1
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Boucher A, Murray J, Rao S. Cohesin mutations in acute myeloid leukemia. Leukemia 2024:10.1038/s41375-024-02406-4. [PMID: 39251741 DOI: 10.1038/s41375-024-02406-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2024] [Revised: 08/29/2024] [Accepted: 09/02/2024] [Indexed: 09/11/2024]
Abstract
The cohesin complex, encoded by SMC3, SMC1A, RAD21, and STAG2, is a critical regulator of DNA-looping and gene expression. Over a decade has passed since recurrent mutations affecting cohesin subunits were first identified in myeloid malignancies such as Acute Myeloid Leukemia (AML). Since that time there has been tremendous progress in our understanding of chromatin structure and cohesin biology, but critical questions remain because of the multiple critical functions the cohesin complex is responsible for. Recent findings have been particularly noteworthy with the identification of crosstalk between DNA-looping and chromatin domains, a deeper understanding of how cohesin establishes sister chromatid cohesion, a renewed interest in cohesin's role for DNA damage response, and work demonstrating cohesin's importance for Polycomb repression. Despite these exciting findings, the role of cohesin in normal hematopoiesis, and the precise mechanisms by which cohesin mutations promote cancer, remain poorly understood. This review discusses what is known about the role of cohesin in normal hematopoiesis, and how recent findings could shed light on the mechanisms through which cohesin mutations promote leukemic transformation. Important unanswered questions in the field, such as whether cohesin plays a role in HSC heterogeneity, and the mechanisms by which it regulates gene expression at a molecular level, will also be discussed. Particular attention will be given to the potential therapeutic vulnerabilities of leukemic cells with cohesin subunit mutations.
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Affiliation(s)
- Austin Boucher
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Josiah Murray
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Sridhar Rao
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA.
- Versiti Blood Research Institute, Milwaukee, WI, USA.
- Department of Pediatrics, Division of Hematology/Oncology/Transplantation, Medical College of Wisconsin, Milwaukee, WI, USA.
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2
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Guérin TM, Barrington C, Pobegalov G, Molodtsov MI, Uhlmann F. An extrinsic motor directs chromatin loop formation by cohesin. EMBO J 2024:10.1038/s44318-024-00202-5. [PMID: 39160275 DOI: 10.1038/s44318-024-00202-5] [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: 03/05/2024] [Revised: 07/30/2024] [Accepted: 07/31/2024] [Indexed: 08/21/2024] Open
Abstract
The ring-shaped cohesin complex topologically entraps two DNA molecules to establish sister chromatid cohesion. Cohesin also shapes the interphase chromatin landscape with wide-ranging implications for gene regulation, and cohesin is thought to achieve this by actively extruding DNA loops without topologically entrapping DNA. The 'loop extrusion' hypothesis finds motivation from in vitro observations-whether this process underlies in vivo chromatin loop formation remains untested. Here, using the budding yeast S. cerevisiae, we generate cohesin variants that have lost their ability to extrude DNA loops but retain their ability to topologically entrap DNA. Analysis of these variants suggests that in vivo chromatin loops form independently of loop extrusion. Instead, we find that transcription promotes loop formation, and acts as an extrinsic motor that expands these loops and defines their ultimate positions. Our results necessitate a re-evaluation of the loop extrusion hypothesis. We propose that cohesin, akin to sister chromatid cohesion establishment at replication forks, forms chromatin loops by DNA-DNA capture at places of transcription, thus unifying cohesin's two roles in chromosome segregation and interphase genome organisation.
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Affiliation(s)
- Thomas M Guérin
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK
- Université Paris Cité and Université Paris-Saclay, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, Fontenay-aux-Roses, France
| | - Christopher Barrington
- Bioinformatics & Biostatistics Science Technology Platform, The Francis Crick Institute, London, UK
| | - Georgii Pobegalov
- Mechanobiology and Biophysics Laboratory, The Francis Crick Institute, London, UK
- Department of Physics and Astronomy, University College London, London, UK
| | - Maxim I Molodtsov
- Mechanobiology and Biophysics Laboratory, The Francis Crick Institute, London, UK
- Department of Physics and Astronomy, University College London, London, UK
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK.
