, in stoichiometric complexes of the two enzymes each inhibits the activity of the other: the ParC subunit of Topo IV inhibits the MukF-stimulated ATPase activity of MukB and MukB inhibits both DNA crossover trapping and DNA cleavage by Topo IV. These observations suggest that when in complex on the DNA, Topo IV inhibits the motor function of MukB and the two proteins provide a stable scaffold for chromosomal DNA condensation.
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Affiliation(s)
- Rupesh Kumar
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Soon Bahng
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Kenneth J Marians
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
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15
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The spatial position effect: synthetic biology enters the era of 3D genomics. Trends Biotechnol 2021; 40:539-548. [PMID: 34607694 DOI: 10.1016/j.tibtech.2021.09.001] [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: 07/23/2021] [Revised: 08/31/2021] [Accepted: 09/01/2021] [Indexed: 11/23/2022]
Abstract
Microbial cell factories are critical to achieving green biomanufacturing. A position effect occurs when a synthetic gene circuit is expressed from different positions in the chassis strain genome. Here, we propose the concept of the 'spatial position effect,' which uses technologies in 3D genomics to reveal the spatial structure characteristics of the 3D genome of the chassis. On this basis, we propose to rationally design the integration sites of synthetic gene circuits, use reporter genes for preliminary screening, and integrate synthetic gene circuits into promising sites for further experiments. This approach can produce stable and efficient chassis strains for green biomanufacturing. The proposed spatial position effect brings synthetic biology into the era of 3D genomics.
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16
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Lioy VS, Lorenzi JN, Najah S, Poinsignon T, Leh H, Saulnier C, Aigle B, Lautru S, Thibessard A, Lespinet O, Leblond P, Jaszczyszyn Y, Gorrichon K, Varoquaux N, Junier I, Boccard F, Pernodet JL, Bury-Moné S. Dynamics of the compartmentalized Streptomyces chromosome during metabolic differentiation. Nat Commun 2021; 12:5221. [PMID: 34471117 PMCID: PMC8410849 DOI: 10.1038/s41467-021-25462-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 07/21/2021] [Indexed: 02/07/2023] Open
Abstract
Bacteria of the genus Streptomyces are prolific producers of specialized metabolites, including antibiotics. The linear chromosome includes a central region harboring core genes, as well as extremities enriched in specialized metabolite biosynthetic gene clusters. Here, we show that chromosome structure in Streptomyces ambofaciens correlates with genetic compartmentalization during exponential phase. Conserved, large and highly transcribed genes form boundaries that segment the central part of the chromosome into domains, whereas the terminal ends tend to be transcriptionally quiescent compartments with different structural features. The onset of metabolic differentiation is accompanied by a rearrangement of chromosome architecture, from a rather 'open' to a 'closed' conformation, in which highly expressed specialized metabolite biosynthetic genes form new boundaries. Thus, our results indicate that the linear chromosome of S. ambofaciens is partitioned into structurally distinct entities, suggesting a link between chromosome folding, gene expression and genome evolution.
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Affiliation(s)
- Virginia S Lioy
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France.
| | - Jean-Noël Lorenzi
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Soumaya Najah
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Thibault Poinsignon
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Hervé Leh
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Corinne Saulnier
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | | | - Sylvie Lautru
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | | | - Olivier Lespinet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | | | - Yan Jaszczyszyn
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Kevin Gorrichon
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Nelle Varoquaux
- Université Grenoble Alpes, CNRS, Grenoble INP, TIMC-IMAG, Grenoble, France
| | - Ivan Junier
- Université Grenoble Alpes, CNRS, Grenoble INP, TIMC-IMAG, Grenoble, France
| | - Frédéric Boccard
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Jean-Luc Pernodet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Stéphanie Bury-Moné
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France.
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17
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Higashi TL, Pobegalov G, Tang M, Molodtsov MI, Uhlmann F. A Brownian ratchet model for DNA loop extrusion by the cohesin complex. eLife 2021; 10:e67530. [PMID: 34309513 PMCID: PMC8313234 DOI: 10.7554/elife.67530] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 06/10/2021] [Indexed: 12/12/2022] Open
Abstract
The cohesin complex topologically encircles DNA to promote sister chromatid cohesion. Alternatively, cohesin extrudes DNA loops, thought to reflect chromatin domain formation. Here, we propose a structure-based model explaining both activities. ATP and DNA binding promote cohesin conformational changes that guide DNA through a kleisin N-gate into a DNA gripping state. Two HEAT-repeat DNA binding modules, associated with cohesin's heads and hinge, are now juxtaposed. Gripping state disassembly, following ATP hydrolysis, triggers unidirectional hinge module movement, which completes topological DNA entry by directing DNA through the ATPase head gate. If head gate passage fails, hinge module motion creates a Brownian ratchet that, instead, drives loop extrusion. Molecular-mechanical simulations of gripping state formation and resolution cycles recapitulate experimentally observed DNA loop extrusion characteristics. Our model extends to asymmetric and symmetric loop extrusion, as well as z-loop formation. Loop extrusion by biased Brownian motion has important implications for chromosomal cohesin function.
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Affiliation(s)
- Torahiko L Higashi
- Chromosome Segregation Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Georgii Pobegalov
- Mechanobiology and Biophysics Laboratory, The Francis Crick InstituteLondonUnited Kingdom
- Department of Physics and Astronomy, University College LondonLondonUnited Kingdom
| | - Minzhe Tang
- Chromosome Segregation Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Maxim I Molodtsov
- Mechanobiology and Biophysics Laboratory, The Francis Crick InstituteLondonUnited Kingdom
- Department of Physics and Astronomy, University College LondonLondonUnited Kingdom
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick InstituteLondonUnited Kingdom
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18
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Brandão HB, Ren Z, Karaboja X, Mirny LA, Wang X. DNA-loop-extruding SMC complexes can traverse one another in vivo. Nat Struct Mol Biol 2021; 28:642-651. [PMID: 34312537 DOI: 10.1038/s41594-021-00626-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 06/17/2021] [Indexed: 02/06/2023]
Abstract
Chromosome organization mediated by structural maintenance of chromosomes (SMC) complexes is vital in many organisms. SMC complexes act as motors that extrude DNA loops, but it remains unclear what happens when multiple complexes encounter one another on the same DNA in living cells and how these interactions may help to organize an active genome. We therefore created a crash-course track system to study SMC complex encounters in vivo by engineering defined SMC loading sites in the Bacillus subtilis chromosome. Chromosome conformation capture (Hi-C) analyses of over 20 engineered strains show an amazing variety of chromosome folding patterns. Through three-dimensional polymer simulations and theory, we determine that these patterns require SMC complexes to bypass each other in vivo, as recently seen in an in vitro study. We posit that the bypassing activity enables SMC complexes to avoid traffic jams while spatially organizing the genome.
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Affiliation(s)
- Hugo B Brandão
- Graduate Program in Biophysics, Harvard University, Cambridge, MA, USA
| | - Zhongqing Ren
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Xheni Karaboja
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Leonid A Mirny
- Graduate Program in Biophysics, Harvard University, Cambridge, MA, USA. .,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Xindan Wang
- Department of Biology, Indiana University, Bloomington, IN, USA.
