1
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Chauhan AS, Jhujh SS, Stewart GS. E3 ligases: a ubiquitous link between DNA repair, DNA replication and human disease. Biochem J 2024; 481:923-944. [PMID: 38985307 DOI: 10.1042/bcj20240124] [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: 03/20/2024] [Revised: 05/20/2024] [Accepted: 05/24/2024] [Indexed: 07/11/2024]
Abstract
Maintenance of genome stability is of paramount importance for the survival of an organism. However, genomic integrity is constantly being challenged by various endogenous and exogenous processes that damage DNA. Therefore, cells are heavily reliant on DNA repair pathways that have evolved to deal with every type of genotoxic insult that threatens to compromise genome stability. Notably, inherited mutations in genes encoding proteins involved in these protective pathways trigger the onset of disease that is driven by chromosome instability e.g. neurodevelopmental abnormalities, neurodegeneration, premature ageing, immunodeficiency and cancer development. The ability of cells to regulate the recruitment of specific DNA repair proteins to sites of DNA damage is extremely complex but is primarily mediated by protein post-translational modifications (PTMs). Ubiquitylation is one such PTM, which controls genome stability by regulating protein localisation, protein turnover, protein-protein interactions and intra-cellular signalling. Over the past two decades, numerous ubiquitin (Ub) E3 ligases have been identified to play a crucial role not only in the initiation of DNA replication and DNA damage repair but also in the efficient termination of these processes. In this review, we discuss our current understanding of how different Ub E3 ligases (RNF168, TRAIP, HUWE1, TRIP12, FANCL, BRCA1, RFWD3) function to regulate DNA repair and replication and the pathological consequences arising from inheriting deleterious mutations that compromise the Ub-dependent DNA damage response.
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Affiliation(s)
- Anoop S Chauhan
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, U.K
| | - Satpal S Jhujh
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, U.K
| | - Grant S Stewart
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, U.K
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2
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Sun Q, Sui Y, Li S, Zhou R, Fu Z, Luo J, Zhao W. RNF8-mediated multi-ubiquitination of MCM7: Linking disassembly of the CMG helicase with DNA damage response in human cells. Life Sci 2024:122912. [PMID: 39004272 DOI: 10.1016/j.lfs.2024.122912] [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: 04/13/2024] [Revised: 06/26/2024] [Accepted: 07/10/2024] [Indexed: 07/16/2024]
Abstract
DNA damage causes genomic instability. To maintain genome integrity, cells have evolved DNA damage response, which is involved in replication fork disassembly and DNA replication termination. However, the mechanism underlying the regulation of replication fork disassembly and its connection with DNA damage repair remain elusive. The CMG-MCM7 subunit ubiquitination functions on the eukaryotic replication fork disassembly at replication termination. Until now, only ubiquitin ligases CUL2LRR1 have been reported catalyzing MCM7 ubiquitination in human cells. This study discovered that in human cells, the ubiquitin ligase RNF8 catalyzes K63-linked multi-ubiquitination of MCM7 at K145 both in vivo and in vitro. The multi-ubiquitination of MCM7 is dynamically regulated during the cell cycle, primarily presenting on chromatin during the late S phase. Additionally, MCM7 polyubiquitylation is promoted by RNF168 and BRCA1 during DNA replication termination. Upon DNA damage, the RNF8-mediated polyubiquitination of MCM7 decreased significantly during the late S phase. This study highlights the novel role of RNF8-catalyzed polyubiquitination of MCM7 in the regulation of replication fork disassembly in human cells and linking it to DNA damage response.
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Affiliation(s)
- Qianqian Sun
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing 10005, China
| | - Yaqi Sui
- School of Life Sciences, Chongqing University; Chongqing 401331, China
| | - Shirui Li
- School of Life Sciences, Chongqing University; Chongqing 401331, China
| | - Rui Zhou
- School of Life Sciences, Chongqing University; Chongqing 401331, China
| | - Zhisong Fu
- School of Life Sciences, Chongqing University; Chongqing 401331, China
| | - Jing Luo
- School of Life Sciences, Chongqing University; Chongqing 401331, China
| | - Wenhui Zhao
- School of Life Sciences, Chongqing University; Chongqing 401331, China.
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3
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Krishnamoorthy V, Foglizzo M, Dilley RL, Wu A, Datta A, Dutta P, Campbell LJ, Degtjarik O, Musgrove LJ, Calabrese AN, Zeqiraj E, Greenberg RA. The SPATA5-SPATA5L1 ATPase complex directs replisome proteostasis to ensure genome integrity. Cell 2024; 187:2250-2268.e31. [PMID: 38554706 PMCID: PMC11055677 DOI: 10.1016/j.cell.2024.03.002] [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: 02/02/2023] [Revised: 12/27/2023] [Accepted: 03/02/2024] [Indexed: 04/02/2024]
Abstract
Ubiquitin-dependent unfolding of the CMG helicase by VCP/p97 is required to terminate DNA replication. Other replisome components are not processed in the same fashion, suggesting that additional mechanisms underlie replication protein turnover. Here, we identify replisome factor interactions with a protein complex composed of AAA+ ATPases SPATA5-SPATA5L1 together with heterodimeric partners C1orf109-CINP (55LCC). An integrative structural biology approach revealed a molecular architecture of SPATA5-SPATA5L1 N-terminal domains interacting with C1orf109-CINP to form a funnel-like structure above a cylindrically shaped ATPase motor. Deficiency in the 55LCC complex elicited ubiquitin-independent proteotoxicity, replication stress, and severe chromosome instability. 55LCC showed ATPase activity that was specifically enhanced by replication fork DNA and was coupled to cysteine protease-dependent cleavage of replisome substrates in response to replication fork damage. These findings define 55LCC-mediated proteostasis as critical for replication fork progression and genome stability and provide a rationale for pathogenic variants seen in associated human neurodevelopmental disorders.
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Affiliation(s)
- Vidhya Krishnamoorthy
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Martina Foglizzo
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Robert L Dilley
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA.
| | - Angela Wu
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Arindam Datta
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Parul Dutta
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Lisa J Campbell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Oksana Degtjarik
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Laura J Musgrove
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Antonio N Calabrese
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Elton Zeqiraj
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
| | - Roger A Greenberg
- Department of Cancer Biology, Penn Center for Genome Integrity, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6160, USA.
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4
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Foster BM, Wang Z, Schmidt CK. DoUBLing up: ubiquitin and ubiquitin-like proteases in genome stability. Biochem J 2024; 481:515-545. [PMID: 38572758 PMCID: PMC11088880 DOI: 10.1042/bcj20230284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 03/05/2024] [Accepted: 03/18/2024] [Indexed: 04/05/2024]
Abstract
Maintaining stability of the genome requires dedicated DNA repair and signalling processes that are essential for the faithful duplication and propagation of chromosomes. These DNA damage response (DDR) mechanisms counteract the potentially mutagenic impact of daily genotoxic stresses from both exogenous and endogenous sources. Inherent to these DNA repair pathways is the activity of protein factors that instigate repair processes in response to DNA lesions. The regulation, coordination, and orchestration of these DDR factors is carried out, in a large part, by post-translational modifications, such as phosphorylation, ubiquitylation, and modification with ubiquitin-like proteins (UBLs). The importance of ubiquitylation and UBLylation with SUMO in DNA repair is well established, with the modified targets and downstream signalling consequences relatively well characterised. However, the role of dedicated erasers for ubiquitin and UBLs, known as deubiquitylases (DUBs) and ubiquitin-like proteases (ULPs) respectively, in genome stability is less well established, particularly for emerging UBLs such as ISG15 and UFM1. In this review, we provide an overview of the known regulatory roles and mechanisms of DUBs and ULPs involved in genome stability pathways. Expanding our understanding of the molecular agents and mechanisms underlying the removal of ubiquitin and UBL modifications will be fundamental for progressing our knowledge of the DDR and likely provide new therapeutic avenues for relevant human diseases, such as cancer.
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Affiliation(s)
- Benjamin M. Foster
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, U.K
| | - Zijuan Wang
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, U.K
| | - Christine K. Schmidt
- Manchester Cancer Research Centre (MCRC), Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, 555 Wilmslow Road, Manchester M20 4GJ, U.K
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5
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Jones RM, Reynolds-Winczura A, Gambus A. A Decade of Discovery-Eukaryotic Replisome Disassembly at Replication Termination. BIOLOGY 2024; 13:233. [PMID: 38666845 PMCID: PMC11048390 DOI: 10.3390/biology13040233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 03/23/2024] [Accepted: 03/25/2024] [Indexed: 04/28/2024]
Abstract
The eukaryotic replicative helicase (CMG complex) is assembled during DNA replication initiation in a highly regulated manner, which is described in depth by other manuscripts in this Issue. During DNA replication, the replicative helicase moves through the chromatin, unwinding DNA and facilitating nascent DNA synthesis by polymerases. Once the duplication of a replicon is complete, the CMG helicase and the remaining components of the replisome need to be removed from the chromatin. Research carried out over the last ten years has produced a breakthrough in our understanding, revealing that replication termination, and more specifically replisome disassembly, is indeed a highly regulated process. This review brings together our current understanding of these processes and highlights elements of the mechanism that are conserved or have undergone divergence throughout evolution. Finally, we discuss events beyond the classic termination of DNA replication in S-phase and go over the known mechanisms of replicative helicase removal from chromatin in these particular situations.
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Affiliation(s)
- Rebecca M. Jones
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham B15 2TT, UK; (R.M.J.); (A.R.-W.)
- School of Biosciences, Aston University, Birmingham B4 7ET, UK
| | - Alicja Reynolds-Winczura
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham B15 2TT, UK; (R.M.J.); (A.R.-W.)
| | - Agnieszka Gambus
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham B15 2TT, UK; (R.M.J.); (A.R.-W.)
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6
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Price NE, Gates KS. Novel Processes Associated with the Repair of Interstrand Cross-Links Derived from Abasic Sites in Duplex DNA: Roles for the Base Excision Repair Glycosylase NEIL3 and the SRAP Protein HMCES. Chem Res Toxicol 2024; 37:199-207. [PMID: 38198604 DOI: 10.1021/acs.chemrestox.3c00345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Recent studies have defined a novel pathway for the repair of interstrand cross-links derived from the reaction of an adenine residue with an apurinic/apyrimidinic (AP) site on the opposing strand of DNA (dA-AP ICL). Stalling of a replication fork at the dA-AP ICL triggers TRAIP-dependent ubiquitylation of the CMG helicase that recruits the base excision repair glycosylase NEIL3 to the lesion. NEIL3 unhooks the dA-AP ICL to regenerate the native adenine residue on one strand and an AP site on the other strand. Covalent capture of the abasic site by the SRAP protein HMCES protects against genomic instability that would result from cleavage of the abasic site in the context of single-stranded DNA at the replication fork. After repair synthesis moves the HMCES-AP adduct into the context of double-stranded DNA, the DNA-protein cross-link is resolved by a nonproteolytic mechanism involving dissociation of thiazolidine attachment. The AP site in duplex DNA is then repaired by the base excision repair pathway.
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Affiliation(s)
- Nathan E Price
- Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States
| | - Kent S Gates
- Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States
- Department of Biochemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States
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7
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Spegg V, Altmeyer M. Genome maintenance meets mechanobiology. Chromosoma 2024; 133:15-36. [PMID: 37581649 PMCID: PMC10904543 DOI: 10.1007/s00412-023-00807-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/20/2023] [Accepted: 07/26/2023] [Indexed: 08/16/2023]
Abstract
Genome stability is key for healthy cells in healthy organisms, and deregulated maintenance of genome integrity is a hallmark of aging and of age-associated diseases including cancer and neurodegeneration. To maintain a stable genome, genome surveillance and repair pathways are closely intertwined with cell cycle regulation and with DNA transactions that occur during transcription and DNA replication. Coordination of these processes across different time and length scales involves dynamic changes of chromatin topology, clustering of fragile genomic regions and repair factors into nuclear repair centers, mobilization of the nuclear cytoskeleton, and activation of cell cycle checkpoints. Here, we provide a general overview of cell cycle regulation and of the processes involved in genome duplication in human cells, followed by an introduction to replication stress and to the cellular responses elicited by perturbed DNA synthesis. We discuss fragile genomic regions that experience high levels of replication stress, with a particular focus on telomere fragility caused by replication stress at the ends of linear chromosomes. Using alternative lengthening of telomeres (ALT) in cancer cells and ALT-associated PML bodies (APBs) as examples of replication stress-associated clustered DNA damage, we discuss compartmentalization of DNA repair reactions and the role of protein properties implicated in phase separation. Finally, we highlight emerging connections between DNA repair and mechanobiology and discuss how biomolecular condensates, components of the nuclear cytoskeleton, and interfaces between membrane-bound organelles and membraneless macromolecular condensates may cooperate to coordinate genome maintenance in space and time.
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Affiliation(s)
- Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland.
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8
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Evrin C, Alvarez V, Ainsworth J, Fujisawa R, Alabert C, Labib KPM. DONSON is required for CMG helicase assembly in the mammalian cell cycle. EMBO Rep 2023; 24:e57677. [PMID: 37781960 PMCID: PMC10626419 DOI: 10.15252/embr.202357677] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 09/15/2023] [Accepted: 09/19/2023] [Indexed: 10/03/2023] Open
Abstract
DONSON is one of 13 genes mutated in a form of primordial microcephalic dwarfism known as Meier-Gorlin syndrome. The other 12 encode components of the CDC45-MCM-GINS helicase, around which the eukaryotic replisome forms, or are factors required for helicase assembly during DNA replication initiation. A role for DONSON in CDC45-MCM-GINS assembly was unanticipated, since DNA replication initiation can be reconstituted in vitro with purified proteins from budding yeast, which lacks DONSON. Using mouse embryonic stem cells as a model for the mammalian helicase, we show that DONSON binds directly but transiently to CDC45-MCM-GINS during S-phase and is essential for chromosome duplication. Rapid depletion of DONSON leads to the disappearance of the CDC45-MCM-GINS helicase from S-phase cells and our data indicate that DONSON is dispensable for loading of the MCM2-7 helicase core onto chromatin during G1-phase, but instead is essential for CDC45-MCM-GINS assembly during S-phase. These data identify DONSON as a missing link in our understanding of mammalian chromosome duplication and provide a molecular explanation for why mutations in human DONSON are associated with Meier-Gorlin syndrome.
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Affiliation(s)
- Cecile Evrin
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
| | - Vanesa Alvarez
- Division of Molecular, Cell & Developmental Biology, School of Life SciencesUniversity of DundeeDundeeUK
| | - Johanna Ainsworth
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
| | - Ryo Fujisawa
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
| | - Constance Alabert
- Division of Molecular, Cell & Developmental Biology, School of Life SciencesUniversity of DundeeDundeeUK
| | - Karim PM Labib
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
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9
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Scaramuzza S, Jones RM, Sadurni MM, Reynolds-Winczura A, Poovathumkadavil D, Farrell A, Natsume T, Rojas P, Cuesta CF, Kanemaki MT, Saponaro M, Gambus A. TRAIP resolves DNA replication-transcription conflicts during the S-phase of unperturbed cells. Nat Commun 2023; 14:5071. [PMID: 37604812 PMCID: PMC10442450 DOI: 10.1038/s41467-023-40695-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 08/08/2023] [Indexed: 08/23/2023] Open
Abstract
Cell division is the basis for the propagation of life and requires accurate duplication of all genetic information. DNA damage created during replication (replication stress) is a major cause of cancer, premature aging and a spectrum of other human disorders. Over the years, TRAIP E3 ubiquitin ligase has been shown to play a role in various cellular processes that govern genome integrity and faultless segregation. TRAIP is essential for cell viability, and mutations in TRAIP ubiquitin ligase activity lead to primordial dwarfism in patients. Here, we have determined the mechanism of inhibition of cell proliferation in TRAIP-depleted cells. We have taken advantage of the auxin induced degron system to rapidly degrade TRAIP within cells and to dissect the importance of various functions of TRAIP in different stages of the cell cycle. We conclude that upon rapid TRAIP degradation, specifically in S-phase, cells cease to proliferate, arrest in G2 stage of the cell cycle and undergo senescence. Our findings reveal that TRAIP works in S-phase to prevent DNA damage at transcription start sites, caused by replication-transcription conflicts.
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Affiliation(s)
- Shaun Scaramuzza
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, UK
- Cancer Research UK - Manchester Institute, Manchester Cancer Research Centre, Manchester, UK
| | - Rebecca M Jones
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, UK
| | - Martina Muste Sadurni
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, UK
| | - Alicja Reynolds-Winczura
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, UK
| | - Divyasree Poovathumkadavil
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, UK
| | - Abigail Farrell
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, UK
| | - Toyoaki Natsume
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems, Mishima, Shizuoka, Japan
- Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka, Japan
- Research Center for Genome & Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Patricia Rojas
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, UK
| | - Cyntia Fernandez Cuesta
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, UK
| | - Masato T Kanemaki
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems, Mishima, Shizuoka, Japan
- Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka, Japan
| | - Marco Saponaro
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, UK
| | - Agnieszka Gambus
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, UK.
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10
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Song HY, Shen R, Mahasin H, Guo YN, Wang DG. DNA replication: Mechanisms and therapeutic interventions for diseases. MedComm (Beijing) 2023; 4:e210. [PMID: 36776764 PMCID: PMC9899494 DOI: 10.1002/mco2.210] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 01/08/2023] [Accepted: 01/09/2023] [Indexed: 02/09/2023] Open
Abstract
Accurate and integral cellular DNA replication is modulated by multiple replication-associated proteins, which is fundamental to preserve genome stability. Furthermore, replication proteins cooperate with multiple DNA damage factors to deal with replication stress through mechanisms beyond their role in replication. Cancer cells with chronic replication stress exhibit aberrant DNA replication and DNA damage response, providing an exploitable therapeutic target in tumors. Numerous evidence has indicated that posttranslational modifications (PTMs) of replication proteins present distinct functions in DNA replication and respond to replication stress. In addition, abundant replication proteins are involved in tumorigenesis and development, which act as diagnostic and prognostic biomarkers in some tumors, implying these proteins act as therapeutic targets in clinical. Replication-target cancer therapy emerges as the times require. In this context, we outline the current investigation of the DNA replication mechanism, and simultaneously enumerate the aberrant expression of replication proteins as hallmark for various diseases, revealing their therapeutic potential for target therapy. Meanwhile, we also discuss current observations that the novel PTM of replication proteins in response to replication stress, which seems to be a promising strategy to eliminate diseases.
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Affiliation(s)
- Hao-Yun Song
- School of Basic Medical Sciences Lanzhou University Lanzhou Gansu China
| | - Rong Shen
- School of Basic Medical Sciences Lanzhou University Lanzhou Gansu China
| | - Hamid Mahasin
- School of Basic Medical Sciences Lanzhou University Lanzhou Gansu China
| | - Ya-Nan Guo
- School of Basic Medical Sciences Lanzhou University Lanzhou Gansu China
| | - De-Gui Wang
- School of Basic Medical Sciences Lanzhou University Lanzhou Gansu China
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11
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Barnes RP, Thosar SA, Opresko PL. Telomere Fragility and MiDAS: Managing the Gaps at the End of the Road. Genes (Basel) 2023; 14:genes14020348. [PMID: 36833275 PMCID: PMC9956152 DOI: 10.3390/genes14020348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/20/2023] [Accepted: 01/24/2023] [Indexed: 01/31/2023] Open
Abstract
Telomeres present inherent difficulties to the DNA replication machinery due to their repetitive sequence content, formation of non-B DNA secondary structures, and the presence of the nucleo-protein t-loop. Especially in cancer cells, telomeres are hot spots for replication stress, which can result in a visible phenotype in metaphase cells termed "telomere fragility". A mechanism cells employ to mitigate replication stress, including at telomeres, is DNA synthesis in mitosis (MiDAS). While these phenomena are both observed in mitotic cells, the relationship between them is poorly understood; however, a common link is DNA replication stress. In this review, we will summarize what is known to regulate telomere fragility and telomere MiDAS, paying special attention to the proteins which play a role in these telomere phenotypes.
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Affiliation(s)
- Ryan P. Barnes
- Department of Environmental and Occupational Health, School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
- UPMC Hillman Cancer Center, University of Pittsburgh, 5117 Centre Avenue, Pittsburgh, PA 15213, USA
- Correspondence: (R.P.B.); (P.L.O.)
| | - Sanjana A. Thosar
- Department of Environmental and Occupational Health, School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
- UPMC Hillman Cancer Center, University of Pittsburgh, 5117 Centre Avenue, Pittsburgh, PA 15213, USA
| | - Patricia L. Opresko
- Department of Environmental and Occupational Health, School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
- UPMC Hillman Cancer Center, University of Pittsburgh, 5117 Centre Avenue, Pittsburgh, PA 15213, USA
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Correspondence: (R.P.B.); (P.L.O.)
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12
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Funk L, Su KC, Ly J, Feldman D, Singh A, Moodie B, Blainey PC, Cheeseman IM. The phenotypic landscape of essential human genes. Cell 2022; 185:4634-4653.e22. [PMID: 36347254 PMCID: PMC10482496 DOI: 10.1016/j.cell.2022.10.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 09/01/2022] [Accepted: 10/14/2022] [Indexed: 11/09/2022]
Abstract
Understanding the basis for cellular growth, proliferation, and function requires determining the roles of essential genes in diverse cellular processes, including visualizing their contributions to cellular organization and morphology. Here, we combined pooled CRISPR-Cas9-based functional screening of 5,072 fitness-conferring genes in human HeLa cells with microscopy-based imaging of DNA, the DNA damage response, actin, and microtubules. Analysis of >31 million individual cells identified measurable phenotypes for >90% of gene knockouts, implicating gene targets in specific cellular processes. Clustering of phenotypic similarities based on hundreds of quantitative parameters further revealed co-functional genes across diverse cellular activities, providing predictions for gene functions and associations. By conducting pooled live-cell screening of ∼450,000 cell division events for 239 genes, we additionally identified diverse genes with functional contributions to chromosome segregation. Our work establishes a resource detailing the consequences of disrupting core cellular processes that represents the functional landscape of essential human genes.
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Affiliation(s)
- Luke Funk
- Broad Institute of MIT and Harvard, 415 Main St., Cambridge, MA 02142, USA; Harvard-MIT Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Kuan-Chung Su
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Jimmy Ly
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - David Feldman
- Broad Institute of MIT and Harvard, 415 Main St., Cambridge, MA 02142, USA
| | - Avtar Singh
- Broad Institute of MIT and Harvard, 415 Main St., Cambridge, MA 02142, USA
| | - Brittania Moodie
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Paul C Blainey
- Broad Institute of MIT and Harvard, 415 Main St., Cambridge, MA 02142, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA; Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA 02142, USA.
| | - Iain M Cheeseman
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
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13
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Vipat S, Gupta D, Jonchhe S, Anderspuk H, Rothenberg E, Moiseeva TN. The non-catalytic role of DNA polymerase epsilon in replication initiation in human cells. Nat Commun 2022; 13:7099. [PMID: 36402816 PMCID: PMC9675812 DOI: 10.1038/s41467-022-34911-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 11/10/2022] [Indexed: 11/21/2022] Open
Abstract
DNA polymerase epsilon (PolE) in an enzyme essential for DNA replication. Deficiencies and mutations in PolE cause severe developmental abnormalities and cancers. Paradoxically, the catalytic domain of yeast PolE catalytic subunit is dispensable for survival, and its non-catalytic essential function is linked with replicative helicase (CMG) assembly. Less is known about the PolE role in replication initiation in human cells. Here we use an auxin-inducible degron system to study the effect of POLE1 depletion on replication initiation in U2OS cells. POLE1-depleted cells were able to assemble CMG helicase and initiate DNA synthesis that failed shortly after. Expression of POLE1 non-catalytic domain rescued this defect resulting in slow, but continuous DNA synthesis. We propose a model where in human U2OS cells POLE1/POLE2 are dispensable for CMG assembly, but essential during later steps of replication initiation. Our study provides some insights into the role of PolE in replication initiation in human cells.
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Affiliation(s)
- Sameera Vipat
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, 12618, Estonia
| | - Dipika Gupta
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA
| | - Sagun Jonchhe
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA
| | - Hele Anderspuk
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, 12618, Estonia
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA
| | - Tatiana N Moiseeva
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, 12618, Estonia.
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14
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Kochenova OV, Mukkavalli S, Raman M, Walter JC. Cooperative assembly of p97 complexes involved in replication termination. Nat Commun 2022; 13:6591. [PMID: 36329031 PMCID: PMC9633789 DOI: 10.1038/s41467-022-34210-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 10/18/2022] [Indexed: 11/06/2022] Open
Abstract
The p97 ATPase extracts polyubiquitylated proteins from diverse cellular structures in preparation for destruction by the proteasome. p97 functions with Ufd1-Npl4 and a variety of UBA-UBX co-factors, but how p97 complexes assemble on ubiquitylated substrates is unclear. To address this, we investigated how p97 disassembles the CMG helicase after it is ubiquitylated during replication termination. We show that p97Ufd1-Npl4 recruitment to CMG requires the UBA-UBX protein Ubxn7, and conversely, stable Ubxn7 binding to CMG requires p97Ufd1-Npl4. This cooperative assembly involves interactions between Ubxn7, p97, Ufd1-Npl4, and ubiquitin. Another p97 co-factor, Faf1, partially compensates for the loss of Ubxn7. Surprisingly, p97Ufd1-Npl4-Ubxn7 and p97Ufd1-Npl4-Faf1 also assemble cooperatively on unanchored ubiquitin chains. We propose that cooperative and substrate-independent recognition of ubiquitin chains allows p97 to recognize an unlimited number of polyubiquitylated proteins while avoiding the formation of partial, inactive complexes.
