51
|
Jimeno S, Mejías-Navarro F, Prados-Carvajal R, Huertas P. Controlling the balance between chromosome break repair pathways. DNA Repair (Amst) 2019; 115:95-134. [DOI: 10.1016/bs.apcsb.2018.10.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
|
52
|
Nishi R, Wijnhoven PWG, Kimura Y, Matsui M, Konietzny R, Wu Q, Nakamura K, Blundell TL, Kessler BM. The deubiquitylating enzyme UCHL3 regulates Ku80 retention at sites of DNA damage. Sci Rep 2018; 8:17891. [PMID: 30559450 PMCID: PMC6297141 DOI: 10.1038/s41598-018-36235-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 11/16/2018] [Indexed: 02/02/2023] Open
Abstract
Non-homologous end-joining (NHEJ), which can promote genomic instability when dysfunctional, is a major DNA double-strand break (DSB) repair pathway. Although ubiquitylation of the core NHEJ factor, Ku (Ku70-Ku80), which senses broken DNA ends, is important for its removal from sites of damage upon completion of NHEJ, the mechanism regulating Ku ubiquitylation remains elusive. We provide evidence showing that the ubiquitin carboxyl-terminal hydrolase L3 (UCHL3) interacts with and directly deubiquitylates one of the Ku heterodimer subunits, Ku80. Additionally, depleting UCHL3 resulted in reduced Ku80 foci formation, Ku80 binding to chromatin after DSB induction, moderately sensitized cells to ionizing radiation and decreased NHEJ efficiencies. Mechanistically, we show that DNA damage induces UCHL3 phosphorylation, which is dependent on ATM, downstream NHEJ factors and UCHL3 catalytic activity. Furthermore, this phosphorylation destabilizes UCHL3, despite having no effect on its catalytic activity. Collectively, these data suggest that UCHL3 facilitates cellular viability after DSB induction by antagonizing Ku80 ubiquitylation to enhance Ku80 retention at sites of damage.
Collapse
Affiliation(s)
- Ryotaro Nishi
- The Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Biology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, United Kingdom.
- Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Shiga, 525-8577, Japan.
| | - Paul W G Wijnhoven
- The Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Biology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, United Kingdom
- Bioscience Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, United Kingdom
| | - Yusuke Kimura
- Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Shiga, 525-8577, Japan
| | - Misaki Matsui
- Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Shiga, 525-8577, Japan
| | - Rebecca Konietzny
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, United Kingdom
| | - Qian Wu
- Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, Cambridge, CB2 1GA, United Kingdom
| | - Keisuke Nakamura
- Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Shiga, 525-8577, Japan
| | - Tom L Blundell
- Department of Biochemistry, University of Cambridge, Sanger Building, Tennis Court Road, Cambridge, CB2 1GA, United Kingdom
| | - Benedikt M Kessler
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, United Kingdom
| |
Collapse
|
53
|
Lamarche BJ, Orazio NI, Goben B, Meisenhelder J, You Z, Weitzman MD, Hunter T. Repair of protein-linked DNA double strand breaks: Using the adenovirus genome as a model substrate in cell-based assays. DNA Repair (Amst) 2018; 74:80-90. [PMID: 30583959 DOI: 10.1016/j.dnarep.2018.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 12/07/2018] [Accepted: 12/07/2018] [Indexed: 11/29/2022]
Abstract
The DNA double strand breaks (DSBs) created during meiotic recombination and during some types of chemotherapy contain protein covalently attached to their 5' termini. Removal of the end-blocking protein is a prerequisite to DSB processing by non-homologous end-joining or homologous recombination. One mechanism for removing the protein involves CtIP-stimulated Mre11-catalyzed nicking of the protein-linked strand distal to the DSB terminus, releasing the end-blocking protein while it remains covalently attached to an oligonucleotide. Much of what is known about this repair process has recently been deciphered through in vitro reconstitution studies. We present here a novel model system based on adenovirus (Ad), which contains the Ad terminal protein covalently linked to the 5' terminus of its dsDNA genome, for studying the repair of 5' protein-linked DSBs in vivo. It was previously shown that the genome of Ad mutants that lack early region 4 (E4) can be joined into concatemers in vivo, suggesting that the Ad terminal protein had been removed from the genome termini prior to ligation. Here we show that during infection with the E4-deleted Ad mutant dl1004, the Ad terminal protein is removed in a manner that recapitulates removal of end-blocking proteins from cellular DSBs. In addition to displaying a dependence on CtIP, and Mre11 acting as the endonuclease, the protein-linked oligonucleotides that are released from the viral genome are similar in size to the oligos that remain attached to Spo11 and Top2 after they are removed from the 5' termini of DSBs during meiotic recombination and etoposide chemotherapy, respectively. The single nucleotide resolution that is possible with this assay, combined with the single sequence context in which the lesion is presented, make it a useful tool for further refining our mechanistic understanding of how blocking proteins are removed from the 5' termini of DSBs.