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19
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Davidson IF, Peters JM. Genome folding through loop extrusion by SMC complexes. Nat Rev Mol Cell Biol 2021; 22:445-464. [PMID: 33767413 DOI: 10.1038/s41580-021-00349-7] [Citation(s) in RCA: 206] [Impact Index Per Article: 68.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2021] [Indexed: 02/02/2023]
Abstract
Genomic DNA is folded into loops and topologically associating domains (TADs), which serve important structural and regulatory roles. It has been proposed that these genomic structures are formed by a loop extrusion process, which is mediated by structural maintenance of chromosomes (SMC) protein complexes. Recent single-molecule studies have shown that the SMC complexes condensin and cohesin are indeed able to extrude DNA into loops. In this Review, we discuss how the loop extrusion hypothesis can explain key features of genome architecture; cellular functions of loop extrusion, such as separation of replicated DNA molecules, facilitation of enhancer-promoter interactions and immunoglobulin gene recombination; and what is known about the mechanism of loop extrusion and its regulation, for example, by chromatin boundaries that depend on the DNA binding protein CTCF. We also discuss how the loop extrusion hypothesis has led to a paradigm shift in our understanding of both genome architecture and the functions of SMC complexes.
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Affiliation(s)
- Iain F Davidson
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria.
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20
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Gogou C, Japaridze A, Dekker C. Mechanisms for Chromosome Segregation in Bacteria. Front Microbiol 2021; 12:685687. [PMID: 34220773 PMCID: PMC8242196 DOI: 10.3389/fmicb.2021.685687] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/19/2021] [Indexed: 11/13/2022] Open
Abstract
The process of DNA segregation, the redistribution of newly replicated genomic material to daughter cells, is a crucial step in the life cycle of all living systems. Here, we review DNA segregation in bacteria which evolved a variety of mechanisms for partitioning newly replicated DNA. Bacterial species such as Caulobacter crescentus and Bacillus subtilis contain pushing and pulling mechanisms that exert forces and directionality to mediate the moving of newly synthesized chromosomes to the bacterial poles. Other bacteria such as Escherichia coli lack such active segregation systems, yet exhibit a spontaneous de-mixing of chromosomes due to entropic forces as DNA is being replicated under the confinement of the cell wall. Furthermore, we present a synopsis of the main players that contribute to prokaryotic genome segregation. We finish with emphasizing the importance of bottom-up approaches for the investigation of the various factors that contribute to genome segregation.
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Affiliation(s)
- Christos Gogou
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, Netherlands
| | - Aleksandre Japaridze
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, Netherlands
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, Netherlands
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21
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Peters JM. How DNA loop extrusion mediated by cohesin enables V(D)J recombination. Curr Opin Cell Biol 2021; 70:75-83. [PMID: 33422934 DOI: 10.1016/j.ceb.2020.11.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 11/28/2020] [Indexed: 12/16/2022]
Abstract
'Structural maintenance of chromosomes' (SMC) complexes are required for the folding of genomic DNA into loops. Theoretical considerations and single-molecule experiments performed with the SMC complexes cohesin and condensin indicate that DNA folding occurs via loop extrusion. Recent work indicates that this process is essential for the assembly of antigen receptor genes by V(D)J recombination in developing B and T cells of the vertebrate immune system. Here, I review how recent studies of the mouse immunoglobulin heavy chain locus Igh have provided evidence for this hypothesis and how the formation of chromatin loops by cohesin and regulation of this process by CTCF and Wapl might ensure that all variable gene segments in this locus (VH segments) participate in recombination with a re-arranged DJH segment, to ensure generation of a maximally diverse repertoire of B-cell receptors and antibodies.
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Affiliation(s)
- Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria.
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22
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Lioy VS, Junier I, Lagage V, Vallet I, Boccard F. Distinct Activities of Bacterial Condensins for Chromosome Management in Pseudomonas aeruginosa. Cell Rep 2021; 33:108344. [PMID: 33147461 DOI: 10.1016/j.celrep.2020.108344] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/11/2020] [Accepted: 10/12/2020] [Indexed: 12/17/2022] Open
Abstract
Three types of structurally related structural maintenance of chromosomes (SMC) complexes, referred to as condensins, have been identified in bacteria. Smc-ScpAB is present in most bacteria, whereas MukBEF is found in enterobacteria and MksBEF is scattered over the phylogenic tree. The contributions of these condensins to chromosome management were characterized in Pseudomonas aeruginosa, which carries both Smc-ScpAB and MksBEF. In this bacterium, SMC-ScpAB controls chromosome disposition by juxtaposing chromosome arms. In contrast, MksBEF is critical for chromosome segregation in the absence of the main segregation system, and it affects the higher-order architecture of the chromosome by promoting DNA contacts in the megabase range. Strikingly, our results reveal a prevalence of Smc-ScpAB over MksBEF involving a coordination of their activities with chromosome replication. They also show that E. coli MukBEF can substitute for MksBEF in P. aeruginosa while prevailing over Smc-ScpAB. Our results reveal a hierarchy between activities of bacterial condensins on the same chromosome.
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Affiliation(s)
- Virginia S Lioy
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Ivan Junier
- CNRS, Université Grenoble Alpes, TIMC-IMAG, 38000 Grenoble, France
| | - Valentine Lagage
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Isabelle Vallet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
| | - Frédéric Boccard
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
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23
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Kim KD. Potential roles of condensin in genome organization and beyond in fission yeast. J Microbiol 2021; 59:449-459. [PMID: 33877578 DOI: 10.1007/s12275-021-1039-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 11/24/2022]
Abstract
The genome is highly organized hierarchically by the function of structural maintenance of chromosomes (SMC) complex proteins such as condensin and cohesin from bacteria to humans. Although the roles of SMC complex proteins have been well characterized, their specialized roles in nuclear processes remain unclear. Condensin and cohesin have distinct binding sites and mediate long-range and short-range genomic associations, respectively, to form cell cycle-specific genome organization. Condensin can be recruited to highly expressed genes as well as dispersed repeat genetic elements, such as Pol III-transcribed genes, LTR retrotransposon, and rDNA repeat. In particular, mitotic transcription factors Ace2 and Ams2 recruit condensin to their target genes, forming centromeric clustering during mitosis. Condensin is potentially involved in various chromosomal processes such as the mobility of chromosomes, chromosome territories, DNA reannealing, and transcription factories. The current knowledge of condensin in fission yeast summarized in this review can help us understand how condensin mediates genome organization and participates in chromosomal processes in other organisms.
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Affiliation(s)
- Kyoung-Dong Kim
- Department of Systems Biotechnology, Chung-Ang University, Anseong, 17546, Republic of Korea.
