1
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Zheng Y, Zhao Y, Dong K, Miao L, Zhou X, Gong Y, Zhang L. A novel Mre11 protein from the hyperthermophilic euryarchaeon Thermococcus barophilus Ch5 possesses 5'-3' exonuclease and endonuclease activities. Int J Biol Macromol 2024; 272:132654. [PMID: 38810854 DOI: 10.1016/j.ijbiomac.2024.132654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 05/21/2024] [Accepted: 05/23/2024] [Indexed: 05/31/2024]
Abstract
Mre11 is one of important proteins that are involved in DNA repair and recombination by processing DNA ends to produce 3'-single stranded DNA, thus providing a platform for other DNA repair and recombination proteins. In this work, we characterized the Mre11 protein from the hyperthermophilic euryarchaeon Thermococcus barophilus Ch5 (Tba-Mre11) biochemically and dissected the roles of its four conserved residues, which is the first report on Mre11 proteins from Thermococcus. Tba-Mre11 possesses exonuclease activity for degrading ssDNA and dsDNA in the 5'-3' direction, which contrasts with other reported Mre11 homologs. Maximum degradation efficiency was observed with Mn2+ at 80 °C and at pH 7.5-9.5. In addition to possessing 5'-3' exonuclease activity, Tba-Mre11 has endonuclease activity that nicks plasmid DNA and circular ssDNA. Mutational data show that residues D10, D51 and N86 in Tba-Mre11 are essential for DNA degradation since almost no activity was observed for the D10A, D51A and N86A mutants. By comparison, residue D44 in Tba-Mre11 is not responsible for DNA degradation since the D44A mutant possessed the similar WT protein activity. Notably, the D44A mutant almost completely abolished the ability to bind DNA, suggesting that residue D44 is essential for binding DNA.
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Affiliation(s)
- Yaqi Zheng
- College of Environmental Science and Engineering, Yangzhou University, China
| | - Yang Zhao
- College of Environmental Science and Engineering, Yangzhou University, China
| | - Kunming Dong
- College of Environmental Science and Engineering, Yangzhou University, China
| | - Li Miao
- College of Environmental Science and Engineering, Yangzhou University, China
| | - Xiaojian Zhou
- College of Environmental Science and Engineering, Yangzhou University, China
| | - Yong Gong
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, China
| | - Likui Zhang
- College of Environmental Science and Engineering, Yangzhou University, China.
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2
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Sheng X, Xia Z, Yang H, Hu R. The ubiquitin codes in cellular stress responses. Protein Cell 2024; 15:157-190. [PMID: 37470788 PMCID: PMC10903993 DOI: 10.1093/procel/pwad045] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 07/04/2023] [Indexed: 07/21/2023] Open
Abstract
Ubiquitination/ubiquitylation, one of the most fundamental post-translational modifications, regulates almost every critical cellular process in eukaryotes. Emerging evidence has shown that essential components of numerous biological processes undergo ubiquitination in mammalian cells upon exposure to diverse stresses, from exogenous factors to cellular reactions, causing a dazzling variety of functional consequences. Various forms of ubiquitin signals generated by ubiquitylation events in specific milieus, known as ubiquitin codes, constitute an intrinsic part of myriad cellular stress responses. These ubiquitination events, leading to proteolytic turnover of the substrates or just switch in functionality, initiate, regulate, or supervise multiple cellular stress-associated responses, supporting adaptation, homeostasis recovery, and survival of the stressed cells. In this review, we attempted to summarize the crucial roles of ubiquitination in response to different environmental and intracellular stresses, while discussing how stresses modulate the ubiquitin system. This review also updates the most recent advances in understanding ubiquitination machinery as well as different stress responses and discusses some important questions that may warrant future investigation.
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Affiliation(s)
- Xiangpeng Sheng
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
- State Key Laboratory of Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Zhixiong Xia
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Hanting Yang
- Department of Neurology, State Key Laboratory of Medical Neurobiology, Institute for Translational Brain Research, MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Ronggui Hu
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
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3
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van de Kooij B, Schreuder A, Pavani R, Garzero V, Uruci S, Wendel TJ, van Hoeck A, San Martin Alonso M, Everts M, Koerse D, Callen E, Boom J, Mei H, Cuppen E, Luijsterburg MS, van Vugt MATM, Nussenzweig A, van Attikum H, Noordermeer SM. EXO1 protects BRCA1-deficient cells against toxic DNA lesions. Mol Cell 2024; 84:659-674.e7. [PMID: 38266640 DOI: 10.1016/j.molcel.2023.12.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 10/14/2023] [Accepted: 12/22/2023] [Indexed: 01/26/2024]
Abstract
Inactivating mutations in the BRCA1 and BRCA2 genes impair DNA double-strand break (DSB) repair by homologous recombination (HR), leading to chromosomal instability and cancer. Importantly, BRCA1/2 deficiency also causes therapeutically targetable vulnerabilities. Here, we identify the dependency on the end resection factor EXO1 as a key vulnerability of BRCA1-deficient cells. EXO1 deficiency generates poly(ADP-ribose)-decorated DNA lesions during S phase that associate with unresolved DSBs and genomic instability in BRCA1-deficient but not in wild-type or BRCA2-deficient cells. Our data indicate that BRCA1/EXO1 double-deficient cells accumulate DSBs due to impaired repair by single-strand annealing (SSA) on top of their HR defect. In contrast, BRCA2-deficient cells retain SSA activity in the absence of EXO1 and hence tolerate EXO1 loss. Consistent with a dependency on EXO1-mediated SSA, we find that BRCA1-mutated tumors show elevated EXO1 expression and increased SSA-associated genomic scars compared with BRCA1-proficient tumors. Overall, our findings uncover EXO1 as a promising therapeutic target for BRCA1-deficient tumors.
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Affiliation(s)
- Bert van de Kooij
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Department of Medical Oncology, University Medical Center Groningen, Groningen 9713 GZ, the Netherlands
| | - Anne Schreuder
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands
| | - Raphael Pavani
- Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Veronica Garzero
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands
| | - Sidrit Uruci
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Tiemen J Wendel
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands
| | - Arne van Hoeck
- Oncode Institute, Utrecht 3521 AL, the Netherlands; Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht 3584 CG, the Netherlands
| | - Marta San Martin Alonso
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands
| | - Marieke Everts
- Department of Medical Oncology, University Medical Center Groningen, