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Wojtaszek JL, Williams RS. From the TOP: Formation, recognition and resolution of topoisomerase DNA protein crosslinks. DNA Repair (Amst) 2024; 142:103751. [PMID: 39180935 PMCID: PMC11404304 DOI: 10.1016/j.dnarep.2024.103751] [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: 04/22/2024] [Revised: 08/07/2024] [Accepted: 08/12/2024] [Indexed: 08/27/2024]
Abstract
Since the report of "DNA untwisting" activity in 1972, ∼50 years of research has revealed seven topoisomerases in humans (TOP1, TOP1mt, TOP2α, TOP2β, TOP3α, TOP3β and Spo11). These conserved regulators of DNA topology catalyze controlled breakage to the DNA backbone to relieve the torsional stress that accumulates during essential DNA transactions including DNA replication, transcription, and DNA repair. Each topoisomerase-catalyzed reaction involves the formation of a topoisomerase cleavage complex (TOPcc), a covalent protein-DNA reaction intermediate formed between the DNA phosphodiester backbone and a topoisomerase catalytic tyrosine residue. A variety of perturbations to topoisomerase reaction cycles can trigger failure of the enzyme to re-ligate the broken DNA strand(s), thereby generating topoisomerase DNA-protein crosslinks (TOP-DPC). TOP-DPCs pose unique threats to genomic integrity. These complex lesions are comprised of structurally diverse protein components covalently linked to genomic DNA, which are bulky DNA adducts that can directly impact progression of the transcription and DNA replication apparatus. A variety of genome maintenance pathways have evolved to recognize and resolve TOP-DPCs. Eukaryotic cells harbor tyrosyl DNA phosphodiesterases (TDPs) that directly reverse 3'-phosphotyrosyl (TDP1) and 5'-phoshotyrosyl (TDP2) protein-DNA linkages. The broad specificity Mre11-Rad50-Nbs1 and APE2 nucleases are also critical for mitigating topoisomerase-generated DNA damage. These DNA-protein crosslink metabolizing enzymes are further enabled by proteolytic degradation, with the proteasome, Spartan, GCNA, Ddi2, and FAM111A proteases implicated thus far. Strategies to target, unfold, and degrade the protein component of TOP-DPCs have evolved as well. Here we survey mechanisms for addressing Topoisomerase 1 (TOP1) and Topoisomerase 2 (TOP2) DPCs, highlighting systems for which molecular structure information has illuminated function of these critical DNA damage response pathways.
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Affiliation(s)
- Jessica L Wojtaszek
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, United States
| | - R Scott Williams
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, United States.
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2
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Palermo V, Malacaria E, Semproni M, Camerini S, Casella M, Perdichizzi B, Valenzisi P, Sanchez M, Marini F, Pellicioli A, Franchitto A, Pichierri P. Switch-like phosphorylation of WRN integrates end-resection with RAD51 metabolism at collapsed replication forks. Nucleic Acids Res 2024:gkae807. [PMID: 39315694 DOI: 10.1093/nar/gkae807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/25/2024] [Accepted: 09/03/2024] [Indexed: 09/25/2024] Open
Abstract
Replication-dependent DNA double-strand breaks are harmful lesions preferentially repaired by homologous recombination (HR), a process that requires processing of DNA ends to allow RAD51-mediated strand invasion. End resection and subsequent repair are two intertwined processes, but the mechanism underlying their execution is still poorly appreciated. The WRN helicase is one of the crucial factors for end resection and is instrumental in selecting the proper repair pathway. Here, we reveal that ordered phosphorylation of WRN by the CDK1, ATM and ATR kinases defines a complex regulatory layer essential for correct long-range end resection, connecting it to repair by HR. We establish that long-range end resection requires an ATM-dependent phosphorylation of WRN at Ser1058 and that phosphorylation at Ser1141, together with dephosphorylation at the CDK1 site Ser1133, is needed for the proper metabolism of RAD51 foci and RAD51-dependent repair. Collectively, our findings suggest that regulation of WRN by multiple kinases functions as a molecular switch to allow timely execution of end resection and repair at replication-dependent DNA double-strand breaks.
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Affiliation(s)
- Valentina Palermo
- Department of Environment and Health, Mechanisms, Biomarkers and Models Section, Genome Stability Group, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Eva Malacaria
- Department of Environment and Health, Mechanisms, Biomarkers and Models Section, Genome Stability Group, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Maurizio Semproni
- Department of Environment and Health, Mechanisms, Biomarkers and Models Section, Genome Stability Group, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Serena Camerini
- FAST, Core Facilities Service, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Marialuisa Casella
- FAST, Core Facilities Service, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Benedetta Perdichizzi
- Department of Environment and Health, Mechanisms, Biomarkers and Models Section, Genome Stability Group, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Pasquale Valenzisi
- Department of Environment and Health, Mechanisms, Biomarkers and Models Section, Genome Stability Group, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Massimo Sanchez
- FAST, Core Facilities Service, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Federica Marini
- Department of Biosciences, Genomic Instability and Human Pathologies Section, Università degli Studi di Milano, Via Giovanni Celoria 26, 20133 Milan, Italy
| | - Achille Pellicioli
- Department of Biosciences, Genomic Instability and Human Pathologies Section, Università degli Studi di Milano, Via Giovanni Celoria 26, 20133 Milan, Italy
| | - Annapaola Franchitto
- Department of Environment and Health, Mechanisms, Biomarkers and Models Section, Genome Stability Group, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Pietro Pichierri
- Department of Environment and Health, Mechanisms, Biomarkers and Models Section, Genome Stability Group, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
- Istituto Nazionale di Biostrutture e Biosistemi, Viale delle Medaglie d'Oro 305, 00134 Rome, Italy
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3
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Přibylová A, Fischer L. How to use CRISPR/Cas9 in plants: from target site selection to DNA repair. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:5325-5343. [PMID: 38648173 PMCID: PMC11389839 DOI: 10.1093/jxb/erae147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 04/21/2024] [Indexed: 04/25/2024]
Abstract
A tool for precise, target-specific, efficient, and affordable genome editing is a dream for many researchers, from those who conduct basic research to those who use it for applied research. Since 2012, we have tool that almost fulfils such requirements; it is based on clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) systems. However, even CRISPR/Cas has limitations and obstacles that might surprise its users. In this review, we focus on the most frequently used variant, CRISPR/Cas9 from Streptococcus pyogenes, and highlight key factors affecting its mutagenesis outcomes: (i) factors affecting the CRISPR/Cas9 activity, such as the effect of the target sequence, chromatin state, or Cas9 variant, and how long it remains in place after cleavage; and (ii) factors affecting the follow-up DNA repair mechanisms including mostly the cell type and cell cycle phase, but also, for example, the type of DNA ends produced by Cas9 cleavage (blunt/staggered). Moreover, we note some differences between using CRISPR/Cas9 in plants, yeasts, and animals, as knowledge from individual kingdoms is not fully transferable. Awareness of these factors can increase the likelihood of achieving the expected results of plant genome editing, for which we provide detailed guidelines.
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Affiliation(s)
- Adéla Přibylová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 12800, Prague 2, Czech Republic
| | - Lukáš Fischer
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 12800, Prague 2, Czech Republic
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4
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Park JM, Forsburg SL. Analysis of transcriptional response in haploid and diploid Schizosaccharomyces pombe under genotoxic stress. G3 (BETHESDA, MD.) 2024; 14:jkae177. [PMID: 39120426 PMCID: PMC11373635 DOI: 10.1093/g3journal/jkae177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Accepted: 07/15/2024] [Indexed: 08/10/2024]
Abstract
Whole genome duplications are implicated in genome instability and tumorigenesis. Human and yeast polyploids exhibit increased replication stress and chromosomal instability, both hallmarks of cancer. In this study, we investigate the transcriptional response of Schizosaccharomyces pombe to increased ploidy generally, and in response to treatment with the genotoxin methyl methanesulfonate (MMS). We find that treatment of MMS induces upregulation of genes involved in general response to genotoxins, in addition to cell cycle regulatory genes. Downregulated genes are enriched in transport and sexual reproductive pathways. We find that the diploid response to MMS is muted compared to the haploid response, although the enriched pathways remain largely the same. Overall, our data suggests that the global S. pombe transcriptome doubles in response to increased ploidy but undergoes modest transcriptional changes in both unperturbed and genotoxic stress conditions.
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Affiliation(s)
- Joshua M Park
- Section of Molecular & Computational Biology, University of Southern California, 1050 Childs Way, RRI 108, Los Angeles, CA 90089, USA
| | - Susan L Forsburg
- Section of Molecular & Computational Biology, University of Southern California, 1050 Childs Way, RRI 108, Los Angeles, CA 90089, USA
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5
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Bedir M, Outwin E, Colnaghi R, Bassett L, Abramowicz I, O'Driscoll M. A novel role for the peptidyl-prolyl cis-trans isomerase Cyclophilin A in DNA-repair following replication fork stalling via the MRE11-RAD50-NBS1 complex. EMBO Rep 2024; 25:3432-3455. [PMID: 38943005 PMCID: PMC11315929 DOI: 10.1038/s44319-024-00184-9] [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: 02/02/2024] [Revised: 05/28/2024] [Accepted: 06/05/2024] [Indexed: 06/30/2024] Open
Abstract
Cyclosporin A (CsA) induces DNA double-strand breaks in LIG4 syndrome fibroblasts, specifically upon transit through S-phase. The basis underlying this has not been described. CsA-induced genomic instability may reflect a direct role of Cyclophilin A (CYPA) in DNA repair. CYPA is a peptidyl-prolyl cis-trans isomerase (PPI). CsA inhibits the PPI activity of CYPA. Using an integrated approach involving CRISPR/Cas9-engineering, siRNA, BioID, co-immunoprecipitation, pathway-specific DNA repair investigations as well as protein expression interaction analysis, we describe novel impacts of CYPA loss and inhibition on DNA repair. We characterise a direct CYPA interaction with the NBS1 component of the MRE11-RAD50-NBS1 complex, providing evidence that CYPA influences DNA repair at the level of DNA end resection. We define a set of genetic vulnerabilities associated with CYPA loss and inhibition, identifying DNA replication fork protection as an important determinant of viability. We explore examples of how CYPA inhibition may be exploited to selectively kill cancers sharing characteristic genomic instability profiles, including MYCN-driven Neuroblastoma, Multiple Myeloma and Chronic Myelogenous Leukaemia. These findings propose a repurposing strategy for Cyclophilin inhibitors.
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Affiliation(s)
- Marisa Bedir
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Brighton, BN1 9RQ, UK
| | - Emily Outwin
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Brighton, BN1 9RQ, UK
| | - Rita Colnaghi
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Brighton, BN1 9RQ, UK
| | - Lydia Bassett
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Brighton, BN1 9RQ, UK
| | - Iga Abramowicz
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Brighton, BN1 9RQ, UK
| | - Mark O'Driscoll
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Brighton, BN1 9RQ, UK.
