1
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Lambert MW. Critical role of alpha spectrin in DNA repair: the importance of μ-calpain and Fanconi anemia proteins. Exp Biol Med (Maywood) 2025; 250:10537. [PMID: 40375875 PMCID: PMC12078185 DOI: 10.3389/ebm.2025.10537] [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: 02/21/2025] [Accepted: 04/17/2025] [Indexed: 05/18/2025] Open
Abstract
Nonerythroid spectrins are proteins important in maintaining the structural integrity and flexibility of the cell and nuclear membranes and are essential for a number of functionally important cellular processes. One of these proteins, nonerythroid α spectrin (αSpII), plays a critical role in DNA repair, specifically repair of DNA interstrand crosslinks (ICLs), where it acts as a scaffold, recruiting repair proteins to sites of damage. Loss or breakdown of αSpII is an important factor in a number of disorders. One of these is Fanconi anemia (FA), a genetic disorder characterized by bone marrow failure, chromosome instability, cancer predisposition, congenital abnormalities and a defect in DNA ICL repair. Significantly, breakdown of αSpII occurs in cells from a number of FA complementation groups, due to excessive cleavage by the protease, μ-calpain, leading to defective repair of DNA ICLs in telomeric and non-telomeric DNA. Knockdown of μ-calpain in FA cells by μ-calpain siRNA results in restoration of αSpII levels to normal and repair of DNA ICLs in telomeric and non-telomeric DNA, demonstrating the importance of αSpII stability in the repair process. It is hypothesized that there is a mechanistic link between excessive cleavage of αSpII by μ-calpain and defective DNA ICL repair in FA and that FA proteins, which are deficient in FA, play a key role in maintaining the stability of αSpII and preventing its cleavage by μ-calpain. All of these events are proposed to be important key factors involved in the pathophysiology of FA and suggest new avenues for potential therapeutic intervention.
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2
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Verschuren J, van Schendel R, van Bostelen I, Verkennis AEE, Knipscheer P, Tijsterman M. FAN1-mediated translesion synthesis and POLQ/HELQ-mediated end joining generate interstrand crosslink-induced mutations. Nat Commun 2025; 16:2495. [PMID: 40082407 PMCID: PMC11906846 DOI: 10.1038/s41467-025-57764-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 03/04/2025] [Indexed: 03/16/2025] Open
Abstract
To counteract the damaging effects of DNA interstrand crosslinks (ICLs), cells have evolved various specialized ICL repair pathways. However, how ICL repair impacts genetic integrity remains incompletely understood. Here, we determined the mutagenic consequences of psoralen ICL repair in the animal model C. elegans and identify two mutagenic repair mechanisms: (i) translesion synthesis through POLH and REV1/3-mediated bypass, leading to single nucleotide polymorphisms (SNVs), and (ii) end joining via POLQ or HELQ action resulting in deletions. While we found no role for the Fanconi anemia genes FANCD2 and FANCI, disruption of TRAIP, which triggers unloading of the CMG helicase at sites of blocked replication, led to a strikingly altered repair profile, suggesting a role for DNA replication in the etiology of ICL-induced deletions. TRAIP deficiency did not affect SNV formation; instead, we found these SNVs to depend on the functionality of the Fanconi anemia-associated nuclease FAN1.
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Affiliation(s)
- Jip Verschuren
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Robin van Schendel
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Ivo van Bostelen
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Alex E E Verkennis
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Puck Knipscheer
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marcel Tijsterman
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
- Institute of Biology Leiden, Leiden University, Leiden, The Netherlands.
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3
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Kutz J, Schmietendorf H, Rahman SA, Opel F, Pospiech H. HROB Is Implicated in DNA Replication. Genes (Basel) 2024; 15:1587. [PMID: 39766854 PMCID: PMC11675949 DOI: 10.3390/genes15121587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2024] [Revised: 11/29/2024] [Accepted: 12/05/2024] [Indexed: 01/11/2025] Open
Abstract
DNA replication represents a series of precisely regulated events performed by a complex protein machinery that guarantees accurate duplication of the genetic information. Since DNA replication is permanently faced by a variety of exogenous and endogenous stressors, DNA damage response, repair and replication must be closely coordinated to maintain genomic integrity. HROB has been identified recently as a binding partner and activator of the Mcm8/9 helicase involved in DNA interstrand crosslink (ICL) repair. We identified HROB independently as a nuclear protein whose expression is co-regulated with various DNA replication factors. Accordingly, the HROB protein level showed a maximum in S phase and a downregulation in quiescence. Structural prediction and homology searches revealed that HROB is a largely intrinsically disordered protein bearing a helix-rich region and a canonical oligonucleotide/oligosaccharide-binding-fold motif that originated early in eukaryotic evolution. Employing a flow cytometry Förster resonance energy transfer (FRET) assay, we detected associations between HROB and proteins of the DNA replication machinery. Moreover, ectopic expression of HROB protein led to an almost complete shutdown of DNA replication. The available data imply a function for HROB during DNA replication across barriers such as ICLs.
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Affiliation(s)
- Julia Kutz
- Project Group Biochemistry, Leibniz Institute on Aging—Fritz Lipmann Institute, D-07745 Jena, Germany; (J.K.); (H.S.); (S.A.R.); (F.O.)
- Institute of Biochemistry and Biophysics, Faculty of Biological Sciences, Friedrich Schiller University, D-07745 Jena, Germany
| | - Hannes Schmietendorf
- Project Group Biochemistry, Leibniz Institute on Aging—Fritz Lipmann Institute, D-07745 Jena, Germany; (J.K.); (H.S.); (S.A.R.); (F.O.)
- Institute of Biochemistry and Biophysics, Faculty of Biological Sciences, Friedrich Schiller University, D-07745 Jena, Germany
| | - Sheikh Anika Rahman
- Project Group Biochemistry, Leibniz Institute on Aging—Fritz Lipmann Institute, D-07745 Jena, Germany; (J.K.); (H.S.); (S.A.R.); (F.O.)
- Institute of Biochemistry and Biophysics, Faculty of Biological Sciences, Friedrich Schiller University, D-07745 Jena, Germany
| | - Franz Opel
- Project Group Biochemistry, Leibniz Institute on Aging—Fritz Lipmann Institute, D-07745 Jena, Germany; (J.K.); (H.S.); (S.A.R.); (F.O.)
- Department of Medical Engineering and Biotechnology, Ernst-Abbe University of Applied Sciences, D-07745 Jena, Germany
| | - Helmut Pospiech
- Project Group Biochemistry, Leibniz Institute on Aging—Fritz Lipmann Institute, D-07745 Jena, Germany; (J.K.); (H.S.); (S.A.R.); (F.O.)
- Institute of Biochemistry and Biophysics, Faculty of Biological Sciences, Friedrich Schiller University, D-07745 Jena, Germany
- Department of Obstetrics and Gynecology, University Hospital Düsseldorf and Heinrich-Heine University, D-40225 Düsseldorf, Germany
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4
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Jahjah T, Singh JK, Gottifredi V, Quinet A. Tolerating DNA damage by repriming: Gap filling in the spotlight. DNA Repair (Amst) 2024; 142:103758. [PMID: 39236419 DOI: 10.1016/j.dnarep.2024.103758] [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: 05/17/2024] [Revised: 08/14/2024] [Accepted: 08/25/2024] [Indexed: 09/07/2024]
Abstract
Timely and accurate DNA replication is critical for safeguarding genome integrity and ensuring cell viability. Yet, this process is challenged by DNA damage blocking the progression of the replication machinery. To counteract replication fork stalling, evolutionary conserved DNA damage tolerance (DDT) mechanisms promote DNA damage bypass and fork movement. One of these mechanisms involves "skipping" DNA damage through repriming downstream of the lesion, leaving single-stranded DNA (ssDNA) gaps behind the advancing forks (also known as post-replicative gaps). In vertebrates, repriming in damaged leading templates is proposed to be mainly promoted by the primase and polymerase PRIMPOL. In this review, we discuss recent advances towards our understanding of the physiological and pathological conditions leading to repriming activation in human models, revealing a regulatory network of PRIMPOL activity. Upon repriming by PRIMPOL, post-replicative gaps formed can be filled-in by the DDT mechanisms translesion synthesis and template switching. We discuss novel findings on how these mechanisms are regulated and coordinated in time to promote gap filling. Finally, we discuss how defective gap filling and aberrant gap expansion by nucleases underlie the cytotoxicity associated with post-replicative gap accumulation. Our increasing knowledge of this repriming mechanism - from gap formation to gap filling - is revealing that targeting the last step of this pathway is a promising approach to exploit post-replicative gaps in anti-cancer therapeutic strategies.
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Affiliation(s)
- Tiya Jahjah
- Université Paris Cité, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRS/iRCM/IBFJ, Fontenay-aux-Roses F-92265, France; Université Paris-Saclay, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRS/iRCM/IBFJ, Fontenay-aux-Roses F-92265, France
| | - Jenny K Singh
- Université Paris Cité, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRS/iRCM/IBFJ, Fontenay-aux-Roses F-92265, France; Université Paris-Saclay, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRS/iRCM/IBFJ, Fontenay-aux-Roses F-92265, France
| | - Vanesa Gottifredi
- Fundación Instituto Leloir, IIBBA, CONICET, Buenos Aires 1405, Argentina
| | - Annabel Quinet
- Université Paris Cité, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRS/iRCM/IBFJ, Fontenay-aux-Roses F-92265, France; Université Paris-Saclay, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRS/iRCM/IBFJ, Fontenay-aux-Roses F-92265, France.
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5
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Adolph MB, Cortez D. Mechanisms and regulation of replication fork reversal. DNA Repair (Amst) 2024; 141:103731. [PMID: 39089193 PMCID: PMC11877614 DOI: 10.1016/j.dnarep.2024.103731] [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: 04/24/2024] [Revised: 07/15/2024] [Accepted: 07/17/2024] [Indexed: 08/03/2024]
Abstract
DNA replication is remarkably accurate with estimates of only a handful of mutations per human genome per cell division cycle. Replication stress caused by DNA lesions, transcription-replication conflicts, and other obstacles to the replication machinery must be efficiently overcome in ways that minimize errors and maximize completion of DNA synthesis. Replication fork reversal is one mechanism that helps cells tolerate replication stress. This process involves reannealing of parental template DNA strands and generation of a nascent-nascent DNA duplex. While fork reversal may be beneficial by facilitating DNA repair or template switching, it must be confined to the appropriate contexts to preserve genome stability. Many enzymes have been implicated in this process including ATP-dependent DNA translocases like SMARCAL1, ZRANB3, HLTF, and the helicase FBH1. In addition, the RAD51 recombinase is required. Many additional factors and regulatory activities also act to ensure reversal is beneficial instead of yielding undesirable outcomes. Finally, reversed forks must also be stabilized and often need to be restarted to complete DNA synthesis. Disruption or deregulation of fork reversal causes a variety of human diseases. In this review we will describe the latest models for reversal and key mechanisms of regulation.
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Affiliation(s)
- Madison B Adolph
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, United States
| | - David Cortez
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, United States.