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3
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Wulfridge P, Sarma K. Intertwining roles of R-loops and G-quadruplexes in DNA repair, transcription and genome organization. Nat Cell Biol 2024; 26:1025-1036. [PMID: 38914786 DOI: 10.1038/s41556-024-01437-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 05/10/2024] [Indexed: 06/26/2024]
Abstract
R-loops are three-stranded nucleic acid structures that are abundant and widespread across the genome and that have important physiological roles in many nuclear processes. Their accumulation is observed in cancers and neurodegenerative disorders. Recent studies have implicated a function for R-loops and G-quadruplex (G4) structures, which can form on the displaced single strand of R-loops, in three-dimensional genome organization in both physiological and pathological contexts. Here we discuss the interconnected functions of DNA:RNA hybrids and G4s within R-loops, their impact on DNA repair and gene regulatory networks, and their emerging roles in genome organization during development and disease.
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Affiliation(s)
- Phillip Wulfridge
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, PA, USA
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Kavitha Sarma
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, PA, USA.
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA.
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4
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Harju J, van Teeseling MCF, Broedersz CP. Loop-extruders alter bacterial chromosome topology to direct entropic forces for segregation. Nat Commun 2024; 15:4618. [PMID: 38816445 PMCID: PMC11139863 DOI: 10.1038/s41467-024-49039-w] [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: 11/28/2023] [Accepted: 05/21/2024] [Indexed: 06/01/2024] Open
Abstract
Entropic forces have been argued to drive bacterial chromosome segregation during replication. In many bacterial species, however, specifically evolved mechanisms, such as loop-extruding SMC complexes and the ParABS origin segregation system, contribute to or are even required for chromosome segregation, suggesting that entropic forces alone may be insufficient. The interplay between and the relative contributions of these segregation mechanisms remain unclear. Here, we develop a biophysical model showing that purely entropic forces actually inhibit bacterial chromosome segregation until late replication stages. By contrast, our model reveals that loop-extruders loaded at the origins of replication, as observed in many bacterial species, alter the effective topology of the chromosome, thereby redirecting and enhancing entropic forces to enable accurate chromosome segregation during replication. We confirm our model predictions with polymer simulations: purely entropic forces do not allow for concurrent replication and segregation, whereas entropic forces steered by specifically loaded loop-extruders lead to robust, global chromosome segregation during replication. Finally, we show how loop-extruders can complement locally acting origin separation mechanisms, such as the ParABS system. Together, our results illustrate how changes in the geometry and topology of the polymer, induced by DNA-replication and loop-extrusion, impact the organization and segregation of bacterial chromosomes.
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Affiliation(s)
- Janni Harju
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Muriel C F van Teeseling
- Junior research group Prokaryotic Cell Biology, Department for Microbial Interactions, Institute of Microbiology, Friedrich-Schiller-Universität, Jena, Germany
| | - Chase P Broedersz
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
- Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilian-University Munich, Munich, Germany.
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5
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Lebreton J, Colin L, Chatre E, Bernard P. RNAP II antagonizes mitotic chromatin folding and chromosome segregation by condensin. Cell Rep 2024; 43:113901. [PMID: 38446663 DOI: 10.1016/j.celrep.2024.113901] [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: 08/27/2023] [Revised: 12/07/2023] [Accepted: 02/16/2024] [Indexed: 03/08/2024] Open
Abstract
Condensin shapes mitotic chromosomes by folding chromatin into loops, but whether it does so by DNA-loop extrusion remains speculative. Although loop-extruding cohesin is stalled by transcription, the impact of transcription on condensin, which is enriched at highly expressed genes in many species, remains unclear. Using degrons of Rpb1 or the torpedo nuclease Dhp1XRN2 to either deplete or displace RNAPII on chromatin in fission yeast metaphase cells, we show that RNAPII does not load condensin on DNA. Instead, RNAPII retains condensin in cis and hinders its ability to fold mitotic chromatin and to support chromosome segregation, consistent with the stalling of a loop extruder. Transcription termination by Dhp1 limits such a hindrance. Our results shed light on the integrated functioning of condensin, and we argue that a tight control of transcription underlies mitotic chromosome assembly by loop-extruding condensin.