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6
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Escherich CS, Chen W, Li Y, Yang W, Nishii R, Li Z, Raetz EA, Devidas M, Wu G, Nichols KE, Inaba H, Pui CH, Jeha S, Camitta BM, Larsen E, Hunger SP, Loh ML, Yang JJ. Germ line genetic NBN variation and predisposition to B-cell acute lymphoblastic leukemia in children. Blood 2024; 143:2270-2283. [PMID: 38446568 PMCID: PMC11443573 DOI: 10.1182/blood.2023023336] [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: 11/20/2023] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 03/08/2024] Open
Abstract
ABSTRACT Biallelic mutation in the DNA-damage repair gene NBN is the genetic cause of Nijmegen breakage syndrome, which is associated with predisposition to lymphoid malignancies. Heterozygous carriers of germ line NBN variants may also be at risk for leukemia development, although this is much less characterized. By sequencing 4325 pediatric patients with B-cell acute lymphoblastic leukemia (B-ALL), we systematically examined the frequency of germ line NBN variants and identified 25 unique, putatively damaging NBN coding variants in 50 patients. Compared with the frequency of NBN variants in gnomAD noncancer controls (189 unique, putatively damaging NBN coding variants in 472 of 118 479 individuals), we found significant overrepresentation in pediatric B-ALL (P = .004; odds ratio, 1.8). Most B-ALL-risk variants were missense and cluster within the NBN N-terminal domains. Using 2 functional assays, we verified 14 of 25 variants with severe loss-of-function phenotypes and thus classified these as nonfunctional or partially functional. Finally, we found that germ line NBN variant carriers, all of whom were identified as heterozygous genotypes, showed similar survival outcomes relative to those with wild type status. Taken together, our findings provide novel insights into the genetic predisposition to B-ALL, and the impact of NBN variants on protein function and suggest that heterozygous NBN variant carriers may safely receive B-ALL therapy. These trials were registered at www.clinicaltrials.gov as #NCT01225874, NCT00075725, NCT00103285, NCI-T93-0101D, and NCT00137111.
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Affiliation(s)
- Carolin S Escherich
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN
- Department for Pediatric Oncology, Hematology, and Clinical Immunology, Medical Faculty, Heinrich-Heine University, Duesseldorf, Germany
| | - Wenan Chen
- Department of Pathology, Center for Applied Bioinformatics, St. Jude Children's Research Hospital, Memphis, TN
| | - Yizhen Li
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN
| | - Wenjian Yang
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN
| | - Rina Nishii
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN
| | - Zhenhua Li
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN
| | - Elizabeth A Raetz
- Department of Pediatrics and Perlmutter Cancer Center, New York University Langone Health, New York, NY
| | - Meenakshi Devidas
- Department of Global Pediatric Medicine, St. Jude Children's Research Hospital, Memphis, TN
| | - Gang Wu
- Department of Pathology, Center for Applied Bioinformatics, St. Jude Children's Research Hospital, Memphis, TN
| | - Kim E Nichols
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN
| | - Hiroto Inaba
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN
| | - Ching-Hon Pui
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN
| | - Sima Jeha
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN
| | - Bruce M Camitta
- Department of Pediatrics, Midwest Center for Cancer and Blood Disorders, Medical College of Wisconsin, Milwaukee, WI
| | - Eric Larsen
- Department of Pediatrics, Maine Children's Cancer Program, Scarborough, ME
| | - Stephen P Hunger
- Department of Pediatrics and Center for Childhood Cancer Research, Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Mignon L Loh
- Department of Pediatrics and the Ben Towne Center for Childhood Cancer Research, Seattle Children's Hospital, University of Washington, Seattle, WA
| | - Jun J Yang
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN
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7
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Lorković ZJ, Klingenbrunner M, Cho CH, Berger F. Identification of plants' functional counterpart of the metazoan mediator of DNA Damage checkpoint 1. EMBO Rep 2024; 25:1936-1961. [PMID: 38438802 PMCID: PMC11014961 DOI: 10.1038/s44319-024-00107-8] [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: 01/04/2024] [Revised: 02/13/2024] [Accepted: 02/19/2024] [Indexed: 03/06/2024] Open
Abstract
Induction of DNA damage triggers rapid phosphorylation of the histone H2A.X (γH2A.X). In animals, mediator of DNA damage checkpoint 1 (MDC1) binds γH2A.X through a tandem BRCA1 carboxyl-terminal (tBRCT) domain and mediates recruitment of downstream effectors of DNA damage response (DDR). However, readers of this modification in plants have remained elusive. We show that from the Arabidopsis BRCT domain proteome, BCP1-4 proteins with tBRCT domains are involved in DDR. Through its tBRCT domain BCP4 binds γH2A.X in vitro and localizes to DNA damage-induced foci in an H2A.X-dependent manner. BCP4 also contains a domain that interacts directly with NBS1 and thus acts as a functional counterpart of MDC1. We also show that BCP1, that contains two tBRCT domains, co-localizes with γH2A.X but it does not bind γH2A.X suggesting functional similarity with human PAXIP1. A phylogenetic analysis supports that PAXIP1 and MDC1 in metazoa and their plant counterparts evolved independently from common ancestors with tBRCT domains. Collectively, our study reveals missing components and provides mechanistic and evolutionary insights into plant DDR.
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Affiliation(s)
- Zdravko J Lorković
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria.
| | - Michael Klingenbrunner
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Chung Hyun Cho
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria.
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8
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Zheng Y, Li Y, Zhou K, Li T, VanDusen NJ, Hua Y. Precise genome-editing in human diseases: mechanisms, strategies and applications. Signal Transduct Target Ther 2024; 9:47. [PMID: 38409199 PMCID: PMC10897424 DOI: 10.1038/s41392-024-01750-2] [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: 05/17/2023] [Revised: 01/15/2024] [Accepted: 01/17/2024] [Indexed: 02/28/2024] Open
Abstract
Precise genome-editing platforms are versatile tools for generating specific, site-directed DNA insertions, deletions, and substitutions. The continuous enhancement of these tools has led to a revolution in the life sciences, which promises to deliver novel therapies for genetic disease. Precise genome-editing can be traced back to the 1950s with the discovery of DNA's double-helix and, after 70 years of development, has evolved from crude in vitro applications to a wide range of sophisticated capabilities, including in vivo applications. Nonetheless, precise genome-editing faces constraints such as modest efficiency, delivery challenges, and off-target effects. In this review, we explore precise genome-editing, with a focus on introduction of the landmark events in its history, various platforms, delivery systems, and applications. First, we discuss the landmark events in the history of precise genome-editing. Second, we describe the current state of precise genome-editing strategies and explain how these techniques offer unprecedented precision and versatility for modifying the human genome. Third, we introduce the current delivery systems used to deploy precise genome-editing components through DNA, RNA, and RNPs. Finally, we summarize the current applications of precise genome-editing in labeling endogenous genes, screening genetic variants, molecular recording, generating disease models, and gene therapy, including ex vivo therapy and in vivo therapy, and discuss potential future advances.
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Affiliation(s)
- Yanjiang Zheng
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Yifei Li
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Kaiyu Zhou
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Tiange Li
- Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Nathan J VanDusen
- Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
| | - Yimin Hua
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.
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9
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Atkinson J, Bezak E, Le H, Kempson I. DNA Double Strand Break and Response Fluorescent Assays: Choices and Interpretation. Int J Mol Sci 2024; 25:2227. [PMID: 38396904 PMCID: PMC10889524 DOI: 10.3390/ijms25042227] [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: 12/22/2023] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 02/25/2024] Open
Abstract
Accurately characterizing DNA double-stranded breaks (DSBs) and understanding the DNA damage response (DDR) is crucial for assessing cellular genotoxicity, maintaining genomic integrity, and advancing gene editing technologies. Immunofluorescence-based techniques have proven to be invaluable for quantifying and visualizing DSB repair, providing valuable insights into cellular repair processes. However, the selection of appropriate markers for analysis can be challenging due to the intricate nature of DSB repair mechanisms, often leading to ambiguous interpretations. This comprehensively summarizes the significance of immunofluorescence-based techniques, with their capacity for spatiotemporal visualization, in elucidating complex DDR processes. By evaluating the strengths and limitations of different markers, we identify where they are most relevant chronologically from DSB detection to repair, better contextualizing what each assay represents at a molecular level. This is valuable for identifying biases associated with each assay and facilitates accurate data interpretation. This review aims to improve the precision of DSB quantification, deepen the understanding of DDR processes, assay biases, and pathway choices, and provide practical guidance on marker selection. Each assay offers a unique perspective of the underlying processes, underscoring the need to select markers that are best suited to specific research objectives.
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Affiliation(s)
- Jake Atkinson
- Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia;
| | - Eva Bezak
- UniSA Allied Health and Human Performance, University of South Australia, Adelaide, SA 5095, Australia; (E.B.)
- Department of Physics, University of Adelaide, North Terrace, Adelaide, SA 5005, Australia
| | - Hien Le
- UniSA Allied Health and Human Performance, University of South Australia, Adelaide, SA 5095, Australia; (E.B.)
- Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, SA 5000, Australia
| | - Ivan Kempson
- Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia;
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10
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Möller C, Sharma R, Öz R, Reginato G, Cannavo E, Ceppi I, Sriram KK, Cejka P, Westerlund F. Xrs2/NBS1 promote end-bridging activity of the MRE11-RAD50 complex. Biochem Biophys Res Commun 2024; 695:149464. [PMID: 38217957 DOI: 10.1016/j.bbrc.2023.149464] [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: 10/10/2023] [Revised: 12/04/2023] [Accepted: 12/29/2023] [Indexed: 01/15/2024]
Abstract
DNA double strand breaks (DSBs) can be detrimental to the cell and need to be efficiently repaired. A first step in DSB repair is to bring the free ends in close proximity to enable ligation by non-homologous end-joining (NHEJ), while the more precise, but less available, repair by homologous recombination (HR) requires close proximity of a sister chromatid. The human MRE11-RAD50-NBS1 (MRN) complex, Mre11-Rad50-Xrs2 (MRX) in yeast, is involved in both repair pathways. Here we use nanofluidic channels to study, on the single DNA molecule level, how MRN, MRX and their constituents interact with long DNA and promote DNA bridging. Nanofluidics is a suitable method to study reactions on DNA ends since no anchoring of the DNA end(s) is required. We demonstrate that NBS1 and Xrs2 play important, but differing, roles in the DNA tethering by MRN and MRX. NBS1 promotes DNA bridging by MRN consistent with tethering of a repair template. MRX shows a "synapsis-like" DNA end-bridging, stimulated by the Xrs2 subunit. Our results highlight the different ways MRN and MRX bridge DNA, and the results are in agreement with their key roles in HR and NHEJ, respectively, and contribute to the understanding of the roles of NBS1 and Xrs2 in DSB repair.
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Affiliation(s)
- Carl Möller
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, SE, 41296, Sweden
| | - Rajhans Sharma
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, SE, 41296, Sweden
| | - Robin Öz
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, SE, 41296, Sweden
| | - Giordano Reginato
- Institute for Research in Biomedicine, Universitá della Svizzera Italiana, Bellinzona, CH 6500, Switzerland
| | - Elda Cannavo
- Institute for Research in Biomedicine, Universitá della Svizzera Italiana, Bellinzona, CH 6500, Switzerland
| | - Ilaria Ceppi
- Institute for Research in Biomedicine, Universitá della Svizzera Italiana, Bellinzona, CH 6500, Switzerland
| | - K K Sriram
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, SE, 41296, Sweden
| | - Petr Cejka
- Institute for Research in Biomedicine, Universitá della Svizzera Italiana, Bellinzona, CH 6500, Switzerland; Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland
| | - Fredrik Westerlund
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, SE, 41296, Sweden.