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24
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Gradual opening of Smc arms in prokaryotic condensin. Cell Rep 2021; 35:109051. [PMID: 33910021 DOI: 10.1016/j.celrep.2021.109051] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 01/20/2021] [Accepted: 04/07/2021] [Indexed: 12/19/2022] Open
Abstract
Multi-subunit SMC ATPases control chromosome superstructure apparently by catalyzing a DNA-loop-extrusion reaction. SMC proteins harbor an ABC-type ATPase "head" and a "hinge" dimerization domain connected by a coiled coil "arm." Two arms in a SMC dimer can co-align, thereby forming a rod-shaped particle. Upon ATP binding, SMC heads engage, and arms are thought to separate. Here, we study the shape of Bacillus subtilis Smc-ScpAB by electron-spin resonance spectroscopy. Arm separation is readily detected proximal to the heads in the absence of ligands, and separation near the hinge largely depends on ATP and DNA. Artificial blockage of arm opening eliminates DNA stimulation of ATP hydrolysis but does not prevent basal ATPase activity. We report an arm contact as being important for controlling the transformations. Point mutations at this arm interface eliminated Smc function. We propose that partially open, intermediary conformations provide directionality to SMC DNA translocation by (un)binding suitable DNA substrates.
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25
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Xiang JF, Corces VG. Regulation of 3D chromatin organization by CTCF. Curr Opin Genet Dev 2021; 67:33-40. [PMID: 33259986 PMCID: PMC8084898 DOI: 10.1016/j.gde.2020.10.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/18/2020] [Accepted: 10/26/2020] [Indexed: 01/12/2023]
Abstract
Studies of nuclear architecture using chromosome conformation capture methods have provided a detailed view of how chromatin folds in the 3D nuclear space. New variants of this technology now afford unprecedented resolution and allow the identification of ever smaller folding domains that offer new insights into the mechanisms by which this organization is established and maintained. Here we review recent results in this rapidly evolving field with an emphasis on CTCF function, with the goal of gaining a mechanistic understanding of the principles by which chromatin is folded in the eukaryotic nucleus.
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Affiliation(s)
- Jian-Feng Xiang
- Emory University School of Medicine, Department of Human Genetics, 615 Michael Street, Atlanta, GA 30322, USA
| | - Victor G Corces
- Emory University School of Medicine, Department of Human Genetics, 615 Michael Street, Atlanta, GA 30322, USA.
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26
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Birnie A, Dekker C. Genome-in-a-Box: Building a Chromosome from the Bottom Up. ACS NANO 2021; 15:111-124. [PMID: 33347266 PMCID: PMC7844827 DOI: 10.1021/acsnano.0c07397] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 12/16/2020] [Indexed: 05/24/2023]
Abstract
Chromosome structure and dynamics are essential for life, as the way that our genomes are spatially organized within cells is crucial for gene expression, differentiation, and genome transfer to daughter cells. There is a wide variety of methods available to study chromosomes, ranging from live-cell studies to single-molecule biophysics, which we briefly review. While these technologies have yielded a wealth of data, such studies still leave a significant gap between top-down experiments on live cells and bottom-up in vitro single-molecule studies of DNA-protein interactions. Here, we introduce "genome-in-a-box" (GenBox) as an alternative in vitro approach to build and study chromosomes, which bridges this gap. The concept is to assemble a chromosome from the bottom up by taking deproteinated genome-sized DNA isolated from live cells and subsequently add purified DNA-organizing elements, followed by encapsulation in cell-sized containers using microfluidics. Grounded in the rationale of synthetic cell research, the approach would enable to experimentally study emergent effects at the global genome level that arise from the collective action of local DNA-structuring elements. We review the various DNA-structuring elements present in nature, from nucleoid-associated proteins and SMC complexes to phase separation and macromolecular crowders. Finally, we discuss how GenBox can contribute to several open questions on chromosome structure and dynamics.
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Affiliation(s)
- Anthony Birnie
- Department of Bionanoscience, Kavli
Institute of Nanoscience Delft, Delft University
of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Cees Dekker
- Department of Bionanoscience, Kavli
Institute of Nanoscience Delft, Delft University
of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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Karaboja X, Ren Z, Brandão HB, Paul P, Rudner DZ, Wang X. XerD unloads bacterial SMC complexes at the replication terminus. Mol Cell 2021; 81:756-766.e8. [PMID: 33472056 DOI: 10.1016/j.molcel.2020.12.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 10/11/2020] [Accepted: 12/14/2020] [Indexed: 11/24/2022]
Abstract
Bacillus subtilis structural maintenance of chromosomes (SMC) complexes are topologically loaded at centromeric sites adjacent to the replication origin by the partitioning protein ParB. These ring-shaped ATPases then translocate down the left and right chromosome arms while tethering them together. Here, we show that the site-specific recombinase XerD, which resolves chromosome dimers, is required to unload SMC tethers when they reach the terminus. We identify XerD-specific binding sites in the terminus region and show that they dictate the site of unloading in a manner that depends on XerD but not its catalytic residue, its partner protein XerC, or the recombination site dif. Finally, we provide evidence that ParB and XerD homologs perform similar functions in Staphylococcus aureus. Thus, two broadly conserved factors that act at the origin and terminus have second functions in loading and unloading SMC complexes that travel between them.
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Affiliation(s)
- Xheni Karaboja
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Zhongqing Ren
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Hugo B Brandão
- Graduate Program in Biophysics, Harvard University, Cambridge, MA 02138, USA
| | - Payel Paul
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - David Z Rudner
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA.
| | - Xindan Wang
- Department of Biology, Indiana University, Bloomington, IN 47405, USA.
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28
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Matityahu A, Onn I. Hit the brakes - a new perspective on the loop extrusion mechanism of cohesin and other SMC complexes. J Cell Sci 2021; 134:jcs247577. [PMID: 33419949 DOI: 10.1242/jcs.247577] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The three-dimensional structure of chromatin is determined by the action of protein complexes of the structural maintenance of chromosome (SMC) family. Eukaryotic cells contain three SMC complexes, cohesin, condensin, and a complex of Smc5 and Smc6. Initially, cohesin was linked to sister chromatid cohesion, the process that ensures the fidelity of chromosome segregation in mitosis. In recent years, a second function in the organization of interphase chromatin into topologically associated domains has been determined, and loop extrusion has emerged as the leading mechanism of this process. Interestingly, fundamental mechanistic differences exist between mitotic tethering and loop extrusion. As distinct molecular switches that aim to suppress loop extrusion in different biological contexts have been identified, we hypothesize here that loop extrusion is the default biochemical activity of cohesin and that its suppression shifts cohesin into a tethering mode. With this model, we aim to provide an explanation for how loop extrusion and tethering can coexist in a single cohesin complex and also apply it to the other eukaryotic SMC complexes, describing both similarities and differences between them. Finally, we present model-derived molecular predictions that can be tested experimentally, thus offering a new perspective on the mechanisms by which SMC complexes shape the higher-order structure of chromatin.
