1
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Schreuder A, Wendel TJ, Dorresteijn CGV, Noordermeer SM. (Single-stranded DNA) gaps in understanding BRCAness. Trends Genet 2024:S0168-9525(24)00100-8. [PMID: 38789375 DOI: 10.1016/j.tig.2024.04.013] [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: 02/02/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/26/2024]
Abstract
The tumour-suppressive roles of BRCA1 and 2 have been attributed to three seemingly distinct functions - homologous recombination, replication fork protection, and single-stranded (ss)DNA gap suppression - and their relative importance is under debate. In this review, we examine the origin and resolution of ssDNA gaps and discuss the recent advances in understanding the role of BRCA1/2 in gap suppression. There are ample data showing that gap accumulation in BRCA1/2-deficient cells is linked to genomic instability and chemosensitivity. However, it remains unclear whether there is a causative role and the function of BRCA1/2 in gap suppression cannot unambiguously be dissected from their other functions. We therefore conclude that the three functions of BRCA1 and 2 are closely intertwined and not mutually exclusive.
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Affiliation(s)
- Anne Schreuder
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands
| | - Tiemen J Wendel
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands
| | - Carlo G V Dorresteijn
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands
| | - Sylvie M Noordermeer
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands.
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2
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Jiang YK, Medley EA, Brown GW. Two independent DNA repair pathways cause mutagenesis in template switching deficient Saccharomyces cerevisiae. Genetics 2023; 225:iyad153. [PMID: 37594077 DOI: 10.1093/genetics/iyad153] [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: 06/27/2023] [Accepted: 08/08/2023] [Indexed: 08/19/2023] Open
Abstract
Upon DNA replication stress, cells utilize the postreplication repair pathway to repair single-stranded DNA and maintain genome integrity. Postreplication repair is divided into 2 branches: error-prone translesion synthesis, signaled by proliferating cell nuclear antigen (PCNA) monoubiquitination, and error-free template switching, signaled by PCNA polyubiquitination. In Saccharomyces cerevisiae, Rad5 is involved in both branches of repair during DNA replication stress. When the PCNA polyubiquitination function of Rad5 s disrupted, Rad5 recruits translesion synthesis polymerases to stalled replication forks, resulting in mutagenic repair. Details of how mutagenic repair is carried out, as well as the relationship between Rad5-mediated mutagenic repair and the canonical PCNA-mediated mutagenic repair, remain to be understood. We find that Rad5-mediated mutagenic repair requires the translesion synthesis polymerase ζ but does not require other yeast translesion polymerase activities. Furthermore, we show that Rad5-mediated mutagenic repair is independent of PCNA binding by Rev1 and so is separable from canonical mutagenic repair. In the absence of error-free template switching, both modes of mutagenic repair contribute additively to replication stress response in a replication timing-independent manner. Cellular contexts where error-free template switching is compromised are not simply laboratory phenomena, as we find that a natural variant in RAD5 is defective in PCNA polyubiquitination and therefore defective in error-free repair, resulting in Rad5- and PCNA-mediated mutagenic repair. Our results highlight the importance of Rad5 in regulating spontaneous mutagenesis and genetic diversity in S. cerevisiae through different modes of postreplication repair.
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Affiliation(s)
- Yangyang Kate Jiang
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Eleanor A Medley
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Grant W Brown
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
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3
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Sun H, Ma L, Tsai YF, Abeywardana T, Shen B, Zheng L. Okazaki fragment maturation: DNA flap dynamics for cell proliferation and survival. Trends Cell Biol 2023; 33:221-234. [PMID: 35879148 PMCID: PMC9867784 DOI: 10.1016/j.tcb.2022.06.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/28/2022] [Accepted: 06/30/2022] [Indexed: 01/24/2023]
Abstract
Unsuccessful processing of Okazaki fragments leads to the accumulation of DNA breaks which are associated with many human diseases including cancer and neurodegenerative disorders. Recently, Okazaki fragment maturation (OFM) has received renewed attention regarding how unprocessed Okazaki fragments are sensed and repaired, and how inappropriate OFM impacts on genome stability and cell viability, especially in cancer cells. We provide an overview of the highly efficient and faithful canonical OFM pathways and their regulation of genomic integrity and cell survival. We also discuss how cells induce alternative error-prone OFM processes to promote cell survival in response to environmental stresses. Such stress-induced OFM processes may be important mechanisms driving mutagenesis, cellular evolution, and resistance to radio/chemotherapy and targeted therapeutics in human cancers.
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Affiliation(s)
- Haitao Sun
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA
| | - Lingzi Ma
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA
| | - Ya-Fang Tsai
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA
| | - Tharindu Abeywardana
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA
| | - Binghui Shen
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA.
| | - Li Zheng
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA.
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4
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Wegmann S, Meister C, Renz C, Yakoub G, Wollscheid HP, Takahashi DT, Mikicic I, Beli P, Ulrich HD. Linkage reprogramming by tailor-made E3s reveals polyubiquitin chain requirements in DNA-damage bypass. Mol Cell 2022; 82:1589-1602.e5. [PMID: 35263628 PMCID: PMC9098123 DOI: 10.1016/j.molcel.2022.02.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 01/05/2022] [Accepted: 02/08/2022] [Indexed: 12/22/2022]
Abstract
A polyubiquitin chain can adopt a variety of shapes, depending on how the ubiquitin monomers are joined. However, the relevance of linkage for the signaling functions of polyubiquitin chains is often poorly understood because of our inability to control or manipulate this parameter in vivo. Here, we present a strategy for reprogramming polyubiquitin chain linkage by means of tailor-made, linkage- and substrate-selective ubiquitin ligases. Using the polyubiquitylation of the budding yeast replication factor PCNA in response to DNA damage as a model case, we show that altering the features of a polyubiquitin chain in vivo can change the fate of the modified substrate. We also provide evidence for redundancy between distinct but structurally similar linkages, and we demonstrate by proof-of-principle experiments that the method can be generalized to targets beyond PCNA. Our study illustrates a promising approach toward the in vivo analysis of polyubiquitin signaling.
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Affiliation(s)
- Sabrina Wegmann
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, 55128 Mainz, Germany
| | - Cindy Meister
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, 55128 Mainz, Germany
| | - Christian Renz
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, 55128 Mainz, Germany
| | - George Yakoub
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, 55128 Mainz, Germany
| | | | - Diane T Takahashi
- Université de Strasbourg, UMR7242 Biotechnologie et Signalisation Cellulaire, Ecole Supérieure de Biotechnologie de Strasbourg, 10413 Illkirch, Strasbourg, France
| | - Ivan Mikicic
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, 55128 Mainz, Germany
| | - Petra Beli
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, 55128 Mainz, Germany; Institute for Developmental Biology and Neurobiology, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - Helle D Ulrich
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, 55128 Mainz, Germany.
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5
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Spivakovsky-Gonzalez E, Polleys EJ, Masnovo C, Cebrian J, Molina-Vargas AM, Freudenreich CH, Mirkin SM. Rad9-mediated checkpoint activation is responsible for elevated expansions of GAA repeats in CST-deficient yeast. Genetics 2021; 219:6343461. [PMID: 34849883 DOI: 10.1093/genetics/iyab125] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/26/2021] [Indexed: 11/13/2022] Open
Abstract
Large-scale expansion of (GAA)n repeats in the first intron of the FXN gene is responsible for the severe neurodegenerative disease, Friedreich's ataxia in humans. We have previously conducted an unbiased genetic screen for GAA repeat instability in a yeast experimental system. The majority of genes that came from this screen encoded the components of DNA replication machinery, strongly implying that replication irregularities are at the heart of GAA repeat expansions. This screen, however, also produced two unexpected hits: members of the CST complex, CDC13 and TEN1 genes, which are required for telomere maintenance. To understand how the CST complex could affect intra-chromosomal GAA repeats, we studied the well-characterized temperature-sensitive cdc13-1 mutation and its effects on GAA repeat instability in yeast. We found that in-line with the screen results, this mutation leads to ∼10-fold increase in the rate of large-scale expansions of the (GAA)100 repeat at semi-permissive temperature. Unexpectedly, the hyper-expansion phenotype of the cdc13-1 mutant largely depends on activation of the G2/M checkpoint, as deletions of individual genes RAD9, MEC1, RAD53, and EXO1 belonging to this pathway rescued the increased GAA expansions. Furthermore, the hyper-expansion phenotype of the cdc13-1 mutant depended on the subunit of DNA polymerase δ, Pol32. We hypothesize, therefore, that increased repeat expansions in the cdc13-1 mutant happen during post-replicative repair of nicks or small gaps within repetitive tracts during the G2 phase of the cell cycle upon activation of the G2/M checkpoint.