Collapse
Affiliation(s)
- Brandon J Lamarche
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California, 92037, USA; Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, 92037, USA
| | - Nicole I Orazio
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California, 92037, USA
| | - Brittany Goben
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, 92037, USA
| | - Jill Meisenhelder
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, 92037, USA
| | - Zhongsheng You
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Matthew D Weitzman
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California, 92037, USA.
| | - Tony Hunter
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, 92037, USA.
| |
Collapse
|
54
|
Makharashvili N, Arora S, Yin Y, Fu Q, Wen X, Lee JH, Kao CH, Leung JWC, Miller KM, Paull TT. Sae2/CtIP prevents R-loop accumulation in eukaryotic cells. eLife 2018; 7:e42733. [PMID: 30523780 PMCID: PMC6296784 DOI: 10.7554/elife.42733] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 11/30/2018] [Indexed: 02/06/2023] Open
Abstract
The Sae2/CtIP protein is required for efficient processing of DNA double-strand breaks that initiate homologous recombination in eukaryotic cells. Sae2/CtIP is also important for survival of single-stranded Top1-induced lesions and CtIP is known to associate directly with transcription-associated complexes in mammalian cells. Here we investigate the role of Sae2/CtIP at single-strand lesions in budding yeast and in human cells and find that depletion of Sae2/CtIP promotes the accumulation of stalled RNA polymerase and RNA-DNA hybrids at sites of highly expressed genes. Overexpression of the RNA-DNA helicase Senataxin suppresses DNA damage sensitivity and R-loop accumulation in Sae2/CtIP-deficient cells, and a catalytic mutant of CtIP fails to complement this sensitivity, indicating a role for CtIP nuclease activity in the repair process. Based on this evidence, we propose that R-loop processing by 5' flap endonucleases is a necessary step in the stabilization and removal of nascent R-loop initiating structures in eukaryotic cells.
Collapse
Affiliation(s)
- Nodar Makharashvili
- Howard Hughes Medical Institute, The University of Texas at AustinAustinUnited states
- Department of Molecular BiosciencesThe University of Texas at AustinAustinUnited States
| | - Sucheta Arora
- Howard Hughes Medical Institute, The University of Texas at AustinAustinUnited states
- Department of Molecular BiosciencesThe University of Texas at AustinAustinUnited States
| | - Yizhi Yin
- Howard Hughes Medical Institute, The University of Texas at AustinAustinUnited states
- Department of Molecular BiosciencesThe University of Texas at AustinAustinUnited States
| | - Qiong Fu
- Gastrointestinal Malignancy Section, Thoracic and Gastrointestinal Oncology Branch, Center for Cancer ResearchNational Cancer Institute, National Institutes of HealthBethesdaUnited States
| | - Xuemei Wen
- Department of Molecular BiosciencesThe University of Texas at AustinAustinUnited States
| | - Ji-Hoon Lee
- Department of Molecular BiosciencesThe University of Texas at AustinAustinUnited States
| | - Chung-Hsuan Kao
- Department of Molecular BiosciencesThe University of Texas at AustinAustinUnited States
| | - Justin WC Leung
- Department of Radiation OncologyUniversity of Arkansas for Medical SciencesLittle RockUnited States
| | - Kyle M Miller
- Department of Molecular BiosciencesThe University of Texas at AustinAustinUnited States
| | - Tanya T Paull
- Howard Hughes Medical Institute, The University of Texas at AustinAustinUnited states
- Department of Molecular BiosciencesThe University of Texas at AustinAustinUnited States
| |
Collapse
|
55
|
Sizemore ST, Zhang M, Cho JH, Sizemore GM, Hurwitz B, Kaur B, Lehman NL, Ostrowski MC, Robe PA, Miao W, Wang Y, Chakravarti A, Xia F. Pyruvate kinase M2 regulates homologous recombination-mediated DNA double-strand break repair. Cell Res 2018; 28:1090-1102. [PMID: 30297868 PMCID: PMC6218445 DOI: 10.1038/s41422-018-0086-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 07/23/2018] [Accepted: 08/16/2018] [Indexed: 02/08/2023] Open
Abstract
Resistance to genotoxic therapies is a primary cause of treatment failure and tumor recurrence. The underlying mechanisms that activate the DNA damage response (DDR) and allow cancer cells to escape the lethal effects of genotoxic therapies remain unclear. Here, we uncover an unexpected mechanism through which pyruvate kinase M2 (PKM2), the highly expressed PK isoform in cancer cells and a master regulator of cancer metabolic reprogramming, integrates with the DDR to directly promote DNA double-strand break (DSB) repair. In response to ionizing radiation and oxidative stress, ATM phosphorylates PKM2 at T328 resulting in its nuclear accumulation. pT328-PKM2 is required and sufficient to promote homologous recombination (HR)-mediated DNA DSB repair through phosphorylation of CtBP-interacting protein (CtIP) on T126 to increase CtIP's recruitment at DSBs and resection of DNA ends. Disruption of the ATM-PKM2-CtIP axis sensitizes cancer cells to a variety of DNA-damaging agents and PARP1 inhibition. Furthermore, increased nuclear pT328-PKM2 level is associated with significantly worse survival in glioblastoma patients. Combined, these data advocate the use of PKM2-targeting strategies as a means to not only disrupt cancer metabolism but also inhibit an important mechanism of resistance to genotoxic therapies.