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Affiliation(s)
- Avi Matityahu
- 8 Henrietta Szold St., The Azrieli Faculty of Medicine, Bar-Ilan University, P.O. Box 1589 Safed, Israel
| | - Itay Onn
- 8 Henrietta Szold St., The Azrieli Faculty of Medicine, Bar-Ilan University, P.O. Box 1589 Safed, Israel
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Tang B, Kang P, Zhu L, Xuan L, Wang H, Zhang H, Wang X, Xu J. Simvastatin protects heart function and myocardial energy metabolism in pulmonary arterial hypertension induced right heart failure. J Bioenerg Biomembr 2021; 53:1-12. [PMID: 33394312 DOI: 10.1007/s10863-020-09867-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 12/13/2020] [Indexed: 01/10/2023]
Abstract
The favorable effect of simvastatin on pulmonary arterial hypertension (PAH) has been well defined despite the unknown etiology of PAH. However, whether simvastatin exerts similar effects on PAH induced right heart failure (RHF) remains to be determined. We aimed to investigate the function of simvastatin in PAH induced RHF. Rats in the RHF and simvastatin groups were injected intraperitoneally with monocrotaline to establish PAH-induced RHF model. The expression of miR-21-5p in rat myocardium was detected and miR-21-5p expression was inhibited using antagomiRNA. The effect of simvastatin on hemodynamic indexes, ventricular remodeling of myocardial tissues, myocardial energy metabolism, and calmodulin was explored. Dual-luciferase reporter system was used to verify the binding relationship between miR-21-5p and Smad7. In addition, the regulatory role of simvastatin in Smad7, TGFBR1 and Smad2/3 was investigated. Simvastatin treatment improved hemodynamic condition, myocardial tissue remodeling, and myocardial energy metabolism, as well as increasing calmodulin expression in rats with PAH-induced RHF. After simvastatin treatment, the expression of miR-21-5p in myocardium of rats was decreased significantly. miR-21-5p targeted Smad7 and inhibited the expression of Smad7. Compared with RHF rats, the expressions of TGFBR1 and Smad2/3 in myocardium of simvastatin-treated rats were decreased significantly. Collectively, we provided evidence that simvastatin can protect ATPase activity and maintain myocardial ATP energy reserve through the miR-21-5p/Smad/TGF-β axis, thus ameliorating PAH induced RHF.
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Affiliation(s)
- Bi Tang
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, Anhui, People's Republic of China
| | - Pinfang Kang
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, Anhui, People's Republic of China
| | - Lei Zhu
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, Anhui, People's Republic of China
| | - Ling Xuan
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, Anhui, People's Republic of China
| | - Hongju Wang
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, Anhui, People's Republic of China
| | - Heng Zhang
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, Anhui, People's Republic of China
| | - Xiaojing Wang
- Clinical and Basic Provincial Laboratory of Respiratory System Diseases of Anhui Province, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, Anhui, People's Republic of China
| | - Jiali Xu
- Department of Paediatrics, The First Affiliated Hospital of Bengbu Medical College, No. 287, Changhuai Road, Bengbu, 233004, Anhui, People's Republic of China.
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30
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Zabolotnaya E, Mela I, Henderson RM, Robinson NP. Turning the Mre11/Rad50 DNA repair complex on its head: lessons from SMC protein hinges, dynamic coiled-coil movements and DNA loop-extrusion? Biochem Soc Trans 2020; 48:2359-2376. [PMID: 33300987 PMCID: PMC7752040 DOI: 10.1042/bst20170168] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 10/19/2020] [Accepted: 10/22/2020] [Indexed: 12/12/2022]
Abstract
The bacterial SbcC/SbcD DNA repair proteins were identified over a quarter of a century ago. Following the subsequent identification of the homologous Mre11/Rad50 complex in the eukaryotes and archaea, it has become clear that this conserved chromosomal processing machinery is central to DNA repair pathways and the maintenance of genomic stability in all forms of life. A number of experimental studies have explored this intriguing genome surveillance machinery, yielding significant insights and providing conceptual advances towards our understanding of how this complex operates to mediate DNA repair. However, the inherent complexity and dynamic nature of this chromosome-manipulating machinery continue to obfuscate experimental interrogations, and details regarding the precise mechanisms that underpin the critical repair events remain unanswered. This review will summarize our current understanding of the dramatic structural changes that occur in Mre11/Rad50 complex to mediate chromosomal tethering and accomplish the associated DNA processing events. In addition, undetermined mechanistic aspects of the DNA enzymatic pathways driven by this vital yet enigmatic chromosomal surveillance and repair apparatus will be discussed. In particular, novel and putative models of DNA damage recognition will be considered and comparisons will be made between the modes of action of the Rad50 protein and other related ATPases of the overarching SMC superfamily.
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Affiliation(s)
| | - Ioanna Mela
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, U.K
| | | | - Nicholas P. Robinson
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YG, U.K
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31
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Bylino OV, Ibragimov AN, Shidlovskii YV. Evolution of Regulated Transcription. Cells 2020; 9:E1675. [PMID: 32664620 PMCID: PMC7408454 DOI: 10.3390/cells9071675] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 07/07/2020] [Accepted: 07/10/2020] [Indexed: 12/12/2022] Open
Abstract
The genomes of all organisms abound with various cis-regulatory elements, which control gene activity. Transcriptional enhancers are a key group of such elements in eukaryotes and are DNA regions that form physical contacts with gene promoters and precisely orchestrate gene expression programs. Here, we follow gradual evolution of this regulatory system and discuss its features in different organisms. In eubacteria, an enhancer-like element is often a single regulatory element, is usually proximal to the core promoter, and is occupied by one or a few activators. Activation of gene expression in archaea is accompanied by the recruitment of an activator to several enhancer-like sites in the upstream promoter region. In eukaryotes, activation of expression is accompanied by the recruitment of activators to multiple enhancers, which may be distant from the core promoter, and the activators act through coactivators. The role of the general DNA architecture in transcription control increases in evolution. As a whole, it can be seen that enhancers of multicellular eukaryotes evolved from the corresponding prototypic enhancer-like regulatory elements with the gradually increasing genome size of organisms.
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Affiliation(s)
- Oleg V. Bylino
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia; (O.V.B.); (A.N.I.)
| | - Airat N. Ibragimov
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia; (O.V.B.); (A.N.I.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia
| | - Yulii V. Shidlovskii
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia; (O.V.B.); (A.N.I.)
- I.M. Sechenov First Moscow State Medical University, 8, bldg. 2 Trubetskaya St., 119048 Moscow, Russia
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32
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Kong M, Cutts EE, Pan D, Beuron F, Kaliyappan T, Xue C, Morris EP, Musacchio A, Vannini A, Greene EC. Human Condensin I and II Drive Extensive ATP-Dependent Compaction of Nucleosome-Bound DNA. Mol Cell 2020; 79:99-114.e9. [PMID: 32445620 PMCID: PMC7335352 DOI: 10.1016/j.molcel.2020.04.026] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 02/08/2020] [Accepted: 04/22/2020] [Indexed: 12/15/2022]
Abstract
Structural maintenance of chromosomes (SMC) complexes are essential for genome organization from bacteria to humans, but their mechanisms of action remain poorly understood. Here, we characterize human SMC complexes condensin I and II and unveil the architecture of the human condensin II complex, revealing two putative DNA-entrapment sites. Using single-molecule imaging, we demonstrate that both condensin I and II exhibit ATP-dependent motor activity and promote extensive and reversible compaction of double-stranded DNA. Nucleosomes are incorporated into DNA loops during compaction without being displaced from the DNA, indicating that condensin complexes can readily act upon nucleosome-bound DNA molecules. These observations shed light on critical processes involved in genome organization in human cells.