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Affiliation(s)
- Olga V Kochenova
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA, 02115, USA
- Howard Hughes Medical Institute, Boston, MA, USA
| | - Sirisha Mukkavalli
- Department of Developmental Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Malavika Raman
- Department of Developmental Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Johannes C Walter
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA, 02115, USA.
- Howard Hughes Medical Institute, Boston, MA, USA.
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15
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Fujisawa R, Polo Rivera C, Labib KPM. Multiple UBX proteins reduce the ubiquitin threshold of the mammalian p97-UFD1-NPL4 unfoldase. eLife 2022; 11:e76763. [PMID: 35920641 PMCID: PMC9377798 DOI: 10.7554/elife.76763] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 08/02/2022] [Indexed: 11/17/2022] Open
Abstract
The p97/Cdc48 ATPase and its ubiquitin receptors Ufd1-Npl4 are essential to unfold ubiquitylated proteins in many areas of eukaryotic cell biology. In yeast, Cdc48-Ufd1-Npl4 is controlled by a quality control mechanism, whereby substrates must be conjugated to at least five ubiquitins. Here, we show that mammalian p97-UFD1-NPL4 is governed by a complex interplay between additional p97 cofactors and the number of conjugated ubiquitins. Using reconstituted assays for the disassembly of ubiquitylated CMG (Cdc45-MCM-GINS) helicase by human p97-UFD1-NPL4, we show that the unfoldase has a high ubiquitin threshold for substrate unfolding, which can be reduced by the UBX proteins UBXN7, FAF1, or FAF2. Our data indicate that the UBX proteins function by binding to p97-UFD1-NPL4 and stabilising productive interactions between UFD1-NPL4 and K48-linked chains of at least five ubiquitins. Stimulation by UBXN7 is dependent upon known ubiquitin-binding motifs, whereas FAF1 and FAF2 use a previously uncharacterised coiled-coil domain to reduce the ubiquitin threshold of p97-UFD1-NPL4. We show that deleting the Ubnx7 and Faf1 genes impairs CMG disassembly during S-phase and mitosis and sensitises cells to reduced ubiquitin ligase activity. These findings indicate that multiple UBX proteins are important for the efficient unfolding of ubiquitylated proteins by p97-UFD1-NPL4 in mammalian cells.
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Affiliation(s)
- Ryo Fujisawa
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | - Cristian Polo Rivera
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | - Karim PM Labib
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of DundeeDundeeUnited Kingdom
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16
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O'Neill RS, Rusan NM. Traip controls mushroom body size by suppressing mitotic defects. Development 2022; 149:dev199987. [PMID: 35297981 PMCID: PMC8995085 DOI: 10.1242/dev.199987] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 02/28/2022] [Indexed: 05/12/2024]
Abstract
Microcephaly is a failure to develop proper brain size and neuron number. Mutations in diverse genes are linked to microcephaly, including several with DNA damage repair (DDR) functions; however, it is not well understood how these DDR gene mutations limit brain size. One such gene is TRAIP, which has multiple functions in DDR. We characterized the Drosophila TRAIP homolog nopo, hereafter traip, and found that traip mutants (traip-) have a brain-specific defect in the mushroom body (MB). traip- MBs were smaller and contained fewer neurons, but no neurodegeneration, consistent with human primary microcephaly. Reduced neuron numbers in traip- were explained by premature loss of MB neuroblasts (MB-NBs), in part via caspase-dependent cell death. Many traip- MB-NBs had prominent chromosome bridges in anaphase, along with polyploidy, aneuploidy or micronuclei. Traip localization during mitosis is sufficient for MB development, suggesting that Traip can repair chromosome bridges during mitosis if necessary. Our results suggest that proper brain size is ensured by the recently described role for TRAIP in unloading stalled replication forks in mitosis, which suppresses DNA bridges and premature neural stem cell loss to promote proper neuron number.