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Affiliation(s)
- Jérémy Lebreton
- ENS de Lyon, University Lyon, 46 allée d'Italie, 69007 Lyon, France
| | - Léonard Colin
- CNRS Laboratory of Biology and Modelling of the Cell, UMR 5239, ENS de Lyon, 46 allée d'Italie, 69007 Lyon, France
| | - Elodie Chatre
- Lymic-Platim, University Lyon, Université Claude Bernard Lyon 1, ENS de Lyon, CNRS UAR3444, Inserm US8, SFR Biosciences, 50 Avenue Tony Garnier, 69007 Lyon, France
| | - Pascal Bernard
- ENS de Lyon, University Lyon, 46 allée d'Italie, 69007 Lyon, France; CNRS Laboratory of Biology and Modelling of the Cell, UMR 5239, ENS de Lyon, 46 allée d'Italie, 69007 Lyon, France.
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6
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Bastié N, Chapard C, Cournac A, Nejmi S, Mboumba H, Gadal O, Thierry A, Beckouët F, Koszul R. Sister chromatid cohesion halts DNA loop expansion. Mol Cell 2024; 84:1139-1148.e5. [PMID: 38452765 DOI: 10.1016/j.molcel.2024.02.004] [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: 07/26/2023] [Revised: 12/02/2023] [Accepted: 02/06/2024] [Indexed: 03/09/2024]
Abstract
Eukaryotic genomes are folded into DNA loops mediated by structural maintenance of chromosomes (SMC) complexes such as cohesin, condensin, and Smc5/6. This organization regulates different DNA-related processes along the cell cycle, such as transcription, recombination, segregation, and DNA repair. During the G2 stage, SMC-mediated DNA loops coexist with cohesin complexes involved in sister chromatid cohesion (SCC). However, the articulation between the establishment of SCC and the formation of SMC-mediated DNA loops along the chromatin remains unknown. Here, we show that SCC is indeed a barrier to cohesin-mediated DNA loop expansion along G2/M Saccharomyces cerevisiae chromosomes.
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Affiliation(s)
- Nathalie Bastié
- Molecular, Cellular, and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Christophe Chapard
- Institut Pasteur, CNRS UMR 3525, Université Paris Cité, Unité Régulation Spatiale des Génomes, 75015 Paris, France
| | - Axel Cournac
- Institut Pasteur, CNRS UMR 3525, Université Paris Cité, Unité Régulation Spatiale des Génomes, 75015 Paris, France
| | - Sanae Nejmi
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France
| | - Henri Mboumba
- Molecular, Cellular, and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Olivier Gadal
- Molecular, Cellular, and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Agnès Thierry
- Institut Pasteur, CNRS UMR 3525, Université Paris Cité, Unité Régulation Spatiale des Génomes, 75015 Paris, France
| | - Frederic Beckouët
- Molecular, Cellular, and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France.
| | - Romain Koszul
- Institut Pasteur, CNRS UMR 3525, Université Paris Cité, Unité Régulation Spatiale des Génomes, 75015 Paris, France.
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7
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Jeppsson K, Pradhan B, Sutani T, Sakata T, Umeda Igarashi M, Berta DG, Kanno T, Nakato R, Shirahige K, Kim E, Björkegren C. Loop-extruding Smc5/6 organizes transcription-induced positive DNA supercoils. Mol Cell 2024; 84:867-882.e5. [PMID: 38295804 DOI: 10.1016/j.molcel.2024.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 11/16/2023] [Accepted: 01/08/2024] [Indexed: 03/10/2024]
Abstract
The structural maintenance of chromosomes (SMC) protein complexes-cohesin, condensin, and the Smc5/6 complex (Smc5/6)-are essential for chromosome function. At the molecular level, these complexes fold DNA by loop extrusion. Accordingly, cohesin creates chromosome loops in interphase, and condensin compacts mitotic chromosomes. However, the role of Smc5/6's recently discovered DNA loop extrusion activity is unknown. Here, we uncover that Smc5/6 associates with transcription-induced positively supercoiled DNA at cohesin-dependent loop boundaries on budding yeast (Saccharomyces cerevisiae) chromosomes. Mechanistically, single-molecule imaging reveals that dimers of Smc5/6 specifically recognize the tip of positively supercoiled DNA plectonemes and efficiently initiate loop extrusion to gather the supercoiled DNA into a large plectonemic loop. Finally, Hi-C analysis shows that Smc5/6 links chromosomal regions containing transcription-induced positive supercoiling in cis. Altogether, our findings indicate that Smc5/6 controls the three-dimensional organization of chromosomes by recognizing and initiating loop extrusion on positively supercoiled DNA.
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Affiliation(s)
- Kristian Jeppsson
- Karolinska Institutet, Department of Cell and Molecular Biology, Biomedicum, Tomtebodavägen 16, 171 77 Stockholm, Sweden; Karolinska Institutet, Department of Biosciences and Nutrition, Neo, Hälsovägen 7c, 141 83 Huddinge, Sweden; Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
| | - Biswajit Pradhan
- Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Takashi Sutani
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Toyonori Sakata
- Karolinska Institutet, Department of Cell and Molecular Biology, Biomedicum, Tomtebodavägen 16, 171 77 Stockholm, Sweden; Karolinska Institutet, Department of Biosciences and Nutrition, Neo, Hälsovägen 7c, 141 83 Huddinge, Sweden; Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Miki Umeda Igarashi
- Karolinska Institutet, Department of Cell and Molecular Biology, Biomedicum, Tomtebodavägen 16, 171 77 Stockholm, Sweden; Karolinska Institutet, Department of Biosciences and Nutrition, Neo, Hälsovägen 7c, 141 83 Huddinge, Sweden
| | - Davide Giorgio Berta
- Karolinska Institutet, Department of Cell and Molecular Biology, Biomedicum, Tomtebodavägen 16, 171 77 Stockholm, Sweden
| | - Takaharu Kanno
- Karolinska Institutet, Department of Cell and Molecular Biology, Biomedicum, Tomtebodavägen 16, 171 77 Stockholm, Sweden; Karolinska Institutet, Department of Biosciences and Nutrition, Neo, Hälsovägen 7c, 141 83 Huddinge, Sweden
| | - Ryuichiro Nakato
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Katsuhiko Shirahige
- Karolinska Institutet, Department of Cell and Molecular Biology, Biomedicum, Tomtebodavägen 16, 171 77 Stockholm, Sweden; Karolinska Institutet, Department of Biosciences and Nutrition, Neo, Hälsovägen 7c, 141 83 Huddinge, Sweden; Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Eugene Kim
- Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.
| | - Camilla Björkegren
- Karolinska Institutet, Department of Cell and Molecular Biology, Biomedicum, Tomtebodavägen 16, 171 77 Stockholm, Sweden; Karolinska Institutet, Department of Biosciences and Nutrition, Neo, Hälsovägen 7c, 141 83 Huddinge, Sweden.
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8
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Allyn BM, Hayer KE, Oyeniran C, Nganga V, Lee K, Mishra B, Sacan A, Oltz EM, Bassing CH. Locus folding mechanisms determine modes of antigen receptor gene assembly. J Exp Med 2024; 221:e20230985. [PMID: 38189780 PMCID: PMC10772921 DOI: 10.1084/jem.20230985] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 10/12/2023] [Accepted: 12/15/2023] [Indexed: 01/09/2024] Open
Abstract
The dynamic folding of genomes regulates numerous biological processes, including antigen receptor (AgR) gene assembly. We show that, unlike other AgR loci, homotypic chromatin interactions and bidirectional chromosome looping both contribute to structuring Tcrb for efficient long-range V(D)J recombination. Inactivation of the CTCF binding element (CBE) or promoter at the most 5'Vβ segment (Trbv1) impaired loop extrusion originating locally and extending to DβJβ CBEs at the opposite end of Tcrb. Promoter or CBE mutation nearly eliminated Trbv1 contacts and decreased RAG endonuclease-mediated Trbv1 recombination. Importantly, Trbv1 rearrangement can proceed independent of substrate orientation, ruling out scanning by DβJβ-bound RAG as the sole mechanism of Vβ recombination, distinguishing it from Igh. Our data indicate that CBE-dependent generation of loops cooperates with promoter-mediated activation of chromatin to juxtapose Vβ and DβJβ segments for recombination through diffusion-based synapsis. Thus, the mechanisms that fold a genomic region can influence molecular processes occurring in that space, which may include recombination, repair, and transcriptional programming.