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Affiliation(s)
- Muwen Kong
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Erin E Cutts
- Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, UK
| | - Dongqing Pan
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Fabienne Beuron
- Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, UK
| | - Thangavelu Kaliyappan
- Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, UK
| | - Chaoyou Xue
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Edward P Morris
- Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, UK
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Alessandro Vannini
- Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, UK; Fondazione Human Technopole, Structural Biology Research Centre, 20157 Milan, Italy.
| | - Eric C Greene
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, NY 10032, USA.
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33
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Chromosome Segregation in Bacillus subtilis Follows an Overall Pattern of Linear Movement and Is Highly Robust against Cell Cycle Perturbations. mSphere 2020; 5:5/3/e00255-20. [PMID: 32554717 PMCID: PMC7300352 DOI: 10.1128/msphere.00255-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
We have followed the segregation of origin regions on the Bacillus subtilis chromosome in the fastest practically achievable temporal manner, for a large fraction of the cell cycle. We show that segregation occurred in highly variable patterns but overall in an almost linear manner throughout the cell cycle. Segregation was slowed down, but not arrested, by treatment of cells that led to transient blocks in DNA replication, showing that segregation is highly robust against cell cycle perturbation. Computer simulations based on entropy-driven separation of newly synthesized DNA polymers can recapitulate sudden bursts of movement and segregation patterns compatible with the observed in vivo patterns, indicating that for Bacillus, segregation patterns may include entropic forces helping to separate chromosomes during the cell cycle. Although several proteins have been identified that facilitate chromosome segregation in bacteria, no clear analogue of the mitotic machinery in eukaryotic cells has been identified. In order to investigate if recognizable patterns of segregation exist during the cell cycle, we tracked the segregation of duplicated origin regions in Bacillus subtilis for 60 min in the fastest practically achievable resolution, achieving 10-s intervals. We found that while separation occurred in random patterns, often including backwards movement, overall, segregation of loci near the origins of replication was linear for the entire cell cycle. Thus, the process of partitioning can be best described as directed motion. Simulations with entropy-driven separation of polymers synthesized by two polymerases show sudden bursts of movement and segregation patterns compatible with the observed in vivo patterns, showing that for Bacillus, segregation patterns can be modeled based on entropic forces. To test if obstacles for replication forks lead to an alteration of the partitioning pattern, we challenged cells with chemicals inducing DNA damage or blocking of topoisomerase activity. Both treatments led to a moderate slowing down of separation, but linear segregation was retained, showing that chromosome segregation is highly robust against cell cycle perturbation. IMPORTANCE We have followed the segregation of origin regions on the Bacillus subtilis chromosome in the fastest practically achievable temporal manner, for a large fraction of the cell cycle. We show that segregation occurred in highly variable patterns but overall in an almost linear manner throughout the cell cycle. Segregation was slowed down, but not arrested, by treatment of cells that led to transient blocks in DNA replication, showing that segregation is highly robust against cell cycle perturbation. Computer simulations based on entropy-driven separation of newly synthesized DNA polymers can recapitulate sudden bursts of movement and segregation patterns compatible with the observed in vivo patterns, indicating that for Bacillus, segregation patterns may include entropic forces helping to separate chromosomes during the cell cycle.
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34
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Loop extrusion: theory meets single-molecule experiments. Curr Opin Cell Biol 2020; 64:124-138. [PMID: 32534241 DOI: 10.1016/j.ceb.2020.04.011] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/24/2020] [Accepted: 04/28/2020] [Indexed: 11/20/2022]
Abstract
Chromosomes are organized as chromatin loops that promote segregation, enhancer-promoter interactions, and other genomic functions. Loops were hypothesized to form by 'loop extrusion,' by which structural maintenance of chromosomes (SMC) complexes, such as condensin and cohesin, bind to chromatin, reel it in, and extrude it as a loop. However, such exotic motor activity had never been observed. Following an explosion of indirect evidence, recent single-molecule experiments directly imaged DNA loop extrusion by condensin and cohesin in vitro. These experiments observe rapid (kb/s) extrusion that requires ATP hydrolysis and stalls under pN forces. Surprisingly, condensin extrudes loops asymmetrically, challenging previous models. Extrusion by cohesin is symmetric but requires the protein Nipbl. We discuss how SMC complexes may perform their functions on chromatin in vivo.
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35
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Adamus M, Lelkes E, Potesil D, Ganji SR, Kolesar P, Zabrady K, Zdrahal Z, Palecek JJ. Molecular Insights into the Architecture of the Human SMC5/6 Complex. J Mol Biol 2020; 432:3820-3837. [PMID: 32389690 DOI: 10.1016/j.jmb.2020.04.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 04/16/2020] [Accepted: 04/27/2020] [Indexed: 01/03/2023]
Abstract
A family of Structural Maintenance of Chromosome (SMC) complexes is essential for key cellular processes ensuring proper cohesion, condensation and replication. They share a common SMC-kleisin architecture allowing them to embrace DNA. In SMC5/6, the NSE1 and NSE3 KITE and NSE4 kleisin subunits form a stable subcomplex that binds DNA and regulates essential processes. In addition, NSE5 and NSE6 subunits associate with the core SMC5/6 complex and recruit it to DNA repair sites. The architecture of the SMC5/6 complex is crucial for its proper functioning, and mutations within the human SMC5/6 subunits result in severe syndromes. Therefore, we aimed to analyze interactions within the human SMC5/6 complex and determine its detailed architecture. Firstly, we analyzed different parts of SMC5/6 by crosslinking and MS/MS analysis. Our data suggested domain arrangements of hNSE1-hNSE3 and orientation of hNSE4 within the hNSE1-hNSE3-hNSE4 subcomplex. The crosslinking and electron microscopic analysis of the SMC5/6 core complex showed its rod-like architecture with juxtaposed hSMC5-hSMC6 arms. Additionally, we observed fully or partially opened hSMC5-hSMC6 shapes with the hNSE1-hNSE3-hNSE4 trimer localized in the SMC head domains. To complete mapping of the human SMC5/6 complex architecture, we analyzed positions of hNSE5-hNSE6 at the hSMC5-hSMC6 arms. We showed that hNSE6 binding to hNSE5 and the coiled-coil arm of hSMC6 is mediated by a conserved FAM178 domain, which we therefore renamed CANIN (Coiled-coil SMC6 And NSE5 INteracting) domain. Interestingly, hNSE6 bound both hSMC5 and hSMC6 arms, suggesting that hNSE6 may lock the arms and regulate the dynamics of the human SMC5/6 complex.
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Affiliation(s)
- M Adamus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic
| | - E Lelkes
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic
| | - D Potesil
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - S R Ganji
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - P Kolesar
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic
| | - K Zabrady
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic
| | - Z Zdrahal
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic
| | - J J Palecek
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic.