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Affiliation(s)
| | - Erica J Polleys
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Chiara Masnovo
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Jorge Cebrian
- Department of Biology, Tufts University, Medford, MA 02155, USA.,Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, CIBERCV, Madrid 28040, Spain
| | - Adrian M Molina-Vargas
- Department of Biology, Tufts University, Medford, MA 02155, USA.,Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642, USA
| | | | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02155, USA
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6
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Prado F. Non-Recombinogenic Functions of Rad51, BRCA2, and Rad52 in DNA Damage Tolerance. Genes (Basel) 2021; 12:genes12101550. [PMID: 34680945 PMCID: PMC8535942 DOI: 10.3390/genes12101550] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 09/20/2021] [Accepted: 09/23/2021] [Indexed: 12/28/2022] Open
Abstract
The DNA damage tolerance (DDT) response is aimed to timely and safely complete DNA replication by facilitating the advance of replication forks through blocking lesions. This process is associated with an accumulation of single-strand DNA (ssDNA), both at the fork and behind the fork. Lesion bypass and ssDNA filling can be performed by translation synthesis (TLS) and template switching mechanisms. TLS uses low-fidelity polymerases to incorporate a dNTP opposite the blocking lesion, whereas template switching uses a Rad51/ssDNA nucleofilament and the sister chromatid to bypass the lesion. Rad51 is loaded at this nucleofilament by two mediator proteins, BRCA2 and Rad52, and these three factors are critical for homologous recombination (HR). Here, we review recent advances showing that Rad51, BRCA2, and Rad52 perform some of these functions through mechanisms that do not require the strand exchange activity of Rad51: the formation and protection of reversed fork structures aimed to bypass blocking lesions, and the promotion of TLS. These findings point to the central HR proteins as potential molecular switches in the choice of the mechanism of DDT.
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Affiliation(s)
- Félix Prado
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Consejo Superior de Investigaciones Científicas, Universidad de Sevilla, Universidad Pablo de Olavide, 41092 Seville, Spain
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7
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Somyajit K, Spies J, Coscia F, Kirik U, Rask MB, Lee JH, Neelsen KJ, Mund A, Jensen LJ, Paull TT, Mann M, Lukas J. Homology-directed repair protects the replicating genome from metabolic assaults. Dev Cell 2021; 56:461-477.e7. [PMID: 33621493 DOI: 10.1016/j.devcel.2021.01.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 10/14/2020] [Accepted: 01/20/2021] [Indexed: 12/18/2022]
Abstract
Homology-directed repair (HDR) safeguards DNA integrity under various forms of stress, but how HDR protects replicating genomes under extensive metabolic alterations remains unclear. Here, we report that besides stalling replication forks, inhibition of ribonucleotide reductase (RNR) triggers metabolic imbalance manifested by the accumulation of increased reactive oxygen species (ROS) in cell nuclei. This leads to a redox-sensitive activation of the ATM kinase followed by phosphorylation of the MRE11 nuclease, which in HDR-deficient settings degrades stalled replication forks. Intriguingly, nascent DNA degradation by the ROS-ATM-MRE11 cascade is also triggered by hypoxia, which elevates signaling-competent ROS and attenuates functional HDR without arresting replication forks. Under these conditions, MRE11 degrades daughter-strand DNA gaps, which accumulate behind active replisomes and attract error-prone DNA polymerases to escalate mutation rates. Thus, HDR safeguards replicating genomes against metabolic assaults by restraining mutagenic repair at aberrantly processed nascent DNA. These findings have implications for cancer evolution and tumor therapy.
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Affiliation(s)
- Kumar Somyajit
- Protein Signaling Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, DK-2200 Copenhagen, Denmark.
| | - Julian Spies
- Protein Signaling Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, DK-2200 Copenhagen, Denmark
| | - Fabian Coscia
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, DK-2200 Copenhagen, Denmark
| | - Ufuk Kirik
- Disease Systems Biology Program, Novo Nordisk Foundation Center for Protein, Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, DK-2200 Copenhagen, Denmark
| | - Maj-Britt Rask
- Protein Signaling Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, DK-2200 Copenhagen, Denmark
| | - Ji-Hoon Lee
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Kai John Neelsen
- Protein Signaling Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, DK-2200 Copenhagen, Denmark
| | - Andreas Mund
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, DK-2200 Copenhagen, Denmark
| | - Lars Juhl Jensen
- Disease Systems Biology Program, Novo Nordisk Foundation Center for Protein, Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, DK-2200 Copenhagen, Denmark
| | - Tanya T Paull
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Matthias Mann
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, DK-2200 Copenhagen, Denmark
| | - Jiri Lukas
- Protein Signaling Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, DK-2200 Copenhagen, Denmark.
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8
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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 DOI: 10.1016/j.dnarep.2021.103209] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [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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9
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Arbel M, Liefshitz B, Kupiec M. DNA damage bypass pathways and their effect on mutagenesis in yeast. FEMS Microbiol Rev 2021; 45:5896953. [PMID: 32840566 DOI: 10.1093/femsre/fuaa038] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/23/2020] [Indexed: 12/11/2022] Open
Abstract
What is the origin of mutations? In contrast to the naïve notion that mutations are unfortunate accidents, genetic research in microorganisms has demonstrated that most mutations are created by genetically encoded error-prone repair mechanisms. However, error-free repair pathways also exist, and it is still unclear how cells decide when to use one repair method or the other. Here, we summarize what is known about the DNA damage tolerance mechanisms (also known as post-replication repair) for perhaps the best-studied organism, the yeast Saccharomyces cerevisiae. We describe the latest research, which has established the existence of at least two error-free and two error-prone inter-related mechanisms of damage tolerance that compete for the handling of spontaneous DNA damage. We explore what is known about the induction of mutations by DNA damage. We point to potential paradoxes and to open questions that still remain unanswered.
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Affiliation(s)
- Matan Arbel
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Batia Liefshitz
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Martin Kupiec
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
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10
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Checkpoint-mediated DNA polymerase ε exonuclease activity curbing counteracts resection-driven fork collapse. Mol Cell 2021; 81:2778-2792.e4. [PMID: 33932350 PMCID: PMC7612761 DOI: 10.1016/j.molcel.2021.04.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 04/06/2021] [Accepted: 04/08/2021] [Indexed: 02/01/2023]
Abstract
DNA polymerase ε (Polε) carries out high-fidelity leading strand synthesis owing to its exonuclease activity. Polε polymerase and exonuclease activities are balanced, because of partitioning of nascent DNA strands between catalytic sites, so that net resection occurs when synthesis is impaired. In vivo, DNA synthesis stalling activates replication checkpoint kinases, which act to preserve the functional integrity of replication forks. We show that stalled Polε drives nascent strand resection causing fork functional collapse, averted via checkpoint-dependent phosphorylation. Polε catalytic subunit Pol2 is phosphorylated on serine 430, influencing partitioning between polymerase and exonuclease active sites. A phosphormimetic S430D change reduces exonucleolysis in vitro and counteracts fork collapse. Conversely, non-phosphorylatable pol2-S430A expression causes resection-driven stressed fork defects. Our findings reveal that checkpoint kinases switch Polε to an exonuclease-safe mode preventing nascent strand resection and stabilizing stalled replication forks. Elective partitioning suppression has implications for the diverse Polε roles in genome integrity maintenance.
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11
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Técher H, Pasero P. The Replication Stress Response on a Narrow Path Between Genomic Instability and Inflammation. Front Cell Dev Biol 2021; 9:702584. [PMID: 34249949 PMCID: PMC8270677 DOI: 10.3389/fcell.2021.702584] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/03/2021] [Indexed: 02/06/2023] Open
Abstract
The genome of eukaryotic cells is particularly at risk during the S phase of the cell cycle, when megabases of chromosomal DNA are unwound to generate two identical copies of the genome. This daunting task is executed by thousands of micro-machines called replisomes, acting at fragile structures called replication forks. The correct execution of this replication program depends on the coordinated action of hundreds of different enzymes, from the licensing of replication origins to the termination of DNA replication. This review focuses on the mechanisms that ensure the completion of DNA replication under challenging conditions of endogenous or exogenous origin. It also covers new findings connecting the processing of stalled forks to the release of small DNA fragments into the cytoplasm, activating the cGAS-STING pathway. DNA damage and fork repair comes therefore at a price, which is the activation of an inflammatory response that has both positive and negative impacts on the fate of stressed cells. These new findings have broad implications for the etiology of interferonopathies and for cancer treatment.
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Affiliation(s)
- Hervé Técher
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue Contre le Cancer, Montpellier, France
| | - Philippe Pasero
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue Contre le Cancer, Montpellier, France
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12
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Wong RP, Petriukov K, Ulrich HD. Daughter-strand gaps in DNA replication - substrates of lesion processing and initiators of distress signalling. DNA Repair (Amst) 2021; 105:103163. [PMID: 34186497 DOI: 10.1016/j.dnarep.2021.103163] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/18/2021] [Accepted: 06/19/2021] [Indexed: 10/21/2022]
Abstract
Dealing with DNA lesions during genome replication is particularly challenging because damaged replication templates interfere with the progression of the replicative DNA polymerases and thereby endanger the stability of the replisome. A variety of mechanisms for the recovery of replication forks exist, but both bacteria and eukaryotic cells also have the option of continuing replication downstream of the lesion, leaving behind a daughter-strand gap in the newly synthesized DNA. In this review, we address the significance of these single-stranded DNA structures as sites of DNA damage sensing and processing at a distance from ongoing genome replication. We describe the factors controlling the emergence of daughter-strand gaps from stalled replication intermediates, the benefits and risks of their expansion and repair via translesion synthesis or recombination-mediated template switching, and the mechanisms by which they activate local as well as global replication stress signals. Our growing understanding of daughter-strand gaps not only identifies them as targets of fundamental genome maintenance mechanisms, but also suggests that proper control over their activities has important practical implications for treatment strategies and resistance mechanisms in cancer therapy.
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Affiliation(s)
- Ronald P Wong
- Institute of Molecular Biology (IMB) gGmbH, Ackermannweg 4, D - 55128 Mainz, Germany
| | - Kirill Petriukov
- Institute of Molecular Biology (IMB) gGmbH, Ackermannweg 4, D - 55128 Mainz, Germany
| | - Helle D Ulrich
- Institute of Molecular Biology (IMB) gGmbH, Ackermannweg 4, D - 55128 Mainz, Germany.
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13
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Xing P, Dong Y, Zhao J, Zhou Z, Li Z, Wang Y, Li M, Zhang X, Chen X. Mrc1-Dependent Chromatin Compaction Represses DNA Double-Stranded Break Repair by Homologous Recombination Upon Replication Stress. Front Cell Dev Biol 2021; 9:630777. [PMID: 33681209 PMCID: PMC7928320 DOI: 10.3389/fcell.2021.630777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 01/06/2021] [Indexed: 11/13/2022] Open
Abstract
The coordination of DNA replication and repair is critical for the maintenance of genome stability. It has been shown that the Mrc1-mediated S phase checkpoint inhibits DNA double-stranded break (DSB) repair through homologous recombination (HR). How the replication checkpoint inhibits HR remains only partially understood. Here we show that replication stress induces the suppression of both Sgs1/Dna2- and Exo1-mediated resection pathways in an Mrc1-dependent manner. As a result, the loading of the single-stranded DNA binding factor replication protein A (RPA) and Rad51 and DSB repair by HR were severely impaired under replication stress. Notably, the deletion of MRC1 partially restored the recruitment of resection enzymes, DSB end resection, and the loading of RPA and Rad51. The role of Mrc1 in inhibiting DSB end resection is independent of Csm3, Tof1, or Ctf4. Mechanistically, we reveal that replication stress induces global chromatin compaction in a manner partially dependent on Mrc1, and this chromatin compaction limits the access of chromatin remodeling factors and HR proteins, leading to the suppression of HR. Our study reveals a critical role of the Mrc1-dependent chromatin structure change in coordinating DNA replication and recombination under replication stress.
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Affiliation(s)
- Poyuan Xing
- Hubei Key Laboratory of Cell Homeostasis and the Institute for Advanced Studies, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yang Dong
- Hubei Key Laboratory of Cell Homeostasis and the Institute for Advanced Studies, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jingyu Zhao
- Hubei Key Laboratory of Cell Homeostasis and the Institute for Advanced Studies, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhou Zhou
- Hubei Key Laboratory of Cell Homeostasis and the Institute for Advanced Studies, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhao Li
- Hubei Key Laboratory of Cell Homeostasis and the Institute for Advanced Studies, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yu Wang
- Hubei Key Laboratory of Cell Homeostasis and the Institute for Advanced Studies, College of Life Sciences, Wuhan University, Wuhan, China
| | - Mengfei Li
- Hubei Key Laboratory of Cell Homeostasis and the Institute for Advanced Studies, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xinghua Zhang
- Hubei Key Laboratory of Cell Homeostasis and the Institute for Advanced Studies, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xuefeng Chen
- Hubei Key Laboratory of Cell Homeostasis and the Institute for Advanced Studies, College of Life Sciences, Wuhan University, Wuhan, China
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14
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DNA-damage tolerance through PCNA ubiquitination and sumoylation. Biochem J 2021; 477:2655-2677. [PMID: 32726436 DOI: 10.1042/bcj20190579] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/08/2020] [Accepted: 07/10/2020] [Indexed: 12/12/2022]
Abstract
DNA-damage tolerance (DDT) is employed by eukaryotic cells to bypass replication-blocking lesions induced by DNA-damaging agents. In budding yeast Saccharomyces cerevisiae, DDT is mediated by RAD6 epistatic group genes and the central event for DDT is sequential ubiquitination of proliferating cell nuclear antigen (PCNA), a DNA clamp required for replication and DNA repair. DDT consists of two parallel pathways: error-prone DDT is mediated by PCNA monoubiquitination, which recruits translesion synthesis DNA polymerases to bypass lesions with decreased fidelity; and error-free DDT is mediated by K63-linked polyubiquitination of PCNA at the same residue of monoubiquitination, which facilitates homologous recombination-mediated template switch. Interestingly, the same PCNA residue is also subjected to sumoylation, which leads to inhibition of unwanted recombination at replication forks. All three types of PCNA posttranslational modifications require dedicated conjugating and ligation enzymes, and these enzymes are highly conserved in eukaryotes, from yeast to human.
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15
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Cano‐Linares MI, Yáñez‐Vilches A, García‐Rodríguez N, Barrientos‐Moreno M, González‐Prieto R, San‐Segundo P, Ulrich HD, Prado F. Non-recombinogenic roles for Rad52 in translesion synthesis during DNA damage tolerance. EMBO Rep 2021; 22:e50410. [PMID: 33289333 PMCID: PMC7788459 DOI: 10.15252/embr.202050410] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 10/09/2020] [Accepted: 10/15/2020] [Indexed: 01/09/2023] Open
Abstract
DNA damage tolerance relies on homologous recombination (HR) and translesion synthesis (TLS) mechanisms to fill in the ssDNA gaps generated during passing of the replication fork over DNA lesions in the template. Whereas TLS requires specialized polymerases able to incorporate a dNTP opposite the lesion and is error-prone, HR uses the sister chromatid and is mostly error-free. We report that the HR protein Rad52-but not Rad51 and Rad57-acts in concert with the TLS machinery (Rad6/Rad18-mediated PCNA ubiquitylation and polymerases Rev1/Pol ζ) to repair MMS and UV light-induced ssDNA gaps through a non-recombinogenic mechanism, as inferred from the different phenotypes displayed in the absence of Rad52 and Rad54 (essential for MMS- and UV-induced HR); accordingly, Rad52 is required for efficient DNA damage-induced mutagenesis. In addition, Rad52, Rad51, and Rad57, but not Rad54, facilitate Rad6/Rad18 binding to chromatin and subsequent DNA damage-induced PCNA ubiquitylation. Therefore, Rad52 facilitates the tolerance process not only by HR but also by TLS through Rad51/Rad57-dependent and -independent processes, providing a novel role for the recombination proteins in maintaining genome integrity.