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11
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El‐Kamand S, Adams MN, Matthews JM, Du Plessis M, Crossett B, Connolly A, Breen N, Dudley A, Richard DJ, Gamsjaeger R, Cubeddu L. The molecular details of a novel phosphorylation-dependent interaction between MRN and the SOSS complex. Protein Sci 2023; 32:e4782. [PMID: 37705456 PMCID: PMC10521234 DOI: 10.1002/pro.4782] [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: 04/21/2023] [Revised: 08/08/2023] [Accepted: 09/11/2023] [Indexed: 09/15/2023]
Abstract
The repair of double-strand DNA breaks (DSBs) by homologous recombination is crucial in the maintenance of genome integrity. While the key role of the Mre11-Rad50-Nbs1 (MRN) complex in repair is well known, hSSB1 (SOSSB and OBFC2B), one of the main components of the sensor of single-stranded DNA (SOSS) protein complex, has also been shown to rapidly localize to DSB breaks and promote repair. We have previously demonstrated that hSSB1 binds directly to Nbs1, a component of the MRN complex, in a DNA damage-independent manner. However, recruitment of the MRN complex has also been demonstrated by an interaction between Integrator Complex Subunit 3 (INTS3; also known as SOSSA), another member of the SOSS complex, and Nbs1. In this study, we utilize a combined approach of in silico, biochemical, and functional experiments to uncover the molecular details of INTS3 binding to Nbs1. We demonstrate that the forkhead-associated domain of Nbs1 interacts with INTS3 via phosphorylation-dependent binding to INTS3 at Threonine 592, with contributions from Serine 590. Based on these data, we propose a model of MRN recruitment to a DSB via INTS3.
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Affiliation(s)
- Serene El‐Kamand
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Mark N. Adams
- Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of HealthTranslational Research Institute, Queensland University of TechnologyBrisbaneQueenslandAustralia
| | - Jacqueline M. Matthews
- School of Life and Environmental SciencesUniversity of SydneySydneyNew South WalesAustralia
| | | | - Ben Crossett
- Sydney Mass SpectrometryUniversity of SydneySydneyNew South WalesAustralia
| | - Angela Connolly
- Sydney Mass SpectrometryUniversity of SydneySydneyNew South WalesAustralia
| | - Natasha Breen
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Alexander Dudley
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Derek J. Richard
- Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of HealthTranslational Research Institute, Queensland University of TechnologyBrisbaneQueenslandAustralia
| | - Roland Gamsjaeger
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
- School of Life and Environmental SciencesUniversity of SydneySydneyNew South WalesAustralia
| | - Liza Cubeddu
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
- School of Life and Environmental SciencesUniversity of SydneySydneyNew South WalesAustralia
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12
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Tan J, Sun X, Zhao H, Guan H, Gao S, Zhou P. Double-strand DNA break repair: molecular mechanisms and therapeutic targets. MedComm (Beijing) 2023; 4:e388. [PMID: 37808268 PMCID: PMC10556206 DOI: 10.1002/mco2.388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 08/29/2023] [Accepted: 09/08/2023] [Indexed: 10/10/2023] Open
Abstract
Double-strand break (DSB), a significant DNA damage brought on by ionizing radiation, acts as an initiating signal in tumor radiotherapy, causing cancer cells death. The two primary pathways for DNA DSB repair in mammalian cells are nonhomologous end joining (NHEJ) and homologous recombination (HR), which cooperate and compete with one another to achieve effective repair. The DSB repair mechanism depends on numerous regulatory variables. DSB recognition and the recruitment of DNA repair components, for instance, depend on the MRE11-RAD50-NBS1 (MRN) complex and the Ku70/80 heterodimer/DNA-PKcs (DNA-PK) complex, whose control is crucial in determining the DSB repair pathway choice and efficiency of HR and NHEJ. In-depth elucidation on the DSB repair pathway's molecular mechanisms has greatly facilitated for creation of repair proteins or pathways-specific inhibitors to advance precise cancer therapy and boost the effectiveness of cancer radiotherapy. The architectures, roles, molecular processes, and inhibitors of significant target proteins in the DSB repair pathways are reviewed in this article. The strategy and application in cancer therapy are also discussed based on the advancement of inhibitors targeted DSB damage response and repair proteins.
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Affiliation(s)
- Jinpeng Tan
- Hengyang Medical CollegeUniversity of South ChinaHengyangHunan ProvinceChina
- Department of Radiation BiologyBeijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Xingyao Sun
- Hengyang Medical CollegeUniversity of South ChinaHengyangHunan ProvinceChina
- Department of Radiation BiologyBeijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Hongling Zhao
- Department of Radiation BiologyBeijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Hua Guan
- Department of Radiation BiologyBeijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Shanshan Gao
- Department of Radiation BiologyBeijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Ping‐Kun Zhou
- Hengyang Medical CollegeUniversity of South ChinaHengyangHunan ProvinceChina
- Department of Radiation BiologyBeijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
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13
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Vertemara J, Tisi R. Dynamic Properties of the DNA Damage Response Mre11/Rad50 Complex. Int J Mol Sci 2023; 24:12377. [PMID: 37569756 PMCID: PMC10418313 DOI: 10.3390/ijms241512377] [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: 07/05/2023] [Revised: 07/28/2023] [Accepted: 08/01/2023] [Indexed: 08/13/2023] Open
Abstract
DNA double-strand breaks (DSBs) are a significant threat to cell viability due to the induction of genome instability and the potential loss of genetic information. One of the key players for early DNA damage response is the conserved Mre11/Rad50 Nbs1/Xrs2 (MRN/X) complex, which is quickly recruited to the DNA's ruptured ends and is required for their tethering and their subsequent repair via different pathways. The MRN/X complex associates with several other proteins to exert its functions, but it also exploits sophisticated internal dynamic properties to orchestrate the several steps required to address the damage. In this review, we summarize the intrinsic molecular features of the MRN/X complex through biophysical, structural, and computational analyses in order to describe the conformational transitions that allow for this complex to accomplish its multiple functions.
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Affiliation(s)
| | - Renata Tisi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, 20126 Milan, Italy;
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14
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Escherich C, Chen W, Li Y, Yang W, Nishii R, Li Z, Raetz EA, Devidas M, Wu G, Nichols KE, Inaba H, Pui CH, Jeha S, Camitta BM, Larsen E, Hunger SP, Loh ML, Yang JJ. Germline Genetic NBN Variation and Predisposition to B-cell Acute Lymphoblastic Leukemia in Children. RESEARCH SQUARE 2023:rs.3.rs-3171814. [PMID: 37503171 PMCID: PMC10371123 DOI: 10.21203/rs.3.rs-3171814/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Biallelic mutation in the DNA-damage repair gene NBN is the genetic cause of Nijmegen Breakage Syndrome, which is associated with predisposition to lymphoid malignancies. Heterozygous carriers of germline NBN variants may also be at risk for leukemia development, although this is much less characterized. We systematically examined the frequency of germline NBN variants in pediatric B-ALL and identified 25 putatively damaging NBN coding variants in 50 of 4,183 B-ALL patients. Compared with the frequency of NBN variants in 118,479 gnomAD non-cancer controls we found significant overrepresentation in pediatric B-ALL (p=0.004, OR=1.77). Most B-ALL-risk variants were missense and cluster within the NBN N-terminal domains. Using two functional assays, we verified 14 of 25 variants with severe loss-of-function phenotypes and thus classified these as pathogenic or likely pathogenic. Finally, we found that heterozygous germline NBN variant carriers showed similar survival outcomes relative to those with WT status. Taken together, our findings provide novel insights into the genetic predisposition to B-ALL, the impact of NBN variants on protein function and suggest that heterozygous NBN variant carriers may safely receive B-ALL therapy.
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Affiliation(s)
- Carolin Escherich
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, TN, USA
- Department for Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich-Heine University, Duesseldorf, Germany
| | - Wenan Chen
- Center for Applied Bioinformatics, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Yizhen Li
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Wenjian Yang
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Rina Nishii
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Zhenhua Li
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Elizabeth A. Raetz
- Department of Pediatrics and Perlmutter Cancer Center, New York University Langone Health, New York, NY, USA
| | - Meenakshi Devidas
- Department of Global Pediatric Medicine, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Gang Wu
- Center for Applied Bioinformatics, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Kim E. Nichols
- Department of Oncology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Hiroto Inaba
- Department of Oncology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Ching-Hon Pui
- Department of Oncology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Sima Jeha
- Department of Oncology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Bruce M. Camitta
- Department of Pediatrics, Midwest Center for Cancer and Blood Disorders, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Eric Larsen
- Department of Pediatrics, Maine Children’s Cancer Program, Scarborough, ME, USA
| | - Stephen P. Hunger
- Department of Pediatrics and Center for Childhood Cancer Research, Children’s Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Mignon L. Loh
- Seattle Children’s Hospital, the Ben Towne Center for Childhood Cancer Research, University of Washington, Seattle, WA, USA
| | - Jun J. Yang
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, TN, USA
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15
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Vaurs M, Naiman K, Bouabboune C, Rai S, Ptasińska K, Rives M, Matmati S, Carr AM, Géli V, Coulon S. Stn1-Ten1 and Taz1 independently promote replication of subtelomeric fragile sequences in fission yeast. Cell Rep 2023; 42:112537. [PMID: 37243596 DOI: 10.1016/j.celrep.2023.112537] [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: 09/15/2022] [Revised: 03/01/2023] [Accepted: 05/03/2023] [Indexed: 05/29/2023] Open
Abstract
Efficient replication of terminal DNA is crucial to maintain telomere stability. In fission yeast, Taz1 and the Stn1-Ten1 (ST) complex play prominent roles in DNA-ends replication. However, their function remains elusive. Here, we have analyzed genome-wide replication and show that ST does not affect genome-wide replication but is crucial for the efficient replication of a subtelomeric region called STE3-2. We further show that, when ST function is compromised, a homologous recombination (HR)-based fork restart mechanism becomes necessary for STE3-2 stability. While both Taz1 and Stn1 bind to STE3-2, we find that the STE3-2 replication function of ST is independent of Taz1 but relies on its association with the shelterin proteins Pot1-Tpz1-Poz1. Finally, we demonstrate that the firing of an origin normally inhibited by Rif1 can circumvent the replication defect of subtelomeres when ST function is compromised. Our results help illuminate why fission yeast telomeres are terminal fragile sites.
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Affiliation(s)
- Mélina Vaurs
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Karel Naiman
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France; Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK
| | - Chaïnez Bouabboune
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Sudhir Rai
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Katarzyna Ptasińska
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK
| | - Marion Rives
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Samah Matmati
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Antony M Carr
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK
| | - Vincent Géli
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France.
| | - Stéphane Coulon
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France.
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16
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Otahalova B, Volkova Z, Soukupova J, Kleiblova P, Janatova M, Vocka M, Macurek L, Kleibl Z. Importance of Germline and Somatic Alterations in Human MRE11, RAD50, and NBN Genes Coding for MRN Complex. Int J Mol Sci 2023; 24:ijms24065612. [PMID: 36982687 PMCID: PMC10051278 DOI: 10.3390/ijms24065612] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 03/11/2023] [Accepted: 03/13/2023] [Indexed: 03/17/2023] Open
Abstract
The MRE11, RAD50, and NBN genes encode for the nuclear MRN protein complex, which senses the DNA double strand breaks and initiates the DNA repair. The MRN complex also participates in the activation of ATM kinase, which coordinates DNA repair with the p53-dependent cell cycle checkpoint arrest. Carriers of homozygous germline pathogenic variants in the MRN complex genes or compound heterozygotes develop phenotypically distinct rare autosomal recessive syndromes characterized by chromosomal instability and neurological symptoms. Heterozygous germline alterations in the MRN complex genes have been associated with a poorly-specified predisposition to various cancer types. Somatic alterations in the MRN complex genes may represent valuable predictive and prognostic biomarkers in cancer patients. MRN complex genes have been targeted in several next-generation sequencing panels for cancer and neurological disorders, but interpretation of the identified alterations is challenging due to the complexity of MRN complex function in the DNA damage response. In this review, we outline the structural characteristics of the MRE11, RAD50 and NBN proteins, the assembly and functions of the MRN complex from the perspective of clinical interpretation of germline and somatic alterations in the MRE11, RAD50 and NBN genes.