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Affiliation(s)
- Brittney M. Allyn
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Katharina E. Hayer
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Biomedical Engineering Doctoral Degree Program, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics, Children’s Hospital of Philadelphia, Perelman School of Medicine, Philadelphia, PA, USA
| | - Clement Oyeniran
- Department of Microbial Infection and Immunity, Ohio State College of Medicine, Ohio State University, Columbus, OH, USA
| | - Vincent Nganga
- Department of Microbial Infection and Immunity, Ohio State College of Medicine, Ohio State University, Columbus, OH, USA
| | - Kyutae Lee
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Bikash Mishra
- Department of Microbial Infection and Immunity, Ohio State College of Medicine, Ohio State University, Columbus, OH, USA
| | - Ahmet Sacan
- Biomedical Engineering Doctoral Degree Program, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA
| | - Eugene M. Oltz
- Department of Microbial Infection and Immunity, Ohio State College of Medicine, Ohio State University, Columbus, OH, USA
| | - Craig H. Bassing
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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9
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González-Acosta D, Lopes M. DNA replication and replication stress response in the context of nuclear architecture. Chromosoma 2024; 133:57-75. [PMID: 38055079 PMCID: PMC10904558 DOI: 10.1007/s00412-023-00813-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 12/07/2023]
Abstract
The DNA replication process needs to be coordinated with other DNA metabolism transactions and must eventually extend to the full genome, regardless of chromatin status, gene expression, secondary structures and DNA lesions. Completeness and accuracy of DNA replication are crucial to maintain genome integrity, limiting transformation in normal cells and offering targeting opportunities for proliferating cancer cells. DNA replication is thus tightly coordinated with chromatin dynamics and 3D genome architecture, and we are only beginning to understand the underlying molecular mechanisms. While much has recently been discovered on how DNA replication initiation is organised and modulated in different genomic regions and nuclear territories-the so-called "DNA replication program"-we know much less on how the elongation of ongoing replication forks and particularly the response to replication obstacles is affected by the local nuclear organisation. Also, it is still elusive how specific components of nuclear architecture participate in the replication stress response. Here, we review known mechanisms and factors orchestrating replication initiation, and replication fork progression upon stress, focusing on recent evidence linking genome organisation and nuclear architecture with the cellular responses to replication interference, and highlighting open questions and future challenges to explore this exciting new avenue of research.
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Affiliation(s)
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland.
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10
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Hoareau M, Gerges E, Crémazy FGE. Shedding Light on Bacterial Chromosome Structure: Exploring the Significance of 3C-Based Approaches. Methods Mol Biol 2024; 2819:3-26. [PMID: 39028499 DOI: 10.1007/978-1-0716-3930-6_1] [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] [Indexed: 07/20/2024]
Abstract
The complex architecture of DNA within living organisms is essential for maintaining the genetic information that dictates their functions and characteristics. Among the many complexities of genetic material organization, the folding and arrangement of DNA into chromosomes play a critical role in regulating gene expression, replication, and other essential cellular processes. Bacteria, despite their apparently simple cellular structure, exhibit a remarkable level of chromosomal organization that influences their adaptability and survival in diverse environments. Understanding the three-dimensional arrangement of bacterial chromosomes has long been a challenge due to technical limitations, but the development of Chromosome Conformation Capture (3C) methods revolutionized our ability to explore the hierarchical structure and the dynamics of bacterial genomes. Here, we review the major advances in the field of bacterial chromosome structure using 3C technology over the past decade.
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Affiliation(s)
- Marion Hoareau
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, Montigny-Le-Bretonneux, France
| | - Elias Gerges
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, Montigny-Le-Bretonneux, France
| | - Frédéric G E Crémazy
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, Montigny-Le-Bretonneux, France.