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6
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Bellani MA, Shaik A, Majumdar I, Ling C, Seidman MM. Repair of genomic interstrand crosslinks. DNA Repair (Amst) 2024; 141:103739. [PMID: 39106540 PMCID: PMC11423799 DOI: 10.1016/j.dnarep.2024.103739] [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: 03/12/2024] [Revised: 07/11/2024] [Accepted: 07/25/2024] [Indexed: 08/09/2024]
Abstract
Genomic interstrand crosslinks (ICLs) are formed by reactive species generated during normal cellular metabolism, produced by the microbiome, and employed in cancer chemotherapy. While there are multiple options for replication dependent and independent ICL repair, the crucial step for each is unhooking one DNA strand from the other. Much of our insight into mechanisms of unhooking comes from powerful model systems based on plasmids with defined ICLs introduced into cells or cell free extracts. Here we describe the properties of exogenous and endogenous ICL forming compounds and provide an historical perspective on early work on ICL repair. We discuss the modes of unhooking elucidated in the model systems, the concordance or lack thereof in drug resistant tumors, and the evolving view of DNA adducts, including ICLs, formed by metabolic aldehydes.
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Affiliation(s)
- Marina A Bellani
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Althaf Shaik
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Ishani Majumdar
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Chen Ling
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Michael M Seidman
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
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7
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Pokharel D, Shaik A, Gali H, Ling C, Bellani MA, Seidman MM. A bifunctional antibody conjugate marks the location of DNA binding proteins on deproteinized DNA fibers. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.29.609705. [PMID: 39257800 PMCID: PMC11383660 DOI: 10.1101/2024.08.29.609705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2024]
Abstract
Immunofluorescent foci of DNA Damage Response (DDR) proteins serve as surrogates for DNA damage and are frequently interpreted as denoting specific lesions. For example, Double Strand Breaks (DSBs) are potent inducers of the DDR, whose best-known factor is the phosphorylated histone variant H2AX (γ-H2AX). The association with DSBs is so well established that the reverse interpretation that γ-H2AX invariably implies DSBs is routine. However, this conclusion is inferential and has been challenged. The resolution of this question has been hampered by the lack of methods for distinguishing the location of DDR proteins relative to DSBs caused by sequence indifferent agents. Here, we describe an approach for marking the location of DDR factors in relation to DSBs on DNA fibers. We synthesized a two-arm "Y" conjugate containing biotin and trimethylpsoralen (TMP) coupled to a secondary antibody. After exposure to a DNA breaker, permeabilized mammalian cells were incubated with a primary antibody against the DDR factor followed by binding of the secondary antibody in the conjugate to the primary antibody. Exposure to longwave UV light covalently linked the psoralen to the DNA. DNA fibers were spread, and the immunofluorescence of the biotin tag denoted the location of the target protein. Abstract Figure
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8
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Abbouche L, Bythell-Douglas R, Deans AJ. FANCM branchpoint translocase: Master of traverse, reverse and adverse DNA repair. DNA Repair (Amst) 2024; 140:103701. [PMID: 38878565 DOI: 10.1016/j.dnarep.2024.103701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 05/15/2024] [Accepted: 05/30/2024] [Indexed: 07/13/2024]
Abstract
FANCM is a multifunctional DNA repair enzyme that acts as a sensor and coordinator of replication stress responses, especially interstrand crosslink (ICL) repair mediated by the Fanconi anaemia (FA) pathway. Its specialised ability to bind and remodel branched DNA structures enables diverse genome maintenance activities. Through ATP-powered "branchpoint translocation", FANCM can promote fork reversal, facilitate replication traverse of ICLs, resolve deleterious R-loop structures, and restrain recombination. These remodelling functions also support a role as sensor of perturbed replication, eliciting checkpoint signalling and recruitment of downstream repair factors like the Fanconi anaemia FANCI:FANCD2 complex. Accordingly, FANCM deficiency causes chromosome fragility and cancer susceptibility. Other recent advances link FANCM to roles in gene editing efficiency and meiotic recombination, along with emerging synthetic lethal relationships, and targeting opportunities in ALT-positive cancers. Here we review key properties of FANCM's biochemical activities, with a particular focus on branchpoint translocation as a distinguishing characteristic.
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Affiliation(s)
- Lara Abbouche
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia; Department of Medicine (St Vincent's), University of Melbourne, Fitzroy, VIC, Australia
| | - Rohan Bythell-Douglas
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia
| | - Andrew J Deans
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia; Department of Medicine (St Vincent's), University of Melbourne, Fitzroy, VIC, Australia.
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9
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Liu Z, Jiang H, Lee SY, Kong N, Chan YW. FANCM promotes PARP inhibitor resistance by minimizing ssDNA gap formation and counteracting resection inhibition. Cell Rep 2024; 43:114464. [PMID: 38985669 DOI: 10.1016/j.celrep.2024.114464] [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: 12/19/2023] [Revised: 05/22/2024] [Accepted: 06/24/2024] [Indexed: 07/12/2024] Open
Abstract
Poly(ADP-ribose) polymerase inhibitors (PARPis) exhibit remarkable anticancer activity in tumors with homologous recombination (HR) gene mutations. However, the role of other DNA repair proteins in PARPi-induced lethality remains elusive. Here, we reveal that FANCM promotes PARPi resistance independent of the core Fanconi anemia (FA) complex. FANCM-depleted cells retain HR proficiency, acting independently of BRCA1 in response to PARPis. FANCM depletion leads to increased DNA damage in the second S phase after PARPi exposure, driven by elevated single-strand DNA (ssDNA) gap formation behind replication forks in the first S phase. These gaps arise from both 53BP1- and primase and DNA directed polymerase (PRIMPOL)-dependent mechanisms. Notably, FANCM-depleted cells also exhibit reduced resection of collapsed forks, while 53BP1 deletion restores resection and mitigates PARPi sensitivity. Our results suggest that FANCM counteracts 53BP1 to repair PARPi-induced DNA damage. Furthermore, FANCM depletion leads to increased chromatin bridges and micronuclei formation after PARPi treatment, elucidating the mechanism underlying extensive cell death in FANCM-depleted cells.
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Affiliation(s)
- Zeyuan Liu
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Huadong Jiang
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Sze Yuen Lee
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Nannan Kong
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Ying Wai Chan
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
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10
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Sanchez-Lopez I, Orantos-Aguilera Y, Pozo-Guisado E, Alvarez-Barrientos A, Lilla S, Zanivan S, Lachaud C, Martin-Romero FJ. STIM1 translocation to the nucleus protects cells from DNA damage. Nucleic Acids Res 2024; 52:2389-2415. [PMID: 38224453 PMCID: PMC10954485 DOI: 10.1093/nar/gkae001] [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: 03/31/2023] [Revised: 10/30/2023] [Accepted: 01/01/2024] [Indexed: 01/16/2024] Open
Abstract
DNA damage represents a challenge for cells, as this damage must be eliminated to preserve cell viability and the transmission of genetic information. To reduce or eliminate unscheduled chemical modifications in genomic DNA, an extensive signaling network, known as the DNA damage response (DDR) pathway, ensures this repair. In this work, and by means of a proteomic analysis aimed at studying the STIM1 protein interactome, we have found that STIM1 is closely related to the protection from endogenous DNA damage, replicative stress, as well as to the response to interstrand crosslinks (ICLs). Here we show that STIM1 has a nuclear localization signal that mediates its translocation to the nucleus, and that this translocation and the association of STIM1 to chromatin increases in response to mitomycin-C (MMC), an ICL-inducing agent. Consequently, STIM1-deficient cell lines show higher levels of basal DNA damage, replicative stress, and increased sensitivity to MMC. We show that STIM1 normalizes FANCD2 protein levels in the nucleus, which explains the increased sensitivity of STIM1-KO cells to MMC. This study not only unveils a previously unknown nuclear function for the endoplasmic reticulum protein STIM1 but also expands our understanding of the genes involved in DNA repair.
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Affiliation(s)
- Irene Sanchez-Lopez
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Universidad de Extremadura, Badajoz 06006, Spain
- Institute of Molecular Pathology Biomarkers, Universidad de Extremadura, Badajoz 06006, Spain
| | - Yolanda Orantos-Aguilera
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Universidad de Extremadura, Badajoz 06006, Spain
- Institute of Molecular Pathology Biomarkers, Universidad de Extremadura, Badajoz 06006, Spain
| | - Eulalia Pozo-Guisado
- Institute of Molecular Pathology Biomarkers, Universidad de Extremadura, Badajoz 06006, Spain
- Department of Cell Biology, School of Medicine, Universidad de Extremadura, Badajoz 06006, Spain
| | | | - Sergio Lilla
- CRUK Scotland Institute, Switchback Road, Glasgow G61 1BD, UK
| | - Sara Zanivan
- CRUK Scotland Institute, Switchback Road, Glasgow G61 1BD, UK
- School of Cancer Sciences, University of Glasgow, Switchback Road, Glasgow G61 1QH, UK
| | - Christophe Lachaud
- Cancer Research Centre of Marseille, Aix-Marseille Univ, Inserm, CNRS, Institut Paoli Calmettes, CRCM, Marseille, France
- OPALE Carnot Institute, Paris, France
| | - Francisco Javier Martin-Romero
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Universidad de Extremadura, Badajoz 06006, Spain
- Institute of Molecular Pathology Biomarkers, Universidad de Extremadura, Badajoz 06006, Spain
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Price NE, Gates KS. Novel Processes Associated with the Repair of Interstrand Cross-Links Derived from Abasic Sites in Duplex DNA: Roles for the Base Excision Repair Glycosylase NEIL3 and the SRAP Protein HMCES. Chem Res Toxicol 2024; 37:199-207. [PMID: 38198604 DOI: 10.1021/acs.chemrestox.3c00345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Recent studies have defined a novel pathway for the repair of interstrand cross-links derived from the reaction of an adenine residue with an apurinic/apyrimidinic (AP) site on the opposing strand of DNA (dA-AP ICL). Stalling of a replication fork at the dA-AP ICL triggers TRAIP-dependent ubiquitylation of the CMG helicase that recruits the base excision repair glycosylase NEIL3 to the lesion. NEIL3 unhooks the dA-AP ICL to regenerate the native adenine residue on one strand and an AP site on the other strand. Covalent capture of the abasic site by the SRAP protein HMCES protects against genomic instability that would result from cleavage of the abasic site in the context of single-stranded DNA at the replication fork. After repair synthesis moves the HMCES-AP adduct into the context of double-stranded DNA, the DNA-protein cross-link is resolved by a nonproteolytic mechanism involving dissociation of thiazolidine attachment. The AP site in duplex DNA is then repaired by the base excision repair pathway.