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Affiliation(s)
- María I Cano‐Linares
- Department of Genome BiologyAndalusian Molecular Biology and Regenerative Medicine Center (CABIMER)CSIC‐University of Seville‐University Pablo de OlavideSevilleSpain
| | - Aurora Yáñez‐Vilches
- Department of Genome BiologyAndalusian Molecular Biology and Regenerative Medicine Center (CABIMER)CSIC‐University of Seville‐University Pablo de OlavideSevilleSpain
| | - Néstor García‐Rodríguez
- Institute of Molecular Biology (IMB)MainzGermany
- Present address:
Department of Genome BiologyAndalusian Molecular Biology and Regenerative Medicine Center (CABIMER)CSIC‐University of Seville‐University Pablo de OlavideSevilleSpain
| | - Marta Barrientos‐Moreno
- Department of Genome BiologyAndalusian Molecular Biology and Regenerative Medicine Center (CABIMER)CSIC‐University of Seville‐University Pablo de OlavideSevilleSpain
| | - Román González‐Prieto
- Department of Genome BiologyAndalusian Molecular Biology and Regenerative Medicine Center (CABIMER)CSIC‐University of Seville‐University Pablo de OlavideSevilleSpain
- Present address:
Department of Cell and Chemical BiologyLeiden University Medical CenterLeidenThe Netherlands
| | - Pedro San‐Segundo
- Institute of Functional Biology and Genomics (IBFG)CSIC‐University of SalamancaSalamancaSpain
| | | | - Félix Prado
- Department of Genome BiologyAndalusian Molecular Biology and Regenerative Medicine Center (CABIMER)CSIC‐University of Seville‐University Pablo de OlavideSevilleSpain
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16
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Mognato M, Burdak-Rothkamm S, Rothkamm K. Interplay between DNA replication stress, chromatin dynamics and DNA-damage response for the maintenance of genome stability. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2020; 787:108346. [PMID: 34083038 DOI: 10.1016/j.mrrev.2020.108346] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/02/2020] [Accepted: 11/09/2020] [Indexed: 12/17/2022]
Abstract
DNA replication stress is a major source of DNA damage, including double-stranded breaks that promote DNA damage response (DDR) signaling. Inefficient repair of such lesions can affect genome integrity. During DNA replication different factors act on chromatin remodeling in a coordinated way. While recent studies have highlighted individual molecular mechanisms of interaction, less is known about the orchestration of chromatin changes under replication stress. In this review we attempt to explore the complex relationship between DNA replication stress, DDR and genome integrity in mammalian cells, taking into account the role of chromatin disposition as an important modulator of DNA repair. Recent data on chromatin restoration and epigenetic re-establishment after DNA replication stress are reviewed.
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Affiliation(s)
| | - Susanne Burdak-Rothkamm
- University Medical Center Hamburg-Eppendorf, Department of Radiotherapy, Laboratory of Radiobiology & Experimental Radiation Oncology, Germany.
| | - Kai Rothkamm
- University Medical Center Hamburg-Eppendorf, Department of Radiotherapy, Laboratory of Radiobiology & Experimental Radiation Oncology, Germany.
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17
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Piberger AL, Bowry A, Kelly RDW, Walker AK, González-Acosta D, Bailey LJ, Doherty AJ, Méndez J, Morris JR, Bryant HE, Petermann E. PrimPol-dependent single-stranded gap formation mediates homologous recombination at bulky DNA adducts. Nat Commun 2020; 11:5863. [PMID: 33203852 PMCID: PMC7673990 DOI: 10.1038/s41467-020-19570-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 10/15/2020] [Indexed: 11/09/2022] Open
Abstract
Stalled replication forks can be restarted and repaired by RAD51-mediated homologous recombination (HR), but HR can also perform post-replicative repair after bypass of the obstacle. Bulky DNA adducts are important replication-blocking lesions, but it is unknown whether they activate HR at stalled forks or behind ongoing forks. Using mainly BPDE-DNA adducts as model lesions, we show that HR induced by bulky adducts in mammalian cells predominantly occurs at post-replicative gaps formed by the DNA/RNA primase PrimPol. RAD51 recruitment under these conditions does not result from fork stalling, but rather occurs at gaps formed by PrimPol re-priming and resection by MRE11 and EXO1. In contrast, RAD51 loading at double-strand breaks does not require PrimPol. At bulky adducts, PrimPol promotes sister chromatid exchange and genetic recombination. Our data support that HR at bulky adducts in mammalian cells involves post-replicative gap repair and define a role for PrimPol in HR-mediated DNA damage tolerance.
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Affiliation(s)
- Ann Liza Piberger
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
| | - Akhil Bowry
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Richard D W Kelly
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Alexandra K Walker
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | | | - Laura J Bailey
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9RQ, UK
| | - Aidan J Doherty
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9RQ, UK
| | - Juan Méndez
- Molecular Oncology Program, Spanish National Cancer Research Centre, Madrid, Spain
| | - Joanna R Morris
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Helen E Bryant
- Department of Oncology & Metabolism, The Medical School, University of Sheffield, Sheffield, S10 2RX, UK
| | - Eva Petermann
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
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18
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Morafraile EC, Bugallo A, Carreira R, Fernández M, Martín-Castellanos C, Blanco MG, Segurado M. Exo1 phosphorylation inhibits exonuclease activity and prevents fork collapse in rad53 mutants independently of the 14-3-3 proteins. Nucleic Acids Res 2020; 48:3053-3070. [PMID: 32020204 PMCID: PMC7102976 DOI: 10.1093/nar/gkaa054] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/15/2020] [Accepted: 01/20/2020] [Indexed: 01/04/2023] Open
Abstract
The S phase checkpoint is crucial to maintain genome stability under conditions that threaten DNA replication. One of its critical functions is to prevent Exo1-dependent fork degradation, and Exo1 is phosphorylated in response to different genotoxic agents. Exo1 seemed to be regulated by several post-translational modifications in the presence of replicative stress, but the specific contribution of checkpoint-dependent phosphorylation to Exo1 control and fork stability is not clear. We show here that Exo1 phosphorylation is Dun1-independent and Rad53-dependent in response to DNA damage or dNTP depletion, and in both situations Exo1 is similarly phosphorylated at multiple sites. To investigate the correlation between Exo1 phosphorylation and fork stability, we have generated phospho-mimic exo1 alleles that rescue fork collapse in rad53 mutants as efficiently as exo1-nuclease dead mutants or the absence of Exo1, arguing that Rad53-dependent phosphorylation is the mayor requirement to preserve fork stability. We have also shown that this rescue is Bmh1–2 independent, arguing that the 14-3-3 proteins are dispensable for fork stabilization, at least when Exo1 is downregulated. Importantly, our results indicated that phosphorylation specifically inhibits the 5' to 3'exo-nuclease activity, suggesting that this activity of Exo1 and not the flap-endonuclease, is the enzymatic activity responsible of the collapse of stalled replication forks in checkpoint mutants.
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Affiliation(s)
- Esther C Morafraile
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
| | - Alberto Bugallo
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
| | - Raquel Carreira
- Departamento de Bioquímica y Biología Molecular, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS) - Instituto de Investigación Sanitaria (IDIS), Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - María Fernández
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
| | | | - Miguel G Blanco
- Departamento de Bioquímica y Biología Molecular, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS) - Instituto de Investigación Sanitaria (IDIS), Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Mónica Segurado
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain.,Departamento de Microbiología y Genética, Campus Miguel de Unamuno, Universidad de Salamanca, Salamanca 37007, Spain
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19
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Arbel M, Liefshitz B, Kupiec M. How yeast cells deal with stalled replication forks. Curr Genet 2020; 66:911-915. [PMID: 32394094 DOI: 10.1007/s00294-020-01082-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 04/24/2020] [Accepted: 04/29/2020] [Indexed: 12/27/2022]
Abstract
DNA polymerases sometimes stall during DNA replication at sites where DNA is damaged, or upon encounter with proteins or secondary structures of DNA. When that happens, the polymerase clamp PCNA can become modified with a single ubiquitin moiety at lysine 164, opening DNA Damage Tolerance (DDT) mechanisms that either repair or bypass the lesions. An alternative repair mechanism is the salvage recombination (SR) pathway, which copies information from the sister chromatid. SUMOylation of PCNA at the same lysine, or at lysine 127, can recruit the Srs2 helicase, which negatively controls SR. Recently, we have dissected the relationship between SR and the DDT pathways, and showed that overexpression of either the PCNA unloader Elg1, or the Rad52 homologous recombination protein, can bypass the repression by Srs2. Our results shed light on the interactions between different DNA damage repair/bypass proteins, and underscore the importance of PCNA modifications in organizing the complex task of dealing with DNA damage during replication of the genetic material.
