1
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Mitotic DNA synthesis in response to replication stress requires the sequential action of DNA polymerases zeta and delta in human cells. Nat Commun 2023; 14:706. [PMID: 36759509 PMCID: PMC9911744 DOI: 10.1038/s41467-023-35992-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 01/11/2023] [Indexed: 02/11/2023] Open
Abstract
Oncogene activation creates DNA replication stress (RS) in cancer cells, which can generate under-replicated DNA regions (UDRs) that persist until cells enter mitosis. UDRs also have the potential to generate DNA bridges in anaphase cells or micronuclei in the daughter cells, which could promote genomic instability. To suppress such damaging changes to the genome, human cells have developed a strategy to conduct 'unscheduled' DNA synthesis in mitosis (termed MiDAS) that serves to rescue under-replicated loci. Previous studies have shown that MiDAS proceeds via a POLD3-dependent pathway that shows some features of break-induced replication. Here, we define how human cells utilize both DNA gap filling (REV1 and Pol ζ) and replicative (Pol δ) DNA polymerases to complete genome duplication following a perturbed S-phase. We present evidence for the existence of a polymerase-switch during MiDAS that is required for new DNA synthesis at UDRs. Moreover, we reveal that, upon oncogene activation, cancer cell survival is significantly compromised when REV1 is depleted, suggesting that REV1 inhibition might be a feasible approach for the treatment of some human cancers.
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2
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Bhat DS, Spies MA, Spies M. A moving target for drug discovery: Structure activity relationship and many genome (de)stabilizing functions of the RAD52 protein. DNA Repair (Amst) 2022; 120:103421. [PMID: 36327799 PMCID: PMC9888176 DOI: 10.1016/j.dnarep.2022.103421] [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: 07/29/2022] [Revised: 10/18/2022] [Accepted: 10/24/2022] [Indexed: 02/02/2023]
Abstract
BRCA-ness phenotype, a signature of many breast and ovarian cancers, manifests as deficiency in homologous recombination, and as defects in protection and repair of damaged DNA replication forks. A dependence of such cancers on DNA repair factors less important for survival of BRCA-proficient cells, offers opportunities for development of novel chemotherapeutic interventions. The first drugs targeting BRCA-deficient cancers, poly-ADP-ribose polymerase (PARP) inhibitors have been approved for the treatment of advanced, chemotherapy resistant cancers in patients with BRCA1/2 germline mutations. Nine additional proteins that can be targeted to selectively kill BRCA-deficient cancer cells have been identified. Among them, a DNA repair protein RAD52 is an especially attractive target due to general tolerance of the RAD52 loss of function, and protective role of an inactivating mutation. Yet, the effective pharmacological inhibitors of RAD52 have not been forthcoming. In this review, we discuss advances in the state of our knowledge of the RAD52 structure, activities and cellular functions, with a specific focus on the features that make RAD52 an attractive, but difficult drug target.
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Affiliation(s)
- Divya S Bhat
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA
| | - M Ashley Spies
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA; Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, The University of Iowa, Iowa City, Iowa 52242, USA
| | - Maria Spies
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA.
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3
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Bhowmick R, Lerdrup M, Gadi SA, Rossetti GG, Singh MI, Liu Y, Halazonetis TD, Hickson ID. RAD51 protects human cells from transcription-replication conflicts. Mol Cell 2022; 82:3366-3381.e9. [PMID: 36002000 DOI: 10.1016/j.molcel.2022.07.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 06/02/2022] [Accepted: 07/16/2022] [Indexed: 12/16/2022]
Abstract
Oncogene activation during tumorigenesis promotes DNA replication stress (RS), which subsequently drives the formation of cancer-associated chromosomal rearrangements. Many episodes of physiological RS likely arise due to conflicts between the DNA replication and transcription machineries operating simultaneously at the same loci. One role of the RAD51 recombinase in human cells is to protect replication forks undergoing RS. Here, we have identified a key role for RAD51 in preventing transcription-replication conflicts (TRCs) from triggering replication fork breakage. The genomic regions most affected by RAD51 deficiency are characterized by being replicated and transcribed in early S-phase and show significant overlap with loci prone to cancer-associated amplification. Consistent with a role for RAD51 in protecting against transcription-replication conflicts, many of the adverse effects of RAD51 depletion are ameliorated by inhibiting early S-phase transcription. We propose a model whereby RAD51 suppresses fork breakage and subsequent inadvertent amplification of genomic loci prone to experiencing TRCs.
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Affiliation(s)
- Rahul Bhowmick
- Center for Chromosome Stability, Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Mads Lerdrup
- Center for Chromosome Stability, Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Sampath Amitash Gadi
- Center for Chromosome Stability, Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Giacomo G Rossetti
- Department of Molecular Biology, University of Geneva, 30, quai Ernest-Ansermet, 1205, Geneva, Switzerland
| | - Manika I Singh
- Center for Chromosome Stability, Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Ying Liu
- Center for Chromosome Stability, Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Thanos D Halazonetis
- Department of Molecular Biology, University of Geneva, 30, quai Ernest-Ansermet, 1205, Geneva, Switzerland
| | - Ian D Hickson
- Center for Chromosome Stability, Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark.