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Affiliation(s)
- Nathan E Price
- Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States
| | - Kent S Gates
- Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States
- Department of Biochemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States
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12
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Stewart GS. DONSON: Slding in 2 the limelight. DNA Repair (Amst) 2024; 134:103616. [PMID: 38159447 DOI: 10.1016/j.dnarep.2023.103616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/18/2023] [Accepted: 12/19/2023] [Indexed: 01/03/2024]
Abstract
For over a decade, it has been known that yeast Sld2, Dpb11, GINS and Polε form the pre-loading complex (pre-LC), which is recruited to a CDC45-bound MCM2-7 complex by the Sld3/Sld7 heterodimer in a phospho-dependent manner. Whilst functional orthologs of Dbp11 (TOPBP1), Sld3 (TICRR) and Sld7 (MTBP) have been identified in metazoans, controversy has surrounded the identity of the Sld2 ortholog. It was originally proposed that the RECQ helicase, RECQL4, which is mutated in Rothmund-Thomson syndrome, represented the closest vertebrate ortholog of Sld2 due to a small region of sequence homology at its N-Terminus. However, there is no clear evidence that RECQL4 is required for CMG loading. Recently, new findings suggest that the functional ortholog of Sld2 is actually DONSON, a replication fork stability factor mutated in a range of neurodevelopmental disorders characterised by microcephaly, short stature and limb abnormalities. These studies show that DONSON forms a complex with TOPBP1, GINS and Polε analogous to the pre-LC in yeast, which is required to position the GINS complex on the MCM complex and initiate DNA replication. Taken together with previously published functions for DONSON, these observations indicate that DONSON plays two roles in regulating DNA replication, one in promoting replication initiation and one in stabilising the fork during elongation. Combined, these findings may help to uncover why DONSON mutations are associated with such a wide range of clinical deficits.
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Affiliation(s)
- Grant S Stewart
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.
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13
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Xu MJ, Jordan PW. SMC5/6 Promotes Replication Fork Stability via Negative Regulation of the COP9 Signalosome. Int J Mol Sci 2024; 25:952. [PMID: 38256025 PMCID: PMC10815603 DOI: 10.3390/ijms25020952] [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: 12/04/2023] [Revised: 01/06/2024] [Accepted: 01/10/2024] [Indexed: 01/24/2024] Open
Abstract
It is widely accepted that DNA replication fork stalling is a common occurrence during cell proliferation, but there are robust mechanisms to alleviate this and ensure DNA replication is completed prior to chromosome segregation. The SMC5/6 complex has consistently been implicated in the maintenance of replication fork integrity. However, the essential role of the SMC5/6 complex during DNA replication in mammalian cells has not been elucidated. In this study, we investigate the molecular consequences of SMC5/6 loss at the replication fork in mouse embryonic stem cells (mESCs), employing the auxin-inducible degron (AID) system to deplete SMC5 acutely and reversibly in the defined cellular contexts of replication fork stall and restart. In SMC5-depleted cells, we identify a defect in the restart of stalled replication forks, underpinned by excess MRE11-mediated fork resection and a perturbed localization of fork protection factors to the stalled fork. Previously, we demonstrated a physical and functional interaction of SMC5/6 with the COP9 signalosome (CSN), a cullin deneddylase that enzymatically regulates cullin ring ligase (CRL) activity. Employing a combination of DNA fiber techniques, the AID system, small-molecule inhibition assays, and immunofluorescence microscopy analyses, we show that SMC5/6 promotes the localization of fork protection factors to stalled replication forks by negatively modulating the COP9 signalosome (CSN). We propose that the SMC5/6-mediated modulation of the CSN ensures that CRL activity and their roles in DNA replication fork stabilization are maintained to allow for efficient replication fork restart when a replication fork stall is alleviated.
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Affiliation(s)
- Michelle J. Xu
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Philip W. Jordan
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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14
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Bellani MA, Shaik A, Majumdar I, Ling C, Seidman MM. The Response of the Replication Apparatus to Leading Template Strand Blocks. Cells 2023; 12:2607. [PMID: 37998342 PMCID: PMC10670059 DOI: 10.3390/cells12222607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 11/25/2023] Open
Abstract
Duplication of the genome requires the replication apparatus to overcome a variety of impediments, including covalent DNA adducts, the most challenging of which is on the leading template strand. Replisomes consist of two functional units, a helicase to unwind DNA and polymerases to synthesize it. The helicase is a multi-protein complex that encircles the leading template strand and makes the first contact with a leading strand adduct. The size of the channel in the helicase would appear to preclude transit by large adducts such as DNA: protein complexes (DPC). Here we discuss some of the extensively studied pathways that support replication restart after replisome encounters with leading template strand adducts. We also call attention to recent work that highlights the tolerance of the helicase for adducts ostensibly too large to pass through the central channel.
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Affiliation(s)
| | | | | | | | - Michael M. Seidman
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA; (M.A.B.)
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15
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Hashimoto Y, Sadano K, Miyata N, Ito H, Tanaka H. Novel role of DONSON in CMG helicase assembly during vertebrate DNA replication initiation. EMBO J 2023; 42:e114131. [PMID: 37458194 PMCID: PMC10476173 DOI: 10.15252/embj.2023114131] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/27/2023] [Accepted: 06/29/2023] [Indexed: 09/05/2023] Open
Abstract
CMG (Cdc45-MCM-GINS) helicase assembly at the replication origin is the culmination of eukaryotic DNA replication initiation. This process can be reconstructed in vitro using defined factors in Saccharomyces cerevisiae; however, in vertebrates, origin-dependent CMG formation has not yet been achieved partly due to the lack of a complete set of known initiator proteins. Since a microcephaly gene product, DONSON, was reported to remodel the CMG helicase under replication stress, we analyzed its role in DNA replication using a Xenopus cell-free system. We found that DONSON was essential for the replisome assembly. In vertebrates, DONSON physically interacted with GINS and Polε via its conserved N-terminal PGY and NPF motifs, and the DONSON-GINS interaction contributed to the replisome assembly. DONSON's chromatin association during replication initiation required the pre-replicative complex, TopBP1, and kinase activities of S-CDK and DDK. Both S-CDK and DDK required DONSON to trigger replication initiation. Moreover, human DONSON could substitute for the Xenopus protein in a cell-free system. These findings indicate that vertebrate DONSON is a novel initiator protein essential for CMG helicase assembly.
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Affiliation(s)
- Yoshitami Hashimoto
- School of Life SciencesTokyo University of Pharmacy and Life SciencesTokyoJapan
| | - Kota Sadano
- School of Life SciencesTokyo University of Pharmacy and Life SciencesTokyoJapan
| | - Nene Miyata
- School of Life SciencesTokyo University of Pharmacy and Life SciencesTokyoJapan
| | - Haruka Ito
- School of Life SciencesTokyo University of Pharmacy and Life SciencesTokyoJapan
| | - Hirofumi Tanaka
- School of Life SciencesTokyo University of Pharmacy and Life SciencesTokyoJapan
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16
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Berrada S, Martínez-Balsalobre E, Larcher L, Azzoni V, Vasquez N, Da Costa M, Abel S, Audoly G, Lee L, Montersino C, Castellano R, Combes S, Gelot C, Ceccaldi R, Guervilly JH, Soulier J, Lachaud C. A clickable melphalan for monitoring DNA interstrand crosslink accumulation and detecting ICL repair defects in Fanconi anemia patient cells. Nucleic Acids Res 2023; 51:7988-8004. [PMID: 37395445 PMCID: PMC10450163 DOI: 10.1093/nar/gkad559] [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: 11/25/2022] [Revised: 06/14/2023] [Accepted: 06/21/2023] [Indexed: 07/04/2023] Open
Abstract
Fanconi anemia (FA) is a genetic disorder associated with developmental defects, bone marrow failure and cancer. The FA pathway is crucial for the repair of DNA interstrand crosslinks (ICLs). In this study, we have developed and characterized a new tool to investigate ICL repair: a clickable version of the crosslinking agent melphalan which we name click-melphalan. Our results demonstrate that click-melphalan is as effective as its unmodified counterpart in generating ICLs and associated toxicity. The lesions induced by click-melphalan can be detected in cells by post-labelling with a fluorescent reporter and quantified using flow cytometry. Since click-melphalan induces both ICLs and monoadducts, we generated click-mono-melphalan, which only induces monoadducts, in order to distinguish between the two types of DNA repair. By using both molecules, we show that FANCD2 knock-out cells are deficient in removing click-melphalan-induced lesions. We also found that these cells display a delay in repairing click-mono-melphalan-induced monoadducts. Our data further revealed that the presence of unrepaired ICLs inhibits monoadduct repair. Finally, our study demonstrates that these clickable molecules can differentiate intrinsic DNA repair deficiencies in primary FA patient cells from those in primary xeroderma pigmentosum patient cells. As such, these molecules may have potential for developing diagnostic tests.
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Affiliation(s)
- Sara Berrada
- Aix-Marseille Univ, INSERM, CNRS, Institut Paoli-Calmettes, CRCM, Marseille, France
| | | | - Lise Larcher
- University Paris Cité, Institut de Recherche Saint-Louis, INSERM U944, and CNRS UMR7212, Paris, France
- Laboratoire de biologie médicale de référence (LBMR) “Aplastic anemia”, Service d’Hématologie biologique, Hôpital Saint-Louis, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Violette Azzoni
- Aix-Marseille Univ, INSERM, CNRS, Institut Paoli-Calmettes, CRCM, Marseille, France
| | - Nadia Vasquez
- University Paris Cité, Institut de Recherche Saint-Louis, INSERM U944, and CNRS UMR7212, Paris, France
- Laboratoire de biologie médicale de référence (LBMR) “Aplastic anemia”, Service d’Hématologie biologique, Hôpital Saint-Louis, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Mélanie Da Costa
- University Paris Cité, Institut de Recherche Saint-Louis, INSERM U944, and CNRS UMR7212, Paris, France
- Laboratoire de biologie médicale de référence (LBMR) “Aplastic anemia”, Service d’Hématologie biologique, Hôpital Saint-Louis, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Sébastien Abel
- Aix-Marseille Univ, INSERM, CNRS, Institut Paoli-Calmettes, CRCM, Marseille, France
| | - Gilles Audoly
- Aix-Marseille Univ, INSERM, CNRS, Institut Paoli-Calmettes, CRCM, Marseille, France
| | - Lara Lee
- Aix-Marseille Univ, INSERM, CNRS, Institut Paoli-Calmettes, CRCM, Marseille, France
| | - Camille Montersino
- Aix-Marseille Univ, INSERM, CNRS, Institut Paoli-Calmettes, CRCM, Marseille, France
| | - Rémy Castellano
- Aix-Marseille Univ, INSERM, CNRS, Institut Paoli-Calmettes, CRCM, Marseille, France
| | - Sébastien Combes
- Aix-Marseille Univ, INSERM, CNRS, Institut Paoli-Calmettes, CRCM, Marseille, France
| | - Camille Gelot
- Inserm U830, PSL Research University, Institut Curie, Paris, France
| | - Raphaël Ceccaldi
- Inserm U830, PSL Research University, Institut Curie, Paris, France
| | | | - Jean Soulier
- University Paris Cité, Institut de Recherche Saint-Louis, INSERM U944, and CNRS UMR7212, Paris, France
- Laboratoire de biologie médicale de référence (LBMR) “Aplastic anemia”, Service d’Hématologie biologique, Hôpital Saint-Louis, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Christophe Lachaud
- Aix-Marseille Univ, INSERM, CNRS, Institut Paoli-Calmettes, CRCM, Marseille, France
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17
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Bellani MA, Huang J, Zhang J, Gali H, Thazhathveetil AK, Pokharel D, Majumdar I, Shaik A, Seidman MM. Imaging the cellular response to an antigen tagged interstrand crosslinking agent. DNA Repair (Amst) 2023; 128:103525. [PMID: 37320956 PMCID: PMC10413329 DOI: 10.1016/j.dnarep.2023.103525] [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: 04/02/2023] [Revised: 06/02/2023] [Accepted: 06/08/2023] [Indexed: 06/17/2023]
Abstract
Immunofluorescence imaging is a standard experimental tool for monitoring the response of cellular factors to DNA damage. Visualizing the recruitment of DNA Damage Response (DDR) components requires high affinity antibodies, which are generally available. In contrast, reagents for the display of the lesions that induce the response are far more limited. Consequently, DDR factor accumulation often serves as a surrogate for damage, without reporting the actual inducing structure. This limitation has practical implications given the importance of the response to DNA reactive drugs such as those used in cancer therapy. These include interstrand crosslink (ICL) forming compounds which are frequently employed clinically. Among them are the psoralens, natural products that form ICLs upon photoactivation and applied therapeutically since antiquity. However, despite multiple attempts, antibodies against psoralen ICLs have not been developed. To overcome this limitation, we developed a psoralen tagged with an antigen for which there are commercial antibodies. In this report we describe our application of the tagged psoralen in imaging experiments, and the unexpected discoveries they revealed.