Collapse
Affiliation(s)
- Steven T Sizemore
- Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, OH, 43210, USA
| | - Manchao Zhang
- Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Ju Hwan Cho
- Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, OH, 43210, USA
| | - Gina M Sizemore
- Department of Cancer Biology & Genetics, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, OH, 43210, USA
| | - Brian Hurwitz
- Department of Neurological Surgery, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, OH, 43210, USA
| | - Balveen Kaur
- Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, OH, 43210, USA
- Department of Neurological Surgery, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, OH, 43210, USA
| | - Norman L Lehman
- Department of Pathology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, OH, 43210, USA
| | - Michael C Ostrowski
- Department of Cancer Biology & Genetics, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, OH, 43210, USA
| | - Pierre A Robe
- Department of Neurology and Neurosurgery, Rudolf Magnus Brain Institute, University Medical Center of Utrecht, Utrecht, The Netherlands
- Departments of Neurosurgery and Human Genetics, University of Liege, Liege, Belgium
| | - Weili Miao
- Department of Chemistry, University of California, Riverside, CA, 92521, USA
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, CA, 92521, USA
| | - Arnab Chakravarti
- Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, OH, 43210, USA
| | - Fen Xia
- Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA.
| |
Collapse
|
56
|
Barnard SGR, Moquet J, Lloyd S, Ellender M, Ainsbury EA, Quinlan RA. Dotting the eyes: mouse strain dependency of the lens epithelium to low dose radiation-induced DNA damage. Int J Radiat Biol 2018; 94:1116-1124. [PMID: 30359158 DOI: 10.1080/09553002.2018.1532609] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE Epidemiological evidence regarding the radiosensitivity of the lens of the eye and radiation cataract development has led to changes in the EU Basic Safety Standards for protection of the lens against ionizing radiation. However, mechanistic details of lens radiation response pathways and their significance for cataractogenesis remain unclear. Radiation-induced DNA damage and the potential impairment of repair pathways within the lens epithelium, a cell monolayer that covers the anterior hemisphere of the lens, are likely to be involved. MATERIALS AND METHODS In this work, the lens epithelium has been analyzed for its DNA double-strand break (DSB) repair response to ionizing radiation. The responses of epithelial cells located at the anterior pole (central region) have been compared to at the very periphery of the monolayer (germinative and transitional zones). Described here are the different responses in the two regions and across four strains (C57BL/6, 129S2, BALB/c and CBA/Ca) over a low dose (0-25 mGy) in-vivo whole body X-irradiation range up to 24 hours post exposure. RESULTS DNA damage and repair as visualized through 53BP1 staining was present across the lens epithelium, although repair kinetics appeared non-uniform. Epithelial cells in the central region have significantly more 53BP1 foci. The sensitivities of different mouse strains have also been compared. CONCLUSIONS 129S2 and BALB/c showed higher levels of DNA damage, with BALB/c showing significantly less inter-individual variability and appearing to be a more robust model for future DNA damage and repair studies. As a result of this study, BALB/c was identified as a suitable radiosensitive lens strain to detect and quantify early low dose ionizing radiation DNA damage effects in the mouse eye lens specifically, as an indicator of cataract formation.
Collapse
Affiliation(s)
- S G R Barnard
- a Centre for Radiation, Chemical and Environmental Hazards , Public Health England , Chilton , Oxon, UK.,b Department of Biosciences , Durham University , Durham , UK
| | - J Moquet
- a Centre for Radiation, Chemical and Environmental Hazards , Public Health England , Chilton , Oxon, UK
| | - S Lloyd
- a Centre for Radiation, Chemical and Environmental Hazards , Public Health England , Chilton , Oxon, UK.,c School of Biosciences , The University of Birmingham , Edgbaston , UK
| | - M Ellender
- a Centre for Radiation, Chemical and Environmental Hazards , Public Health England , Chilton , Oxon, UK
| | - E A Ainsbury
- a Centre for Radiation, Chemical and Environmental Hazards , Public Health England , Chilton , Oxon, UK
| | - R A Quinlan
- b Department of Biosciences , Durham University , Durham , UK
| |
Collapse
|
57
|
Kawale AS, Akopiants K, Valerie K, Ruis B, Hendrickson EA, Huang SYN, Pommier Y, Povirk LF. TDP1 suppresses mis-joining of radiomimetic DNA double-strand breaks and cooperates with Artemis to promote optimal nonhomologous end joining. Nucleic Acids Res 2018; 46:8926-8939. [PMID: 30113698 PMCID: PMC6158748 DOI: 10.1093/nar/gky694] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 07/18/2018] [Accepted: 07/29/2018] [Indexed: 01/04/2023] Open
Abstract
The Artemis nuclease and tyrosyl-DNA phosphodiesterase (TDP1) are each capable of resolving protruding 3'-phosphoglycolate (PG) termini of DNA double-strand breaks (DSBs). Consequently, both a knockout of Artemis and a knockout/knockdown of TDP1 rendered cells sensitive to the radiomimetic agent neocarzinostatin (NCS), which induces 3'-PG-terminated DSBs. Unexpectedly, however, a knockdown or knockout of TDP1 in Artemis-null cells did not confer any greater sensitivity than either deficiency alone, indicating a strict epistasis between TDP1 and Artemis. Moreover, a deficiency in Artemis, but not TDP1, resulted in a fraction of unrepaired DSBs, which were assessed as 53BP1 foci. Conversely, a deficiency in TDP1, but not Artemis, resulted in a dramatic increase in dicentric chromosomes following NCS treatment. An inhibitor of DNA-dependent protein kinase, a key regulator of the classical nonhomologous end joining (C-NHEJ) pathway sensitized cells to NCS, but eliminated the sensitizing effects of both TDP1 and Artemis deficiencies. These results suggest that TDP1 and Artemis perform different functions in the repair of terminally blocked DSBs by the C-NHEJ pathway, and that whereas an Artemis deficiency prevents end joining of some DSBs, a TDP1 deficiency tends to promote DSB mis-joining.