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11
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Lyu X, Rowley MJ, Kulik MJ, Dalton S, Corces VG. Regulation of CTCF loop formation during pancreatic cell differentiation. Nat Commun 2023; 14:6314. [PMID: 37813869 PMCID: PMC10562423 DOI: 10.1038/s41467-023-41964-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 09/22/2023] [Indexed: 10/11/2023] Open
Abstract
Transcription reprogramming during cell differentiation involves targeting enhancers to genes responsible for establishment of cell fates. To understand the contribution of CTCF-mediated chromatin organization to cell lineage commitment, we analyzed 3D chromatin architecture during the differentiation of human embryonic stem cells into pancreatic islet organoids. We find that CTCF loops are formed and disassembled at different stages of the differentiation process by either recruitment of CTCF to new anchor sites or use of pre-existing sites not previously involved in loop formation. Recruitment of CTCF to new sites in the genome involves demethylation of H3K9me3 to H3K9me2, demethylation of DNA, recruitment of pioneer factors, and positioning of nucleosomes flanking the new CTCF sites. Existing CTCF sites not involved in loop formation become functional loop anchors via the establishment of new cohesin loading sites containing NIPBL and YY1 at sites between the new anchors. In both cases, formation of new CTCF loops leads to strengthening of enhancer promoter interactions and increased transcription of genes adjacent to loop anchors. These results suggest an important role for CTCF and cohesin in controlling gene expression during cell differentiation.
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Affiliation(s)
- Xiaowen Lyu
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA.
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Reproductive Health Research, School of Medicine, Faculty of Medicine and Life Sciences, Xiamen University, 361102, Xiamen, China.
- Fujian Provincial Key Laboratory of Organ and Tissue Regeneration, School of Medicine, Faculty of Medicine and Life Sciences, Xiamen University, 361102, Xiamen, China.
| | - M Jordan Rowley
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Michael J Kulik
- Department of Biochemistry and Molecular Biology, The University of Georgia, Athens, GA, 30602, USA
- Center for Molecular Medicine, The University of Georgia, Athens, GA, 30602, USA
| | - Stephen Dalton
- Department of Biochemistry and Molecular Biology, The University of Georgia, Athens, GA, 30602, USA
- Center for Molecular Medicine, The University of Georgia, Athens, GA, 30602, USA
- School of Biomedical Sciences, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Victor G Corces
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA.
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12
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Abstract
Many cellular processes require large-scale rearrangements of chromatin structure. Structural maintenance of chromosomes (SMC) protein complexes are molecular machines that can provide structure to chromatin. These complexes can connect DNA elements in cis, walk along DNA, build and processively enlarge DNA loops and connect DNA molecules in trans to hold together the sister chromatids. These DNA-shaping abilities place SMC complexes at the heart of many DNA-based processes, including chromosome segregation in mitosis, transcription control and DNA replication, repair and recombination. In this Review, we discuss the latest insights into how SMC complexes such as cohesin, condensin and the SMC5-SMC6 complex shape DNA to direct these fundamental chromosomal processes. We also consider how SMC complexes, by building chromatin loops, can counteract the natural tendency of alike chromatin regions to cluster. SMC complexes thus control nuclear organization by participating in a molecular tug of war that determines the architecture of our genome.
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Affiliation(s)
- Claire Hoencamp
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Benjamin D Rowland
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
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13
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Zhang H, Shi Z, Banigan EJ, Kim Y, Yu H, Bai XC, Finkelstein IJ. CTCF and R-loops are boundaries of cohesin-mediated DNA looping. Mol Cell 2023; 83:2856-2871.e8. [PMID: 37536339 DOI: 10.1016/j.molcel.2023.07.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 05/10/2023] [Accepted: 07/06/2023] [Indexed: 08/05/2023]
Abstract
Cohesin and CCCTC-binding factor (CTCF) are key regulatory proteins of three-dimensional (3D) genome organization. Cohesin extrudes DNA loops that are anchored by CTCF in a polar orientation. Here, we present direct evidence that CTCF binding polarity controls cohesin-mediated DNA looping. Using single-molecule imaging, we demonstrate that a critical N-terminal motif of CTCF blocks cohesin translocation and DNA looping. The cryo-EM structure of the cohesin-CTCF complex reveals that this CTCF motif ahead of zinc fingers can only reach its binding site on the STAG1 cohesin subunit when the N terminus of CTCF faces cohesin. Remarkably, a C-terminally oriented CTCF accelerates DNA compaction by cohesin. DNA-bound Cas9 and Cas12a ribonucleoproteins are also polar cohesin barriers, indicating that stalling may be intrinsic to cohesin itself. Finally, we show that RNA-DNA hybrids (R-loops) block cohesin-mediated DNA compaction in vitro and are enriched with cohesin subunits in vivo, likely forming TAD boundaries.