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4
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Break-induced replication: unraveling each step. Trends Genet 2022; 38:752-765. [PMID: 35459559 DOI: 10.1016/j.tig.2022.03.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/11/2022] [Accepted: 03/14/2022] [Indexed: 10/18/2022]
Abstract
Break-induced replication (BIR) repairs one-ended double-strand DNA breaks through invasion into a homologous template followed by DNA synthesis. Different from S-phase replication, BIR copies the template DNA in a migrating displacement loop (D-loop) and results in conservative inheritance of newly synthesized DNA. This unusual mode of DNA synthesis makes BIR a source of various genetic instabilities like those associated with cancer in humans. This review focuses on recent progress in delineating the mechanism of Rad51-dependent BIR in budding yeast. In addition, we discuss new data that describe changes in BIR efficiency and fidelity on encountering replication obstacles as well as the implications of these findings for BIR-dependent processes such as telomere maintenance and the repair of collapsed replication forks.
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5
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Wu X, Malkova A. Break-induced replication mechanisms in yeast and mammals. Curr Opin Genet Dev 2021; 71:163-170. [PMID: 34481360 DOI: 10.1016/j.gde.2021.08.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/17/2021] [Accepted: 08/05/2021] [Indexed: 11/26/2022]
Abstract
Break-induced replication (BIR) is a pathway specialized in repair of double-strand DNA breaks with only one end capable of invading homologous template that can arise following replication collapse, telomere erosion or DNA cutting by site-specific endonucleases. For a long time, yeast remained the only model system to study BIR. Studies in yeast demonstrated that BIR represents an unusual mode of DNA synthesis that is driven by a migrating bubble and leads to conservative inheritance of newly synthesized DNA. This unusual type of DNA synthesis leads to high levels of mutations and chromosome rearrangements. Recently, multiple examples of BIR were uncovered in mammalian cells that allowed the comparison of BIR between organisms. It appeared initially that BIR in mammalian cells is predominantly independent of RAD51, and therefore different from BIR that is predominantly Rad51-dependent in yeast. However, a series of systematic studies utilizing site-specific DNA breaks for BIR initiation in mammalian reporters led to the discovery of highly efficient RAD51-dependent BIR, allowing side-by side comparison with BIR in yeast which is the focus of this review.
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Affiliation(s)
- Xiaohua Wu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, United States.
| | - Anna Malkova
- Department of Biology, University of Iowa, Iowa City, IA 52242, United States.
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6
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Tomasini PP, Guecheva TN, Leguisamo NM, Péricart S, Brunac AC, Hoffmann JS, Saffi J. Analyzing the Opportunities to Target DNA Double-Strand Breaks Repair and Replicative Stress Responses to Improve Therapeutic Index of Colorectal Cancer. Cancers (Basel) 2021; 13:3130. [PMID: 34201502 PMCID: PMC8268241 DOI: 10.3390/cancers13133130] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/15/2021] [Accepted: 06/18/2021] [Indexed: 12/22/2022] Open
Abstract
Despite the ample improvements of CRC molecular landscape, the therapeutic options still rely on conventional chemotherapy-based regimens for early disease, and few targeted agents are recommended for clinical use in the metastatic setting. Moreover, the impact of cytotoxic, targeted agents, and immunotherapy combinations in the metastatic scenario is not fully satisfactory, especially the outcomes for patients who develop resistance to these treatments need to be improved. Here, we examine the opportunity to consider therapeutic agents targeting DNA repair and DNA replication stress response as strategies to exploit genetic or functional defects in the DNA damage response (DDR) pathways through synthetic lethal mechanisms, still not explored in CRC. These include the multiple actors involved in the repair of DNA double-strand breaks (DSBs) through homologous recombination (HR), classical non-homologous end joining (NHEJ), and microhomology-mediated end-joining (MMEJ), inhibitors of the base excision repair (BER) protein poly (ADP-ribose) polymerase (PARP), as well as inhibitors of the DNA damage kinases ataxia-telangiectasia and Rad3 related (ATR), CHK1, WEE1, and ataxia-telangiectasia mutated (ATM). We also review the biomarkers that guide the use of these agents, and current clinical trials with targeted DDR therapies.
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Affiliation(s)
- Paula Pellenz Tomasini
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre, Avenida Sarmento Leite, 245, Porto Alegre 90050-170, Brazil; (P.P.T.); (N.M.L.)
- Post-Graduation Program in Cell and Molecular Biology, Federal University of Rio Grande do Sul, Avenida Bento Gonçalves, 9500, Porto Alegre 91501-970, Brazil
| | - Temenouga Nikolova Guecheva
- Cardiology Institute of Rio Grande do Sul, University Foundation of Cardiology (IC-FUC), Porto Alegre 90620-000, Brazil;
| | - Natalia Motta Leguisamo
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre, Avenida Sarmento Leite, 245, Porto Alegre 90050-170, Brazil; (P.P.T.); (N.M.L.)
| | - Sarah Péricart
- Laboratoire D’Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irène-Joliot-Curie, 31059 Toulouse, France; (S.P.); (A.-C.B.); (J.S.H.)
| | - Anne-Cécile Brunac
- Laboratoire D’Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irène-Joliot-Curie, 31059 Toulouse, France; (S.P.); (A.-C.B.); (J.S.H.)
| | - Jean Sébastien Hoffmann
- Laboratoire D’Excellence Toulouse Cancer (TOUCAN), Laboratoire de Pathologie, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irène-Joliot-Curie, 31059 Toulouse, France; (S.P.); (A.-C.B.); (J.S.H.)
| | - Jenifer Saffi
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre, Avenida Sarmento Leite, 245, Porto Alegre 90050-170, Brazil; (P.P.T.); (N.M.L.)