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Affiliation(s)
- Barbora Otahalova
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12800 Prague, Czech Republic
- Department of Biochemistry, Faculty of Natural Science, Charles University in Prague, 12800 Prague, Czech Republic
| | - Zuzana Volkova
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12800 Prague, Czech Republic
| | - Jana Soukupova
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12800 Prague, Czech Republic
| | - Petra Kleiblova
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12800 Prague, Czech Republic
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12800 Prague, Czech Republic
| | - Marketa Janatova
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12800 Prague, Czech Republic
| | - Michal Vocka
- Department of Oncology, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12800 Prague, Czech Republic
| | - Libor Macurek
- Laboratory of Cancer Cell Biology, Institute of Molecular Genetics, Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Zdenek Kleibl
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12800 Prague, Czech Republic
- Institute of Pathological Physiology, First Faculty of Medicine and General University Hospital in Prague, 12853 Prague, Czech Republic
- Correspondence: ; Tel.: +420-22496-4287
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17
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Mre11-Rad50: the DNA end game. Biochem Soc Trans 2023; 51:527-538. [PMID: 36892213 DOI: 10.1042/bst20220754] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/09/2023] [Accepted: 02/17/2023] [Indexed: 03/10/2023]
Abstract
The Mre11-Rad50-(Nbs1/Xrs2) complex is an evolutionarily conserved factor for the repair of DNA double-strand breaks and other DNA termini in all kingdoms of life. It is an intricate DNA associated molecular machine that cuts, among other functions, a large variety of free and obstructed DNA termini for DNA repair by end joining or homologous recombination, yet leaves undamaged DNA intact. Recent years have brought progress in both the structural and functional analyses of Mre11-Rad50 orthologs, revealing mechanisms of DNA end recognition, endo/exonuclease activities, nuclease regulation and DNA scaffolding. Here, I review our current understanding and recent progress on the functional architecture Mre11-Rad50 and how this chromosome associated coiled-coil ABC ATPase acts as DNA topology specific endo-/exonuclease.
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18
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Mann A, Ramirez-Otero MA, De Antoni A, Hanthi YW, Sannino V, Baldi G, Falbo L, Schrempf A, Bernardo S, Loizou J, Costanzo V. POLθ prevents MRE11-NBS1-CtIP-dependent fork breakage in the absence of BRCA2/RAD51 by filling lagging-strand gaps. Mol Cell 2022; 82:4218-4231.e8. [PMID: 36400008 DOI: 10.1016/j.molcel.2022.09.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 07/16/2022] [Accepted: 09/09/2022] [Indexed: 11/18/2022]
Abstract
POLθ promotes repair of DNA double-strand breaks (DSBs) resulting from collapsed forks in homologous recombination (HR) defective tumors. Inactivation of POLθ results in synthetic lethality with the loss of HR genes BRCA1/2, which induces under-replicated DNA accumulation. However, it is unclear whether POLθ-dependent DNA replication prevents HR-deficiency-associated lethality. Here, we isolated Xenopus laevis POLθ and showed that it processes stalled Okazaki fragments, directly visualized by electron microscopy, thereby suppressing ssDNA gaps accumulating on lagging strands in the absence of RAD51 and preventing fork reversal. Inhibition of POLθ DNA polymerase activity leaves fork gaps unprotected, enabling their cleavage by the MRE11-NBS1-CtIP endonuclease, which produces broken forks with asymmetric single-ended DSBs, hampering BRCA2-defective cell survival. These results reveal a POLθ-dependent genome protection function preventing stalled forks rupture and highlight possible resistance mechanisms to POLθ inhibitors.
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Affiliation(s)
- Anjali Mann
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy
| | - Miguel Angel Ramirez-Otero
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy
| | - Anna De Antoni
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy
| | - Yodhara Wijesekara Hanthi
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy
| | - Vincenzo Sannino
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy
| | - Giorgio Baldi
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy
| | - Lucia Falbo
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy
| | - Anna Schrempf
- Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Centre, Medical University of Vienna, Vienna, Austria
| | - Sara Bernardo
- Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Centre, Medical University of Vienna, Vienna, Austria
| | - Joanna Loizou
- Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Centre, Medical University of Vienna, Vienna, Austria
| | - Vincenzo Costanzo
- IFOM ETS, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy.
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19
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DiRusso CJ, Dashtiahangar M, Gilmore TD. Scaffold proteins as dynamic integrators of biological processes. J Biol Chem 2022; 298:102628. [PMID: 36273588 PMCID: PMC9672449 DOI: 10.1016/j.jbc.2022.102628] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/14/2022] [Accepted: 10/15/2022] [Indexed: 11/15/2022] Open
Abstract
Scaffold proteins act as molecular hubs for the docking of multiple proteins to organize efficient functional units for signaling cascades. Over 300 human proteins have been characterized as scaffolds, acting in a variety of signaling pathways. While the term scaffold implies a static, supportive platform, it is now clear that scaffolds are not simply inert docking stations but can undergo conformational changes that affect their dependent signaling pathways. In this review, we catalog scaffold proteins that have been shown to undergo actionable conformational changes, with a focus on the role that conformational change plays in the activity of the classic yeast scaffold STE5, as well as three human scaffold proteins (KSR, NEMO, SHANK3) that are integral to well-known signaling pathways (RAS, NF-κB, postsynaptic density). We also discuss scaffold protein conformational changes vis-à-vis liquid-liquid phase separation. Changes in scaffold structure have also been implicated in human disease, and we discuss how aberrant conformational changes may be involved in disease-related dysregulation of scaffold and signaling functions. Finally, we discuss how understanding these conformational dynamics will provide insight into the flexibility of signaling cascades and may enhance our ability to treat scaffold-associated diseases.
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20
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Montales K, Ruis K, Lindsay H, Michael WM. MRN-dependent and independent pathways for recruitment of TOPBP1 to DNA double-strand breaks. PLoS One 2022; 17:e0271905. [PMID: 35917319 PMCID: PMC9345342 DOI: 10.1371/journal.pone.0271905] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 07/08/2022] [Indexed: 12/31/2022] Open
Abstract
Ataxia Telangiectasia mutated and RAD3-related (ATR) kinase is activated by DNA replication stress and also by various forms of DNA damage, including DNA double-strand breaks (DSBs). Recruitment to sites of damage is insufficient for ATR activation as one of two known ATR activators, either topoisomerase II-binding protein (TOPBP1) or Ewing’s tumor-associated antigen 1, must also be present for signaling to initiate. Here, we employ our recently established DSB-mediated ATR activation in Xenopus egg extract (DMAX) system to examine how TOPBP1 is recruited to DSBs, so that it may activate ATR. We report that TOPBP1 is only transiently present at DSBs, with a half-life of less than 10 minutes. We also examined the relationship between TOPBP1 and the MRE11-RAD50-NBS1 (MRN), CtBP interacting protein (CtIP), and Ataxia Telangiectasia mutated (ATM) network of proteins. Loss of MRN prevents CtIP recruitment to DSBs, and partially inhibits TOPBP1 recruitment. Loss of CtIP has no impact on either MRN or TOPBP1 recruitment. Loss of ATM kinase activity prevents CtIP recruitment and enhances MRN and TOPBP1 recruitment. These findings demonstrate that there are MRN-dependent and independent pathways that recruit TOPBP1 to DSBs for ATR activation. Lastly, we find that both the 9-1-1 complex and MDC1 are dispensable for TOPBP1 recruitment to DSBs.
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Affiliation(s)
- Katrina Montales
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, California, United States of America
| | - Kenna Ruis
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, California, United States of America
| | - Howard Lindsay
- Faculty of Health and Medicine, Lancaster Medical School, Lancaster University, Lancaster, United Kingdom
| | - W. Matthew Michael
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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21
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The Role of Hsp90-R2TP in Macromolecular Complex Assembly and Stabilization. Biomolecules 2022; 12:biom12081045. [PMID: 36008939 PMCID: PMC9406135 DOI: 10.3390/biom12081045] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/19/2022] [Accepted: 07/25/2022] [Indexed: 01/27/2023] Open
Abstract
Hsp90 is a ubiquitous molecular chaperone involved in many cell signaling pathways, and its interactions with specific chaperones and cochaperones determines which client proteins to fold. Hsp90 has been shown to be involved in the promotion and maintenance of proper protein complex assembly either alone or in association with other chaperones such as the R2TP chaperone complex. Hsp90-R2TP acts through several mechanisms, such as by controlling the transcription of protein complex subunits, stabilizing protein subcomplexes before their incorporation into the entire complex, and by recruiting adaptors that facilitate complex assembly. Despite its many roles in protein complex assembly, detailed mechanisms of how Hsp90-R2TP assembles protein complexes have yet to be determined, with most findings restricted to proteomic analyses and in vitro interactions. This review will discuss our current understanding of the function of Hsp90-R2TP in the assembly, stabilization, and activity of the following seven classes of protein complexes: L7Ae snoRNPs, spliceosome snRNPs, RNA polymerases, PIKKs, MRN, TSC, and axonemal dynein arms.
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22
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Danforth JM, Provencher L, Goodarzi AA. Chromatin and the Cellular Response to Particle Radiation-Induced Oxidative and Clustered DNA Damage. Front Cell Dev Biol 2022; 10:910440. [PMID: 35912116 PMCID: PMC9326100 DOI: 10.3389/fcell.2022.910440] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 06/21/2022] [Indexed: 12/03/2022] Open
Abstract
Exposure to environmental ionizing radiation is prevalent, with greatest lifetime doses typically from high Linear Energy Transfer (high-LET) alpha particles via the radioactive decay of radon gas in indoor air. Particle radiation is highly genotoxic, inducing DNA damage including oxidative base lesions and DNA double strand breaks. Due to the ionization density of high-LET radiation, the consequent damage is highly clustered wherein ≥2 distinct DNA lesions occur within 1–2 helical turns of one another. These multiply-damaged sites are difficult for eukaryotic cells to resolve either quickly or accurately, resulting in the persistence of DNA damage and/or the accumulation of mutations at a greater rate per absorbed dose, relative to lower LET radiation types. The proximity of the same and different types of DNA lesions to one another is challenging for DNA repair processes, with diverse pathways often confounding or interplaying with one another in complex ways. In this context, understanding the state of the higher order chromatin compaction and arrangements is essential, as it influences the density of damage produced by high-LET radiation and regulates the recruitment and activity of DNA repair factors. This review will summarize the latest research exploring the processes by which clustered DNA damage sites are induced, detected, and repaired in the context of chromatin.