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Affiliation(s)
- Ryan S. O'Neill
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nasser M. Rusan
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
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17
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Jenkyn-Bedford M, Jones ML, Baris Y, Labib KPM, Cannone G, Yeeles JTP, Deegan TD. A conserved mechanism for regulating replisome disassembly in eukaryotes. Nature 2021; 600:743-747. [PMID: 34700328 PMCID: PMC8695382 DOI: 10.1038/s41586-021-04145-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/14/2021] [Indexed: 11/28/2022]
Abstract
Replisome disassembly is the final step of eukaryotic DNA replication and is triggered by ubiquitylation of the CDC45-MCM-GINS (CMG) replicative helicase1-3. Despite being driven by evolutionarily diverse E3 ubiquitin ligases in different eukaryotes (SCFDia2 in budding yeast1, CUL2LRR1 in metazoa4-7), replisome disassembly is governed by a common regulatory principle, in which ubiquitylation of CMG is suppressed before replication termination, to prevent replication fork collapse. Recent evidence suggests that this suppression is mediated by replication fork DNA8-10. However, it is unknown how SCFDia2 and CUL2LRR1 discriminate terminated from elongating replisomes, to selectively ubiquitylate CMG only after termination. Here we used cryo-electron microscopy to solve high-resolution structures of budding yeast and human replisome-E3 ligase assemblies. Our structures show that the leucine-rich repeat domains of Dia2 and LRR1 are structurally distinct, but bind to a common site on CMG, including the MCM3 and MCM5 zinc-finger domains. The LRR-MCM interaction is essential for replisome disassembly and, crucially, is occluded by the excluded DNA strand at replication forks, establishing the structural basis for the suppression of CMG ubiquitylation before termination. Our results elucidate a conserved mechanism for the regulation of replisome disassembly in eukaryotes, and reveal a previously unanticipated role for DNA in preserving replisome integrity.
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Affiliation(s)
| | | | | | - Karim P M Labib
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, UK
| | | | | | - Tom D Deegan
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, UK.
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK.
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18
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Coordinating DNA Replication and Mitosis through Ubiquitin/SUMO and CDK1. Int J Mol Sci 2021; 22:ijms22168796. [PMID: 34445496 PMCID: PMC8395760 DOI: 10.3390/ijms22168796] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/11/2021] [Accepted: 08/12/2021] [Indexed: 12/30/2022] Open
Abstract
Post-translational modification of the DNA replication machinery by ubiquitin and SUMO plays key roles in the faithful duplication of the genetic information. Among other functions, ubiquitination and SUMOylation serve as signals for the extraction of factors from chromatin by the AAA ATPase VCP. In addition to the regulation of DNA replication initiation and elongation, we now know that ubiquitination mediates the disassembly of the replisome after DNA replication termination, a process that is essential to preserve genomic stability. Here, we review the recent evidence showing how active DNA replication restricts replisome ubiquitination to prevent the premature disassembly of the DNA replication machinery. Ubiquitination also mediates the removal of the replisome to allow DNA repair. Further, we discuss the interplay between ubiquitin-mediated replisome disassembly and the activation of CDK1 that is required to set up the transition from the S phase to mitosis. We propose the existence of a ubiquitin–CDK1 relay, where the disassembly of terminated replisomes increases CDK1 activity that, in turn, favors the ubiquitination and disassembly of more replisomes. This model has important implications for the mechanism of action of cancer therapies that induce the untimely activation of CDK1, thereby triggering premature replisome disassembly and DNA damage.
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19
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Le TT, Ainsworth J, Polo Rivera C, Macartney T, Labib KP. Reconstitution of human CMG helicase ubiquitylation by CUL2LRR1 and multiple E2 enzymes. Biochem J 2021; 478:2825-2842. [PMID: 34195792 PMCID: PMC8331092 DOI: 10.1042/bcj20210315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 11/17/2022]
Abstract
Cullin ubiquitin ligases drive replisome disassembly during DNA replication termination. In worm, frog and mouse cells, CUL2LRR1 is required to ubiquitylate the MCM7 subunit of the CMG helicase. Here, we show that cullin ligases also drive CMG-MCM7 ubiquitylation in human cells, thereby making the helicase into a substrate for the p97 unfoldase. Using purified human proteins, including a panel of E2 ubiquitin-conjugating enzymes, we have reconstituted CMG helicase ubiquitylation, dependent upon neddylated CUL2LRR1. The reaction is highly specific to CMG-MCM7 and requires the LRR1 substrate targeting subunit, since replacement of LRR1 with the alternative CUL2 adaptor VHL switches ubiquitylation from CMG-MCM7 to HIF1. CUL2LRR1 firstly drives monoubiquitylation of CMG-MCM7 by the UBE2D class of E2 enzymes. Subsequently, CUL2LRR1 activates UBE2R1/R2 or UBE2G1/G2 to extend a single K48-linked ubiquitin chain on CMG-MCM7. Thereby, CUL2LRR1 converts CMG into a substrate for p97, which disassembles the ubiquitylated helicase during DNA replication termination.
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Affiliation(s)
- Thanh Thi Le
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Johanna Ainsworth
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Cristian Polo Rivera
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Thomas Macartney
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Karim P.M. Labib
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
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20
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Xia Y. The Fate of Two Unstoppable Trains After Arriving Destination: Replisome Disassembly During DNA Replication Termination. Front Cell Dev Biol 2021; 9:658003. [PMID: 34368118 PMCID: PMC8335557 DOI: 10.3389/fcell.2021.658003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 06/14/2021] [Indexed: 12/30/2022] Open
Abstract
In eukaryotes, the perfect duplication of the chromosomes is executed by a dynamic molecular machine called the replisome. As a key step to finishing DNA replication, replisome disassembly is triggered by ubiquitylation of the MCM7 subunit of the helicase complex CMG. Afterwards, the CDC48/p97 "unfoldase" is recruited to the ubiquitylated helicase to unfold MCM7 and disassemble the replisome. Here we summarise recently discovered mechanisms of replisome disassembly that are likely to be broadly conserved in eukaryotes. We also discuss two crucial questions that remain to be explored further in the future. Firstly, how is CMG ubiquitylation repressed by the replication fork throughout elongation? Secondly, what is the biological significance of replisome disassembly and what are the consequences of failing to ubiquitylate and disassemble the CMG helicase?