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Affiliation(s)
- Matan Arbel
- School of Molecular Cell Biology and Biotechnology, Tel Aviv University, 69978, Ramat, Aviv, Israel
| | - Batia Liefshitz
- School of Molecular Cell Biology and Biotechnology, Tel Aviv University, 69978, Ramat, Aviv, Israel
| | - Martin Kupiec
- School of Molecular Cell Biology and Biotechnology, Tel Aviv University, 69978, Ramat, Aviv, Israel.
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20
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Access to PCNA by Srs2 and Elg1 Controls the Choice between Alternative Repair Pathways in Saccharomyces cerevisiae. mBio 2020; 11:mBio.00705-20. [PMID: 32371600 PMCID: PMC7403780 DOI: 10.1128/mbio.00705-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
PCNA, the ring that encircles DNA maintaining the processivity of DNA polymerases, is modified by ubiquitin and SUMO. Whereas ubiquitin is required for bypassing lesions through the DNA damage tolerance (DDT) pathways, we show here that SUMOylation represses another pathway, salvage recombination. The Srs2 helicase is recruited to SUMOylated PCNA and prevents the salvage pathway from acting. The pathway can be induced by overexpressing the PCNA unloader Elg1, or the homologous recombination protein Rad52. Our results underscore the role of PCNA modifications in controlling the various bypass and DNA repair mechanisms. During DNA replication, stalling can occur when the replicative DNA polymerases encounter lesions or hard-to replicate regions. Under these circumstances, the processivity factor PCNA gets ubiquitylated at lysine 164, inducing the DNA damage tolerance (DDT) mechanisms that can bypass lesions encountered during DNA replication. PCNA can also be SUMOylated at the same residue or at lysine 127. Surprisingly, pol30-K164R mutants display a higher degree of sensitivity to DNA-damaging agents than pol30-KK127,164RR strains, unable to modify any of the lysines. Here, we show that in addition to translesion synthesis and strand-transfer DDT mechanisms, an alternative repair mechanism (“salvage recombination”) that copies information from the sister chromatid is repressed by the recruitment of Srs2 to SUMOylated PCNA. Overexpression of Elg1, the PCNA unloader, or of the recombination protein Rad52 allows its activation. We dissect the genetic requirements for this pathway, as well as the interactions between Srs2 and Elg1.
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21
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Forey R, Poveda A, Sharma S, Barthe A, Padioleau I, Renard C, Lambert R, Skrzypczak M, Ginalski K, Lengronne A, Chabes A, Pardo B, Pasero P. Mec1 Is Activated at the Onset of Normal S Phase by Low-dNTP Pools Impeding DNA Replication. Mol Cell 2020; 78:396-410.e4. [PMID: 32169162 DOI: 10.1016/j.molcel.2020.02.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 01/09/2020] [Accepted: 02/24/2020] [Indexed: 10/24/2022]
Abstract
The Mec1 and Rad53 kinases play a central role during acute replication stress in budding yeast. They are also essential for viability in normal growth conditions, but the signal that activates the Mec1-Rad53 pathway in the absence of exogenous insults is currently unknown. Here, we show that this pathway is active at the onset of normal S phase because deoxyribonucleotide triphosphate (dNTP) levels present in G1 phase may not be sufficient to support processive DNA synthesis and impede DNA replication. This activation can be suppressed experimentally by increasing dNTP levels in G1 phase. Moreover, we show that unchallenged cells entering S phase in the absence of Rad53 undergo irreversible fork collapse and mitotic catastrophe. Together, these data indicate that cells use suboptimal dNTP pools to detect the onset of DNA replication and activate the Mec1-Rad53 pathway, which in turn maintains functional forks and triggers dNTP synthesis, allowing the completion of DNA replication.
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Affiliation(s)
- Romain Forey
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France
| | - Ana Poveda
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France; Instituto de Investigación en Salud Pública y Zoonosis, Facultad de Ciencias Químicas, Universidad Central del Ecuador, Quito, Ecuador
| | - Sushma Sharma
- Department of Medical Biochemistry and Biophysics and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Antoine Barthe
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France
| | - Ismael Padioleau
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France
| | - Claire Renard
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France
| | - Robin Lambert
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France
| | - Magdalena Skrzypczak
- Laboratory of Bioinformatics and Systems Biology, Centre of New Technologies, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Krzysztof Ginalski
- Laboratory of Bioinformatics and Systems Biology, Centre of New Technologies, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Armelle Lengronne
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Benjamin Pardo
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France.
| | - Philippe Pasero
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France.
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22
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Ovejero S, Bueno A, Sacristán MP. Working on Genomic Stability: From the S-Phase to Mitosis. Genes (Basel) 2020; 11:E225. [PMID: 32093406 PMCID: PMC7074175 DOI: 10.3390/genes11020225] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 12/15/2022] Open
Abstract
Fidelity in chromosome duplication and segregation is indispensable for maintaining genomic stability and the perpetuation of life. Challenges to genome integrity jeopardize cell survival and are at the root of different types of pathologies, such as cancer. The following three main sources of genomic instability exist: DNA damage, replicative stress, and chromosome segregation defects. In response to these challenges, eukaryotic cells have evolved control mechanisms, also known as checkpoint systems, which sense under-replicated or damaged DNA and activate specialized DNA repair machineries. Cells make use of these checkpoints throughout interphase to shield genome integrity before mitosis. Later on, when the cells enter into mitosis, the spindle assembly checkpoint (SAC) is activated and remains active until the chromosomes are properly attached to the spindle apparatus to ensure an equal segregation among daughter cells. All of these processes are tightly interconnected and under strict regulation in the context of the cell division cycle. The chromosomal instability underlying cancer pathogenesis has recently emerged as a major source for understanding the mitotic processes that helps to safeguard genome integrity. Here, we review the special interconnection between the S-phase and mitosis in the presence of under-replicated DNA regions. Furthermore, we discuss what is known about the DNA damage response activated in mitosis that preserves chromosomal integrity.
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Affiliation(s)
- Sara Ovejero
- Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Universidad de Salamanca-CSIC, Campus Miguel de Unamuno, 37007 Salamanca, Spain
- Institute of Human Genetics, CNRS, University of Montpellier, 34000 Montpellier, France
- Department of Biological Hematology, CHU Montpellier, 34295 Montpellier, France
| | - Avelino Bueno
- Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Universidad de Salamanca-CSIC, Campus Miguel de Unamuno, 37007 Salamanca, Spain
- Departamento de Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain
| | - María P. Sacristán
- Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Universidad de Salamanca-CSIC, Campus Miguel de Unamuno, 37007 Salamanca, Spain
- Departamento de Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain
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23
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Sobolewska A, Halas A, Plachta M, McIntyre J, Sledziewska-Gojska E. Regulation of the abundance of Y-family polymerases in the cell cycle of budding yeast in response to DNA damage. Curr Genet 2020; 66:749-763. [PMID: 32076806 PMCID: PMC7363672 DOI: 10.1007/s00294-020-01061-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 01/21/2020] [Accepted: 02/04/2020] [Indexed: 02/07/2023]
Abstract
Y-family DNA polymerases mediate DNA damage tolerance via translesion synthesis (TLS). Because of the intrinsically error-prone nature of these enzymes, their activities are regulated at several levels. Here, we demonstrate the common regulation of the cellular abundance of Y-family polymerases, polymerase eta (Pol eta), and Rev1, in response to DNA damage at various stages of the cell cycle. UV radiation influenced polymerase abundance more when cells were exposed in S-phase than in G1- or G2-phases. We noticed two opposing effects of UV radiation in S-phase. On one hand, exposure to increasing doses of UV radiation at the beginning of this phase increasingly delayed S-phase progression. As a result, the accumulation of Pol eta and Rev1, which in nonirradiated yeast is initiated at the S/G2-phase boundary, was gradually shifted into the prolonged S-phase. On the other hand, the extent of polymerase accumulation was inversely proportional to the dose of irradiation, such that the accumulation was significantly lower after exposure to 80 J/m2 in S-phase than after exposure to 50 J/m2 or 10 J/m2. The limitation of polymerase accumulation in S-phase-arrested cells in response to high UV dose was suppressed upon RAD9 (but not MRC1) deletion. Additionally, hydroxyurea, which activates mainly the Mrc1-dependent checkpoint, did not limit Pol eta or Rev1 accumulation in S-phase-arrested cells. The results show that the accumulation of Y-family TLS polymerases is limited in S-phase-arrested cells due to high levels of DNA damage and suggest a role of the Rad9 checkpoint protein in this process.