Collapse
Affiliation(s)
- Ajinkya S Kawale
- Department of Pharmacology and Toxicology and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Konstantin Akopiants
- Department of Pharmacology and Toxicology and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Kristoffer Valerie
- Department of Radiation Oncology and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Brian Ruis
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Eric A Hendrickson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Shar-yin N Huang
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Building 37, Room 5068, Bethesda, MD 20892-4255, USA
| | - Yves Pommier
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Building 37, Room 5068, Bethesda, MD 20892-4255, USA
| | - Lawrence F Povirk
- Department of Pharmacology and Toxicology and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA
| |
Collapse
|
58
|
Syed A, Tainer JA. The MRE11-RAD50-NBS1 Complex Conducts the Orchestration of Damage Signaling and Outcomes to Stress in DNA Replication and Repair. Annu Rev Biochem 2018; 87:263-294. [PMID: 29709199 PMCID: PMC6076887 DOI: 10.1146/annurev-biochem-062917-012415] [Citation(s) in RCA: 255] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Genomic instability in disease and its fidelity in health depend on the DNA damage response (DDR), regulated in part from the complex of meiotic recombination 11 homolog 1 (MRE11), ATP-binding cassette-ATPase (RAD50), and phosphopeptide-binding Nijmegen breakage syndrome protein 1 (NBS1). The MRE11-RAD50-NBS1 (MRN) complex forms a multifunctional DDR machine. Within its network assemblies, MRN is the core conductor for the initial and sustained responses to DNA double-strand breaks, stalled replication forks, dysfunctional telomeres, and viral DNA infection. MRN can interfere with cancer therapy and is an attractive target for precision medicine. Its conformations change the paradigm whereby kinases initiate damage sensing. Delineated results reveal kinase activation, posttranslational targeting, functional scaffolding, conformations storing binding energy and enabling access, interactions with hub proteins such as replication protein A (RPA), and distinct networks at DNA breaks and forks. MRN biochemistry provides prototypic insights into how it initiates, implements, and regulates multifunctional responses to genomic stress.
Collapse
Affiliation(s)
- Aleem Syed
- Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA; ,
| | - John A Tainer
- Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA; ,
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| |
Collapse
|
59
|
Prados-Carvajal R, López-Saavedra A, Cepeda-García C, Jimeno S, Huertas P. Multiple roles of the splicing complex SF3B in DNA end resection and homologous recombination. DNA Repair (Amst) 2018; 66-67:11-23. [PMID: 29705135 DOI: 10.1016/j.dnarep.2018.04.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 04/11/2018] [Accepted: 04/18/2018] [Indexed: 01/15/2023]
Abstract
The appropriate repair of DNA double strand breaks is critical for genome maintenance. Thus, several cellular pathways collaborate to orchestrate a coordinated response. These include the repair of the breaks, which could be achieved by different mechanisms. A key protein involved in the regulation of the repair of broken chromosomes is CtIP. Here, we have found new partners of CtIP involved in the regulation of DNA break repair through affecting DNA end resection. We focus on the splicing complex SF3B and show that its depletion impairs DNA end resection and hampers homologous recombination. Functionally, SF3B controls CtIP function at, as least, two levels: by affecting CtIP mRNA levels and controlling CtIP recruitment to DNA breaks, in a way that requires ATM-mediated phosphorylation of SF3B2 at serine 289. Indeed, overexpression of CtIP rescues the resection defect caused by SF3B downregulation. Strikingly, other SF3B depletion phenotypes, such as impaired homologous recombination or cellular sensitivity to DNA damaging agents, are independent of CtIP levels, suggesting a more general role of SF3B in controlling the response to chromosome breaks.
Collapse
Affiliation(s)
- Rosario Prados-Carvajal
- Departamento de Genética, Universidad de Sevilla, Sevilla, 41080, Spain; Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla, 41092, Spain
| | - Ana López-Saavedra
- Departamento de Genética, Universidad de Sevilla, Sevilla, 41080, Spain; Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla, 41092, Spain
| | - Cristina Cepeda-García
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla, 41092, Spain
| | - Sonia Jimeno
- Departamento de Genética, Universidad de Sevilla, Sevilla, 41080, Spain; Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla, 41092, Spain
| | - Pablo Huertas
- Departamento de Genética, Universidad de Sevilla, Sevilla, 41080, Spain; Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla, 41092, Spain.