- Post-Graduation Program in Cell and Molecular Biology, Federal University of Rio Grande do Sul, Avenida Bento Gonçalves, 9500, Porto Alegre 91501-970, Brazil
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7
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The epigenetic regulator LSH maintains fork protection and genomic stability via MacroH2A deposition and RAD51 filament formation. Nat Commun 2021; 12:3520. [PMID: 34112784 PMCID: PMC8192551 DOI: 10.1038/s41467-021-23809-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 05/12/2021] [Indexed: 12/18/2022] Open
Abstract
The Immunodeficiency Centromeric Instability Facial Anomalies (ICF) 4 syndrome is caused by mutations in LSH/HELLS, a chromatin remodeler promoting incorporation of histone variant macroH2A. Here, we demonstrate that LSH depletion results in degradation of nascent DNA at stalled replication forks and the generation of genomic instability. The protection of stalled forks is mediated by macroH2A, whose knockdown mimics LSH depletion and whose overexpression rescues nascent DNA degradation. LSH or macroH2A deficiency leads to an impairment of RAD51 loading, a factor that prevents MRE11 and EXO1 mediated nascent DNA degradation. The defect in RAD51 loading is linked to a disbalance of BRCA1 and 53BP1 accumulation at stalled forks. This is associated with perturbed histone modifications, including abnormal H4K20 methylation that is critical for BRCA1 enrichment and 53BP1 exclusion. Altogether, our results illuminate the mechanism underlying a human syndrome and reveal a critical role of LSH mediated chromatin remodeling in genomic stability. LSH/HELLS is a chromatin remodeler promoting incorporation of histone variant macroH2A. Here the authors reveal a role for LSH in genome stability, in protecting nascent DNA at stalled forks mediated by macroH2A deposition and RAD51 filament formation.
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8
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Kockler ZW, Osia B, Lee R, Musmaker K, Malkova A. Repair of DNA Breaks by Break-Induced Replication. Annu Rev Biochem 2021; 90:165-191. [PMID: 33792375 DOI: 10.1146/annurev-biochem-081420-095551] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Double-strand DNA breaks (DSBs) are the most lethal type of DNA damage, making DSB repair critical for cell survival. However, some DSB repair pathways are mutagenic and promote genome rearrangements, leading to genome destabilization. One such pathway is break-induced replication (BIR), which repairs primarily one-ended DSBs, similar to those formed by collapsed replication forks or telomere erosion. BIR is initiated by the invasion of a broken DNA end into a homologous template, synthesizes new DNA within the context of a migrating bubble, and is associated with conservative inheritance of new genetic material. This mode of synthesis is responsible for a high level of genetic instability associated with BIR. Eukaryotic BIR was initially investigated in yeast, but now it is also actively studied in mammalian systems. Additionally, a significant breakthrough has been made regarding the role of microhomology-mediated BIR in the formation of complex genomic rearrangements that underly various human pathologies.
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Affiliation(s)
- Z W Kockler
- Department of Biology, University of Iowa, Iowa City, Iowa 52242, USA;
| | - B Osia
- Department of Biology, University of Iowa, Iowa City, Iowa 52242, USA;
| | - R Lee
- Department of Biology, University of Iowa, Iowa City, Iowa 52242, USA;
| | - K Musmaker
- Department of Biology, University of Iowa, Iowa City, Iowa 52242, USA;
| | - A Malkova
- Department of Biology, University of Iowa, Iowa City, Iowa 52242, USA;
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9
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Mechanisms of eukaryotic replisome disassembly. Biochem Soc Trans 2021; 48:823-836. [PMID: 32490508 PMCID: PMC7329349 DOI: 10.1042/bst20190363] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/06/2020] [Accepted: 05/11/2020] [Indexed: 12/11/2022]
Abstract
DNA replication is a complex process that needs to be executed accurately before cell division in order to maintain genome integrity. DNA replication is divided into three main stages: initiation, elongation and termination. One of the key events during initiation is the assembly of the replicative helicase at origins of replication, and this mechanism has been very well described over the last decades. In the last six years however, researchers have also focused on deciphering the molecular mechanisms underlying the disassembly of the replicative helicase during termination. Similar to replisome assembly, the mechanism of replisome disassembly is strictly regulated and well conserved throughout evolution, although its complexity increases in higher eukaryotes. While budding yeast rely on just one pathway for replisome disassembly in S phase, higher eukaryotes evolved an additional mitotic pathway over and above the default S phase specific pathway. Moreover, replisome disassembly has been recently found to be a key event prior to the repair of certain DNA lesions, such as under-replicated DNA in mitosis and inter-strand cross-links (ICLs) in S phase. Although replisome disassembly in human cells has not been characterised yet, they possess all of the factors involved in these pathways in model organisms, and de-regulation of many of them are known to contribute to tumorigenesis and other pathological conditions.