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Affiliation(s)
- Aleksandra Sobolewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawinskiego 5A, 02-106, Warsaw, Poland
| | - Agnieszka Halas
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawinskiego 5A, 02-106, Warsaw, Poland
| | - Michal Plachta
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawinskiego 5A, 02-106, Warsaw, Poland
| | - Justyna McIntyre
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawinskiego 5A, 02-106, Warsaw, Poland
| | - Ewa Sledziewska-Gojska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawinskiego 5A, 02-106, Warsaw, Poland.
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24
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Delamarre A, Barthe A, de la Roche Saint-André C, Luciano P, Forey R, Padioleau I, Skrzypczak M, Ginalski K, Géli V, Pasero P, Lengronne A. MRX Increases Chromatin Accessibility at Stalled Replication Forks to Promote Nascent DNA Resection and Cohesin Loading. Mol Cell 2020; 77:395-410.e3. [PMID: 31759824 DOI: 10.1016/j.molcel.2019.10.029] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 08/09/2019] [Accepted: 10/17/2019] [Indexed: 01/04/2023]
Abstract
The recovery of stalled replication forks depends on the controlled resection of nascent DNA and on the loading of cohesin. These processes operate in the context of nascent chromatin, but the impact of nucleosome structure on a fork restart remains poorly understood. Here, we show that the Mre11-Rad50-Xrs2 (MRX) complex acts together with the chromatin modifiers Gcn5 and Set1 and the histone remodelers RSC, Chd1, and Isw1 to promote chromatin remodeling at stalled forks. Increased chromatin accessibility facilitates the resection of nascent DNA by the Exo1 nuclease and the Sgs1 and Chl1 DNA helicases. Importantly, increased ssDNA promotes the recruitment of cohesin to arrested forks in a Scc2-Scc4-dependent manner. Altogether, these results indicate that MRX cooperates with chromatin modifiers to orchestrate the action of remodelers, nucleases, and DNA helicases, promoting the resection of nascent DNA and the loading of cohesin, two key processes involved in the recovery of arrested forks.
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Affiliation(s)
- Axel Delamarre
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue contre le Cancer, Montpellier, France
| | - Antoine Barthe
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue contre le Cancer, Montpellier, France
| | - Christophe de la Roche Saint-André
- Marseille Cancer Research Center (CRCM), CNRS, INSERM, Aix Marseille University, Institut Paoli-Calmettes, Equipe Labélisée Ligue contre le Cancer, 13273 Marseille, France
| | - Pierre Luciano
- Marseille Cancer Research Center (CRCM), CNRS, INSERM, Aix Marseille University, Institut Paoli-Calmettes, Equipe Labélisée Ligue contre le Cancer, 13273 Marseille, France
| | - Romain Forey
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue contre le Cancer, Montpellier, France
| | - Ismaël Padioleau
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue contre le Cancer, Montpellier, France
| | - Magdalena Skrzypczak
- Laboratory of Bioinformatics and Systems Biology, Centre of New Technologies, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Krzysztof Ginalski
- Laboratory of Bioinformatics and Systems Biology, Centre of New Technologies, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Vincent Géli
- Marseille Cancer Research Center (CRCM), CNRS, INSERM, Aix Marseille University, Institut Paoli-Calmettes, Equipe Labélisée Ligue contre le Cancer, 13273 Marseille, France.
| | - Philippe Pasero
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue contre le Cancer, Montpellier, France.
| | - Armelle Lengronne
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue contre le Cancer, Montpellier, France.
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25
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Aiello FA, Palma A, Malacaria E, Zheng L, Campbell JL, Shen B, Franchitto A, Pichierri P. RAD51 and mitotic function of mus81 are essential for recovery from low-dose of camptothecin in the absence of the WRN exonuclease. Nucleic Acids Res 2020; 47:6796-6810. [PMID: 31114910 PMCID: PMC6648349 DOI: 10.1093/nar/gkz431] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 05/02/2019] [Accepted: 05/07/2019] [Indexed: 11/13/2022] Open
Abstract
Stabilization of stalled replication forks prevents excessive fork reversal or degradation, which can undermine genome integrity. The WRN protein is unique among the other human RecQ family members to possess exonuclease activity. However, the biological role of the WRN exonuclease is poorly defined. Recently, the WRN exonuclease has been linked to protection of stalled forks from degradation. Alternative processing of perturbed forks has been associated to chemoresistance of BRCA-deficient cancer cells. Thus, we used WRN exonuclease-deficiency as a model to investigate the fate of perturbed forks undergoing degradation, but in a BRCA wild-type condition. We find that, upon treatment with clinically-relevant nanomolar doses of the Topoisomerase I inhibitor camptothecin, loss of WRN exonuclease stimulates fork inactivation and accumulation of parental gaps, which engages RAD51. Such mechanism affects reinforcement of CHK1 phosphorylation and causes persistence of RAD51 during recovery from treatment. Notably, in WRN exonuclease-deficient cells, persistence of RAD51 correlates with elevated mitotic phosphorylation of MUS81 at Ser87, which is essential to prevent excessive mitotic abnormalities. Altogether, these findings indicate that aberrant fork degradation, in the presence of a wild-type RAD51 axis, stimulates RAD51-mediated post-replicative repair and engagement of the MUS81 complex to limit genome instability and cell death.
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Affiliation(s)
- Francesca Antonella Aiello
- Mechanisms, Biomarkers and Models Unit, Department of Environment and Health, Istituto Superiore di Sanità, Roma, Italy
| | - Anita Palma
- Mechanisms, Biomarkers and Models Unit, Department of Environment and Health, Istituto Superiore di Sanità, Roma, Italy
| | - Eva Malacaria
- Mechanisms, Biomarkers and Models Unit, Department of Environment and Health, Istituto Superiore di Sanità, Roma, Italy
| | - Li Zheng
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010-3000, USA
| | - Judith L Campbell
- Braun Laboratories, California Institute of Technology, Pasadena, CA 91125, USA
| | - Binghui Shen
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010-3000, USA
| | - Annapaola Franchitto
- Mechanisms, Biomarkers and Models Unit, Department of Environment and Health, Istituto Superiore di Sanità, Roma, Italy
| | - Pietro Pichierri
- Mechanisms, Biomarkers and Models Unit, Department of Environment and Health, Istituto Superiore di Sanità, Roma, Italy.,Istituto Nazionale Biostrutture e Biosistemi, Roma, Italy
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26
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Wong RP, García-Rodríguez N, Zilio N, Hanulová M, Ulrich HD. Processing of DNA Polymerase-Blocking Lesions during Genome Replication Is Spatially and Temporally Segregated from Replication Forks. Mol Cell 2019; 77:3-16.e4. [PMID: 31607544 DOI: 10.1016/j.molcel.2019.09.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 08/23/2019] [Accepted: 09/10/2019] [Indexed: 11/25/2022]
Abstract
Tracing DNA repair factors by fluorescence microscopy provides valuable information about how DNA damage processing is orchestrated within cells. Most repair pathways involve single-stranded DNA (ssDNA), making replication protein A (RPA) a hallmark of DNA damage and replication stress. RPA foci emerging during S phase in response to tolerable loads of polymerase-blocking lesions are generally thought to indicate stalled replication intermediates. We now report that in budding yeast they predominantly form far away from sites of ongoing replication, and they do not overlap with any of the repair centers associated with collapsed replication forks or double-strand breaks. Instead, they represent sites of postreplicative DNA damage bypass involving translesion synthesis and homologous recombination. We propose that most RPA and recombination foci induced by polymerase-blocking lesions in the replication template are clusters of repair tracts arising from replication centers by polymerase re-priming and subsequent expansion of daughter-strand gaps over the course of S phase.