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Affiliation(s)
- Marina A Bellani
- Laboratory of Molecular Biology and Immunology, NIA, NIH, Baltimore MD 21224, USA
| | - Jing Huang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, School of Biomedical Sciences, Hunan University, Changsha 410082, China
| | - Jing Zhang
- Department of Neurosurgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Himabindu Gali
- Frederick National Laboratory for Cancer Research, Frederick, MD 21703, USA
| | | | | | - Ishani Majumdar
- Laboratory of Molecular Biology and Immunology, NIA, NIH, Baltimore MD 21224, USA
| | - Althaf Shaik
- Laboratory of Molecular Biology and Immunology, NIA, NIH, Baltimore MD 21224, USA
| | - Michael M Seidman
- Laboratory of Molecular Biology and Immunology, NIA, NIH, Baltimore MD 21224, USA.
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18
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Saldanha J, Rageul J, Patel JA, Kim H. The Adaptive Mechanisms and Checkpoint Responses to a Stressed DNA Replication Fork. Int J Mol Sci 2023; 24:10488. [PMID: 37445667 PMCID: PMC10341514 DOI: 10.3390/ijms241310488] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/13/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
DNA replication is a tightly controlled process that ensures the faithful duplication of the genome. However, DNA damage arising from both endogenous and exogenous assaults gives rise to DNA replication stress associated with replication fork slowing or stalling. Therefore, protecting the stressed fork while prompting its recovery to complete DNA replication is critical for safeguarding genomic integrity and cell survival. Specifically, the plasticity of the replication fork in engaging distinct DNA damage tolerance mechanisms, including fork reversal, repriming, and translesion DNA synthesis, enables cells to overcome a variety of replication obstacles. Furthermore, stretches of single-stranded DNA generated upon fork stalling trigger the activation of the ATR kinase, which coordinates the cellular responses to replication stress by stabilizing the replication fork, promoting DNA repair, and controlling cell cycle and replication origin firing. Deregulation of the ATR checkpoint and aberrant levels of chronic replication stress is a common characteristic of cancer and a point of vulnerability being exploited in cancer therapy. Here, we discuss the various adaptive responses of a replication fork to replication stress and the roles of ATR signaling that bring fork stabilization mechanisms together. We also review how this knowledge is being harnessed for the development of checkpoint inhibitors to trigger the replication catastrophe of cancer cells.
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Affiliation(s)
- Joanne Saldanha
- The Graduate Program in Genetics, Stony Brook University, Stony Brook, NY 11794, USA
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - Julie Rageul
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - Jinal A. Patel
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - Hyungjin Kim
- The Graduate Program in Genetics, Stony Brook University, Stony Brook, NY 11794, USA
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
- Stony Brook Cancer Center, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY 11794, USA
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19
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Rogers CB, Kram RE, Lin K, Myers CL, Sobeck A, Hendrickson EA, Bielinsky AK. Fanconi anemia-associated chromosomal radial formation is dependent on POLθ-mediated alternative end joining. Cell Rep 2023; 42:112428. [PMID: 37086407 DOI: 10.1016/j.celrep.2023.112428] [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: 10/13/2022] [Revised: 01/25/2023] [Accepted: 04/07/2023] [Indexed: 04/23/2023] Open
Abstract
Activation of the Fanconi anemia (FA) pathway after treatment with mitomycin C (MMC) is essential for preventing chromosome translocations termed "radials." When replication forks stall at MMC-induced interstrand crosslinks (ICLs), the FA pathway is activated to orchestrate ICL unhooking and repair of the DNA break intermediates. However, in FA-deficient cells, how ICL-associated breaks are resolved in a manner that leads to radials is unclear. Here, we demonstrate that MMC-induced radials are dependent on DNA polymerase theta (POLθ)-mediated alternative end joining (A-EJ). Specifically, we show that radials observed in FANCD2-/- cells are dependent on POLθ and DNA ligase III and occur independently of classical non-homologous end joining. Furthermore, treatment of FANCD2-/- cells with POLθ inhibitors abolishes radials and leads to the accumulation of breaks co-localizing with common fragile sites. Uniformly, these observations implicate A-EJ in radial formation and provide mechanistic insights into the treatment of FA pathway-deficient cancers with POLθ inhibitors.
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Affiliation(s)
- Colette B Rogers
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Rachel E Kram
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Kevin Lin
- Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Chad L Myers
- Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Alexandra Sobeck
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Eric A Hendrickson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Anja-Katrin Bielinsky
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
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20
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Sohn EJ, Goralsky JA, Shay JW, Min J. The Molecular Mechanisms and Therapeutic Prospects of Alternative Lengthening of Telomeres (ALT). Cancers (Basel) 2023; 15:cancers15071945. [PMID: 37046606 PMCID: PMC10093677 DOI: 10.3390/cancers15071945] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 04/14/2023] Open
Abstract
As detailed by the end replication problem, the linear ends of a cell's chromosomes, known as telomeres, shorten with each successive round of replication until a cell enters into a state of growth arrest referred to as senescence. To maintain their immortal proliferation capacity, cancer cells must employ a telomere maintenance mechanism, such as telomerase activation or the Alternative Lengthening of Telomeres pathway (ALT). With only 10-15% of cancers utilizing the ALT mechanism, progress towards understanding its molecular components and associated hallmarks has only recently been made. This review analyzes the advances towards understanding the ALT pathway by: (1) detailing the mechanisms associated with engaging the ALT pathway as well as (2) identifying potential therapeutic targets of ALT that may lead to novel cancer therapeutic treatments. Collectively, these studies indicate that the ALT molecular mechanisms involve at least two distinct pathways induced by replication stress and damage at telomeres. We suggest exploiting tumor dependency on ALT is a promising field of study because it suggests new approaches to ALT-specific therapies for cancers with poorer prognosis. While substantial progress has been made in the ALT research field, additional progress will be required to realize these advances into clinical practices to treat ALT cancers and improve patient prognoses.
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Affiliation(s)
- Eric J Sohn
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Julia A Goralsky
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA
| | - Jaewon Min
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
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21
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Jaiswal AS, Kim HS, Schärer OD, Sharma N, Williamson E, Srinivasan G, Phillips L, Kong K, Arya S, Misra A, Dutta A, Gupta Y, Walter C, Burma S, Narayan S, Sung P, Nickoloff J, Hromas R. EEPD1 promotes repair of oxidatively-stressed replication forks. NAR Cancer 2023; 5:zcac044. [PMID: 36683914 PMCID: PMC9846428 DOI: 10.1093/narcan/zcac044] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 11/22/2022] [Accepted: 12/14/2022] [Indexed: 01/19/2023] Open
Abstract
Unrepaired oxidatively-stressed replication forks can lead to chromosomal instability and neoplastic transformation or cell death. To meet these challenges cells have evolved a robust mechanism to repair oxidative genomic DNA damage through the base excision repair (BER) pathway, but less is known about repair of oxidative damage at replication forks. We found that depletion or genetic deletion of EEPD1 decreases clonogenic cell survival after oxidative DNA damage. We demonstrate that EEPD1 is recruited to replication forks stressed by oxidative damage induced by H2O2 and that EEPD1 promotes replication fork repair and restart and decreases chromosomal abnormalities after such damage. EEPD1 binds to abasic DNA structures and promotes resolution of genomic abasic sites after oxidative stress. We further observed that restoration of expression of EEPD1 via expression vector transfection restores cell survival and suppresses chromosomal abnormalities induced by oxidative stress in EEPD1-depleted cells. Consistent with this, we found that EEPD1 preserves replication fork integrity by preventing oxidatively-stressed unrepaired fork fusion, thereby decreasing chromosome instability and mitotic abnormalities. Our results indicate a novel role for EEPD1 in replication fork preservation and maintenance of chromosomal stability during oxidative stress.
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Affiliation(s)
- Aruna S Jaiswal
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Hyun-Suk Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Republic of Korea
| | - Orlando D Schärer
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Republic of Korea
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Elizabeth A Williamson
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Gayathri Srinivasan
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Linda Phillips
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Kimi Kong
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Shailee Arya
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Anurag Misra
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Arijit Dutta
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Yogesh Gupta
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Christi A Walter
- Department of Cell Systems and Anatomy, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Sandeep Burma
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
- Department of Neurosurgery, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Satya Narayan
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA
| | - Patrick Sung
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
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22
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Kavlashvili T, Liu W, Mohamed TM, Cortez D, Dewar JM. Replication fork uncoupling causes nascent strand degradation and fork reversal. Nat Struct Mol Biol 2023; 30:115-124. [PMID: 36593312 PMCID: PMC9868089 DOI: 10.1038/s41594-022-00871-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 10/14/2022] [Indexed: 01/03/2023]
Abstract
Genotoxins cause nascent strand degradation (NSD) and fork reversal during DNA replication. NSD and fork reversal are crucial for genome stability and are exploited by chemotherapeutic approaches. However, it is unclear how NSD and fork reversal are triggered. Additionally, the fate of the replicative helicase during these processes is unknown. We developed a biochemical approach to study synchronous, localized NSD and fork reversal using Xenopus egg extracts and validated this approach with experiments in human cells. We show that replication fork uncoupling stimulates NSD of both nascent strands and progressive conversion of uncoupled forks to reversed forks. Notably, the replicative helicase remains bound during NSD and fork reversal. Unexpectedly, NSD occurs before and after fork reversal, indicating that multiple degradation steps take place. Overall, our data show that uncoupling causes NSD and fork reversal and elucidate key events that precede fork reversal.
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Affiliation(s)
- Tamar Kavlashvili
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Wenpeng Liu
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Taha M Mohamed
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - David Cortez
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - James M Dewar
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA.
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23
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Jackson LM, Moldovan GL. Mechanisms of PARP1 inhibitor resistance and their implications for cancer treatment. NAR Cancer 2022; 4:zcac042. [PMID: 36568963 PMCID: PMC9773381 DOI: 10.1093/narcan/zcac042] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/28/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022] Open
Abstract
The discovery of synthetic lethality as a result of the combined loss of PARP1 and BRCA has revolutionized the treatment of DNA repair-deficient cancers. With the development of PARP inhibitors, patients displaying germline or somatic mutations in BRCA1 or BRCA2 were presented with a novel therapeutic strategy. However, a large subset of patients do not respond to PARP inhibitors. Furthermore, many of those who do respond eventually acquire resistance. As such, combating de novo and acquired resistance to PARP inhibitors remains an obstacle in achieving durable responses in patients. In this review, we touch on some of the key mechanisms of PARP inhibitor resistance, including restoration of homologous recombination, replication fork stabilization and suppression of single-stranded DNA gap accumulation, as well as address novel approaches for overcoming PARP inhibitor resistance.