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Ebata H, Loo TM, Takahashi A. Telomere Maintenance and the cGAS-STING Pathway in Cancer. Cells 2022; 11:1958. [PMID: 35741087 PMCID: PMC9221635 DOI: 10.3390/cells11121958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 06/15/2022] [Accepted: 06/16/2022] [Indexed: 11/17/2022] Open
Abstract
Cancer cells exhibit the unique characteristics of high proliferation and aberrant DNA damage response, which prevents cancer therapy from effectively eliminating them. The machinery required for telomere maintenance, such as telomerase and the alternative lengthening of telomeres (ALT), enables cancer cells to proliferate indefinitely. In addition, the molecules in this system are involved in noncanonical pro-tumorigenic functions. Of these, the function of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway, which contains telomere-related molecules, is a well-known contributor to the tumor microenvironment (TME). This review summarizes the current knowledge of the role of telomerase and ALT in cancer regulation, with emphasis on their noncanonical roles beyond telomere maintenance. The components of the cGAS-STING pathway are summarized with respect to intercell communication in the TME. Elucidating the underlying functional connection between telomere-related molecules and TME regulation is important for the development of cancer therapeutics that target cancer-specific pathways in different contexts. Finally, strategies for designing new cancer therapies that target cancer cells and the TME are discussed.
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Affiliation(s)
- Hiroshi Ebata
- Department of Biological Sciences, Faculty of Science, The University of Tokyo, Tokyo 113-0033, Japan;
- Project for Cellular Senescence, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo 135-8550, Japan;
| | - Tze Mun Loo
- Project for Cellular Senescence, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo 135-8550, Japan;
| | - Akiko Takahashi
- Project for Cellular Senescence, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo 135-8550, Japan;
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Abdisalaam S, Mukherjee S, Bhattacharya S, Kumari S, Sinha D, Ortega J, Li GM, Sadek H, Krishnan S, Asaithamby A. NBS1-CtIP-mediated DNA end resection suppresses cGAS binding to micronuclei. Nucleic Acids Res 2022; 50:2681-2699. [PMID: 35189637 PMCID: PMC8934670 DOI: 10.1093/nar/gkac079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 01/12/2022] [Accepted: 01/25/2022] [Indexed: 01/07/2023] Open
Abstract
Cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) is activated in cells with defective DNA damage repair and signaling (DDR) factors, but a direct role for DDR factors in regulating cGAS activation in response to micronuclear DNA is still poorly understood. Here, we provide novel evidence that Nijmegen breakage syndrome 1 (NBS1) protein, a well-studied DNA double-strand break (DSB) sensor-in coordination with Ataxia Telangiectasia Mutated (ATM), a protein kinase, and Carboxy-terminal binding protein 1 interacting protein (CtIP), a DNA end resection factor-functions as an upstream regulator that prevents cGAS from binding micronuclear DNA. When NBS1 binds to micronuclear DNA via its fork-head-associated domain, it recruits CtIP and ATM via its N- and C-terminal domains, respectively. Subsequently, ATM stabilizes NBS1's interaction with micronuclear DNA, and CtIP converts DSB ends into single-strand DNA ends; these two key events prevent cGAS from binding micronuclear DNA. Additionally, by using a cGAS tripartite system, we show that cells lacking NBS1 not only recruit cGAS to a major fraction of micronuclear DNA but also activate cGAS in response to these micronuclear DNA. Collectively, our results underscore how NBS1 and its binding partners prevent cGAS from binding micronuclear DNA, in addition to their classical functions in DDR signaling.
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Affiliation(s)
- Salim Abdisalaam
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Shibani Mukherjee
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Souparno Bhattacharya
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sharda Kumari
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Debapriya Sinha
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Janice Ortega
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Guo-Min Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Hesham A Sadek
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sunil Krishnan
- Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL 32082, USA
| | - Aroumougame Asaithamby
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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25
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Zehtab S, Sattarzadeh Bardsiri M, Mirzaee Khalilabadi R, Ehsan M, Fatemi A. Association of DNA repair genes polymorphisms with childhood acute lymphoblastic leukemia: a high-resolution melting analysis. BMC Res Notes 2022; 15:46. [PMID: 35164849 PMCID: PMC8842869 DOI: 10.1186/s13104-022-05918-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 01/25/2022] [Indexed: 11/16/2022] Open
Abstract
Objective Acute lymphoblastic leukemia (ALL) is one of the most common cancers in children for which the exact pathogenesis is not yet known. Single-nucleotide variants (SNVs) in different DNA repair genes are reported to be associated with ALL risk. This study aimed to determine the association between XRCC1 (rs1799782) and NBN (rs1805794, rs709816) SNVs and childhood ALL risk in a sample of the Iranian population. Fifty children with ALL and 50 age- and sex-matched healthy children were included in this case–control study. Genotyping of the mentioned SNVs was done by high-resolution melting (HRM) analysis. Results The prevalence of all three SNVs in XRCC1 and NBN genes did not differ between the patient and control groups, and these polymorphisms were not associated with childhood ALL risk (P > 0.05). HRM was a practical method for the detection of SNVs in XRCC1 and NBN genes. We found no significant association between XRCC1 (rs1799782) and NBN (rs1805794, rs709816) SNVs and childhood ALL risk. Supplementary Information The online version contains supplementary material available at 10.1186/s13104-022-05918-3.
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Species variations in XRCC1 recruitment strategies for FHA domain-containing proteins. DNA Repair (Amst) 2022; 110:103263. [PMID: 35026705 PMCID: PMC9282668 DOI: 10.1016/j.dnarep.2021.103263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 11/07/2021] [Accepted: 12/21/2021] [Indexed: 02/03/2023]
Abstract
DNA repair scaffolds XRCC1 and XRCC4 utilize a phosphopeptide FHA domain binding motif (FBM) of the form Y-x-x-pS-pT-D-E that supports recruitment of three identified FHA domain-containing DNA repair proteins: polynucleotide kinase/phosphatase (PNKP), aprataxin (APTX), and a third protein, APLF, that functions as a scaffold in support of non-homologous end joining (NHEJ). Mammalian dimeric XRCC4 is able to interact with two of these proteins at any given time, while monomeric XRCC1 binds only one. However, sequence analysis indicates that amphibian and teleost XRCC1 generally contain two FHA binding motifs. X1-FBM1, is similar to the single mammalian XRCC1 FBM and probably functions similarly. X1-FBM2, is more similar to mammalian XRCC4 FBM; it is located closer to the XRCC1 BRCT1 domain and probably is less discriminating among its three likely binding partners. Availability of an additional PNKP or APTX recruitment motif may alleviate the bottleneck that results from using a single FBM motif for recruitment of multiple repair factors. Alternatively, recruitment of APLF by X1-FBM2 may function to rescue a misdirected or unsuccessful SSB repair response by redirecting the damaged DNA to the NHEJ pathway, - a need that results from the ambiguity of the PARP1 signal regarding the nature of the damage. Evaluation of XRCC4 FBMs in acanthomorphs, which account for a majority of the reported teleost sequences, reveals the presence of an additional XRCC4-like paralog, distinct from other previously described members of the XRCC4 superfamily. The FBM is typically absent in acanthomorph XRCC4, but present in the XRCC4-like paralog. Modeling suggests that XRCC4 and its paralog may form homodimers or XRCC4-XRCC4-like heterodimers.
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27
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Kieffer SR, Lowndes NF. Immediate-Early, Early, and Late Responses to DNA Double Stranded Breaks. Front Genet 2022; 13:793884. [PMID: 35173769 PMCID: PMC8841529 DOI: 10.3389/fgene.2022.793884] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 01/10/2022] [Indexed: 12/18/2022] Open
Abstract
Loss or rearrangement of genetic information can result from incorrect responses to DNA double strand breaks (DSBs). The cellular responses to DSBs encompass a range of highly coordinated events designed to detect and respond appropriately to the damage, thereby preserving genomic integrity. In analogy with events occurring during viral infection, we appropriate the terms Immediate-Early, Early, and Late to describe the pre-repair responses to DSBs. A distinguishing feature of the Immediate-Early response is that the large protein condensates that form during the Early and Late response and are resolved upon repair, termed foci, are not visible. The Immediate-Early response encompasses initial lesion sensing, involving poly (ADP-ribose) polymerases (PARPs), KU70/80, and MRN, as well as rapid repair by so-called ‘fast-kinetic’ canonical non-homologous end joining (cNHEJ). Initial binding of PARPs and the KU70/80 complex to breaks appears to be mutually exclusive at easily ligatable DSBs that are repaired efficiently by fast-kinetic cNHEJ; a process that is PARP-, ATM-, 53BP1-, Artemis-, and resection-independent. However, at more complex breaks requiring processing, the Immediate-Early response involving PARPs and the ensuing highly dynamic PARylation (polyADP ribosylation) of many substrates may aid recruitment of both KU70/80 and MRN to DSBs. Complex DSBs rely upon the Early response, largely defined by ATM-dependent focal recruitment of many signalling molecules into large condensates, and regulated by complex chromatin dynamics. Finally, the Late response integrates information from cell cycle phase, chromatin context, and type of DSB to determine appropriate pathway choice. Critical to pathway choice is the recruitment of p53 binding protein 1 (53BP1) and breast cancer associated 1 (BRCA1). However, additional factors recruited throughout the DSB response also impact upon pathway choice, although these remain to be fully characterised. The Late response somehow channels DSBs into the appropriate high-fidelity repair pathway, typically either ‘slow-kinetic’ cNHEJ or homologous recombination (HR). Loss of specific components of the DSB repair machinery results in cells utilising remaining factors to effect repair, but often at the cost of increased mutagenesis. Here we discuss the complex regulation of the Immediate-Early, Early, and Late responses to DSBs proceeding repair itself.
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28
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Warren C, Pavletich NP. Structure of the human ATM kinase and mechanism of Nbs1 binding. eLife 2022; 11:74218. [PMID: 35076389 PMCID: PMC8828054 DOI: 10.7554/elife.74218] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 01/24/2022] [Indexed: 11/27/2022] Open
Abstract
DNA double-strand breaks (DSBs) can lead to mutations, chromosomal rearrangements, genome instability, and cancer. Central to the sensing of DSBs is the ATM (Ataxia-telangiectasia mutated) kinase, which belongs to the phosphatidylinositol 3-kinase-related protein kinase (PIKK) family. In response to DSBs, ATM is activated by the MRN (Mre11-Rad50-Nbs1) protein complex through a poorly understood process that also requires double-stranded DNA. Previous studies indicate that the FxF/Y motif of Nbs1 directly binds to ATM, and is required to retain active ATM at sites of DNA damage. Here, we report the 2.5 Å resolution cryo-EM structures of human ATM and its complex with the Nbs1 FxF/Y motif. In keeping with previous structures of ATM and its yeast homolog Tel1, the dimeric human ATM kinase adopts a symmetric, butterfly-shaped structure. The conformation of the ATM kinase domain is most similar to the inactive states of other PIKKs, suggesting that activation may involve an analogous realigning of the N and C lobes along with relieving the blockage of the substrate-binding site. We also show that the Nbs1 FxF/Y motif binds to a conserved hydrophobic cleft within the Spiral domain of ATM, suggesting an allosteric mechanism of activation. We evaluate the importance of these structural findings with mutagenesis and biochemical assays.