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Affiliation(s)
- Hongshan Zhang
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Zhubing Shi
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China; School of Life Sciences, Westlake University, Hangzhou 310024, Zhejiang, China; Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Edward J Banigan
- Department of Physics, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yoori Kim
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Republic of Korea
| | - Hongtao Yu
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China; School of Life Sciences, Westlake University, Hangzhou 310024, Zhejiang, China; Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Xiao-Chen Bai
- Department of Biophysics, Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Ilya J Finkelstein
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA.
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14
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Bond ML, Davis ES, Quiroga IY, Dey A, Kiran M, Love MI, Won H, Phanstiel DH. Chromatin loop dynamics during cellular differentiation are associated with changes to both anchor and internal regulatory features. Genome Res 2023; 33:1258-1268. [PMID: 37699658 PMCID: PMC10547260 DOI: 10.1101/gr.277397.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 07/07/2023] [Indexed: 09/14/2023]
Abstract
Three-dimensional (3D) chromatin structure has been shown to play a role in regulating gene transcription during biological transitions. Although our understanding of loop formation and maintenance is rapidly improving, much less is known about the mechanisms driving changes in looping and the impact of differential looping on gene transcription. One limitation has been a lack of well-powered differential looping data sets. To address this, we conducted a deeply sequenced Hi-C time course of megakaryocyte development comprising four biological replicates and 6 billion reads per time point. Statistical analysis revealed 1503 differential loops. Gained loop anchors were enriched for AP-1 occupancy and were characterized by large increases in histone H3K27ac (over 11-fold) but relatively small increases in CTCF and RAD21 binding (1.26- and 1.23-fold, respectively). Linear modeling revealed that changes in histone H3K27ac, chromatin accessibility, and JUN binding were better correlated with changes in looping than RAD21 and almost as well correlated as CTCF. Changes to epigenetic features between-rather than at-boundaries were highly predictive of changes in looping. Together these data suggest that although CTCF and RAD21 may be the core machinery dictating where loops form, other features (both at the anchors and within the loop boundaries) may play a larger role than previously anticipated in determining the relative loop strength across cell types and conditions.
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Affiliation(s)
- Marielle L Bond
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Eric S Davis
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Ivana Y Quiroga
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Anubha Dey
- Department of Systems and Computational Biology, University of Hyderabad, Hyderabad 500046, Telangana, India
| | - Manjari Kiran
- Department of Systems and Computational Biology, University of Hyderabad, Hyderabad 500046, Telangana, India
| | - Michael I Love
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514, USA
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Hyejung Won
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514, USA;
- Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Douglas H Phanstiel
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA;
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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15
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Shin H, Kim Y. Regulation of loop extrusion on the interphase genome. Crit Rev Biochem Mol Biol 2023; 58:1-18. [PMID: 36921088 DOI: 10.1080/10409238.2023.2182273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
In the human cell nucleus, dynamically organized chromatin is the substrate for gene regulation, DNA replication, and repair. A central mechanism of DNA loop formation is an ATPase motor cohesin-mediated loop extrusion. The cohesin complexes load and unload onto the chromosome under the control of other regulators that physically interact and affect motor activity. Regulation of the dynamic loading cycle of cohesin influences not only the chromatin structure but also genome-associated human disorders and aging. This review focuses on the recently spotlighted genome organizing factors and the mechanism by which their dynamic interactions shape the genome architecture in interphase.