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10
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Macheret M, Bhowmick R, Sobkowiak K, Padayachy L, Mailler J, Hickson ID, Halazonetis TD. High-resolution mapping of mitotic DNA synthesis regions and common fragile sites in the human genome through direct sequencing. Cell Res 2020; 30:997-1008. [PMID: 32561860 PMCID: PMC7784693 DOI: 10.1038/s41422-020-0358-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 05/31/2020] [Indexed: 12/22/2022] Open
Abstract
DNA replication stress, a feature of human cancers, often leads to instability at specific genomic loci, such as the common fragile sites (CFSs). Cells experiencing DNA replication stress may also exhibit mitotic DNA synthesis (MiDAS). To understand the physiological function of MiDAS and its relationship to CFSs, we mapped, at high resolution, the genomic sites of MiDAS in cells treated with the DNA polymerase inhibitor aphidicolin. Sites of MiDAS were evident as well-defined peaks that were largely conserved between cell lines and encompassed all known CFSs. The MiDAS peaks mapped within large, transcribed, origin-poor genomic regions. In cells that had been treated with aphidicolin, these regions remained unreplicated even in late S phase; MiDAS then served to complete their replication after the cells entered mitosis. Interestingly, leading and lagging strand synthesis were uncoupled in MiDAS, consistent with MiDAS being a form of break-induced replication, a repair mechanism for collapsed DNA replication forks. Our results provide a better understanding of the mechanisms leading to genomic instability at CFSs and in cancer cells.
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Affiliation(s)
- Morgane Macheret
- Department of Molecular Biology, University of Geneva, 1205, Geneva, Switzerland
| | - Rahul Bhowmick
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Katarzyna Sobkowiak
- Department of Molecular Biology, University of Geneva, 1205, Geneva, Switzerland
| | - Laura Padayachy
- Department of Molecular Biology, University of Geneva, 1205, Geneva, Switzerland
| | - Jonathan Mailler
- Department of Molecular Biology, University of Geneva, 1205, Geneva, Switzerland
| | - Ian D Hickson
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark.
| | - Thanos D Halazonetis
- Department of Molecular Biology, University of Geneva, 1205, Geneva, Switzerland.
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11
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Guilliam TA, Yeeles JTP. An updated perspective on the polymerase division of labor during eukaryotic DNA replication. Crit Rev Biochem Mol Biol 2020; 55:469-481. [PMID: 32883112 DOI: 10.1080/10409238.2020.1811630] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In eukaryotes three DNA polymerases (Pols), α, δ, and ε, are tasked with bulk DNA synthesis of nascent strands during genome duplication. Most evidence supports a model where Pol α initiates DNA synthesis before Pol ε and Pol δ replicate the leading and lagging strands, respectively. However, a number of recent reports, enabled by advances in biochemical and genetic techniques, have highlighted emerging roles for Pol δ in all stages of leading-strand synthesis; initiation, elongation, and termination, as well as fork restart. By focusing on these studies, this review provides an updated perspective on the division of labor between the replicative polymerases during DNA replication.
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Affiliation(s)
- Thomas A Guilliam
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Joseph T P Yeeles
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
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12
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Telomere replication-When the going gets tough. DNA Repair (Amst) 2020; 94:102875. [PMID: 32650286 DOI: 10.1016/j.dnarep.2020.102875] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/23/2020] [Accepted: 05/26/2020] [Indexed: 12/28/2022]
Abstract
Telomeres consist of repetitive tracts of DNA that shield a chromosome's contents from erosion and replicative attrition. However, telomeres are also late-replicating regions of the genome in which a myriad of replicative obstructions reside. The obstacles contained within telomeres, as well as their genomic location, drive replicative stalling and subsequent fork collapse in these regions. Consequently, large scale deletions, under-replicated DNA, translocations, and fusion events arise following telomere replication failure. Further, under-replicated DNA and telomere fusions that are permitted to enter mitosis will produce mitotic DNA bridges - known drivers of genetic loss and chromothripsis. Thus, aberrant telomere replication promotes genomic instability, which, in turn leads either to cellular death, senescence or oncogenic transformation. The importance of these issues for organismal well-being necessitates a need for resolute telomere maintenance. Here, we describe recent advances in identifying and understanding the molecular mechanisms that are in place in human cells to escort the replisome through the telomere's unwieldy structures and repetitive sequences. Finally, we review the pathways that combat the deleterious outcomes that occur when telomeric replication forks do collapse.
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13
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Cherdyntseva V, Gagos S. Chromosome extremities under the microscopy lens: molecular cytogenetics in telomere research. Curr Opin Genet Dev 2020; 60:69-76. [PMID: 32193147 DOI: 10.1016/j.gde.2020.02.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 02/03/2020] [Accepted: 02/06/2020] [Indexed: 02/07/2023]
Abstract
At the crossroads of DNA damage repair and genomic instability, telomere research significantly expands our knowledge on fundamental mechanisms involved in cancer initiation and progression, pledging novel tools for targeted and universal onco-therapies. Molecular cytogenetics through the application of a battery of fluorescent hybridization technologies plays an important role toward understanding telomere homeostasis. Herein, we review distinct molecular cytogenetic phenotypes associated with telomere repair, functionality, and elongation. We discuss the underlying mechanisms responsible for their formation or repair, focusing on Break-induced-Replication (BIR)-mediated conservative telomeric neo-synthesis, recently shown to drive the enigmatic Alternative Lengthening of Telomeres in neoplasia.