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Affiliation(s)
- Christopher Warren
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Nikola P Pavletich
- Memorial Sloan Kettering Cancer Center, Howard Hughes Medical Institute, New York, United States
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29
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Ye Z, Shi Y, Lees-Miller SP, Tainer JA. Function and Molecular Mechanism of the DNA Damage Response in Immunity and Cancer Immunotherapy. Front Immunol 2021; 12:797880. [PMID: 34970273 PMCID: PMC8712645 DOI: 10.3389/fimmu.2021.797880] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 11/15/2021] [Indexed: 12/21/2022] Open
Abstract
The DNA damage response (DDR) is an organized network of multiple interwoven components evolved to repair damaged DNA and maintain genome fidelity. Conceptually the DDR includes damage sensors, transducer kinases, and effectors to maintain genomic stability and accurate transmission of genetic information. We have recently gained a substantially improved molecular and mechanistic understanding of how DDR components are interconnected to inflammatory and immune responses to stress. DDR shapes both innate and adaptive immune pathways: (i) in the context of innate immunity, DDR components mainly enhance cytosolic DNA sensing and its downstream STimulator of INterferon Genes (STING)-dependent signaling; (ii) in the context of adaptive immunity, the DDR is needed for the assembly and diversification of antigen receptor genes that is requisite for T and B lymphocyte development. Imbalances between DNA damage and repair impair tissue homeostasis and lead to replication and transcription stress, mutation accumulation, and even cell death. These impacts from DDR defects can then drive tumorigenesis, secretion of inflammatory cytokines, and aberrant immune responses. Yet, DDR deficiency or inhibition can also directly enhance innate immune responses. Furthermore, DDR defects plus the higher mutation load in tumor cells synergistically produce primarily tumor-specific neoantigens, which are powerfully targeted in cancer immunotherapy by employing immune checkpoint inhibitors to amplify immune responses. Thus, elucidating DDR-immune response interplay may provide critical connections for harnessing immunomodulatory effects plus targeted inhibition to improve efficacy of radiation and chemotherapies, of immune checkpoint blockade, and of combined therapeutic strategies.
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Affiliation(s)
- Zu Ye
- Department of Molecular and Cellular Oncology, and Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Yin Shi
- Department of Immunology, Zhejiang University School of Medicine, Hangzhou, China
- Division of Pediatrics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Susan P. Lees-Miller
- Department of Biochemistry and Molecular Biology, Robson DNA Science Centre, Charbonneau Cancer Institute, University of Calgary, Calgary, AB, Canada
| | - John A. Tainer
- Department of Molecular and Cellular Oncology, and Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
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30
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Abstract
DNA double-strand breaks (DSBs) are cytotoxic lesions that threaten genome integrity and cell viability. Typically, cells repair DSBs by either nonhomologous end joining (NHEJ) or homologous recombination (HR). The relative use of these two pathways depends on many factors, including cell cycle stage and the nature of the DNA ends. A critical determinant of repair pathway selection is the initiation of 5'→3' nucleolytic degradation of DNA ends, a process referred to as DNA end resection. End resection is essential to create single-stranded DNA overhangs, which serve as the substrate for the Rad51 recombinase to initiate HR and are refractory to NHEJ repair. Here, we review recent insights into the mechanisms of end resection, how it is regulated, and the pathological consequences of its dysregulation.
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Affiliation(s)
- Petr Cejka
- Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Università della Svizzera italiana (USI), 6500 Bellinzona, Switzerland; .,Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH) Zürich, 8093 Zürich, Switzerland
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA; .,Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA
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31
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Giaccherini C, Gaillard P. Control of structure-specific endonucleases during homologous recombination in eukaryotes. Curr Opin Genet Dev 2021; 71:195-205. [PMID: 34624742 DOI: 10.1016/j.gde.2021.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/10/2021] [Accepted: 09/13/2021] [Indexed: 01/14/2023]
Abstract
Structure-Specific Endonucleases (SSE) are specialized DNA endonucleases that recognize and process DNA secondary structures without any strict dependency on the nucleotide sequence context. This enables them to act virtually anywhere in the genome and to make key contributions to the maintenance of genome stability by removing DNA structures that may stall essential cellular processes such as DNA replication, transcription, repair and chromosome segregation. During repair of double strand breaks by homologous recombination mechanisms, DNA secondary structures are formed and processed in a timely manner. Their homeostasis relies on the combined action of helicases, SSE and topoisomerases. In this review, we focus on how SSE contribute to DNA end resection, single-strand annealing and double-strand break repair, with an emphasis on how their action is fine-tuned in those processes.
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Affiliation(s)
- C Giaccherini
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France
| | - Phl Gaillard
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France.
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32
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Frock RL, Sadeghi C, Meng J, Wang JL. DNA End Joining: G0-ing to the Core. Biomolecules 2021; 11:biom11101487. [PMID: 34680120 PMCID: PMC8533500 DOI: 10.3390/biom11101487] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 12/28/2022] Open
Abstract
Humans have evolved a series of DNA double-strand break (DSB) repair pathways to efficiently and accurately rejoin nascently formed pairs of double-stranded DNA ends (DSEs). In G0/G1-phase cells, non-homologous end joining (NHEJ) and alternative end joining (A-EJ) operate to support covalent rejoining of DSEs. While NHEJ is predominantly utilized and collaborates extensively with the DNA damage response (DDR) to support pairing of DSEs, much less is known about A-EJ collaboration with DDR factors when NHEJ is absent. Non-cycling lymphocyte progenitor cells use NHEJ to complete V(D)J recombination of antigen receptor genes, initiated by the RAG1/2 endonuclease which holds its pair of targeted DSBs in a synapse until each specified pair of DSEs is handed off to the NHEJ DSB sensor complex, Ku. Similar to designer endonuclease DSBs, the absence of Ku allows for A-EJ to access RAG1/2 DSEs but with random pairing to complete their repair. Here, we describe recent insights into the major phases of DSB end joining, with an emphasis on synapsis and tethering mechanisms, and bring together new and old concepts of NHEJ vs. A-EJ and on RAG2-mediated repair pathway choice.
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33
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The chromatin remodeler Chd1 supports MRX and Exo1 functions in resection of DNA double-strand breaks. PLoS Genet 2021; 17:e1009807. [PMID: 34520455 PMCID: PMC8462745 DOI: 10.1371/journal.pgen.1009807] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 09/24/2021] [Accepted: 09/06/2021] [Indexed: 12/31/2022] Open
Abstract
Repair of DNA double-strand breaks (DSBs) by homologous recombination (HR) requires that the 5’-terminated DNA strands are resected to generate single-stranded DNA overhangs. This process is initiated by a short-range resection catalyzed by the MRX (Mre11-Rad50-Xrs2) complex, which is followed by a long-range step involving the nucleases Exo1 and Dna2. Here we show that the Saccharomyces cerevisiae ATP-dependent chromatin-remodeling protein Chd1 participates in both short- and long-range resection by promoting MRX and Exo1 association with the DSB ends. Furthermore, Chd1 reduces histone occupancy near the DSB ends and promotes DSB repair by HR. All these functions require Chd1 ATPase activity, supporting a role for Chd1 in the opening of chromatin at the DSB site to facilitate MRX and Exo1 processing activities. DNA double strand breaks (DSBs) are among the most severe types of damage occurring in the genome because their faulty repair can result in chromosome instability, commonly associated with carcinogenesis. Efficient and accurate repair of DSBs relies on several proteins required to process them. However, eukaryotic genomes are compacted into chromatin, which restricts the access to DNA of the enzymes devoted to repair DNA DSBs. To overcome this natural barrier, eukaryotes have evolved chromatin remodeling enzymes that use energy derived from ATP hydrolysis to modulate chromatin structure. Here, we examine the role in DSB repair of the ATP-dependent chromatin remodeler Chd1, which is frequently mutated in prostate cancer. We find that Chd1 is important to repair DNA DSBs by homologous recombination (HR) because it promotes the association with a damaged site of the MRX complex and Exo1, which are necessary to initiate HR. This Chd1 function requires its ATPase activity, suggesting that Chd1 increases the accessibility to chromatin to initiate repair of DNA lesions.
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34
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Tessier TM, Dodge MJ, MacNeil KM, Evans AM, Prusinkiewicz MA, Mymryk JS. Almost famous: Human adenoviruses (and what they have taught us about cancer). Tumour Virus Res 2021; 12:200225. [PMID: 34500123 PMCID: PMC8449131 DOI: 10.1016/j.tvr.2021.200225] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/25/2021] [Accepted: 09/03/2021] [Indexed: 12/11/2022] Open
Abstract
Papillomaviruses, polyomaviruses and adenoviruses are collectively categorized as the small DNA tumour viruses. Notably, human adenoviruses were the first human viruses demonstrated to be able to cause cancer, albeit in non-human animal models. Despite their long history, no human adenovirus is a known causative agent of human cancers, unlike a subset of their more famous cousins, including human papillomaviruses and human Merkel cell polyomavirus. Nevertheless, seminal research using human adenoviruses has been highly informative in understanding the basics of cell cycle control, gene expression, apoptosis and cell differentiation. This review highlights the contributions of human adenovirus research in advancing our knowledge of the molecular basis of cancer.
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Affiliation(s)
- Tanner M Tessier
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON, Canada
| | - Mackenzie J Dodge
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON, Canada
| | - Katelyn M MacNeil
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON, Canada
| | - Andris M Evans
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON, Canada
| | - Martin A Prusinkiewicz
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON, Canada
| | - Joe S Mymryk
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON, Canada; Department of Otolaryngology, Head & Neck Surgery, The University of Western Ontario, London, ON, Canada; Department of Oncology, The University of Western Ontario, London, ON, Canada; London Regional Cancer Program, Lawson Health Research Institute, London, ON, Canada.
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35
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McPherson KS, Korzhnev DM. Targeting protein-protein interactions in the DNA damage response pathways for cancer chemotherapy. RSC Chem Biol 2021; 2:1167-1195. [PMID: 34458830 PMCID: PMC8342002 DOI: 10.1039/d1cb00101a] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 06/20/2021] [Indexed: 12/11/2022] Open
Abstract
Cellular DNA damage response (DDR) is an extensive signaling network that orchestrates DNA damage recognition, repair and avoidance, cell cycle progression and cell death. DDR alteration is a hallmark of cancer, with the deficiency in one DDR capability often compensated by a dependency on alternative pathways endowing cancer cells with survival and growth advantage. Targeting these DDR pathways has provided multiple opportunities for the development of cancer therapies. Traditional drug discovery has mainly focused on catalytic inhibitors that block enzyme active sites, which limits the number of potential drug targets within the DDR pathways. This review article describes the emerging approach to the development of cancer therapeutics targeting essential protein-protein interactions (PPIs) in the DDR network. The overall strategy for the structure-based design of small molecule PPI inhibitors is discussed, followed by an overview of the major DNA damage sensing, DNA repair, and DNA damage tolerance pathways with a specific focus on PPI targets for anti-cancer drug design. The existing small molecule inhibitors of DDR PPIs are summarized that selectively kill cancer cells and/or sensitize cancers to front-line genotoxic therapies, and a range of new PPI targets are proposed that may lead to the development of novel chemotherapeutics.
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Affiliation(s)
- Kerry Silva McPherson
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center Farmington CT 06030 USA +1 860 679 3408 +1 860 679 2849
| | - Dmitry M Korzhnev
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center Farmington CT 06030 USA +1 860 679 3408 +1 860 679 2849
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36
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Tsubouchi H, Argunhan B, Iwasaki H. Biochemical properties of fission yeast homologous recombination enzymes. Curr Opin Genet Dev 2021; 71:19-26. [PMID: 34246071 DOI: 10.1016/j.gde.2021.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 06/06/2021] [Accepted: 06/14/2021] [Indexed: 12/20/2022]
Abstract
Homologous recombination (HR) is a universal phenomenon conserved from viruses to humans. The mechanisms of HR are essentially the same in humans and simple unicellular eukaryotes like yeast. Two highly diverged yeast species, Saccharomyces cerevisiae and Schizosaccharomyces pombe, have proven exceptionally useful in understanding the fundamental mechanisms of eukaryotic HR by serving as a source for unique biological insights and also complementing each other. Here, we will review the features of S. pombe HR mechanisms in comparison to S. cerevisiae and other model organisms. Particular emphasis will be put on the biochemical characterization of HR mechanisms uncovered using S. pombe proteins.