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Affiliation(s)
- Ronald P Wong
- Institute of Molecular Biology, 55128 Mainz, Germany
| | | | - Nicola Zilio
- Institute of Molecular Biology, 55128 Mainz, Germany
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27
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Shao Z, Niwa S, Higashitani A, Daigaku Y. Vital roles of PCNA K165 modification during C. elegans gametogenesis and embryogenesis. DNA Repair (Amst) 2019; 82:102688. [PMID: 31450086 DOI: 10.1016/j.dnarep.2019.102688] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 07/19/2019] [Accepted: 08/09/2019] [Indexed: 12/16/2022]
Abstract
In eukaryotes, the DNA damage bypass pathway is promoted by ubiquitylation of PCNA at the conserved lysine 164. Using CRISPR-Cas9 system, we introduced amino acid substitution at K165 of C. elegans PCNA that corresponds to K164 in other characterised organisms and examined the contribution of this residue at a variety of stages during development. In the presence of UV-induced DNA lesions, PCNA-K165 is crucial for not only the early embryonic stages but also during larval development, implicating its functions for a broad time period during animal development. We also show that, without induction of DNA damage, concomitant inhibition of PCNA ubiquitylation and checkpoint activation causes abnormal gametogenesis events and severely impairs reproduction of worms. Our findings suggest a conserved function of PCNA ubiquitylation in tolerance of UV-induced damage and also propose that PCNA ubiquitylation contributes to gametogenesis during unperturbed C. elegans development.
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Affiliation(s)
- Zhenhua Shao
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Shinsuke Niwa
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan; Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
| | | | - Yasukazu Daigaku
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan; Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan.
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28
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Li Y, Shen J, Niu H. DNA duplex recognition activates Exo1 nuclease activity. J Biol Chem 2019; 294:11559-11567. [PMID: 31182486 DOI: 10.1074/jbc.ra119.008549] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 06/09/2019] [Indexed: 11/06/2022] Open
Abstract
Exonuclease 1 (Exo1) is an evolutionarily conserved eukaryotic nuclease that plays a multifaceted role in maintaining genome stability. The biochemical attributes of Exo1 have been extensively characterized via conventional assays. However, the key step governing its activation remains elusive. Extending the previous finding that Exo1 can digest a randomly selected single-stranded DNA (ssDNA) but not a poly(dT) oligonucleotide and using purified recombinant Exo1 and nuclease and electrophoretic mobility shift assays, here we determined that DNA hairpins with a stem size of 4 bp or longer are able to activate Exo1-mediated digestion of ssDNA. We further provide evidence suggesting that Exo1 uses an evolutionarily conserved residue, Lys185 This residue interacted with the phosphate group bridging the third and fourth nucleotide on the digestion strand of the substrate DNA for duplex recognition, critical for Exo1 activation on not only ssDNA but also dsDNA. Additionally, the defect of an exo1-K185A mutant in duplex digestion was partially rescued by longer overhanging DNA. However, we noted that the enhanced Exo1 nuclease activity by longer overhanging DNA is largely eliminated by replication protein A (RPA), likely because of the previously reported RPA activity that strips Exo1 off the ssDNA. We conclude that duplex DNA contact by Exo1 is a general mechanism that controls its activation and that this mechanism is particularly important for digestion of duplex DNA whose nascent ssDNA is bound by RPA.
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Affiliation(s)
- Yuxi Li
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405.,Interdisciplinary Biochemistry Program, Indiana University, Bloomington, Indiana 47405
| | - Jiangchuan Shen
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405
| | - Hengyao Niu
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405
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29
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A role for the yeast PCNA unloader Elg1 in eliciting the DNA damage checkpoint. Curr Genet 2019; 66:79-84. [PMID: 31332476 DOI: 10.1007/s00294-019-01020-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 07/16/2019] [Accepted: 07/17/2019] [Indexed: 12/28/2022]
Abstract
During cell proliferation, the genome is constantly threatened by cellular and external factors. When the DNA is damaged, or when its faithful duplication is delayed by DNA polymerase stalling, the cells induce a coordinated response termed the DNA damage response (DDR) or checkpoint. Elg1 forms an RFC-like complex in charge of unloading the DNA polymerase processively factor PCNA during DNA replication and DNA repair. Using checkpoint-inducible strains, a recently published paper (Sau et al. in mBio 10(3):e01159-19. https://doi.org/10.1128/mbio.01159-19, 2019) uncovered a role for Elg1 in eliciting the DNA damage checkpoint (DC), one of the branches of the DDR. The apical kinase Mec1/ATR phosphorylates Elg1, as well as the adaptor proteins Rad9/53BP1 and Dpb11/TopBP1, which are recruited to the site of DNA damage to amplify the checkpoint signal. In the absence of Elg1, Rad9 and Dpb11 are recruited but fail to be phosphorylated and the signal is therefore not amplified. Thus, Elg1 appears to coordinate DNA repair and the induction of the DNA damage checkpoint.
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30
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García-Rodríguez N, Wong RP, Ulrich HD. The helicase Pif1 functions in the template switching pathway of DNA damage bypass. Nucleic Acids Res 2019; 46:8347-8356. [PMID: 30107417 PMCID: PMC6144865 DOI: 10.1093/nar/gky648] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 08/08/2018] [Indexed: 11/13/2022] Open
Abstract
Replication of damaged DNA is challenging because lesions in the replication template frequently interfere with an orderly progression of the replisome. In this situation, complete duplication of the genome is ensured by the action of DNA damage bypass pathways effecting either translesion synthesis by specialized, damage-tolerant DNA polymerases or a recombination-like mechanism called template switching (TS). Here we report that budding yeast Pif1, a helicase known to be involved in the resolution of complex DNA structures as well as the maturation of Okazaki fragments during replication, contributes to DNA damage bypass. We show that Pif1 expands regions of single-stranded DNA, so-called daughter-strand gaps, left behind the replication fork as a consequence of replisome re-priming. This function requires interaction with the replication clamp, proliferating cell nuclear antigen, facilitating its recruitment to damage sites, and complements the activity of an exonuclease, Exo1, in the processing of post-replicative daughter-strand gaps in preparation for TS. Our results thus reveal a novel function of a conserved DNA helicase that is known as a key player in genome maintenance.
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Affiliation(s)
| | - Ronald P Wong
- Institute of Molecular Biology (IMB), Ackermannweg 4, D-55128 Mainz, Germany
| | - Helle D Ulrich
- Institute of Molecular Biology (IMB), Ackermannweg 4, D-55128 Mainz, Germany
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31
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Abstract
The Elg1protein forms an RFC-like complex in charge of unloading PCNA from chromatin during DNA replication and repair. Mutations in the ELG1 gene caused genomic instability in all organisms tested and cancer in mammals. Here we show that Elg1 plays a role in the induction of the DNA damage checkpoint, a cellular response to DNA damage. We show that this defect is due to a defect in the signal amplification process during induction. Thus, cells coordinate the cell's response and the PCNA unloading through the activity of Elg1. The PCNA (proliferating cell nuclear antigen) ring plays central roles during DNA replication and repair. The yeast Elg1 RFC-like complex (RLC) is the principal unloader of chromatin-bound PCNA and thus plays a central role in maintaining genome stability. Here we identify a role for Elg1 in the unloading of PCNA during DNA damage. Using DNA damage checkpoint (DC)-inducible and replication checkpoint (RC)-inducible strains, we show that Elg1 is essential for eliciting the signal in the DC branch. In the absence of Elg1 activity, the Rad9 (53BP1) and Dpb11 (TopBP1) adaptor proteins are recruited but fail to be phosphorylated by Mec1 (ATR), resulting in a lack of checkpoint activation. The chromatin immunoprecipitation of PCNA at the Lac operator sites reveals that accumulated local PCNA influences the checkpoint activation process in elg1 mutants. Our data suggest that Elg1 participates in a mechanism that may coordinate PCNA unloading during DNA repair with DNA damage checkpoint induction.