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Affiliation(s)
- Yisui Xia
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom
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21
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Fan Y, Köberlin MS, Ratnayeke N, Liu C, Deshpande M, Gerhardt J, Meyer T. LRR1-mediated replisome disassembly promotes DNA replication by recycling replisome components. J Cell Biol 2021; 220:212186. [PMID: 34037657 PMCID: PMC8160578 DOI: 10.1083/jcb.202009147] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 03/30/2021] [Accepted: 05/04/2021] [Indexed: 11/22/2022] Open
Abstract
After two converging DNA replication forks meet, active replisomes are disassembled and unloaded from chromatin. A key process in replisome disassembly is the unloading of CMG helicases (CDC45–MCM–GINS), which is initiated in Caenorhabditis elegans and Xenopus laevis by the E3 ubiquitin ligase CRL2LRR1. Here, we show that human cells lacking LRR1 fail to unload CMG helicases and accumulate increasing amounts of chromatin-bound replisome components as cells progress through S phase. Markedly, we demonstrate that the failure to disassemble replisomes reduces the rate of DNA replication increasingly throughout S phase by sequestering rate-limiting replisome components on chromatin and blocking their recycling. Continued binding of CMG helicases to chromatin during G2 phase blocks mitosis by activating an ATR-mediated G2/M checkpoint. Finally, we provide evidence that LRR1 is an essential gene for human cell division, suggesting that CRL2LRR1 enzyme activity is required for the proliferation of cancer cells and is thus a potential target for cancer therapy.
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Affiliation(s)
- Yilin Fan
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA.,Department of Cell and Developmental Biology, Weill Cornell Medicine, New York, NY
| | - Marielle S Köberlin
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA
| | - Nalin Ratnayeke
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA.,Department of Cell and Developmental Biology, Weill Cornell Medicine, New York, NY
| | - Chad Liu
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA
| | - Madhura Deshpande
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY
| | - Jeannine Gerhardt
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY.,Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, NY
| | - Tobias Meyer
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA.,Department of Cell and Developmental Biology, Weill Cornell Medicine, New York, NY
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22
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Villa F, Fujisawa R, Ainsworth J, Nishimura K, Lie‐A‐Ling M, Lacaud G, Labib KPM. CUL2 LRR1 , TRAIP and p97 control CMG helicase disassembly in the mammalian cell cycle. EMBO Rep 2021; 22:e52164. [PMID: 33590678 PMCID: PMC7926238 DOI: 10.15252/embr.202052164] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 12/16/2020] [Accepted: 01/07/2021] [Indexed: 11/26/2022] Open
Abstract
The eukaryotic replisome is disassembled in each cell cycle, dependent upon ubiquitylation of the CMG helicase. Studies of Saccharomyces cerevisiae, Caenorhabditis elegans and Xenopus laevis have revealed surprising evolutionary diversity in the ubiquitin ligases that control CMG ubiquitylation, but regulated disassembly of the mammalian replisome has yet to be explored. Here, we describe a model system for studying the ubiquitylation and chromatin extraction of the mammalian CMG replisome, based on mouse embryonic stem cells. We show that the ubiquitin ligase CUL2LRR1 is required for ubiquitylation of the CMG-MCM7 subunit during S-phase, leading to disassembly by the p97 ATPase. Moreover, a second pathway of CMG disassembly is activated during mitosis, dependent upon the TRAIP ubiquitin ligase that is mutated in primordial dwarfism and mis-regulated in various cancers. These findings indicate that replisome disassembly in diverse metazoa is regulated by a conserved pair of ubiquitin ligases, distinct from those present in other eukaryotes.
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Affiliation(s)
- Fabrizio Villa
- The MRC Protein Phosphorylation and Ubiquitylation UnitSchool of Life SciencesUniversity of DundeeDundeeUK
| | - Ryo Fujisawa
- The MRC Protein Phosphorylation and Ubiquitylation UnitSchool of Life SciencesUniversity of DundeeDundeeUK
| | - Johanna Ainsworth
- The MRC Protein Phosphorylation and Ubiquitylation UnitSchool of Life SciencesUniversity of DundeeDundeeUK
| | - Kohei Nishimura
- The MRC Protein Phosphorylation and Ubiquitylation UnitSchool of Life SciencesUniversity of DundeeDundeeUK
- Division of Biological ScienceGraduate School of ScienceNagoya UniversityNagoyaJapan
| | - Michael Lie‐A‐Ling
- Cancer Research U.K. Manchester InstituteThe University of ManchesterAlderley ParkUK
| | - Georges Lacaud
- Cancer Research U.K. Manchester InstituteThe University of ManchesterAlderley ParkUK
| | - Karim PM Labib
- The MRC Protein Phosphorylation and Ubiquitylation UnitSchool of Life SciencesUniversity of DundeeDundeeUK
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