| |
Collapse
|
60
|
Gavish-Izakson M, Velpula BB, Elkon R, Prados-Carvajal R, Barnabas GD, Ugalde AP, Agami R, Geiger T, Huertas P, Ziv Y, Shiloh Y. Nuclear poly(A)-binding protein 1 is an ATM target and essential for DNA double-strand break repair. Nucleic Acids Res 2018; 46:730-747. [PMID: 29253183 PMCID: PMC5778506 DOI: 10.1093/nar/gkx1240] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 11/28/2017] [Accepted: 12/04/2017] [Indexed: 12/13/2022] Open
Abstract
The DNA damage response (DDR) is an extensive signaling network that is robustly mobilized by DNA double-strand breaks (DSBs). The primary transducer of the DSB response is the protein kinase, ataxia-telangiectasia, mutated (ATM). Here, we establish nuclear poly(A)-binding protein 1 (PABPN1) as a novel target of ATM and a crucial player in the DSB response. PABPN1 usually functions in regulation of RNA processing and stability. We establish that PABPN1 is recruited to the DDR as a critical regulator of DSB repair. A portion of PABPN1 relocalizes to DSB sites and is phosphorylated on Ser95 in an ATM-dependent manner. PABPN1 depletion sensitizes cells to DSB-inducing agents and prolongs the DSB-induced G2/M cell-cycle arrest, and DSB repair is hampered by PABPN1 depletion or elimination of its phosphorylation site. PABPN1 is required for optimal DSB repair via both nonhomologous end-joining (NHEJ) and homologous recombination repair (HRR), and specifically is essential for efficient DNA-end resection, an initial, key step in HRR. Using mass spectrometry analysis, we capture DNA damage-induced interactions of phospho-PABPN1, including well-established DDR players as well as other RNA metabolizing proteins. Our results uncover a novel ATM-dependent axis in the rapidly growing interface between RNA metabolism and the DDR.
Collapse
Affiliation(s)
- Michal Gavish-Izakson
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Bhagya Bhavana Velpula
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ran Elkon
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Rosario Prados-Carvajal
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) and Department of Genetics, University of Sevilla, Sevilla, Spain
| | - Georgina D Barnabas
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Alejandro Pineiro Ugalde
- Division of Biological Stress Response, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Reuven Agami
- Division of Biological Stress Response, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Tamar Geiger
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Pablo Huertas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) and Department of Genetics, University of Sevilla, Sevilla, Spain
| | - Yael Ziv
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yosef Shiloh
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| |
Collapse
|
61
|
Gao X, Wang W, Yang H, Wu L, He Z, Zhou S, Zhao H, Fu Z, Zhou F, Zhou Y. UBE2D3 gene overexpression increases radiosensitivity of EC109 esophageal cancer cells in vitro and in vivo. Oncotarget 2018; 7:32543-53. [PMID: 27105523 PMCID: PMC5078032 DOI: 10.18632/oncotarget.8869] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 03/31/2016] [Indexed: 12/17/2022] Open
Abstract
Ubiquitin-conjugating enzyme E2D3 (UBE2D3), a key component in ubiquitin (Ub) proteasome system, plays a crucial role in tumorigenesis. We previously found that it is bound to hTERT, and UBE2D3 could attenuate radiosensitivity of human breast cancer cells. Here we investigated a contributing role of UBE2D3 in radiosensitivity of esophageal squamous carcinoma. We demonstrated that the overexpression of UBE2D3 in esophageal squamous carcinoma cells (EC109) resulted in prolonged G1 phase and shortened G2/M phase after irradiation. UBE2D3 overexpression also decreased length of telomere and activity of telomerase. In addition, the overexpression of UBE2D3 increased mRNA expression but decreased protein levels of hTERT in both vitro and vivo systems. Compared with untreated cells, the treatment of UBE2D3 overexpressing cells with the specific proteasome inhibitor (MG132) could up-regulate hTERT. MG132 treatment of UBE2D3 overexpressed cells caused a clear and dramatic increase in the amount of ubiquitinated hTERT species. These findings indicate that UBE2D3 enhances radiosensitivity of EC109 cells by degradating hTERT through the ubiquitin proteolysis pathway.
Collapse
Affiliation(s)
- Xiaojia Gao
- Hubei Cancer Clinical Study Center, Hubei Key Laboratory of Tumor Biological Behaviors, Wuhan, China.,Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Wenbo Wang
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Hui Yang
- Hubei Cancer Clinical Study Center, Hubei Key Laboratory of Tumor Biological Behaviors, Wuhan, China.,Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Lin Wu
- Hubei Cancer Clinical Study Center, Hubei Key Laboratory of Tumor Biological Behaviors, Wuhan, China.,Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Zhongshi He
- Hubei Cancer Clinical Study Center, Hubei Key Laboratory of Tumor Biological Behaviors, Wuhan, China.,Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Shuliang Zhou
- Hubei Cancer Clinical Study Center, Hubei Key Laboratory of Tumor Biological Behaviors, Wuhan, China.,Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Hong Zhao
- Hubei Cancer Clinical Study Center, Hubei Key Laboratory of Tumor Biological Behaviors, Wuhan, China.,Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Zhenming Fu
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Fuxiang Zhou
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yunfeng Zhou
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| |
Collapse
|
62
|
Genetic Separation of Sae2 Nuclease Activity from Mre11 Nuclease Functions in Budding Yeast. Mol Cell Biol 2017; 37:MCB.00156-17. [PMID: 28970327 DOI: 10.1128/mcb.00156-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 09/25/2017] [Indexed: 02/01/2023] Open
Abstract
Sae2 promotes the repair of DNA double-strand breaks in Saccharomyces cerevisiae The role of Sae2 is linked to the Mre11/Rad50/Xrs2 (MRX) complex, which is important for the processing of DNA ends into single-stranded substrates for homologous recombination. Sae2 has intrinsic endonuclease activity, but the role of this activity has not been assessed independently from its functions in promoting Mre11 nuclease activity. Here we identify and characterize separation-of-function mutants that lack intrinsic nuclease activity or the ability to promote Mre11 endonucleolytic activity. We find that the ability of Sae2 to promote MRX nuclease functions is important for DNA damage survival, particularly in the absence of Dna2 nuclease activity. In contrast, Sae2 nuclease activity is essential for DNA repair when the Mre11 nuclease is compromised. Resection of DNA breaks is impaired when either Sae2 activity is blocked, suggesting roles for both Mre11 and Sae2 nuclease activities in promoting the processing of DNA ends in vivo Finally, both activities of Sae2 are important for sporulation, indicating that the processing of meiotic breaks requires both Mre11 and Sae2 nuclease activities.