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Affiliation(s)
- Lindsey M Jackson
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - George-Lucian Moldovan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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24
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Elango R, Panday A, Lach FP, Willis NA, Nicholson K, Duffey EE, Smogorzewska A, Scully R. The structure-specific endonuclease complex SLX4-XPF regulates Tus-Ter-induced homologous recombination. Nat Struct Mol Biol 2022; 29:801-812. [PMID: 35941380 PMCID: PMC9941964 DOI: 10.1038/s41594-022-00812-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 07/05/2022] [Indexed: 02/08/2023]
Abstract
Vertebrate replication forks arrested at interstrand DNA cross-links (ICLs) engage the Fanconi anemia pathway to incise arrested forks, 'unhooking' the ICL and forming a double strand break (DSB) that is repaired by homologous recombination (HR). The FANCP product, SLX4, in complex with the XPF (also known as FANCQ or ERCC4)-ERCC1 endonuclease, mediates ICL unhooking. Whether this mechanism operates at replication fork barriers other than ICLs is unknown. Here, we study the role of mouse SLX4 in HR triggered by a site-specific chromosomal DNA-protein replication fork barrier formed by the Escherichia coli-derived Tus-Ter complex. We show that SLX4-XPF is required for Tus-Ter-induced HR but not for error-free HR induced by a replication-independent DSB. We additionally uncover a role for SLX4-XPF in DSB-induced long-tract gene conversion, an error-prone HR pathway related to break-induced replication. Notably, Slx4 and Xpf mutants that are defective for Tus-Ter-induced HR are hypersensitive to ICLs and also to the DNA-protein cross-linking agents 5-aza-2'-deoxycytidine and zebularine. Collectively, these findings show that SLX4-XPF can process DNA-protein fork barriers for HR and that the Tus-Ter system recapitulates this process.
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Affiliation(s)
- Rajula Elango
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Arvind Panday
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Francis P Lach
- Laboratory of Genome Maintenance, The Rockefeller University, New York, NY, USA
| | - Nicholas A Willis
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Kaitlin Nicholson
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Erin E Duffey
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Agata Smogorzewska
- Laboratory of Genome Maintenance, The Rockefeller University, New York, NY, USA
| | - Ralph Scully
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
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25
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Cong K, Cantor SB. Exploiting replication gaps for cancer therapy. Mol Cell 2022; 82:2363-2369. [PMID: 35568026 PMCID: PMC9271608 DOI: 10.1016/j.molcel.2022.04.023] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 03/25/2022] [Accepted: 04/19/2022] [Indexed: 01/08/2023]
Abstract
Defects in DNA double-strand break repair are thought to render BRCA1 or BRCA2 (BRCA) mutant tumors selectively sensitive to PARP inhibitors (PARPis). Challenging this framework, BRCA and PARP1 share functions in DNA synthesis on the lagging strand. Thus, BRCA deficiency or "BRCAness" could reflect an inherent lagging strand problem that is vulnerable to drugs such as PARPi that also target the lagging strand, a combination that generates a toxic accumulation of replication gaps.
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Affiliation(s)
- Ke Cong
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Sharon B Cantor
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA.
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26
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Saxena S, Zou L. Hallmarks of DNA replication stress. Mol Cell 2022; 82:2298-2314. [PMID: 35714587 DOI: 10.1016/j.molcel.2022.05.004] [Citation(s) in RCA: 190] [Impact Index Per Article: 63.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 04/15/2022] [Accepted: 05/04/2022] [Indexed: 12/12/2022]
Abstract
Faithful DNA replication is critical for the maintenance of genomic integrity. Although DNA replication machinery is highly accurate, the process of DNA replication is constantly challenged by DNA damage and other intrinsic and extrinsic stresses throughout the genome. A variety of cellular stresses interfering with DNA replication, which are collectively termed replication stress, pose a threat to genomic stability in both normal and cancer cells. To cope with replication stress and maintain genomic stability, cells have evolved a complex network of cellular responses to alleviate and tolerate replication problems. This review will focus on the major sources of replication stress, the impacts of replication stress in cells, and the assays to detect replication stress, offering an overview of the hallmarks of DNA replication stress.
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Affiliation(s)
- Sneha Saxena
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
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27
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Fu S, Phan AT, Mao D, Wang X, Gao G, Goff SP, Zhu Y. HIV-1 exploits the Fanconi anemia pathway for viral DNA integration. Cell Rep 2022; 39:110840. [PMID: 35613597 PMCID: PMC9250337 DOI: 10.1016/j.celrep.2022.110840] [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: 09/21/2021] [Revised: 03/08/2022] [Accepted: 04/27/2022] [Indexed: 11/24/2022] Open
Abstract
The integration of HIV-1 DNA into the host genome results in single-strand gaps and 2-nt overhangs at the ends of viral DNA, which must be repaired by cellular enzymes. The cellular factors responsible for the DNA damage repair in HIV-1 DNA integration have not yet been well defined. We report here that HIV-1 infection potently activates the Fanconi anemia (FA) DNA repair pathway, and the FA effector proteins FANCI-D2 bind to the C-terminal domain of HIV-1 integrase. Knockout of FANCI blocks productive viral DNA integration and inhibits the replication of HIV-1. Finally, we show that the knockout of DNA polymerases or flap nuclease downstream of FANCI-D2 reduces the levels of integrated HIV-1 DNA, suggesting these enzymes may be responsible for the repair of DNA damages induced by viral DNA integration. These experiments reveal that HIV-1 exploits the FA pathway for the stable integration of viral DNA into host genome.
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Affiliation(s)
- Shaozu Fu
- CAS Key Laboratory of Infection and Immunity, CAS Centre for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - An Thanh Phan
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Dexin Mao
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Xinlu Wang
- CAS Key Laboratory of Infection and Immunity, CAS Centre for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guangxia Gao
- CAS Key Laboratory of Infection and Immunity, CAS Centre for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Stephen P Goff
- Department of Biochemistry and Molecular Biophysics and of Microbiology and Immunology, Columbia University, New York, NY 10032, USA.
| | - Yiping Zhu
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA.
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28
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Peake JD, Noguchi E. Fanconi anemia: current insights regarding epidemiology, cancer, and DNA repair. Hum Genet 2022; 141:1811-1836. [PMID: 35596788 DOI: 10.1007/s00439-022-02462-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 05/09/2022] [Indexed: 12/12/2022]
Abstract
Fanconi anemia is a genetic disorder that is characterized by bone marrow failure, as well as a predisposition to malignancies including leukemia and squamous cell carcinoma (SCC). At least 22 genes are associated with Fanconi anemia, constituting the Fanconi anemia DNA repair pathway. This pathway coordinates multiple processes and proteins to facilitate the repair of DNA adducts including interstrand crosslinks (ICLs) that are generated by environmental carcinogens, chemotherapeutic crosslinkers, and metabolic products of alcohol. ICLs can interfere with DNA transactions, including replication and transcription. If not properly removed and repaired, ICLs cause DNA breaks and lead to genomic instability, a hallmark of cancer. In this review, we will discuss the genetic and phenotypic characteristics of Fanconi anemia, the epidemiology of the disease, and associated cancer risk. The sources of ICLs and the role of ICL-inducing chemotherapeutic agents will also be discussed. Finally, we will review the detailed mechanisms of ICL repair via the Fanconi anemia DNA repair pathway, highlighting critical regulatory processes. Together, the information in this review will underscore important contributions to Fanconi anemia research in the past two decades.
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Affiliation(s)
- Jasmine D Peake
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - Eishi Noguchi
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA.
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29
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Brickner JR, Garzon JL, Cimprich KA. Walking a tightrope: The complex balancing act of R-loops in genome stability. Mol Cell 2022; 82:2267-2297. [PMID: 35508167 DOI: 10.1016/j.molcel.2022.04.014] [Citation(s) in RCA: 124] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/28/2022] [Accepted: 04/10/2022] [Indexed: 12/14/2022]
Abstract
Although transcription is an essential cellular process, it is paradoxically also a well-recognized cause of genomic instability. R-loops, non-B DNA structures formed when nascent RNA hybridizes to DNA to displace the non-template strand as single-stranded DNA (ssDNA), are partially responsible for this instability. Yet, recent work has begun to elucidate regulatory roles for R-loops in maintaining the genome. In this review, we discuss the cellular contexts in which R-loops contribute to genomic instability, particularly during DNA replication and double-strand break (DSB) repair. We also summarize the evidence that R-loops participate as an intermediate during repair and may influence pathway choice to preserve genomic integrity. Finally, we discuss the immunogenic potential of R-loops and highlight their links to disease should they become pathogenic.
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Affiliation(s)
- Joshua R Brickner
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jada L Garzon
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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30
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Bu L, Luo T, Yan J, Li G, Huang J. Single-molecule analysis of genome-wide DNA methylation by fiber FISH coupled with atomic force microscopy. Analyst 2022; 147:1559-1566. [DOI: 10.1039/d2an00216g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A straightforward single-molecule approach was developed for identifying whole-genome DNA methylation through fiber-FISH coupled with AFM. This method has advantages of low DNA input, reproduction, long reads and low cost.
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Affiliation(s)
- Lingli Bu
- Institute of Chemical Biology and Nanomedicine (ICBN), State Key Laboratory of Chemo/Biosensing and Chemometrics, School of Biomedical Sciences, Hunan University, Changsha 410082, China
| | - Tao Luo
- Institute of Chemical Biology and Nanomedicine (ICBN), State Key Laboratory of Chemo/Biosensing and Chemometrics, School of Biomedical Sciences, Hunan University, Changsha 410082, China
| | - Jiangyu Yan
- Institute of Chemical Biology and Nanomedicine (ICBN), State Key Laboratory of Chemo/Biosensing and Chemometrics, School of Biomedical Sciences, Hunan University, Changsha 410082, China
| | - Guorui Li
- Institute of Chemical Biology and Nanomedicine (ICBN), State Key Laboratory of Chemo/Biosensing and Chemometrics, School of Biomedical Sciences, Hunan University, Changsha 410082, China
| | - Jing Huang
- Institute of Chemical Biology and Nanomedicine (ICBN), State Key Laboratory of Chemo/Biosensing and Chemometrics, School of Biomedical Sciences, Hunan University, Changsha 410082, China
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31
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Jones ML, Baris Y, Taylor MRG, Yeeles JTP. Structure of a human replisome shows the organisation and interactions of a DNA replication machine. EMBO J 2021; 40:e108819. [PMID: 34694004 PMCID: PMC8634136 DOI: 10.15252/embj.2021108819] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/28/2021] [Accepted: 09/30/2021] [Indexed: 02/01/2023] Open
Abstract
The human replisome is an elaborate arrangement of molecular machines responsible for accurate chromosome replication. At its heart is the CDC45-MCM-GINS (CMG) helicase, which, in addition to unwinding the parental DNA duplex, arranges many proteins including the leading-strand polymerase Pol ε, together with TIMELESS-TIPIN, CLASPIN and AND-1 that have key and varied roles in maintaining smooth replisome progression. How these proteins are coordinated in the human replisome is poorly understood. We have determined a 3.2 Å cryo-EM structure of a human replisome comprising CMG, Pol ε, TIMELESS-TIPIN, CLASPIN and AND-1 bound to replication fork DNA. The structure permits a detailed understanding of how AND-1, TIMELESS-TIPIN and Pol ε engage CMG, reveals how CLASPIN binds to multiple replisome components and identifies the position of the Pol ε catalytic domain. Furthermore, the intricate network of contacts contributed by MCM subunits and TIMELESS-TIPIN with replication fork DNA suggests a mechanism for strand separation.