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Affiliation(s)
- Hideo Tsubouchi
- Institute of Innovative Research, Tokyo Institute of Technology, Kanagawa, Japan; School of Life Science and Technology, Tokyo Institute of Technology, Kanagawa, Japan.
| | - Bilge Argunhan
- Institute of Innovative Research, Tokyo Institute of Technology, Kanagawa, Japan
| | - Hiroshi Iwasaki
- Institute of Innovative Research, Tokyo Institute of Technology, Kanagawa, Japan; School of Life Science and Technology, Tokyo Institute of Technology, Kanagawa, Japan.
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37
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Morton CR, Rzechorzek NJ, Maman JD, Kuramochi M, Sekiguchi H, Rambo R, Sasaki YC, Davies OR, Pellegrini L. Structural basis for the coiled-coil architecture of human CtIP. Open Biol 2021; 11:210060. [PMID: 34129781 PMCID: PMC8205527 DOI: 10.1098/rsob.210060] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The DNA repair factor CtIP has a critical function in double-strand break (DSB) repair by homologous recombination, promoting the assembly of the repair apparatus at DNA ends and participating in DNA-end resection. However, the molecular mechanisms of CtIP function in DSB repair remain unclear. Here, we present an atomic model for the three-dimensional architecture of human CtIP, derived from a multi-disciplinary approach that includes X-ray crystallography, small-angle X-ray scattering (SAXS) and diffracted X-ray tracking (DXT). Our data show that CtIP adopts an extended dimer-of-dimers structure, in agreement with a role in bridging distant sites on chromosomal DNA during the recombinational repair. The zinc-binding motif in the CtIP N-terminus alters dynamically the coiled-coil structure, with functional implications for the long-range interactions of CtIP with DNA. Our results provide a structural basis for the three-dimensional arrangement of chains in the CtIP tetramer, a key aspect of CtIP function in DNA DSB repair.
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Affiliation(s)
- C R Morton
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - N J Rzechorzek
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - J D Maman
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - M Kuramochi
- Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan.,AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Kashiwa, Japan
| | - H Sekiguchi
- Centre for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - R Rambo
- Diamond Light Source, Didcot, Oxfordshire OX11 0DE, UK
| | - Y C Sasaki
- Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan.,AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Kashiwa, Japan.,Centre for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - O R Davies
- Institute of Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - L Pellegrini
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
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38
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Kim K, Kirby TW, Perera L, London RE. Phosphopeptide interactions of the Nbs1 N-terminal FHA-BRCT1/2 domains. Sci Rep 2021; 11:9046. [PMID: 33907233 PMCID: PMC8079451 DOI: 10.1038/s41598-021-88400-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 04/05/2021] [Indexed: 11/21/2022] Open
Abstract
Human Nbs1, a component of the MRN complex involved in DNA double strand break repair, contains a concatenated N-terminal FHA-BRCT1/2 sequence that supports interaction with multiple phosphopeptide binding partners. MDC1 binding localizes Nbs1 to the damage site, while binding of CDK-phosphorylated CtIP activates additional ATM-dependent CtIP phosphorylation, modulating substrate-dependent resection. We have investigated the phosphopeptide binding characteristics of Nbs1 BRCT1/2 based on a molecular modeling approach that revealed structural homology with the tandem TopBP1 BRCT7/8 domains. Relevance of the model was substantiated by the ability of TopBP1-binding FANCJ phosphopeptide to interact with hsNbsBRCT1/2, albeit with lower affinity. The modeled BRCT1/2 is characterized by low pSer/pThr selectivity, preference for a cationic residue at the + 2 position, and an inter-domain binding cleft selective for hydrophobic residues at the + 3/ + 4 positions. These features provide insight into the basis for interaction of SDT motifs with the BRCT1/2 domains and allowed identification of CtIP pSer347- and pThr847-containing phosphopeptides as high and lower affinity ligands, respectively. Among other binding partners considered, rodent XRCC1 contains an SDT sequence in the second linker consistent with high-affinity Nbs1 binding, while human XRCC1 lacks this motif, but contains other phosphorylated sequences that exhibit low-affinity binding.
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Affiliation(s)
- Kyungmin Kim
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, 27709, USA
| | - Thomas W Kirby
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, 27709, USA
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, 27709, USA
| | - Robert E London
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, 27709, USA.
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39
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Rahman S, Beikzadeh M, Latham MP. Biochemical and structural characterization of analogs of MRE11 breast cancer-associated mutant F237C. Sci Rep 2021; 11:7089. [PMID: 33782469 PMCID: PMC8007570 DOI: 10.1038/s41598-021-86552-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 03/17/2021] [Indexed: 12/25/2022] Open
Abstract
The MRE11-RAD50-NBS1 (MRN) protein complex plays a vital role in DNA double strand break sensing, signaling, and repair. Mutation in any component of this complex may lead to disease as disrupting DNA double strand break repair has the potential to cause translocations and loss of genomic information. Here, we have investigated an MRE11 mutation, F237C, identified in a breast cancer tumor. We found that the analogous mutant of Pyrococcus furiosus Mre11 diminishes both the exonuclease and endonuclease activities of Mre11 in vitro. Solution state NMR experiments show that this mutant causes structural changes in the DNA-bound Mre11 for both exo- and endonuclease substrates and causes the protein to become generally more rigid. Moreover, by comparing the NMR data for this cancer-associated mutant with two previously described Mre11 separation-of-nuclease function mutants, a potential allosteric network was detected within Mre11 that connects the active site to regions responsible for recognizing the DNA ends and for dimerization. Together, our data further highlight the dynamics required for Mre11 nuclease function and illuminate the presence of allostery within the enzyme.
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Affiliation(s)
- Samiur Rahman
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409-1061, USA
| | - Mahtab Beikzadeh
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409-1061, USA
| | - Michael P Latham
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409-1061, USA.
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40
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A conserved Ctp1/CtIP C-terminal peptide stimulates Mre11 endonuclease activity. Proc Natl Acad Sci U S A 2021; 118:2016287118. [PMID: 33836577 DOI: 10.1073/pnas.2016287118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The Mre11-Rad50-Nbs1 complex (MRN) is important for repairing DNA double-strand breaks (DSBs) by homologous recombination (HR). The endonuclease activity of MRN is critical for resecting 5'-ended DNA strands at DSB ends, producing 3'-ended single-strand DNA, a prerequisite for HR. This endonuclease activity is stimulated by Ctp1, the Schizosaccharomyces pombe homolog of human CtIP. Here, with purified proteins, we show that Ctp1 phosphorylation stimulates MRN endonuclease activity by inducing the association of Ctp1 with Nbs1. The highly conserved extreme C terminus of Ctp1 is indispensable for MRN activation. Importantly, a polypeptide composed of the conserved 15 amino acids at the C terminus of Ctp1 (CT15) is sufficient to stimulate Mre11 endonuclease activity. Furthermore, the CT15 equivalent from CtIP can stimulate human MRE11 endonuclease activity, arguing for the generality of this stimulatory mechanism. Thus, we propose that Nbs1-mediated recruitment of CT15 plays a pivotal role in the activation of the Mre11 endonuclease by Ctp1/CtIP.
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41
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Panigrahi R, Glover JNM. Structural insights into DNA double-strand break signaling. Biochem J 2021; 478:135-156. [PMID: 33439989 DOI: 10.1042/bcj20200066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/10/2020] [Accepted: 12/15/2020] [Indexed: 12/14/2022]
Abstract
Genomic integrity is most threatened by double-strand breaks, which, if left unrepaired, lead to carcinogenesis or cell death. The cell generates a network of protein-protein signaling interactions that emanate from the DNA damage which are now recognized as a rich basis for anti-cancer therapy development. Deciphering the structures of signaling proteins has been an uphill task owing to their large size and complex domain organization. Recent advances in mammalian protein expression/purification and cryo-EM-based structure determination have led to significant progress in our understanding of these large multidomain proteins. This review is an overview of the structural principles that underlie some of the key signaling proteins that function at the double-strand break site. We also discuss some plausible ideas that could be considered for future structural approaches to visualize and build a more complete understanding of protein dynamics at the break site.
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Affiliation(s)
- Rashmi Panigrahi
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - J N Mark Glover
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
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42
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Qiu S, Huang J. MRN complex is an essential effector of DNA damage repair. J Zhejiang Univ Sci B 2021; 22:31-37. [PMID: 33448185 PMCID: PMC7818010 DOI: 10.1631/jzus.b2000289] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/16/2020] [Indexed: 01/01/2023]
Abstract
Genome stability can be threatened by both endogenous and exogenous agents. Organisms have evolved numerous mechanisms to repair DNA damage, including homologous recombination (HR) and non-homologous end joining (NHEJ). Among the factors associated with DNA repair, the MRE11-RAD50-NBS1 (MRN) complex (MRE11-RAD50-XRS2 in Saccharomyces cerevisiae) plays important roles not only in DNA damage recognition and signaling but also in subsequent HR or NHEJ repair. Upon detecting DNA damage, the MRN complex activates signaling molecules, such as the protein kinase ataxia-telangiectasia mutated (ATM), to trigger a broad DNA damage response, including cell cycle arrest. The nuclease activity of the MRN complex is responsible for DNA end resection, which guides DNA repair to HR in the presence of sister chromatids. The MRN complex is also involved in NHEJ, and has a species-specific role in hairpin repair. This review focuses on the structure of the MRN complex and its function in DNA damage repair.
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Affiliation(s)
- Shan Qiu
- The MOE Key Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
- Zhejiang University-University of Edinburgh Institute, School of Medicine, Zhejiang University, Haining 314400, China
| | - Jun Huang
- The MOE Key Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China.
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43
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Zabolotnaya E, Mela I, Henderson RM, Robinson NP. Turning the Mre11/Rad50 DNA repair complex on its head: lessons from SMC protein hinges, dynamic coiled-coil movements and DNA loop-extrusion? Biochem Soc Trans 2020; 48:2359-2376. [PMID: 33300987 PMCID: PMC7752040 DOI: 10.1042/bst20170168] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 10/19/2020] [Accepted: 10/22/2020] [Indexed: 12/12/2022]
Abstract
The bacterial SbcC/SbcD DNA repair proteins were identified over a quarter of a century ago. Following the subsequent identification of the homologous Mre11/Rad50 complex in the eukaryotes and archaea, it has become clear that this conserved chromosomal processing machinery is central to DNA repair pathways and the maintenance of genomic stability in all forms of life. A number of experimental studies have explored this intriguing genome surveillance machinery, yielding significant insights and providing conceptual advances towards our understanding of how this complex operates to mediate DNA repair. However, the inherent complexity and dynamic nature of this chromosome-manipulating machinery continue to obfuscate experimental interrogations, and details regarding the precise mechanisms that underpin the critical repair events remain unanswered. This review will summarize our current understanding of the dramatic structural changes that occur in Mre11/Rad50 complex to mediate chromosomal tethering and accomplish the associated DNA processing events. In addition, undetermined mechanistic aspects of the DNA enzymatic pathways driven by this vital yet enigmatic chromosomal surveillance and repair apparatus will be discussed. In particular, novel and putative models of DNA damage recognition will be considered and comparisons will be made between the modes of action of the Rad50 protein and other related ATPases of the overarching SMC superfamily.