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Affiliation(s)
- Veronica Cherdyntseva
- Laboratory of Genetics, Center of Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, 11527, Greece
| | - Sarantis Gagos
- Laboratory of Genetics, Center of Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, 11527, Greece.
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14
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Guadarrama-Ponce R, Aranda-Anzaldo A. The epicenter of chromosomal fragility of Fra14A2, the mouse ortholog of human FRA3B common fragile site, is largely attached to the nuclear matrix in lymphocytes but not in other cell types that do not express such a fragility. J Cell Biochem 2019; 121:2209-2224. [PMID: 31646677 DOI: 10.1002/jcb.29444] [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: 07/05/2019] [Accepted: 10/10/2019] [Indexed: 12/22/2022]
Abstract
Common fragile sites (CFSs) correspond to chromosomal regions susceptible to present breaks, discontinuities or constrictions in metaphase chromosomes from cells subjected to replication stress. They are considered as genomic regions intrinsically difficult to replicate and they are evolutionary conserved at least in mammals. However, the recent discovery that CFSs are cell-type specific indicates that DNA sequence by itself cannot account for CFS instability. Nevertheless, the large gene FHIT that includes FRA3B, the most highly expressed CFS in human lymphocytes, is commonly deleted in a variety of tumors suggesting a tumor suppressor role for its product. Here, we report that the epicenter of fragility of Fra14A2/Fhit, the mouse ortholog of human FRA3B/FHIT that like its human counterpart is the most highly expressed CFS in mouse lymphocytes, is largely attached to the nuclear matrix compartment in naive B lymphocytes but not in primary hepatocytes or cortical neurons that do not express such a CFS. Our results suggest a structural explanation for the difficult-to-replicate nature of such a region and so for its common fragility in lymphocytes, that is independent of the possible tumor suppressor role of the gene harboring such CFS.
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Affiliation(s)
- Rolando Guadarrama-Ponce
- Laboratorio de Biología Molecular y Neurociencias, Facultad de Medicina, Universidad Autónoma del Estado de México, Toluca, Mexico
| | - Armando Aranda-Anzaldo
- Laboratorio de Biología Molecular y Neurociencias, Facultad de Medicina, Universidad Autónoma del Estado de México, Toluca, Mexico
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15
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Sonneville R, Bhowmick R, Hoffmann S, Mailand N, Hickson ID, Labib K. TRAIP drives replisome disassembly and mitotic DNA repair synthesis at sites of incomplete DNA replication. eLife 2019; 8:e48686. [PMID: 31545170 PMCID: PMC6773462 DOI: 10.7554/elife.48686] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/20/2019] [Indexed: 11/13/2022] Open
Abstract
The faithful segregation of eukaryotic chromosomes in mitosis requires that the genome be duplicated completely prior to anaphase. However, cells with large genomes sometimes fail to complete replication during interphase and instead enter mitosis with regions of incompletely replicated DNA. These regions are processed in early mitosis via a process known as mitotic DNA repair synthesis (MiDAS), but little is known about how cells switch from conventional DNA replication to MiDAS. Using the early embryo of the nematode Caenorhabditis elegans as a model system, we show that the TRAIP ubiquitin ligase drives replisome disassembly in response to incomplete DNA replication, thereby providing access to replication forks for other factors. Moreover, TRAIP is essential for MiDAS in human cells, and is important in both systems to prevent mitotic segregation errors. Our data indicate that TRAIP is a master regulator of the processing of incomplete DNA replication during mitosis in metazoa.
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Affiliation(s)
- Remi Sonneville
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUnited Kingdom
| | - Rahul Bhowmick
- Department of Cellular and Molecular Medicine, Center for Chromosome StabilityUniversity of CopenhagenCopenhagenDenmark
| | - Saskia Hoffmann
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Niels Mailand
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Ian D Hickson
- Department of Cellular and Molecular Medicine, Center for Chromosome StabilityUniversity of CopenhagenCopenhagenDenmark
| | - Karim Labib
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUnited Kingdom
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16
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Nieminuszczy J, Broderick R, Bellani MA, Smethurst E, Schwab RA, Cherdyntseva V, Evmorfopoulou T, Lin YL, Minczuk M, Pasero P, Gagos S, Seidman MM, Niedzwiedz W. EXD2 Protects Stressed Replication Forks and Is Required for Cell Viability in the Absence of BRCA1/2. Mol Cell 2019; 75:605-619.e6. [PMID: 31255466 PMCID: PMC6695479 DOI: 10.1016/j.molcel.2019.05.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 04/15/2019] [Accepted: 05/17/2019] [Indexed: 12/15/2022]
Abstract
Accurate DNA replication is essential to preserve genomic integrity and prevent chromosomal instability-associated diseases including cancer. Key to this process is the cells' ability to stabilize and restart stalled replication forks. Here, we show that the EXD2 nuclease is essential to this process. EXD2 recruitment to stressed forks suppresses their degradation by restraining excessive fork regression. Accordingly, EXD2 deficiency leads to fork collapse, hypersensitivity to replication inhibitors, and genomic instability. Impeding fork regression by inactivation of SMARCAL1 or removal of RECQ1's inhibition in EXD2-/- cells restores efficient fork restart and genome stability. Moreover, purified EXD2 efficiently processes substrates mimicking regressed forks. Thus, this work identifies a mechanism underpinned by EXD2's nuclease activity, by which cells balance fork regression with fork restoration to maintain genome stability. Interestingly, from a clinical perspective, we discover that EXD2's depletion is synthetic lethal with mutations in BRCA1/2, implying a non-redundant role in replication fork protection.