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36
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Banigan EJ, van den Berg AA, Brandão HB, Marko JF, Mirny LA. Chromosome organization by one-sided and two-sided loop extrusion. eLife 2020; 9:e53558. [PMID: 32250245 PMCID: PMC7295573 DOI: 10.7554/elife.53558] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 04/03/2020] [Indexed: 12/19/2022] Open
Abstract
SMC complexes, such as condensin or cohesin, organize chromatin throughout the cell cycle by a process known as loop extrusion. SMC complexes reel in DNA, extruding and progressively growing DNA loops. Modeling assuming two-sided loop extrusion reproduces key features of chromatin organization across different organisms. In vitro single-molecule experiments confirmed that yeast condensins extrude loops, however, they remain anchored to their loading sites and extrude loops in a 'one-sided' manner. We therefore simulate one-sided loop extrusion to investigate whether 'one-sided' complexes can compact mitotic chromosomes, organize interphase domains, and juxtapose bacterial chromosomal arms, as can be done by 'two-sided' loop extruders. While one-sided loop extrusion cannot reproduce these phenomena, variants can recapitulate in vivo observations. We predict that SMC complexes in vivo constitute effectively two-sided motors or exhibit biased loading and propose relevant experiments. Our work suggests that loop extrusion is a viable general mechanism of chromatin organization.
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Affiliation(s)
- Edward J Banigan
- Institute for Medical Engineering & Science, Massachusetts Institute of TechnologyCambridgeUnited States
- Department of Physics, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Aafke A van den Berg
- Institute for Medical Engineering & Science, Massachusetts Institute of TechnologyCambridgeUnited States
- Department of Physics, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Hugo B Brandão
- Harvard Graduate Program in Biophysics, Harvard UniversityCambridgeUnited States
| | - John F Marko
- Departments of Molecular Biosciences and Physics & Astronomy, Northwestern UniversityEvanstonUnited States
| | - Leonid A Mirny
- Institute for Medical Engineering & Science, Massachusetts Institute of TechnologyCambridgeUnited States
- Department of Physics, Massachusetts Institute of TechnologyCambridgeUnited States
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37
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Chromosome organization by a conserved condensin-ParB system in the actinobacterium Corynebacterium glutamicum. Nat Commun 2020; 11:1485. [PMID: 32198399 PMCID: PMC7083940 DOI: 10.1038/s41467-020-15238-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 02/21/2020] [Indexed: 01/23/2023] Open
Abstract
Higher-order chromosome folding and segregation are tightly regulated in all domains of life. In bacteria, details on nucleoid organization regulatory mechanisms and function remain poorly characterized, especially in non-model species. Here, we investigate the role of DNA-partitioning protein ParB and SMC condensin complexes in the actinobacterium Corynebacterium glutamicum. Chromosome conformation capture reveals SMC-mediated long-range interactions around ten centromere-like parS sites clustered at the replication origin (oriC). At least one oriC-proximal parS site is necessary for reliable chromosome segregation. We use chromatin immunoprecipitation and photoactivated single-molecule localization microscopy to show the formation of distinct, parS-dependent ParB-nucleoprotein subclusters. We further show that SMC/ScpAB complexes, loaded via ParB at parS sites, mediate chromosomal inter-arm contacts (as previously shown in Bacillus subtilis). However, the MukBEF-like SMC complex MksBEFG does not contribute to chromosomal DNA-folding; instead, this complex is involved in plasmid maintenance and interacts with the polar oriC-tethering factor DivIVA. Our results complement current models of ParB-SMC/ScpAB crosstalk and show that some condensin complexes evolved functions that are apparently uncoupled from chromosome folding. The regulation of higher-order chromosome folding and segregation in bacteria is poorly understood. Here, Böhm et al. provide insights into the roles of DNA partitioning protein ParB and SMC condensin complexes in Corynebacterium glutamicum.
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38
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Organization of the Escherichia coli Chromosome by a MukBEF Axial Core. Mol Cell 2020; 78:250-260.e5. [PMID: 32097603 PMCID: PMC7163298 DOI: 10.1016/j.molcel.2020.02.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 12/03/2019] [Accepted: 02/03/2020] [Indexed: 01/22/2023]
Abstract
Structural maintenance of chromosomes (SMC) complexes organize chromosomes ubiquitously, thereby contributing to their faithful segregation. We demonstrate that under conditions of increased chromosome occupancy of the Escherichia coli SMC complex, MukBEF, the chromosome is organized as a series of loops around a thin (<130 nm) MukBEF axial core, whose length is ∼1,100 times shorter than the chromosomal DNA. The linear order of chromosomal loci is maintained in the axial cores, whose formation requires MukBEF ATP hydrolysis. Axial core structure in non-replicating chromosomes is predominantly linear (1 μm) but becomes circular (1.5 μm) in the absence of MatP because of its failure to displace MukBEF from the 800 kbp replication termination region (ter). Displacement of MukBEF from ter by MatP in wild-type cells directs MukBEF colocalization with the replication origin. We conclude that MukBEF individualizes and compacts the chromosome lengthwise, demonstrating a chromosome organization mechanism similar to condensin in mitotic chromosome formation. MukBEF forms a chromosome axial core dependent on ATP hydrolysis MukBEF compacts the chromosome lengthwise while avoiding links between replichores MatP determines the shape of the axial core by displacing MukBEF from ter The displacement by MatP directs MukBEF colocalization with the replication origin
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Elbatsh AMO, Kim E, Eeftens JM, Raaijmakers JA, van der Weide RH, García-Nieto A, Bravo S, Ganji M, Uit de Bos J, Teunissen H, Medema RH, de Wit E, Haering CH, Dekker C, Rowland BD. Distinct Roles for Condensin's Two ATPase Sites in Chromosome Condensation. Mol Cell 2019; 76:724-737.e5. [PMID: 31629658 PMCID: PMC6900782 DOI: 10.1016/j.molcel.2019.09.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 07/17/2019] [Accepted: 09/13/2019] [Indexed: 01/19/2023]
Abstract
Condensin is a conserved SMC complex that uses its ATPase machinery to structure genomes, but how it does so is largely unknown. We show that condensin's ATPase has a dual role in chromosome condensation. Mutation of one ATPase site impairs condensation, while mutating the second site results in hyperactive condensin that compacts DNA faster than wild-type, both in vivo and in vitro. Whereas one site drives loop formation, the second site is involved in the formation of more stable higher-order Z loop structures. Using hyperactive condensin I, we reveal that condensin II is not intrinsically needed for the shortening of mitotic chromosomes. Condensin II rather is required for a straight chromosomal axis and enables faithful chromosome segregation by counteracting the formation of ultrafine DNA bridges. SMC complexes with distinct roles for each ATPase site likely reflect a universal principle that enables these molecular machines to intricately control chromosome architecture.