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32
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Abstract
Ring-shaped hexameric helicases are essential motor proteins that separate duplex nucleic acid strands for DNA replication, recombination, and transcriptional regulation. Two evolutionarily distinct lineages of these enzymes, predicated on RecA and AAA+ ATPase folds, have been identified and characterized to date. Hexameric helicases couple NTP hydrolysis with conformational changes that move nucleic acid substrates through a central pore in the enzyme. How hexameric helicases productively engage client DNA or RNA segments and use successive rounds of NTPase activity to power translocation and unwinding have been longstanding questions in the field. Recent structural and biophysical findings are beginning to reveal commonalities in NTP hydrolysis and substrate translocation by diverse hexameric helicase families. Here, we review these molecular mechanisms and highlight aspects of their function that are yet to be understood.
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33
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Rozelle AL, Lee S. Genotoxic C8-Arylamino-2'-deoxyadenosines Act as Latent Alkylating Agents to Induce DNA Interstrand Cross-Links. J Am Chem Soc 2021; 143:18960-18976. [PMID: 34726902 DOI: 10.1021/jacs.1c07234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
DNA interstrand cross-links (ICLs) are extremely deleterious and structurally diverse, driving the evolution of ICL repair pathways. Discovering ICL-inducing agents is, thus, crucial for the characterization of ICL repair pathways and Fanconi anemia, a genetic disease caused by mutations in ICL repair genes. Although several studies point to oxidative stress as a cause of ICLs, oxidative stress-induced cross-linking events remain poorly characterized. Also, polycyclic aromatic amines, potent environmental carcinogens, have been implicated in producing ICLs, but their identities and sequences are unknown. To close this knowledge gap, we tested whether ICLs arise by the oxidation of 8-arylamino-2'-deoxyadenosine (ArNHdA) lesions, adducts produced by arylamino carcinogens. Herein, we report that ArNHdA acts as a latent cross-linking agent to generate ICLs under oxidative conditions. The formation of an ICL from 8-aminoadenine, but not from 8-aminoguanine, highlights the specificity of 8-aminopurine-mediated ICL production. Under the influence of the reactive oxygen species (ROS) nitrosoperoxycarbonate, ArNHdA (Ar = biphenyl, fluorenyl) lesions were selectively oxidized to generate ICLs. The cross-linking reaction may occur between the C2-ArNHdA and N2-dG, presumably via oxidation of ArNHdA into a reactive diiminoadenine intermediate followed by the nucleophilic attack of the N2-dG on the diiminoadenine. Overall, ArNHdA-mediated ICLs represent rare examples of ROS-induced ICLs and polycyclic aromatic amine-mediated ICLs. These results reveal novel cross-linking chemistry and the genotoxic effects of arylamino carcinogens and support the hypothesis that C8-modified adenines with low redox potential can cause ICLs in oxidative stress.
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Affiliation(s)
- Aaron L Rozelle
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, United States.,McKetta Department of Chemical Engineering, Cockrell School of Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Seongmin Lee
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, United States
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34
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Cantor SB. Revisiting the BRCA-pathway through the lens of replication gap suppression: "Gaps determine therapy response in BRCA mutant cancer". DNA Repair (Amst) 2021; 107:103209. [PMID: 34419699 PMCID: PMC9049047 DOI: 10.1016/j.dnarep.2021.103209] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 08/06/2021] [Accepted: 08/07/2021] [Indexed: 12/12/2022]
Abstract
The toxic lesion emanating from chemotherapy that targets the DNA was initially debated, but eventually the DNA double strand break (DSB) ultimately prevailed. The reasoning was in part based on the perception that repairing a fractured chromosome necessitated intricate processing or condemned the cell to death. Genetic evidence for the DSB model was also provided by the extreme sensitivity of cells that were deficient in DSB repair. In particular, sensitivity characterized cells harboring mutations in the hereditary breast/ovarian cancer genes, BRCA1 or BRCA2, that function in the repair of DSBs by homologous recombination (HR). Along with functions in HR, BRCA proteins were found to prevent DSBs by protecting stalled replication forks from nuclease degradation. Coming full-circle, BRCA mutant cancer cells that gained resistance to genotoxic chemotherapy often displayed restored DNA repair by HR and/or restored fork protection (FP) implicating that the therapy was tolerated when DSB repair was intact or DSBs were prevented. Despite this well-supported paradigm that has been the impetus for targeted cancer therapy, here we argue that the toxic DNA lesion conferring response is instead single stranded DNA (ssDNA) gaps. We discuss the evidence that persistent ssDNA gaps formed in the wake of DNA replication rather than DSBs are responsible for cell killing following treatment with genotoxic chemotherapeutic agents. We also highlight that proteins, such as BRCA1, BRCA2, and RAD51 known for canonical DSB repair also have critical roles in normal replication as well as replication gap suppression (RGS) and repair. We review the literature that supports the idea that widespread gap induction proximal to treatment triggers apoptosis in a process that does not need or stem from DSB induction. Lastly, we discuss the clinical evidence for gaps and how to exploit them to enhance genotoxic chemotherapy response.
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Affiliation(s)
- Sharon B Cantor
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, LRB 415, 364 Plantation St., Worcester, MA 01605, USA.
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35
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Yoshida K, Fujita M. DNA damage responses that enhance resilience to replication stress. Cell Mol Life Sci 2021; 78:6763-6773. [PMID: 34463774 PMCID: PMC11072782 DOI: 10.1007/s00018-021-03926-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/16/2021] [Accepted: 08/24/2021] [Indexed: 12/12/2022]
Abstract
During duplication of the genome, eukaryotic cells may experience various exogenous and endogenous replication stresses that impede progression of DNA replication along chromosomes. Chemical alterations in template DNA, imbalances of deoxynucleotide pools, repetitive sequences, tight DNA-protein complexes, and conflict with transcription can negatively affect the replication machineries. If not properly resolved, stalled replication forks can cause chromosome breaks leading to genomic instability and tumor development. Replication stress is enhanced in cancer cells due, for example, to the loss of DNA repair genes or replication-transcription conflict caused by activation of oncogenic pathways. To prevent these serious consequences, cells are equipped with diverse mechanisms that enhance the resilience of replication machineries to replication stresses. This review describes DNA damage responses activated at stressed replication forks and summarizes current knowledge on the pathways that promote faithful chromosome replication and protect chromosome integrity, including ATR-dependent replication checkpoint signaling, DNA cross-link repair, and SLX4-mediated responses to tight DNA-protein complexes that act as barriers. This review also focuses on the relevance of replication stress responses to selective cancer chemotherapies.
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Affiliation(s)
- Kazumasa Yoshida
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
- Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka, 814-0180, Japan
- Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka, 814-0180, Japan
| | - Masatoshi Fujita
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
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36
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Zhang J, Bellani MA, Huang J, James RC, Pokharel D, Gichimu J, Gali H, Stewart G, Seidman MM. Replication of the Mammalian Genome by Replisomes Specific for Euchromatin and Heterochromatin. Front Cell Dev Biol 2021; 9:729265. [PMID: 34532320 PMCID: PMC8438199 DOI: 10.3389/fcell.2021.729265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/10/2021] [Indexed: 11/26/2022] Open
Abstract
Replisomes follow a schedule in which replication of DNA in euchromatin is early in S phase while sequences in heterochromatin replicate late. Impediments to DNA replication, referred to as replication stress, can stall replication forks triggering activation of the ATR kinase and downstream pathways. While there is substantial literature on the local consequences of replisome stalling-double strand breaks, reversed forks, or genomic rearrangements-there is limited understanding of the determinants of replisome stalling vs. continued progression. Although many proteins are recruited to stalled replisomes, current models assume a single species of "stressed" replisome, independent of genomic location. Here we describe our approach to visualizing replication fork encounters with the potent block imposed by a DNA interstrand crosslink (ICL) and our discovery of an unexpected pathway of replication restart (traverse) past an intact ICL. Additionally, we found two biochemically distinct replisomes distinguished by activity in different stages of S phase and chromatin environment. Each contains different proteins that contribute to ICL traverse.
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Affiliation(s)
- Jing Zhang
- Department of Neurosurgery, Institute for Advanced Study, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Marina A. Bellani
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Jing Huang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Institute of Chemical Biology and Nanomedicine, Hunan University, Changsha, China
| | - Ryan C. James
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, United States
| | - Durga Pokharel
- Horizon Discovery Group plc, Lafayette, CO, United States
| | - Julia Gichimu
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Himabindu Gali
- Frederick National Laboratory for Cancer Research, Frederick, MD, United States
| | - Grant Stewart
- College of Medical and Dental Sciences, Institute of Cancer and Genomic Science, University of Birmingham, Birmingham, United Kingdom
| | - Michael M. Seidman
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
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37
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Scully R, Elango R, Panday A, Willis NA. Recombination and restart at blocked replication forks. Curr Opin Genet Dev 2021; 71:154-162. [PMID: 34464818 DOI: 10.1016/j.gde.2021.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/28/2021] [Accepted: 08/06/2021] [Indexed: 01/07/2023]
Abstract
Replication fork stalling occurs when the replisome encounters a barrier to normal fork progression. Replisome stalling events are common during scheduled DNA synthesis, but vary in their severity. At one extreme, a lesion may induce only temporary pausing of a DNA polymerase; at the other, it may present a near-absolute barrier to the replicative helicase and effectively block fork progression. Many alternative pathways have evolved to respond to these different types of replication stress. Among these, the homologous recombination (HR) pathway plays an important role, protecting the stalled fork and processing it for repair. Here, we review recent advances in our understanding of how blocked replication forks in vertebrate cells can be processed for recombination and for replication restart.
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Affiliation(s)
- Ralph Scully
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA.
| | - Rajula Elango
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Arvind Panday
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Nicholas A Willis
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
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38
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Guilliam TA. Mechanisms for Maintaining Eukaryotic Replisome Progression in the Presence of DNA Damage. Front Mol Biosci 2021; 8:712971. [PMID: 34295925 PMCID: PMC8290200 DOI: 10.3389/fmolb.2021.712971] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/25/2021] [Indexed: 12/04/2022] Open
Abstract
The eukaryotic replisome coordinates template unwinding and nascent-strand synthesis to drive DNA replication fork progression and complete efficient genome duplication. During its advancement along the parental template, each replisome may encounter an array of obstacles including damaged and structured DNA that impede its progression and threaten genome stability. A number of mechanisms exist to permit replisomes to overcome such obstacles, maintain their progression, and prevent fork collapse. A combination of recent advances in structural, biochemical, and single-molecule approaches have illuminated the architecture of the replisome during unperturbed replication, rationalised the impact of impediments to fork progression, and enhanced our understanding of DNA damage tolerance mechanisms and their regulation. This review focusses on these studies to provide an updated overview of the mechanisms that support replisomes to maintain their progression on an imperfect template.