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Affiliation(s)
| | | | - Marina A Bellani
- Laboratory of Molecular Gerontology, National Institute on Aging, Baltimore, MD, USA
| | | | | | - Veronica Cherdyntseva
- Laboratory of Genetics, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Theodora Evmorfopoulou
- Laboratory of Genetics, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Yea-Lih Lin
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Philippe Pasero
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Montpellier, France
| | - Sarantis Gagos
- Laboratory of Genetics, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Michael M Seidman
- Laboratory of Molecular Gerontology, National Institute on Aging, Baltimore, MD, USA
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17
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Priego Moreno S, Jones RM, Poovathumkadavil D, Scaramuzza S, Gambus A. Mitotic replisome disassembly depends on TRAIP ubiquitin ligase activity. Life Sci Alliance 2019; 2:2/2/e201900390. [PMID: 30979826 PMCID: PMC6464043 DOI: 10.26508/lsa.201900390] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 03/28/2019] [Accepted: 03/29/2019] [Indexed: 01/08/2023] Open
Abstract
Analysis of the mitotic replisome disassembly pathway in X. laevis egg extract shows that any replisomes retained on chromatin past S-phase are unloaded through formation of K6- and K63-linked ubiquitin chains on Mcm7 by TRAIP ubiquitin ligase and p97/VCP activity. We have shown previously that the process of replication machinery (replisome) disassembly at the termination of DNA replication forks in the S-phase is driven through polyubiquitylation of one of the replicative helicase subunits (Mcm7) by Cul2LRR1 ubiquitin ligase. Interestingly, upon inhibition of this pathway in Caenorhabditis elegans embryos, the replisomes retained on chromatin were unloaded in the subsequent mitosis. Here, we show that this mitotic replisome disassembly pathway exists in Xenopus laevis egg extract and we determine the first elements of its regulation. The mitotic disassembly pathway depends on the formation of K6- and K63-linked ubiquitin chains on Mcm7 by TRAIP ubiquitin ligase and the activity of p97/VCP protein segregase. Unlike in lower eukaryotes, however, it does not require SUMO modifications. Importantly, we also show that this process can remove all replisomes from mitotic chromatin, including stalled ones, which indicates a wide application for this pathway over being just a “backup” for terminated replisomes. Finally, we characterise the composition of the replisome retained on chromatin until mitosis.
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Affiliation(s)
- Sara Priego Moreno
- Institute for Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Rebecca M Jones
- Institute for Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Divyasree Poovathumkadavil
- Institute for Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Shaun Scaramuzza
- Institute for Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Agnieszka Gambus
- Institute for Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
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18
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Özer Ö, Hickson ID. Pathways for maintenance of telomeres and common fragile sites during DNA replication stress. Open Biol 2019; 8:rsob.180018. [PMID: 29695617 PMCID: PMC5936717 DOI: 10.1098/rsob.180018] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 04/03/2018] [Indexed: 12/27/2022] Open
Abstract
Oncogene activation during tumour development leads to changes in the DNA replication programme that enhance DNA replication stress. Certain regions of the human genome, such as common fragile sites and telomeres, are particularly sensitive to DNA replication stress due to their inherently ‘difficult-to-replicate’ nature. Indeed, it appears that these regions sometimes fail to complete DNA replication within the period of interphase when cells are exposed to DNA replication stress. Under these conditions, cells use a salvage pathway, termed ‘mitotic DNA repair synthesis (MiDAS)’, to complete DNA synthesis in the early stages of mitosis. If MiDAS fails, the ensuing mitotic errors threaten genome integrity and cell viability. Recent studies have provided an insight into how MiDAS helps cells to counteract DNA replication stress. However, our understanding of the molecular mechanisms and regulation of MiDAS remain poorly defined. Here, we provide an overview of how DNA replication stress triggers MiDAS, with an emphasis on how common fragile sites and telomeres are maintained. Furthermore, we discuss how a better understanding of MiDAS might reveal novel strategies to target cancer cells that maintain viability in the face of chronic oncogene-induced DNA replication stress.