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32
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Gallo D, Kim T, Szakal B, Saayman X, Narula A, Park Y, Branzei D, Zhang Z, Brown GW. Rad5 Recruits Error-Prone DNA Polymerases for Mutagenic Repair of ssDNA Gaps on Undamaged Templates. Mol Cell 2019; 73:900-914.e9. [PMID: 30733119 DOI: 10.1016/j.molcel.2019.01.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 09/13/2018] [Accepted: 12/27/2018] [Indexed: 12/30/2022]
Abstract
Post-replication repair (PRR) allows tolerance of chemical- and UV-induced DNA base lesions in both an error-free and an error-prone manner. In classical PRR, PCNA monoubiquitination recruits translesion synthesis (TLS) DNA polymerases that can replicate through lesions. We find that PRR responds to DNA replication stress that does not cause base lesions. Rad5 forms nuclear foci during normal S phase and after exposure to types of replication stress where DNA base lesions are likely absent. Rad5 binds to the sites of stressed DNA replication forks, where it recruits TLS polymerases to repair single-stranded DNA (ssDNA) gaps, preventing mitotic defects and chromosome breaks. In contrast to the prevailing view of PRR, our data indicate that Rad5 promotes both mutagenic and error-free repair of undamaged ssDNA that arises during physiological and exogenous replication stress.
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Affiliation(s)
- David Gallo
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON M5S 3E1, Canada; Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - TaeHyung Kim
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada; Department of Computer Science, University of Toronto, 1 King's College Circle, Toronto, ON M5S 3E1, Canada
| | - Barnabas Szakal
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
| | - Xanita Saayman
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON M5S 3E1, Canada; Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Ashrut Narula
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON M5S 3E1, Canada; Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Yoona Park
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada; Department of Computer Science, University of Toronto, 1 King's College Circle, Toronto, ON M5S 3E1, Canada
| | - Dana Branzei
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy; Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Via Abbiategrasso 207, 27100 Pavia, Italy
| | - Zhaolei Zhang
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada; Department of Computer Science, University of Toronto, 1 King's College Circle, Toronto, ON M5S 3E1, Canada
| | - Grant W Brown
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON M5S 3E1, Canada; Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada.
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33
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34
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Prado F. Homologous Recombination: To Fork and Beyond. Genes (Basel) 2018; 9:genes9120603. [PMID: 30518053 PMCID: PMC6316604 DOI: 10.3390/genes9120603] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 11/29/2018] [Accepted: 11/29/2018] [Indexed: 12/15/2022] Open
Abstract
Accurate completion of genome duplication is threatened by multiple factors that hamper the advance and stability of the replication forks. Cells need to tolerate many of these blocking lesions to timely complete DNA replication, postponing their repair for later. This process of lesion bypass during DNA damage tolerance can lead to the accumulation of single-strand DNA (ssDNA) fragments behind the fork, which have to be filled in before chromosome segregation. Homologous recombination plays essential roles both at and behind the fork, through fork protection/lesion bypass and post-replicative ssDNA filling processes, respectively. I review here our current knowledge about the recombination mechanisms that operate at and behind the fork in eukaryotes, and how these mechanisms are controlled to prevent unscheduled and toxic recombination intermediates. A unifying model to integrate these mechanisms in a dynamic, replication fork-associated process is proposed from yeast results.
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Affiliation(s)
- Félix Prado
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine Center (CABIMER), CSIC-University of Seville-University Pablo de Olavide, 41092 Seville, Spain.
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35
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DDR Inc., one business, two associates. Curr Genet 2018; 65:445-451. [DOI: 10.1007/s00294-018-0908-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 11/18/2018] [Accepted: 11/19/2018] [Indexed: 01/03/2023]
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36
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Bacal J, Moriel-Carretero M, Pardo B, Barthe A, Sharma S, Chabes A, Lengronne A, Pasero P. Mrc1 and Rad9 cooperate to regulate initiation and elongation of DNA replication in response to DNA damage. EMBO J 2018; 37:e99319. [PMID: 30158111 PMCID: PMC6213276 DOI: 10.15252/embj.201899319] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 07/17/2018] [Accepted: 07/31/2018] [Indexed: 01/04/2023] Open
Abstract
The S-phase checkpoint maintains the integrity of the genome in response to DNA replication stress. In budding yeast, this pathway is initiated by Mec1 and is amplified through the activation of Rad53 by two checkpoint mediators: Mrc1 promotes Rad53 activation at stalled forks, and Rad9 is a general mediator of the DNA damage response. Here, we have investigated the interplay between Mrc1 and Rad9 in response to DNA damage and found that they control DNA replication through two distinct but complementary mechanisms. Mrc1 rapidly activates Rad53 at stalled forks and represses late-firing origins but is unable to maintain this repression over time. Rad9 takes over Mrc1 to maintain a continuous checkpoint signaling. Importantly, the Rad9-mediated activation of Rad53 slows down fork progression, supporting the view that the S-phase checkpoint controls both the initiation and the elongation of DNA replication in response to DNA damage. Together, these data indicate that Mrc1 and Rad9 play distinct functions that are important to ensure an optimal completion of S phase under replication stress conditions.
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Affiliation(s)
- Julien Bacal
- Institut de Génétique Humaine, CNRS, Equipe Labellisée Ligue contre le Cancer, Université de Montpellier, Montpellier, France
| | - María Moriel-Carretero
- Institut de Génétique Humaine, CNRS, Equipe Labellisée Ligue contre le Cancer, Université de Montpellier, Montpellier, France
| | - Benjamin Pardo
- Institut de Génétique Humaine, CNRS, Equipe Labellisée Ligue contre le Cancer, Université de Montpellier, Montpellier, France
| | - Antoine Barthe
- Institut de Génétique Humaine, CNRS, Equipe Labellisée Ligue contre le Cancer, Université de Montpellier, Montpellier, France
| | - Sushma Sharma
- Department of Medical Biochemistry and Biophysics and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Armelle Lengronne
- Institut de Génétique Humaine, CNRS, Equipe Labellisée Ligue contre le Cancer, Université de Montpellier, Montpellier, France
| | - Philippe Pasero
- Institut de Génétique Humaine, CNRS, Equipe Labellisée Ligue contre le Cancer, Université de Montpellier, Montpellier, France
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37
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Galanti L, Pfander B. Right time, right place-DNA damage and DNA replication checkpoints collectively safeguard S phase. EMBO J 2018; 37:embj.2018100681. [PMID: 30287420 DOI: 10.15252/embj.2018100681] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Affiliation(s)
- Lorenzo Galanti
- Max Planck Institute of Biochemistry, DNA Replication and Genome Integrity, Martinsried, Germany
| | - Boris Pfander
- Max Planck Institute of Biochemistry, DNA Replication and Genome Integrity, Martinsried, Germany
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38
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Bhat KP, Cortez D. RPA and RAD51: fork reversal, fork protection, and genome stability. Nat Struct Mol Biol 2018; 25:446-453. [PMID: 29807999 PMCID: PMC6006513 DOI: 10.1038/s41594-018-0075-z] [Citation(s) in RCA: 229] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 04/23/2018] [Accepted: 04/26/2018] [Indexed: 01/23/2023]
Abstract
Replication protein A (RPA) and RAD51 are DNA-binding proteins that help maintain genome stability during DNA replication. These proteins regulate nucleases, helicases, DNA translocases, and signaling proteins to control replication, repair, recombination, and the DNA damage response. Their different DNA-binding mechanisms, enzymatic activities, and binding partners provide unique functionalities that cooperate to ensure that the appropriate activities are deployed at the right time to overcome replication challenges. Here we review and discuss the latest discoveries of the mechanisms by which these proteins work to preserve genome stability, with a focus on their actions in fork reversal and fork protection.
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Affiliation(s)
- Kamakoti P Bhat
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - David Cortez
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
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