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Affiliation(s)
| | - Ioanna Mela
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, U.K
| | | | - Nicholas P. Robinson
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YG, U.K
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44
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McPherson MT, Holub AS, Husbands AY, Petreaca RC. Mutation Spectra of the MRN (MRE11, RAD50, NBS1/NBN) Break Sensor in Cancer Cells. Cancers (Basel) 2020; 12:cancers12123794. [PMID: 33339169 PMCID: PMC7765586 DOI: 10.3390/cancers12123794] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/04/2020] [Accepted: 12/14/2020] [Indexed: 12/12/2022] Open
Abstract
Simple Summary A DNA double strand break cuts a chromosome in two and is one of the most dangerous forms of DNA damage. Improper repair can lead to various chromosomal re-arrangements that have been detected in almost all cancer cells. A complex of three proteins (MRE11, RAD50, NBS1 or NBN) detects chromosome breaks and orchestrates repair processes. Mutations in these “break sensor” genes have been described in a multitude of cancers. Here, we provide a comprehensive analysis of reported mutations from data deposited on the Catalogue of Somatic Mutations in Cancer (COSMIC) archive. We also undertake an evolutionary analysis of these genes with the aim to understand whether these mutations preferentially accumulate in conserved residues. Interestingly, we find that mutations are overrepresented in evolutionarily conserved residues of RAD50 and NBS1/NBN but not MRE11. Abstract The MRN complex (MRE11, RAD50, NBS1/NBN) is a DNA double strand break sensor in eukaryotes. The complex directly participates in, or coordinates, several activities at the break such as DNA resection, activation of the DNA damage checkpoint, chromatin remodeling and recruitment of the repair machinery. Mutations in components of the MRN complex have been described in cancer cells for several decades. Using the Catalogue of Somatic Mutations in Cancer (COSMIC) database, we characterized all the reported MRN mutations. This analysis revealed several hotspot frameshift mutations in all three genes that introduce premature stop codons and truncate large regions of the C-termini. We also found through evolutionary analyses that COSMIC mutations are enriched in conserved residues of NBS1/NBN and RAD50 but not in MRE11. Given that all three genes are important to carcinogenesis, we propose these differential enrichment patterns may reflect a more severe pleiotropic role for MRE11.
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45
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Beikzadeh M, Latham MP. The dynamic nature of the Mre11-Rad50 DNA break repair complex. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 163:14-22. [PMID: 33121960 DOI: 10.1016/j.pbiomolbio.2020.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 10/02/2020] [Accepted: 10/23/2020] [Indexed: 01/18/2023]
Abstract
The Mre11-Rad50-Nbs1/Xrs2 protein complex plays a pivotal role in the detection and repair of DNA double strand breaks. Through traditional and emerging structural biology techniques, various functional structural states of this complex have been visualized; however, relatively little is known about the transitions between these states. Indeed, it is these structural transitions that are important for Mre11-Rad50-mediated DNA unwinding at a break and the activation of downstream repair signaling events. Here, we present a brief overview of the current understanding of the structure of the core Mre11-Rad50 complex. We then highlight our recent studies emphasizing the contributions of solution state NMR spectroscopy and other biophysical techniques in providing insight into the structures and dynamics associated with Mre11-Rad50 functions.
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Affiliation(s)
- Mahtab Beikzadeh
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
| | - Michael P Latham
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA.
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46
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Mechanism and significance of chromosome damage repair by homologous recombination. Essays Biochem 2020; 64:779-790. [DOI: 10.1042/ebc20190093] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/22/2020] [Accepted: 06/29/2020] [Indexed: 12/29/2022]
Abstract
Abstract
Homologous recombination (HR) is a major, conserved pathway of chromosome damage repair. It not only fulfills key functions in the removal of deleterious lesions such as DNA double-strand breaks (DSBs) and interstrand cross-links (ICLs), but also in replication fork repair and protection. Several familial and acquired cancer predisposition syndromes stem from defects in HR. In particular, individuals with mutations in HR genes exhibit predisposition to breast, ovarian, pancreatic, and prostate cancers, and they also show signs of accelerated aging. However, aberrant and untimely HR events can lead to the loss of heterozygosity, genomic rearrangements, and cytotoxic nucleoprotein intermediates. Thus, it is critically important that HR be tightly regulated. In addition to DNA repair, HR is also involved in meiotic chromosome segregation and telomere maintenance in cells that lack telomerase. In this review, we focus on the role of HR in DSB repair (DSBR) and summarize the current state of the field.
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47
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A Survey of Reported Disease-Related Mutations in the MRE11-RAD50-NBS1 Complex. Cells 2020; 9:cells9071678. [PMID: 32668560 PMCID: PMC7407228 DOI: 10.3390/cells9071678] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/01/2020] [Accepted: 07/06/2020] [Indexed: 12/24/2022] Open
Abstract
The MRE11-RAD50-NBS1 (MRN) protein complex is one of the primary vehicles for repairing DNA double strand breaks and maintaining the genomic stability within the cell. The role of the MRN complex to recognize and process DNA double-strand breaks as well as signal other damage response factors is critical for maintaining proper cellular function. Mutations in any one of the components of the MRN complex that effect function or expression of the repair machinery could be detrimental to the cell and may initiate and/or propagate disease. Here, we discuss, in a structural and biochemical context, mutations in each of the three MRN components that have been associated with diseases such as ataxia telangiectasia-like disorder (ATLD), Nijmegen breakage syndrome (NBS), NBS-like disorder (NBSLD) and certain types of cancers. Overall, deepening our understanding of disease-causing mutations of the MRN complex at the structural and biochemical level is foundational to the future aim of treating diseases associated with these aberrations.
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48
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Yu TY, Garcia VE, Symington LS. CDK and Mec1/Tel1-catalyzed phosphorylation of Sae2 regulate different responses to DNA damage. Nucleic Acids Res 2020; 47:11238-11249. [PMID: 31552432 PMCID: PMC6868371 DOI: 10.1093/nar/gkz814] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 09/09/2019] [Accepted: 09/20/2019] [Indexed: 11/14/2022] Open
Abstract
Sae2 functions in the DNA damage response by controlling Mre11-Rad50-Xrs2 (MRX)-catalyzed end resection, an essential step for homology-dependent repair of double-strand breaks (DSBs), and by attenuating DNA damage checkpoint signaling. Phosphorylation of Sae2 by cyclin-dependent kinase (CDK1/Cdc28) activates the Mre11 endonuclease, while the physiological role of Sae2 phosphorylation by Mec1 and Tel1 checkpoint kinases is not fully understood. Here, we compare the phenotype of sae2 mutants lacking the main CDK (sae2-S267A) or Mec1 and Tel1 phosphorylation sites (sae2-5A) with sae2Δ and Mre11 nuclease defective (mre11-nd) mutants. The phosphorylation-site mutations confer DNA damage sensitivity, but not to the same extent as sae2Δ. The sae2-S267A mutation is epistatic to mre11-nd for camptothecin (CPT) sensitivity and synergizes with sgs1Δ, whereas sae2-5A synergizes with mre11-nd and exhibits epistasis with sgs1Δ. We find that attenuation of checkpoint signaling by Sae2 is mostly independent of Mre11 endonuclease activation but requires Mec1 and Tel1-dependent phosphorylation of Sae2. These results support a model whereby CDK-catalyzed phosphorylation of Sae2 activates resection via Mre11 endonuclease, whereas Sae2 phosphorylation by Mec1 and Tel1 promotes resection by the Dna2-Sgs1 and Exo1 pathways indirectly by dampening the DNA damage response.
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Affiliation(s)
- Tai-Yuan Yu
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Valerie E Garcia
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA.,Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA
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49
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Tisi R, Vertemara J, Zampella G, Longhese MP. Functional and structural insights into the MRX/MRN complex, a key player in recognition and repair of DNA double-strand breaks. Comput Struct Biotechnol J 2020; 18:1137-1152. [PMID: 32489527 PMCID: PMC7260605 DOI: 10.1016/j.csbj.2020.05.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 05/07/2020] [Accepted: 05/09/2020] [Indexed: 01/20/2023] Open
Abstract
Chromosomal DNA double-strand breaks (DSBs) are potentially lethal DNA lesions that pose a significant threat to genome stability and therefore need to be repaired to preserve genome integrity. Eukaryotic cells possess two main mechanisms for repairing DSBs: non-homologous end-joining (NHEJ) and homologous recombination (HR). HR requires that the 5' terminated strands at both DNA ends are nucleolytically degraded by a concerted action of nucleases in a process termed DNA-end resection. This degradation leads to the formation of 3'-ended single-stranded DNA (ssDNA) ends that are essential to use homologous DNA sequences for repair. The evolutionarily conserved Mre11-Rad50-Xrs2/NBS1 complex (MRX/MRN) has enzymatic and structural activities to initiate DSB resection and to maintain the DSB ends tethered to each other for their repair. Furthermore, it is required to recruit and activate the protein kinase Tel1/ATM, which plays a key role in DSB signaling. All these functions depend on ATP-regulated DNA binding and nucleolytic activities of the complex. Several structures have been obtained in recent years for Mre11 and Rad50 subunits from archaea, and a few from the bacterial and eukaryotic orthologs. Nevertheless, the mechanism of activation of this protein complex is yet to be fully elucidated. In this review, we focused on recent biophysical and structural insights on the MRX complex and their interplay.
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Affiliation(s)
- Renata Tisi
- Dipartimento di Biotecnologie and Bioscienze, Università degli Studi di Milano-Bicocca, Milan, Italy
| | - Jacopo Vertemara
- Dipartimento di Biotecnologie and Bioscienze, Università degli Studi di Milano-Bicocca, Milan, Italy
| | - Giuseppe Zampella
- Dipartimento di Biotecnologie and Bioscienze, Università degli Studi di Milano-Bicocca, Milan, Italy
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie and Bioscienze, Università degli Studi di Milano-Bicocca, Milan, Italy
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50
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Mutation of Conserved Mre11 Residues Alter Protein Dynamics to Separate Nuclease Functions. J Mol Biol 2020; 432:3289-3308. [PMID: 32246962 DOI: 10.1016/j.jmb.2020.03.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 03/25/2020] [Accepted: 03/26/2020] [Indexed: 02/08/2023]
Abstract
Naked and protein-blocked DNA ends occur naturally during immune cell development, meiosis, and at telomeres as well as from aborted topoisomerase reactions, collapsed replication forks, and other stressors. Damaged DNA ends are dangerous in cells and if left unrepaired can lead to genomic rearrangement, loss of genetic information, and eventually cancer. Mre11 is part of the Mre11-Rad50-Nbs1 complex that recognizes DNA double-strand breaks and has exonuclease and endonuclease activities that help to initiate the repair processes to resolve these broken DNA ends. In fact, these activities are crucial for proper DNA damage repair pathway choice. Here, using Pyrococcus furiosus Mre11, we question how two Mre11 separation-of-function mutants, one previously described but the second first described here, maintain endonuclease activity in the absence of exonuclease activity. To start, we performed solution-state NMR experiments to assign the side-chain methyl groups of the 64-kDa Mre11 nuclease and capping domains, which allowed us to describe the structural differences between Mre11 bound to exo- and endonuclease substrates. Then, through biochemical and biophysical characterization, including NMR structural and dynamics studies, we compared the two mutants and determined that both affect the dynamic features and double-stranded DNA binding properties of Mre11, but in different ways. In total, our results illuminate the structural and dynamic landscape of Mre11 nuclease function.
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