Collapse
|
63
|
Sakasai R, Isono M, Wakasugi M, Hashimoto M, Sunatani Y, Matsui T, Shibata A, Matsunaga T, Iwabuchi K. Aquarius is required for proper CtIP expression and homologous recombination repair. Sci Rep 2017; 7:13808. [PMID: 29061988 PMCID: PMC5653829 DOI: 10.1038/s41598-017-13695-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 09/26/2017] [Indexed: 01/01/2023] Open
Abstract
Accumulating evidence indicates that transcription is closely related to DNA damage formation and that the loss of RNA biogenesis factors causes genome instability. However, whether such factors are involved in DNA damage responses remains unclear. We focus here on the RNA helicase Aquarius (AQR), a known R-loop processing factor, and show that its depletion in human cells results in the accumulation of DNA damage during S phase, mediated by R-loop formation. We investigated the involvement of Aquarius in DNA damage responses and found that AQR knockdown decreased DNA damage-induced foci formation of Rad51 and replication protein A, suggesting that Aquarius contributes to homologous recombination (HR)-mediated repair of DNA double-strand breaks (DSBs). Interestingly, the protein level of CtIP, a DSB processing factor, was decreased in AQR-knockdown cells. Exogenous expression of Aquarius partially restored CtIP protein level; however, CtIP overproduction did not rescue defective HR in AQR-knockdown cells. In accordance with these data, Aquarius depletion sensitized cells to genotoxic agents. We propose that Aquarius contributes to the maintenance of genomic stability via regulation of HR by CtIP-dependent and -independent pathways.
Collapse
Affiliation(s)
- Ryo Sakasai
- Department of Biochemistry I, Kanazawa Medical University, Ishikawa, Japan
| | - Mayu Isono
- Education and Research Support Center, Gunma University, Ishikawa, Japan
| | - Mitsuo Wakasugi
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa, Japan
| | | | - Yumi Sunatani
- Department of Biochemistry I, Kanazawa Medical University, Ishikawa, Japan
| | - Tadashi Matsui
- Department of Biochemistry I, Kanazawa Medical University, Ishikawa, Japan
| | - Atsushi Shibata
- Education and Research Support Center, Gunma University, Ishikawa, Japan
| | - Tsukasa Matsunaga
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa, Japan
| | - Kuniyoshi Iwabuchi
- Department of Biochemistry I, Kanazawa Medical University, Ishikawa, Japan.
| |
Collapse
|
64
|
Chen Y, Liu H, Zhang H, Sun C, Hu Z, Tian Q, Peng C, Jiang P, Hua H, Li X, Pei H. And-1 coordinates with CtIP for efficient homologous recombination and DNA damage checkpoint maintenance. Nucleic Acids Res 2017; 45:2516-2530. [PMID: 27940552 PMCID: PMC5389581 DOI: 10.1093/nar/gkw1212] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 11/25/2016] [Indexed: 12/29/2022] Open
Abstract
To prevent genomic instability, cells respond to DNA lesions by blocking cell cycle progression and initiating DNA repair. Homologous recombination repair of DNA breaks requires CtIP-dependent resection of the DNA ends, which is thought to play a key role in activation of CHK1 kinase to induce the cell cycle checkpoint. But the mechanism is still not fully understood. Here, we establish that And-1, a replisome component, promotes DNA-end resection and DNA repair by homologous recombination. Mechanistically, And-1 interacts with CtIP and regulates CtIP recruitment to DNA damage sites. And-1 localizes to sites of DNA damage dependent on MDC1-RNF8 pathway, and is required for resistance to many DNA-damaging and replication stress-inducing agents. Furthermore, we show that And-1-CtIP axis is critically required for sustained ATR-CHK1 checkpoint signaling and for maintaining both the intra-S- and G2-phase checkpoints. Our findings thus identify And-1 as a novel DNA repair regulator and reveal how the replisome regulates the DNA damage induced checkpoint and genomic stability.