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Affiliation(s)
- Ahmed M O Elbatsh
- Division of Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Eugene Kim
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Jorine M Eeftens
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Jonne A Raaijmakers
- Division of Cell Biology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Robin H van der Weide
- Division of Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Alberto García-Nieto
- Division of Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Sol Bravo
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Mahipal Ganji
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Jelmi Uit de Bos
- Division of Cell Biology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Hans Teunissen
- Division of Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - René H Medema
- Division of Cell Biology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Elzo de Wit
- Division of Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Christian H Haering
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands.
| | - Benjamin D Rowland
- Division of Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands.
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Abstract
Structural maintenance of chromosomes (SMC) complexes are key organizers of chromosome architecture in all kingdoms of life. Despite seemingly divergent functions, such as chromosome segregation, chromosome maintenance, sister chromatid cohesion, and mitotic chromosome compaction, it appears that these complexes function via highly conserved mechanisms and that they represent a novel class of DNA translocases.
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Affiliation(s)
- Stanislau Yatskevich
- Laboratory of Molecular Biology, Medical Research Council, Cambridge University, Cambridge CB2 0QH, United Kingdom
| | - James Rhodes
- Department of Biochemistry, Oxford University, Oxford OX1 3QU, United Kingdom;
| | - Kim Nasmyth
- Department of Biochemistry, Oxford University, Oxford OX1 3QU, United Kingdom;
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41
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Brandão HB, Paul P, van den Berg AA, Rudner DZ, Wang X, Mirny LA. RNA polymerases as moving barriers to condensin loop extrusion. Proc Natl Acad Sci U S A 2019; 116:20489-20499. [PMID: 31548377 PMCID: PMC6789630 DOI: 10.1073/pnas.1907009116] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To separate replicated sister chromatids during mitosis, eukaryotes and prokaryotes have structural maintenance of chromosome (SMC) condensin complexes that were recently shown to organize chromosomes by a process known as DNA loop extrusion. In rapidly dividing bacterial cells, the process of separating sister chromatids occurs concomitantly with ongoing transcription. How transcription interferes with the condensin loop-extrusion process is largely unexplored, but recent experiments have shown that sites of high transcription may directionally affect condensin loop extrusion. We quantitatively investigate different mechanisms of interaction between condensin and elongating RNA polymerases (RNAPs) and find that RNAPs are likely steric barriers that can push and interact with condensins. Supported by chromosome conformation capture and chromatin immunoprecipitation for cells after transcription inhibition and RNAP degradation, we argue that translocating condensins must bypass transcribing RNAPs within ∼1 to 2 s of an encounter at rRNA genes and within ∼10 s at protein-coding genes. Thus, while individual RNAPs have little effect on the progress of loop extrusion, long, highly transcribed operons can significantly impede the extrusion process. Our data and quantitative models further suggest that bacterial condensin loop extrusion occurs by 2 independent, uncoupled motor activities; the motors translocate on DNA in opposing directions and function together to enlarge chromosomal loops, each independently bypassing steric barriers in their path. Our study provides a quantitative link between transcription and 3D genome organization and proposes a mechanism of interactions between SMC complexes and elongating transcription machinery relevant from bacteria to higher eukaryotes.
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Affiliation(s)
- Hugo B Brandão
- Graduate Program in Biophysics, Harvard University, Cambridge, MA 02138
| | - Payel Paul
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Aafke A van den Berg
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - David Z Rudner
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115
| | - Xindan Wang
- Department of Biology, Indiana University, Bloomington, IN 47405;
| | - Leonid A Mirny
- Graduate Program in Biophysics, Harvard University, Cambridge, MA 02138;
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139
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42
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Holzmann J, Politi AZ, Nagasaka K, Hantsche-Grininger M, Walther N, Koch B, Fuchs J, Dürnberger G, Tang W, Ladurner R, Stocsits RR, Busslinger GA, Novák B, Mechtler K, Davidson IF, Ellenberg J, Peters JM. Absolute quantification of cohesin, CTCF and their regulators in human cells. eLife 2019; 8:e46269. [PMID: 31204999 PMCID: PMC6606026 DOI: 10.7554/elife.46269] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 06/13/2019] [Indexed: 12/15/2022] Open
Abstract
The organisation of mammalian genomes into loops and topologically associating domains (TADs) contributes to chromatin structure, gene expression and recombination. TADs and many loops are formed by cohesin and positioned by CTCF. In proliferating cells, cohesin also mediates sister chromatid cohesion, which is essential for chromosome segregation. Current models of chromatin folding and cohesion are based on assumptions of how many cohesin and CTCF molecules organise the genome. Here we have measured absolute copy numbers and dynamics of cohesin, CTCF, NIPBL, WAPL and sororin by mass spectrometry, fluorescence-correlation spectroscopy and fluorescence recovery after photobleaching in HeLa cells. In G1-phase, there are ~250,000 nuclear cohesin complexes, of which ~ 160,000 are chromatin-bound. Comparison with chromatin immunoprecipitation-sequencing data implies that some genomic cohesin and CTCF enrichment sites are unoccupied in single cells at any one time. We discuss the implications of these findings for how cohesin can contribute to genome organisation and cohesion.
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Affiliation(s)
- Johann Holzmann
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)Vienna Biocenter (VBC)ViennaAustria
- Gregor Mendel Institute, Austrian Academy of SciencesVienna Biocenter (VBC)ViennaAustria
| | - Antonio Z Politi
- Cell Biology and Biophysics UnitEuropean Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Kota Nagasaka
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
| | | | - Nike Walther
- Cell Biology and Biophysics UnitEuropean Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Birgit Koch
- Cell Biology and Biophysics UnitEuropean Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Johannes Fuchs
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)Vienna Biocenter (VBC)ViennaAustria
- Gregor Mendel Institute, Austrian Academy of SciencesVienna Biocenter (VBC)ViennaAustria
| | - Gerhard Dürnberger
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)Vienna Biocenter (VBC)ViennaAustria
- Gregor Mendel Institute, Austrian Academy of SciencesVienna Biocenter (VBC)ViennaAustria
| | - Wen Tang
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
| | - Rene Ladurner
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
| | - Roman R Stocsits
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
| | - Georg A Busslinger
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
| | - Béla Novák
- Department of BiochemistryUniversity of OxfordOxfordUnited Kingdom
| | - Karl Mechtler
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)Vienna Biocenter (VBC)ViennaAustria
- Gregor Mendel Institute, Austrian Academy of SciencesVienna Biocenter (VBC)ViennaAustria
| | - Iain Finley Davidson
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
| | - Jan Ellenberg
- Cell Biology and Biophysics UnitEuropean Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
- Medical University of ViennaViennaAustria
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Transient DNA Occupancy of the SMC Interarm Space in Prokaryotic Condensin. Mol Cell 2019; 75:209-223.e6. [PMID: 31201090 DOI: 10.1016/j.molcel.2019.05.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 03/17/2019] [Accepted: 04/30/2019] [Indexed: 12/13/2022]
Abstract
Multi-subunit SMC ATPases control chromosome superstructure and DNA topology, presumably by DNA translocation and loop extrusion. Chromosomal DNA is entrapped within the tripartite SMCkleisin ring. Juxtaposed SMC heads ("J heads") or engaged SMC heads ("E heads") split the SMCkleisin ring into "S" and "K" sub-compartments. Here, we map a DNA-binding interface to the S compartment of E heads SmcScpAB and show that head-DNA association is essential for efficient DNA translocation and for traversing highly transcribed genes in Bacillus subtilis. We demonstrate that in J heads, SmcScpAB chromosomal DNA resides in the K compartment but is absent from the S compartment. Our results imply that the DNA occupancy of the S compartment changes during the ATP hydrolysis cycle. We propose that DNA translocation involves DNA entry into and exit out of the S compartment, possibly by DNA transfer between compartments and DNA segment capture.
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44
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Unraveling quiescence-specific repressive chromatin domains. Curr Genet 2019; 65:1145-1151. [PMID: 31055637 DOI: 10.1007/s00294-019-00985-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 04/29/2019] [Accepted: 04/30/2019] [Indexed: 01/30/2023]
Abstract
Quiescence is a highly conserved inactive life stage in which the cell reversibly exits the cell cycle in response to external cues. Quiescence is essential for diverse processes such as the maintenance of adult stem cell stores, stress resistance, and longevity, and its misregulation has been implicated in cancer. Although the non-cycling nature of quiescent cells has made obtaining sufficient quantities of quiescent cells for study difficult, the development of a Saccharomyces cerevisiae model of quiescence has recently enabled detailed investigation into mechanisms underlying the quiescent state. Like their metazoan counterparts, quiescent budding yeast exhibit widespread transcriptional silencing and dramatic chromatin condensation. We have recently found that the structural maintenance of chromosomes (SMC) complex condensin binds throughout the quiescent budding yeast genome and induces the formation of large chromatin loop domains. In the absence of condensin, quiescent cell chromatin is decondensed and transcription is de-repressed. Here, we briefly discuss our findings in the larger context of the genome organization field.
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45
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Szabo Q, Bantignies F, Cavalli G. Principles of genome folding into topologically associating domains. SCIENCE ADVANCES 2019; 5:eaaw1668. [PMID: 30989119 PMCID: PMC6457944 DOI: 10.1126/sciadv.aaw1668] [Citation(s) in RCA: 317] [Impact Index Per Article: 63.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 02/20/2019] [Indexed: 05/12/2023]
Abstract
This review discusses the features of TADs across species, and their role in chromosome organization, genome function, and evolution.
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Affiliation(s)
- Quentin Szabo
- Institute of Human Genetics, CNRS and University of Montpellier, Montpellier, France
| | - Frédéric Bantignies
- Institute of Human Genetics, CNRS and University of Montpellier, Montpellier, France
| | - Giacomo Cavalli
- Institute of Human Genetics, CNRS and University of Montpellier, Montpellier, France
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46
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Bürmann F, Lee BG, Than T, Sinn L, O'Reilly FJ, Yatskevich S, Rappsilber J, Hu B, Nasmyth K, Löwe J. A folded conformation of MukBEF and cohesin. Nat Struct Mol Biol 2019; 26:227-236. [PMID: 30833788 PMCID: PMC6433275 DOI: 10.1038/s41594-019-0196-z] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 01/25/2019] [Indexed: 11/09/2022]
Abstract
Structural maintenance of chromosomes (SMC)-kleisin complexes organize chromosomal DNAs in all domains of life, with key roles in chromosome segregation, DNA repair and regulation of gene expression. They function through the entrapment and active translocation of DNA, but the underlying conformational changes are largely unclear. Using structural biology, mass spectrometry and cross-linking, we investigated the architecture of two evolutionarily distant SMC-kleisin complexes: MukBEF from Escherichia coli, and cohesin from Saccharomyces cerevisiae. We show that both contain a dynamic coiled-coil discontinuity, the elbow, near the middle of their arms that permits a folded conformation. Bending at the elbow brings into proximity the hinge dimerization domain and the head-kleisin module, situated at opposite ends of the arms. Our findings favour SMC activity models that include a large conformational change in the arms, such as a relative movement between DNA contact sites during DNA loading and translocation.
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Affiliation(s)
| | | | - Thane Than
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Ludwig Sinn
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Francis J O'Reilly
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Stanislau Yatskevich
- Department of Biochemistry, University of Oxford, Oxford, UK
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Juri Rappsilber
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Bin Hu
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Kim Nasmyth
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Jan Löwe
- MRC Laboratory of Molecular Biology, Cambridge, UK.
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47
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Palecek JJ. SMC5/6: Multifunctional Player in Replication. Genes (Basel) 2018; 10:genes10010007. [PMID: 30583551 PMCID: PMC6356406 DOI: 10.3390/genes10010007] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 12/13/2022] Open
Abstract
The genome replication process is challenged at many levels. Replication must proceed through different problematic sites and obstacles, some of which can pause or even reverse the replication fork (RF). In addition, replication of DNA within chromosomes must deal with their topological constraints and spatial organization. One of the most important factors organizing DNA into higher-order structures are Structural Maintenance of Chromosome (SMC) complexes. In prokaryotes, SMC complexes ensure proper chromosomal partitioning during replication. In eukaryotes, cohesin and SMC5/6 complexes assist in replication. Interestingly, the SMC5/6 complexes seem to be involved in replication in many ways. They stabilize stalled RFs, restrain RF regression, participate in the restart of collapsed RFs, and buffer topological constraints during RF progression. In this (mini) review, I present an overview of these replication-related functions of SMC5/6.
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Affiliation(s)
- Jan J Palecek
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic.
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic.
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48
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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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49
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Condensin action and compaction. Curr Genet 2018; 65:407-415. [PMID: 30361853 DOI: 10.1007/s00294-018-0899-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 10/18/2018] [Accepted: 10/20/2018] [Indexed: 12/20/2022]
Abstract
Condensin is a multi-subunit protein complex that belongs to the family of structural maintenance of chromosomes (SMC) complexes. Condensins regulate chromosome structure in a wide range of processes including chromosome segregation, gene regulation, DNA repair and recombination. Recent research defined the structural features and molecular activities of condensins, but it is unclear how these activities are connected to the multitude of phenotypes and functions attributed to condensins. In this review, we briefly discuss the different molecular mechanisms by which condensins may regulate global chromosome compaction, organization of topologically associated domains, clustering of specific loci such as tRNA genes, rDNA segregation, and gene regulation.
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50
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Nichols MH, Corces VG. A tethered-inchworm model of SMC DNA translocation. Nat Struct Mol Biol 2018; 25:906-910. [PMID: 30250225 PMCID: PMC6311135 DOI: 10.1038/s41594-018-0135-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 08/03/2018] [Indexed: 12/17/2022]
Abstract
The DNA loop extrusion model is a provocative new concept explaining the formation of chromatin loops that revolutionizes understanding of genome organization. Central to this model is the structural maintenance of chromosomes (SMC) protein family, which is now thought to function as a DNA motor. In this Perspective, we review and reinterpret the current knowledge of SMC structure and function and propose a novel mechanism for SMC motor activity.
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