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Affiliation(s)
- Özgün Özer
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Ian D Hickson
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
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19
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Deng L, Wu RA, Sonneville R, Kochenova OV, Labib K, Pellman D, Walter JC. Mitotic CDK Promotes Replisome Disassembly, Fork Breakage, and Complex DNA Rearrangements. Mol Cell 2019; 73:915-929.e6. [PMID: 30849395 PMCID: PMC6410736 DOI: 10.1016/j.molcel.2018.12.021] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 10/03/2018] [Accepted: 12/21/2018] [Indexed: 12/27/2022]
Abstract
DNA replication errors generate complex chromosomal rearrangements and thereby contribute to tumorigenesis and other human diseases. One mechanism that triggers these errors is mitotic entry before the completion of DNA replication. To address how mitosis might affect DNA replication, we used Xenopus egg extracts. When mitotic CDK (Cyclin B1-CDK1) is used to drive interphase egg extracts into a mitotic state, the replicative CMG (CDC45/MCM2-7/GINS) helicase undergoes ubiquitylation on its MCM7 subunit, dependent on the E3 ubiquitin ligase TRAIP. Whether replisomes have stalled or undergone termination, CMG ubiquitylation is followed by its extraction from chromatin by the CDC48/p97 ATPase. TRAIP-dependent CMG unloading during mitosis is also seen in C. elegans early embryos. At stalled forks, CMG removal results in fork breakage and end joining events involving deletions and templated insertions. Our results identify a mitotic pathway of global replisome disassembly that can trigger replication fork collapse and DNA rearrangements.
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Affiliation(s)
- Lin Deng
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA
| | - R Alex Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA
| | - Remi Sonneville
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Olga V Kochenova
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA
| | - Karim Labib
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - David Pellman
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Boston, MA 02115, USA.
| | - Johannes C Walter
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston, MA 02115, USA.
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20
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Schmid JA, Berti M, Walser F, Raso MC, Schmid F, Krietsch J, Stoy H, Zwicky K, Ursich S, Freire R, Lopes M, Penengo L. Histone Ubiquitination by the DNA Damage Response Is Required for Efficient DNA Replication in Unperturbed S Phase. Mol Cell 2018; 71:897-910.e8. [PMID: 30122534 DOI: 10.1016/j.molcel.2018.07.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 06/01/2018] [Accepted: 07/11/2018] [Indexed: 01/16/2023]
Abstract
Chromatin ubiquitination by the ubiquitin ligase RNF168 is critical to regulate the DNA damage response (DDR). DDR deficiencies lead to cancer-prone syndromes, but whether this reflects DNA repair defects is still elusive. We identified key factors of the RNF168 pathway as essential mediators of efficient DNA replication in unperturbed S phase. We found that loss of RNF168 leads to reduced replication fork progression and to reversed fork accumulation, particularly evident at repetitive sequences stalling replication. Slow fork progression depends on MRE11-dependent degradation of reversed forks, implicating RNF168 in reversed fork protection and restart. Consistent with regular nucleosomal organization of reversed forks, the replication function of RNF168 requires H2A ubiquitination. As this novel function is shared with the key DDR players ATM, γH2A.X, RNF8, and 53BP1, we propose that double-stranded ends at reversed forks engage classical DDR factors, suggesting an alternative function of this pathway in preventing genome instability and human disease.
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Affiliation(s)
- Jonas Andreas Schmid
- Institute of Molecular Cancer Research, University of Zurich, Zurich 8057, Switzerland
| | - Matteo Berti
- Institute of Molecular Cancer Research, University of Zurich, Zurich 8057, Switzerland
| | - Franziska Walser
- Institute of Molecular Cancer Research, University of Zurich, Zurich 8057, Switzerland
| | - Maria Chiara Raso
- Institute of Molecular Cancer Research, University of Zurich, Zurich 8057, Switzerland
| | - Fabian Schmid
- Institute of Molecular Cancer Research, University of Zurich, Zurich 8057, Switzerland
| | - Jana Krietsch
- Institute of Molecular Cancer Research, University of Zurich, Zurich 8057, Switzerland
| | - Henriette Stoy
- Institute of Molecular Cancer Research, University of Zurich, Zurich 8057, Switzerland
| | - Katharina Zwicky
- Institute of Molecular Cancer Research, University of Zurich, Zurich 8057, Switzerland
| | - Sebastian Ursich
- Institute of Molecular Cancer Research, University of Zurich, Zurich 8057, Switzerland
| | - Raimundo Freire
- Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, Ofra s/n, La Cuesta, La Laguna, Tenerife 38320, Spain
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich 8057, Switzerland.
| | - Lorenza Penengo
- Institute of Molecular Cancer Research, University of Zurich, Zurich 8057, Switzerland.