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Affiliation(s)
- Hyogyung Shin
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Yoori Kim
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea.,New Biology Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
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16
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Banigan EJ, Tang W, van den Berg AA, Stocsits RR, Wutz G, Brandão HB, Busslinger GA, Peters JM, Mirny LA. Transcription shapes 3D chromatin organization by interacting with loop extrusion. Proc Natl Acad Sci U S A 2023; 120:e2210480120. [PMID: 36897969 PMCID: PMC10089175 DOI: 10.1073/pnas.2210480120] [Citation(s) in RCA: 52] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 12/03/2022] [Indexed: 03/12/2023] Open
Abstract
Cohesin folds mammalian interphase chromosomes by extruding the chromatin fiber into numerous loops. "Loop extrusion" can be impeded by chromatin-bound factors, such as CTCF, which generates characteristic and functional chromatin organization patterns. It has been proposed that transcription relocalizes or interferes with cohesin and that active promoters are cohesin loading sites. However, the effects of transcription on cohesin have not been reconciled with observations of active extrusion by cohesin. To determine how transcription modulates extrusion, we studied mouse cells in which we could alter cohesin abundance, dynamics, and localization by genetic "knockouts" of the cohesin regulators CTCF and Wapl. Through Hi-C experiments, we discovered intricate, cohesin-dependent contact patterns near active genes. Chromatin organization around active genes exhibited hallmarks of interactions between transcribing RNA polymerases (RNAPs) and extruding cohesins. These observations could be reproduced by polymer simulations in which RNAPs were moving barriers to extrusion that obstructed, slowed, and pushed cohesins. The simulations predicted that preferential loading of cohesin at promoters is inconsistent with our experimental data. Additional ChIP-seq experiments showed that the putative cohesin loader Nipbl is not predominantly enriched at promoters. Therefore, we propose that cohesin is not preferentially loaded at promoters and that the barrier function of RNAP accounts for cohesin accumulation at active promoters. Altogether, we find that RNAP is an extrusion barrier that is not stationary, but rather, translocates and relocalizes cohesin. Loop extrusion and transcription might interact to dynamically generate and maintain gene interactions with regulatory elements and shape functional genomic organization.
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Affiliation(s)
- Edward J. Banigan
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Wen Tang
- Research Institute of Molecular Pathology, Vienna BioCenter1030Vienna, Austria
| | - Aafke A. van den Berg
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Roman R. Stocsits
- Research Institute of Molecular Pathology, Vienna BioCenter1030Vienna, Austria
| | - Gordana Wutz
- Research Institute of Molecular Pathology, Vienna BioCenter1030Vienna, Austria
| | - Hugo B. Brandão
- Graduate Program in Biophysics, Harvard University, Cambridge, MA02138
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA02139
- The Broad Institute of MIT and Harvard, Cambridge, MA02142
| | - Georg A. Busslinger
- Research Institute of Molecular Pathology, Vienna BioCenter1030Vienna, Austria
- Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna1090, Austria
- Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna1090, Austria
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology, Vienna BioCenter1030Vienna, Austria
| | - Leonid A. Mirny
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA02139
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17
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A de novo transcription-dependent TAD boundary underpins critical multiway interactions during antibody class switch recombination. Mol Cell 2023; 83:681-697.e7. [PMID: 36736317 DOI: 10.1016/j.molcel.2023.01.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 11/04/2022] [Accepted: 01/09/2023] [Indexed: 02/05/2023]
Abstract
Interactions between transcription and cohesin-mediated loop extrusion can influence 3D chromatin architecture. However, their relevance in biology is unclear. Here, we report a direct role for such interactions in the mechanism of antibody class switch recombination (CSR) at the murine immunoglobulin heavy chain locus (Igh). Using Tri-C to measure higher-order multiway interactions on single alleles, we find that the juxtaposition (synapsis) of transcriptionally active donor and acceptor Igh switch (S) sequences, an essential step in CSR, occurs via the interaction of loop extrusion complexes with a de novo topologically associating domain (TAD) boundary formed via transcriptional activity across S regions. Surprisingly, synapsis occurs predominantly in proximity to the 3' CTCF-binding element (3'CBE) rather than the Igh super-enhancer, suggesting a two-step mechanism whereby transcription of S regions is not topologically coupled to synapsis, as has been previously proposed. Altogether, these insights advance our understanding of how 3D chromatin architecture regulates CSR.
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