Collapse
Affiliation(s)
- Yali Chen
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Hailong Liu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Haoxing Zhang
- School of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong Province 518060, China
| | - Changqing Sun
- Department of neurosurgery, Tianjin Baodi Hospital, Baodi Clinical College of Tianjin Medical University, Tianjin 301800, China
| | - Zhaohua Hu
- Department of Orthopedics, Renhe Hospital of Three Gorges University, Yichang 443001, China
| | - Qingsong Tian
- Department of Orthopedics, Renhe Hospital of Three Gorges University, Yichang 443001, China
| | - Changmin Peng
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Industrial Microbiology Key Lab, College of Biotechnology, Tianjin University of Science and Technology, No 29, 13ST. TEDA, Tianjin 300457, China
| | - Pei Jiang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Hui Hua
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Xinzhi Li
- Department of Orthopedics, Renhe Hospital of Three Gorges University, Yichang 443001, China
| | - Huadong Pei
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, Beijing 100850, China
| |
Collapse
|
65
|
DNA end resection requires constitutive sumoylation of CtIP by CBX4. Nat Commun 2017; 8:113. [PMID: 28740167 PMCID: PMC5524638 DOI: 10.1038/s41467-017-00183-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 06/07/2017] [Indexed: 11/20/2022] Open
Abstract
DNA breaks are complex DNA lesions that can be repaired by two alternative mechanisms: non-homologous end-joining and homologous recombination. The decision between them depends on the activation of the DNA resection machinery, which blocks non-homologous end-joining and stimulates recombination. On the other hand, post-translational modifications play a critical role in DNA repair. We have found that the SUMO E3 ligase CBX4 controls resection through the key factor CtIP. Indeed, CBX4 depletion impairs CtIP constitutive sumoylation and DNA end processing. Importantly, mutating lysine 896 in CtIP recapitulates the CBX4-depletion phenotype, blocks homologous recombination and increases genomic instability. Artificial fusion of CtIP and SUMO suppresses the effects of both the non-sumoylatable CtIP mutant and CBX4 depletion. Mechanistically, CtIP sumoylation is essential for its recruitment to damaged DNA. In summary, sumoylation of CtIP at lysine 896 defines a subpopulation of the protein that is involved in DNA resection and recombination. The choice between non-homologous end-joining and homologous recombination to repair a DNA double-strand break depends on activation of the end resection machinery. Here the authors show that SUMO E3 ligase CBX4 sumoylates subpopulation of CtIP to regulate recruitment to breaks and resection.
Collapse
|
66
|
Abstract
The correct duplication and transmission of genetic material to daughter cells is the primary objective of the cell division cycle. DNA replication and chromosome segregation present both challenges and opportunities for DNA repair pathways that safeguard genetic information. As a consequence, there is a profound, two-way connection between DNA repair and cell cycle control. Here, we review how DNA repair processes, and DNA double-strand break repair in particular, are regulated during the cell cycle to optimize genomic integrity.
Collapse
|
67
|
O'Driscoll M. The pathological consequences of impaired genome integrity in humans; disorders of the DNA replication machinery. J Pathol 2017; 241:192-207. [PMID: 27757957 DOI: 10.1002/path.4828] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/12/2016] [Accepted: 10/13/2016] [Indexed: 12/13/2022]
Abstract
Accurate and efficient replication of the human genome occurs in the context of an array of constitutional barriers, including regional topological constraints imposed by chromatin architecture and processes such as transcription, catenation of the helical polymer and spontaneously generated DNA lesions, including base modifications and strand breaks. DNA replication is fundamentally important for tissue development and homeostasis; differentiation programmes are intimately linked with stem cell division. Unsurprisingly, impairments of the DNA replication machinery can have catastrophic consequences for genome stability and cell division. Functional impacts on DNA replication and genome stability have long been known to play roles in malignant transformation through a variety of complex mechanisms, and significant further insights have been gained from studying model organisms in this context. Congenital hypomorphic defects in components of the DNA replication machinery have been and continue to be identified in humans. These disorders present with a wide range of clinical features. Indeed, in some instances, different mutations in the same gene underlie different clinical presentations. Understanding the origin and molecular basis of these features opens a window onto the range of developmental impacts of suboptimal DNA replication and genome instability in humans. Here, I will briefly overview the basic steps involved in DNA replication and the key concepts that have emerged from this area of research, before switching emphasis to the pathological consequences of defects within the DNA replication network; the human disorders. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Mark O'Driscoll
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
| |
Collapse
|
68
|
DNA double-strand-break repair in higher eukaryotes and its role in genomic instability and cancer: Cell cycle and proliferation-dependent regulation. Semin Cancer Biol 2016; 37-38:51-64. [DOI: 10.1016/j.semcancer.2016.03.003] [Citation(s) in RCA: 178] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 03/11/2016] [Accepted: 03/21/2016] [Indexed: 12/18/2022]
|
69
|
Liu T, Huang J. DNA End Resection: Facts and Mechanisms. GENOMICS PROTEOMICS & BIOINFORMATICS 2016; 14:126-130. [PMID: 27240470 PMCID: PMC4936662 DOI: 10.1016/j.gpb.2016.05.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 05/04/2016] [Accepted: 05/05/2016] [Indexed: 01/05/2023]
Abstract
DNA double-strand breaks (DSBs), which arise following exposure to a number of endogenous and exogenous agents, can be repaired by either the homologous recombination (HR) or non-homologous end-joining (NHEJ) pathways in eukaryotic cells. A vital step in HR repair is DNA end resection, which generates a long 3′ single-stranded DNA (ssDNA) tail that can invade the homologous DNA strand. The generation of 3′ ssDNA is not only essential for HR repair, but also promotes activation of the ataxia telangiectasia and Rad3-related protein (ATR). Multiple factors, including the MRN/X complex, C-terminal-binding protein interacting protein (CtIP)/Sae2, exonuclease 1 (EXO1), Bloom syndrome protein (BLM)/Sgs1, DNA2 nuclease/helicase, and several chromatin remodelers, cooperate to complete the process of end resection. Here we review the basic machinery involved in DNA end resection in eukaryotic cells.