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21
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Nakazato A, Kajita K, Ooka M, Akagawa R, Abe T, Takeda S, Branzei D, Hirota K. SPARTAN promotes genetic diversification of the immunoglobulin-variable gene locus in avian DT40 cells. DNA Repair (Amst) 2018; 68:50-57. [PMID: 29935364 DOI: 10.1016/j.dnarep.2018.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 06/12/2018] [Accepted: 06/13/2018] [Indexed: 11/17/2022]
Abstract
Prolonged replication arrest on damaged templates is a cause of fork collapse, potentially resulting in genome instability. Arrested replication is rescued by translesion DNA synthesis (TLS) and homologous recombination (HR)-mediated template switching. SPARTAN, a ubiquitin-PCNA-interacting regulator, regulates TLS via mechanisms incompletely understood. Here we show that SPARTAN promotes diversification of the chicken DT40 immunoglobulin-variable λ gene by facilitating TLS-mediated hypermutation and template switch-mediated gene-conversion, both induced by replication blocks at abasic sites. SPARTAN-/- and SPARTAN-/-/Polη-/-/Polζ-/- cells showed defective and similar decrease in hypermutation rates, as well as alterations in the mutation spectra, with decreased dG-to-dC transversions and increased dG-to-dA transitions. Strikingly, SPARTAN-/- cells also showed reduced template switch-mediated gene-conversion at the immunoglobulin locus, while being proficient in HR-mediated double strand break repair, and sister chromatid recombination. Notably, SPARTAN's ubiquitin-binding zinc-finger 4 domain, but not the PCNA interacting peptide domain or its DNA-binding domain, was specifically required for the promotion of immunoglobulin gene-conversion, while all these three domains were shown to contribute similarly to TLS. In all, our results suggest that SPARTAN mediates TLS in concert with the Polη-Polζ pathway and that it facilitates HR-mediated template switching at a subset of stalled replication forks, potentially by interacting with unknown ubiquitinated proteins.
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Affiliation(s)
- Arisa Nakazato
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan
| | - Kinumi Kajita
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan
| | - Masato Ooka
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan
| | - Remi Akagawa
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshidakonoe, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Takuya Abe
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan; IFOM, The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Shunichi Takeda
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshidakonoe, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Dana Branzei
- IFOM, The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy; Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Via Abbiategrasso 207, 27100, Pavia, Italy.
| | - Kouji Hirota
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan.
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22
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Kramara J, Osia B, Malkova A. Break-Induced Replication: The Where, The Why, and The How. Trends Genet 2018; 34:518-531. [PMID: 29735283 DOI: 10.1016/j.tig.2018.04.002] [Citation(s) in RCA: 167] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Revised: 02/27/2018] [Accepted: 04/05/2018] [Indexed: 01/07/2023]
Abstract
Break-induced replication (BIR) is a pathway that repairs one-ended double-strand breaks (DSBs). For decades, yeast model systems offered the only opportunities to study eukaryotic BIR. These studies described an unusual mode of BIR synthesis that is carried out by a migrating bubble and shows conservative inheritance of newly synthesized DNA, leading to genomic instabilities like those associated with cancer in humans. Yet, evidence of BIR functioning in mammals or during repair of other DNA breaks has been missing. Recent studies have uncovered multiple examples of BIR working in replication restart and repair of eroded telomeres in yeast and mammals, as well as some unexpected findings, including the RAD51 independence of BIR. Strong interest remains in determining the variations in molecular mechanisms that drive and regulate BIR in different genetic backgrounds, across organisms, and particularly in the context of human disease.
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Affiliation(s)
- J Kramara
- These authors contributed equally to this work
| | - B Osia
- These authors contributed equally to this work
| | - A Malkova
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA.
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23
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Kitao H, Iimori M, Kataoka Y, Wakasa T, Tokunaga E, Saeki H, Oki E, Maehara Y. DNA replication stress and cancer chemotherapy. Cancer Sci 2018; 109:264-271. [PMID: 29168596 PMCID: PMC5797825 DOI: 10.1111/cas.13455] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/16/2017] [Accepted: 11/16/2017] [Indexed: 12/11/2022] Open
Abstract
DNA replication is one of the fundamental biological processes in which dysregulation can cause genome instability. This instability is one of the hallmarks of cancer and confers genetic diversity during tumorigenesis. Numerous experimental and clinical studies have indicated that most tumors have experienced and overcome the stresses caused by the perturbation of DNA replication, which is also referred to as DNA replication stress (DRS). When we consider therapeutic approaches for tumors, it is important to exploit the differences in DRS between tumor and normal cells. In this review, we introduce the current understanding of DRS in tumors and discuss the underlying mechanism of cancer therapy from the aspect of DRS.
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Affiliation(s)
- Hiroyuki Kitao
- Department of Molecular Cancer BiologyGraduate School of Pharmaceutical SciencesKyushu UniversityFukuokaJapan
| | - Makoto Iimori
- Department of Molecular Cancer BiologyGraduate School of Pharmaceutical SciencesKyushu UniversityFukuokaJapan
| | - Yuki Kataoka
- Department of Molecular Cancer BiologyGraduate School of Pharmaceutical SciencesKyushu UniversityFukuokaJapan
- Taiho Pharmaceutical Co. Ltd.TokushimaIbarakiJapan
| | - Takeshi Wakasa
- Taiho Pharmaceutical Co. Ltd.TokushimaIbarakiJapan
- Department of Surgery and ScienceGraduate School of Medical SciencesKyushu UniversityFukuokaJapan
| | - Eriko Tokunaga
- Department of Breast OncologyNational Hospital Organization Kyushu Cancer CenterFukuokaJapan
| | - Hiroshi Saeki
- Department of Surgery and ScienceGraduate School of Medical SciencesKyushu UniversityFukuokaJapan
| | - Eiji Oki
- Department of Surgery and ScienceGraduate School of Medical SciencesKyushu UniversityFukuokaJapan
| | - Yoshihiko Maehara
- Department of Surgery and ScienceGraduate School of Medical SciencesKyushu UniversityFukuokaJapan
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