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Affiliation(s)
- Thomas A. Guilliam
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
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39
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Lalonde M, Trauner M, Werner M, Hamperl S. Consequences and Resolution of Transcription-Replication Conflicts. Life (Basel) 2021; 11:life11070637. [PMID: 34209204 PMCID: PMC8303131 DOI: 10.3390/life11070637] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 11/17/2022] Open
Abstract
Transcription–replication conflicts occur when the two critical cellular machineries responsible for gene expression and genome duplication collide with each other on the same genomic location. Although both prokaryotic and eukaryotic cells have evolved multiple mechanisms to coordinate these processes on individual chromosomes, it is now clear that conflicts can arise due to aberrant transcription regulation and premature proliferation, leading to DNA replication stress and genomic instability. As both are considered hallmarks of aging and human diseases such as cancer, understanding the cellular consequences of conflicts is of paramount importance. In this article, we summarize our current knowledge on where and when collisions occur and how these encounters affect the genome and chromatin landscape of cells. Finally, we conclude with the different cellular pathways and multiple mechanisms that cells have put in place at conflict sites to ensure the resolution of conflicts and accurate genome duplication.
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40
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González-Acosta D, Blanco-Romero E, Ubieto-Capella P, Mutreja K, Míguez S, Llanos S, García F, Muñoz J, Blanco L, Lopes M, Méndez J. PrimPol-mediated repriming facilitates replication traverse of DNA interstrand crosslinks. EMBO J 2021; 40:e106355. [PMID: 34128550 PMCID: PMC8280817 DOI: 10.15252/embj.2020106355] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 05/04/2021] [Accepted: 05/04/2021] [Indexed: 12/22/2022] Open
Abstract
DNA interstrand crosslinks (ICLs) induced by endogenous aldehydes or chemotherapeutic agents interfere with essential processes such as replication and transcription. ICL recognition and repair by the Fanconi Anemia pathway require the formation of an X‐shaped DNA structure that may arise from convergence of two replication forks at the crosslink or traversing of the lesion by a single replication fork. Here, we report that ICL traverse strictly requires DNA repriming events downstream of the lesion, which are carried out by PrimPol, the second primase‐polymerase identified in mammalian cells after Polα/Primase. The recruitment of PrimPol to the vicinity of ICLs depends on its interaction with RPA, but not on FANCM translocase or the BLM/TOP3A/RMI1‐2 (BTR) complex that also participate in ICL traverse. Genetic ablation of PRIMPOL makes cells more dependent on the fork convergence mechanism to initiate ICL repair, and PRIMPOL KO cells and mice display hypersensitivity to ICL‐inducing drugs. These results open the possibility of targeting PrimPol activity to enhance the efficacy of chemotherapy based on DNA crosslinking agents.
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Affiliation(s)
- Daniel González-Acosta
- DNA Replication Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Elena Blanco-Romero
- DNA Replication Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Patricia Ubieto-Capella
- DNA Replication Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Karun Mutreja
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Samuel Míguez
- DNA Replication Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Susana Llanos
- DNA Replication Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Fernando García
- Proteomics Unit-ProteoRed-ISCIII, Biotechnology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Javier Muñoz
- Proteomics Unit-ProteoRed-ISCIII, Biotechnology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Luis Blanco
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Juan Méndez
- DNA Replication Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
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41
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Fanconi anemia proteins participate in a break-induced-replication-like pathway to counter replication stress. Nat Struct Mol Biol 2021; 28:487-500. [PMID: 34117478 DOI: 10.1038/s41594-021-00602-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 04/30/2021] [Indexed: 11/08/2022]
Abstract
Fanconi anemia (FA) is a devastating hereditary disease characterized by bone marrow failure (BMF) and acute myeloid leukemia (AML). As FA-deficient cells are hypersensitive to DNA interstrand crosslinks (ICLs), ICLs are widely assumed to be the lesions responsible for FA symptoms. Here, we show that FA-mutated cells are hypersensitive to persistent replication stress and that FA proteins play a role in the break-induced-replication (BIR)-like pathway for fork restart. Both the BIR-like pathway and ICL repair share almost identical molecular mechanisms of 53BP1-BRCA1-controlled signaling response, SLX4- and FAN1-mediated fork cleavage and POLD3-dependent DNA synthesis, suggesting that the FA pathway is intrinsically one of the BIR-like pathways. Replication stress not only triggers BMF in FA-deficient mice, but also specifically induces monosomy 7, which is associated with progression to AML in patients with FA, in FA-deficient cells.
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42
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Abstract
DNA interstrand cross-links (ICLs) covalently connect the two strands of the double helix and are extremely cytotoxic. Defective ICL repair causes the bone marrow failure and cancer predisposition syndrome, Fanconi anemia, and upregulation of repair causes chemotherapy resistance in cancer. The central event in ICL repair involves resolving the cross-link (unhooking). In this review, we discuss the chemical diversity of ICLs generated by exogenous and endogenous agents. We then describe how proliferating and nonproliferating vertebrate cells unhook ICLs. We emphasize fundamentally new unhooking strategies, dramatic progress in the structural analysis of the Fanconi anemia pathway, and insights into how cells govern the choice between different ICL repair pathways. Throughout, we highlight the many gaps that remain in our knowledge of these fascinating DNA repair pathways.
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Affiliation(s)
- Daniel R Semlow
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA; .,Current affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Johannes C Walter
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA; .,Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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43
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Panday A, Willis NA, Elango R, Menghi F, Duffey EE, Liu ET, Scully R. FANCM regulates repair pathway choice at stalled replication forks. Mol Cell 2021; 81:2428-2444.e6. [PMID: 33882298 DOI: 10.1016/j.molcel.2021.03.044] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 02/18/2021] [Accepted: 03/26/2021] [Indexed: 01/19/2023]
Abstract
Repair pathway "choice" at stalled mammalian replication forks is an important determinant of genome stability; however, the underlying mechanisms are poorly understood. FANCM encodes a multi-domain scaffolding and motor protein that interacts with several distinct repair protein complexes at stalled forks. Here, we use defined mutations engineered within endogenous Fancm in mouse embryonic stem cells to study how Fancm regulates stalled fork repair. We find that distinct FANCM repair functions are enacted by molecularly separable scaffolding domains. These findings define FANCM as a key mediator of repair pathway choice at stalled replication forks and reveal its molecular mechanism. Notably, mutations that inactivate FANCM ATPase function disable all its repair functions and "trap" FANCM at stalled forks. We find that Brca1 hypomorphic mutants are synthetic lethal with Fancm null or Fancm ATPase-defective mutants. The ATPase function of FANCM may therefore represent a promising "druggable" target for therapy of BRCA1-linked cancer.
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Affiliation(s)
- Arvind Panday
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, MA 02215, USA
| | - Nicholas A Willis
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, MA 02215, USA
| | - Rajula Elango
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, MA 02215, USA
| | - Francesca Menghi
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06030, USA
| | - Erin E Duffey
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, MA 02215, USA
| | - Edison T Liu
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06030, USA
| | - Ralph Scully
- Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, MA 02215, USA.
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44
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Helbling-Leclerc A, Garcin C, Rosselli F. Beyond DNA repair and chromosome instability-Fanconi anaemia as a cellular senescence-associated syndrome. Cell Death Differ 2021; 28:1159-1173. [PMID: 33723374 PMCID: PMC8026967 DOI: 10.1038/s41418-021-00764-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 02/17/2021] [Accepted: 02/24/2021] [Indexed: 02/07/2023] Open
Abstract
Fanconi anaemia (FA) is the most frequent inherited bone marrow failure syndrome, due to mutations in genes encoding proteins involved in replication fork protection, DNA interstrand crosslink repair and replication rescue through inducing double-strand break repair and homologous recombination. Clinically, FA is characterised by aplastic anaemia, congenital defects and cancer predisposition. In in vitro studies, FA cells presented hallmarks defining senescent cells, including p53-p21 axis activation, altered telomere length, mitochondrial dysfunction, chromatin alterations, and a pro-inflammatory status. Senescence is a programme leading to proliferation arrest that is involved in different physiological contexts, such as embryogenesis, tissue remodelling and repair and guarantees tumour suppression activity. However, senescence can become a driving force for developmental abnormalities, aging and cancer. Herein, we summarise the current knowledge in the field to highlight the mutual relationships between FA and senescence that lead us to consider FA not only as a DNA repair and chromosome fragility syndrome but also as a "senescence syndrome".
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Affiliation(s)
- Anne Helbling-Leclerc
- grid.14925.3b0000 0001 2284 9388UMR9019-CNRS, Gustave Roussy, Villejuif, Cedex France ,grid.460789.40000 0004 4910 6535Université Paris-Saclay, Orsay, France ,Equipe labellisée “La Ligue Contre le Cancer”, Villejuif, France
| | - Cécile Garcin
- grid.14925.3b0000 0001 2284 9388UMR9019-CNRS, Gustave Roussy, Villejuif, Cedex France ,grid.460789.40000 0004 4910 6535Université Paris-Saclay, Orsay, France ,Equipe labellisée “La Ligue Contre le Cancer”, Villejuif, France
| | - Filippo Rosselli
- grid.14925.3b0000 0001 2284 9388UMR9019-CNRS, Gustave Roussy, Villejuif, Cedex France ,grid.460789.40000 0004 4910 6535Université Paris-Saclay, Orsay, France ,Equipe labellisée “La Ligue Contre le Cancer”, Villejuif, France
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45
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Panzarino NJ, Krais JJ, Cong K, Peng M, Mosqueda M, Nayak SU, Bond SM, Calvo JA, Doshi MB, Bere M, Ou J, Deng B, Zhu LJ, Johnson N, Cantor SB. Replication Gaps Underlie BRCA Deficiency and Therapy Response. Cancer Res 2021; 81:1388-1397. [PMID: 33184108 PMCID: PMC8026497 DOI: 10.1158/0008-5472.can-20-1602] [Citation(s) in RCA: 132] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 09/02/2020] [Accepted: 11/09/2020] [Indexed: 11/16/2022]
Abstract
Defects in DNA repair and the protection of stalled DNA replication forks are thought to underlie the chemosensitivity of tumors deficient in the hereditary breast cancer genes BRCA1 and BRCA2 (BRCA). Challenging this assumption are recent findings that indicate chemotherapies, such as cisplatin used to treat BRCA-deficient tumors, do not initially cause DNA double-strand breaks (DSB). Here, we show that ssDNA replication gaps underlie the hypersensitivity of BRCA-deficient cancer and that defects in homologous recombination (HR) or fork protection (FP) do not. In BRCA-deficient cells, ssDNA gaps developed because replication was not effectively restrained in response to stress. Gap suppression by either restoration of fork restraint or gap filling conferred therapy resistance in tissue culture and BRCA patient tumors. In contrast, restored FP and HR could be uncoupled from therapy resistance when gaps were present. Moreover, DSBs were not detected after therapy when apoptosis was inhibited, supporting a framework in which DSBs are not directly induced by genotoxic agents, but rather are induced from cell death nucleases and are not fundamental to the mechanism of action of genotoxic agents. Together, these data indicate that ssDNA replication gaps underlie the BRCA cancer phenotype, "BRCAness," and we propose they are fundamental to the mechanism of action of genotoxic chemotherapies. SIGNIFICANCE: This study suggests that ssDNA replication gaps are fundamental to the toxicity of genotoxic agents and underlie the BRCA-cancer phenotype "BRCAness," yielding promising biomarkers, targets, and opportunities to resensitize refractory disease.See related commentary by Canman, p. 1214.