Collapse
Affiliation(s)
- Ting Liu
- Department of Cell Biology and Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou 310058, China.
| | - Jun Huang
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China.
| |
Collapse
|
70
|
Abstract
Two studies show that the E3 ubiquitin ligase RNF138 is recruited to DNA double-strand break sites, where it ubiquitylates key repair factors to promote DNA-end resection and homologous recombination. These findings add insights into the multilayered regulatory mechanisms underlying DNA double-strand break repair pathway choice in mammalian cells.
Collapse
|
71
|
ER functions of oncogenes and tumor suppressors: Modulators of intracellular Ca(2+) signaling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1364-78. [PMID: 26772784 DOI: 10.1016/j.bbamcr.2016.01.002] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 01/04/2016] [Accepted: 01/05/2016] [Indexed: 12/20/2022]
Abstract
Intracellular Ca(2+) signals that arise from the endoplasmic reticulum (ER), the major intracellular Ca(2+)-storage organelle, impact several mitochondrial functions and dictate cell survival and cell death processes. Furthermore, alterations in Ca(2+) signaling in cancer cells promote survival and establish a high tolerance towards cell stress and damage, so that the on-going oncogenic stress does not result in the activation of cell death. Over the last years, the mechanisms underlying these oncogenic alterations in Ca(2+) signaling have started to emerge. An important aspect of this is the identification of several major oncogenes, including Bcl-2, Bcl-XL, Mcl-1, PKB/Akt, and Ras, and tumor suppressors, such as p53, PTEN, PML, BRCA1, and Beclin 1, as direct and critical regulators of Ca(2+)-transport systems located at the ER membranes, including IP3 receptors and SERCA Ca(2+) pumps. In this way, these proteins execute part of their function by controlling the ER-mitochondrial Ca(2+) fluxes, favoring either survival (oncogenes) or cell death (tumor suppressors). Oncogenic mutations, gene deletions or amplifications alter the expression and/or function of these proteins, thereby changing the delicate balance between oncogenes and tumor suppressors, impacting oncogenesis and favoring malignant cell function and behavior. In this review, we provided an integrated overview of the impact of the major oncogenes and tumor suppressors, often altered in cancer cells, on Ca(2+) signaling from the ER Ca(2+) stores. This article is part of a Special Issue entitled: Calcium and Cell Fate. Guest Editors: Jacques Haiech, Claus Heizmann, Joachim Krebs, Thierry Capiod and Olivier Mignen.
Collapse
|
72
|
Forment JV, Jackson SP, Pellegrini L. When two is not enough: a CtIP tetramer is required for DNA repair by Homologous Recombination. Nucleus 2015; 6:344-8. [PMID: 26305173 PMCID: PMC4915501 DOI: 10.1080/19491034.2015.1086050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 08/17/2015] [Accepted: 08/18/2015] [Indexed: 10/23/2022] Open
Abstract
Homologous recombination (HR) is central to the repair of double-strand DNA breaks that occur in S/G2 phases of the cell cycle. HR relies on the CtIP protein (Ctp1 in fission yeast, Sae2 in budding yeast) for resection of DNA ends, a key step in generating the 3'-DNA overhangs that are required for the HR strand-exchange reaction. Although much has been learned about the biological importance of CtIP in DNA repair, our mechanistic insight into its molecular functions remains incomplete. It has been recently discovered that CtIP and Ctp1 share a conserved tetrameric architecture that is mediated by their N-terminal domains and is critical for their function in HR. The specific arrangement of protein chains in the CtIP/Ctp1 tetramer indicates that an ability to bridge DNA ends might be an important feature of CtIP/Ctp1 function, establishing an intriguing similarity with the known ability of the MRE11-RAD50-NBS1 complex to link DNA ends. Although the exact mechanism of action remains to be elucidated, the remarkable evolutionary conservation of CtIP/Ctp1 tetramerisation clearly points to its crucial role in HR.
Collapse
Affiliation(s)
- Josep V Forment
- The Gurdon Institute; University of Cambridge; Cambridge, UK
- The Wellcome Trust Sanger Institute; Hinxton, UK
- Department of Biochemistry; University of Cambridge; Cambridge, UK
| | - Stephen P Jackson
- The Gurdon Institute; University of Cambridge; Cambridge, UK
- The Wellcome Trust Sanger Institute; Hinxton, UK
- Department of Biochemistry; University of Cambridge; Cambridge, UK
| | - Luca Pellegrini
- Department of Biochemistry; University of Cambridge; Cambridge, UK
| |
Collapse
|