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Affiliation(s)
| | - John J Krais
- Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Ke Cong
- University of Massachusetts Medical School, Worcester, Massachusetts
| | - Min Peng
- University of Massachusetts Medical School, Worcester, Massachusetts
| | - Michelle Mosqueda
- University of Massachusetts Medical School, Worcester, Massachusetts
| | - Sumeet U Nayak
- University of Massachusetts Medical School, Worcester, Massachusetts
| | - Samuel M Bond
- University of Massachusetts Medical School, Worcester, Massachusetts
| | - Jennifer A Calvo
- University of Massachusetts Medical School, Worcester, Massachusetts
| | - Mihir B Doshi
- University of Massachusetts Medical School, Worcester, Massachusetts
| | - Matt Bere
- University of Massachusetts Medical School, Worcester, Massachusetts
| | - Jianhong Ou
- University of Massachusetts Medical School, Worcester, Massachusetts
| | - Bin Deng
- The University of Vermont, Burlington, Vermont
| | - Lihua J Zhu
- University of Massachusetts Medical School, Worcester, Massachusetts
| | - Neil Johnson
- Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Sharon B Cantor
- University of Massachusetts Medical School, Worcester, Massachusetts.
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46
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Quinet A, Tirman S, Cybulla E, Meroni A, Vindigni A. To skip or not to skip: choosing repriming to tolerate DNA damage. Mol Cell 2021; 81:649-658. [PMID: 33515486 PMCID: PMC7935405 DOI: 10.1016/j.molcel.2021.01.012] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/21/2020] [Accepted: 01/06/2021] [Indexed: 12/14/2022]
Abstract
Accurate DNA replication is constantly threatened by DNA lesions arising from endogenous and exogenous sources. Specialized DNA replication stress response pathways ensure replication fork progression in the presence of DNA lesions with minimal delay in fork elongation. These pathways broadly include translesion DNA synthesis, template switching, and replication fork repriming. Here, we discuss recent advances toward our understanding of the mechanisms that regulate the fine-tuned balance between these different replication stress response pathways. We also discuss the molecular pathways required to fill single-stranded DNA gaps that accumulate throughout the genome after repriming and the biological consequences of using repriming instead of other DNA damage tolerance pathways on genome integrity and cell fitness.
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Affiliation(s)
- Annabel Quinet
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Stephanie Tirman
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Emily Cybulla
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Alice Meroni
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Alessandro Vindigni
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
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47
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Wu RA, Pellman DS, Walter JC. The Ubiquitin Ligase TRAIP: Double-Edged Sword at the Replisome. Trends Cell Biol 2021; 31:75-85. [PMID: 33317933 PMCID: PMC7856240 DOI: 10.1016/j.tcb.2020.11.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 11/09/2020] [Accepted: 11/16/2020] [Indexed: 12/12/2022]
Abstract
In preparation for cell division, the genome must be copied with high fidelity. However, replisomes often encounter obstacles, including bulky DNA lesions caused by reactive metabolites and chemotherapeutics, as well as stable nucleoprotein complexes. Here, we discuss recent advances in our understanding of TRAIP, a replisome-associated E3 ubiquitin ligase that is mutated in microcephalic primordial dwarfism. In interphase, TRAIP helps replisomes overcome DNA interstrand crosslinks and DNA-protein crosslinks, whereas in mitosis it triggers disassembly of all replisomes that remain on chromatin. We describe a model to explain how TRAIP performs these disparate functions and how they help maintain genome integrity.
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Affiliation(s)
- R Alex Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA
| | - David S Pellman
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA; Howard Hughes Medical Institute, Cambridge, MA, 02139, USA
| | - Johannes C Walter
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA; Howard Hughes Medical Institute, Cambridge, MA, 02139, USA.
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48
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Housh K, Jha JS, Haldar T, Amin SBM, Islam T, Wallace A, Gomina A, Guo X, Nel C, Wyatt JW, Gates KS. Formation and repair of unavoidable, endogenous interstrand cross-links in cellular DNA. DNA Repair (Amst) 2021; 98:103029. [PMID: 33385969 PMCID: PMC8882318 DOI: 10.1016/j.dnarep.2020.103029] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 02/08/2023]
Abstract
Genome integrity is essential for life and, as a result, DNA repair systems evolved to remove unavoidable DNA lesions from cellular DNA. Many forms of life possess the capacity to remove interstrand DNA cross-links (ICLs) from their genome but the identity of the naturally-occurring, endogenous substrates that drove the evolution and retention of these DNA repair systems across a wide range of life forms remains uncertain. In this review, we describe more than a dozen chemical processes by which endogenous ICLs plausibly can be introduced into cellular DNA. The majority involve DNA degradation processes that introduce aldehyde residues into the double helix or reactions of DNA with endogenous low molecular weight aldehyde metabolites. A smaller number of the cross-linking processes involve reactions of DNA radicals generated by oxidation.
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Affiliation(s)
- Kurt Housh
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211, United States
| | - Jay S Jha
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211, United States
| | - Tuhin Haldar
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211, United States
| | - Saosan Binth Md Amin
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211, United States
| | - Tanhaul Islam
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211, United States
| | - Amanda Wallace
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211, United States
| | - Anuoluwapo Gomina
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211, United States
| | - Xu Guo
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211, United States
| | - Christopher Nel
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211, United States
| | - Jesse W Wyatt
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211, United States
| | - Kent S Gates
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211, United States; University of Missouri, Department of Biochemistry, Columbia, MO 65211, United States.
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49
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Tirman S, Cybulla E, Quinet A, Meroni A, Vindigni A. PRIMPOL ready, set, reprime! Crit Rev Biochem Mol Biol 2021; 56:17-30. [PMID: 33179522 PMCID: PMC7906090 DOI: 10.1080/10409238.2020.1841089] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/15/2020] [Accepted: 10/20/2020] [Indexed: 12/14/2022]
Abstract
DNA replication forks are constantly challenged by DNA lesions induced by endogenous and exogenous sources. DNA damage tolerance mechanisms ensure that DNA replication continues with minimal effects on replication fork elongation either by using specialized DNA polymerases, which have the ability to replicate through the damaged template, or by skipping the damaged DNA, leaving it to be repaired after replication. These mechanisms are evolutionarily conserved in bacteria, yeast, and higher eukaryotes, and are paramount to ensure timely and faithful duplication of the genome. The Primase and DNA-directed Polymerase (PRIMPOL) is a recently discovered enzyme that possesses both primase and polymerase activities. PRIMPOL is emerging as a key player in DNA damage tolerance, particularly in vertebrate and human cells. Here, we review our current understanding of the function of PRIMPOL in DNA damage tolerance by focusing on the structural aspects that define its dual enzymatic activity, as well as on the mechanisms that control its chromatin recruitment and expression levels. We also focus on the latest findings on the mitochondrial and nuclear functions of PRIMPOL and on the impact of loss of these functions on genome stability and cell survival. Defining the function of PRIMPOL in DNA damage tolerance is becoming increasingly important in the context of human disease. In particular, we discuss recent evidence pointing at the PRIMPOL pathway as a novel molecular target to improve cancer cell response to DNA-damaging chemotherapy and as a predictive parameter to stratify patients in personalized cancer therapy.
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Affiliation(s)
- Stephanie Tirman
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis MO, 63110, USA
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Emily Cybulla
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis MO, 63110, USA
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Annabel Quinet
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis MO, 63110, USA
| | - Alice Meroni
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis MO, 63110, USA
| | - Alessandro Vindigni
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis MO, 63110, USA
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50
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Baiken Y, Kanayeva D, Taipakova S, Groisman R, Ishchenko AA, Begimbetova D, Matkarimov B, Saparbaev M. Role of Base Excision Repair Pathway in the Processing of Complex DNA Damage Generated by Oxidative Stress and Anticancer Drugs. Front Cell Dev Biol 2021; 8:617884. [PMID: 33553154 PMCID: PMC7862338 DOI: 10.3389/fcell.2020.617884] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/17/2020] [Indexed: 01/22/2023] Open
Abstract
Chemical alterations in DNA induced by genotoxic factors can have a complex nature such as bulky DNA adducts, interstrand DNA cross-links (ICLs), and clustered DNA lesions (including double-strand breaks, DSB). Complex DNA damage (CDD) has a complex character/structure as compared to singular lesions like randomly distributed abasic sites, deaminated, alkylated, and oxidized DNA bases. CDD is thought to be critical since they are more challenging to repair than singular lesions. Although CDD naturally constitutes a relatively minor fraction of the overall DNA damage induced by free radicals, DNA cross-linking agents, and ionizing radiation, if left unrepaired, these lesions cause a number of serious consequences, such as gross chromosomal rearrangements and genome instability. If not tightly controlled, the repair of ICLs and clustered bi-stranded oxidized bases via DNA excision repair will either inhibit initial steps of repair or produce persistent chromosomal breaks and consequently be lethal for the cells. Biochemical and genetic evidences indicate that the removal of CDD requires concurrent involvement of a number of distinct DNA repair pathways including poly(ADP-ribose) polymerase (PARP)-mediated DNA strand break repair, base excision repair (BER), nucleotide incision repair (NIR), global genome and transcription coupled nucleotide excision repair (GG-NER and TC-NER, respectively), mismatch repair (MMR), homologous recombination (HR), non-homologous end joining (NHEJ), and translesion DNA synthesis (TLS) pathways. In this review, we describe the role of DNA glycosylase-mediated BER pathway in the removal of complex DNA lesions.
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Affiliation(s)
- Yeldar Baiken
- School of Sciences and Humanities, Nazarbayev University, Nur-Sultan, Kazakhstan.,National Laboratory Astana, Nazarbayev University, Nur-Sultan, Kazakhstan.,School of Engineering and Digital Sciences, Nazarbayev University, Nur-Sultan, Kazakhstan
| | - Damira Kanayeva
- School of Sciences and Humanities, Nazarbayev University, Nur-Sultan, Kazakhstan
| | - Sabira Taipakova
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Regina Groisman
- Groupe ≪Mechanisms of DNA Repair and Carcinogenesis≫, Equipe Labellisée LIGUE 2016, CNRS UMR9019, Université Paris-Saclay, Gustave Roussy Cancer Campus, Villejuif, France
| | - Alexander A Ishchenko
- Groupe ≪Mechanisms of DNA Repair and Carcinogenesis≫, Equipe Labellisée LIGUE 2016, CNRS UMR9019, Université Paris-Saclay, Gustave Roussy Cancer Campus, Villejuif, France
| | - Dinara Begimbetova
- National Laboratory Astana, Nazarbayev University, Nur-Sultan, Kazakhstan
| | - Bakhyt Matkarimov
- National Laboratory Astana, Nazarbayev University, Nur-Sultan, Kazakhstan
| | - Murat Saparbaev
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, al-Farabi Kazakh National University, Almaty, Kazakhstan.,Groupe ≪Mechanisms of DNA Repair and Carcinogenesis≫, Equipe Labellisée LIGUE 2016, CNRS UMR9019, Université Paris-Saclay, Gustave Roussy Cancer Campus, Villejuif, France
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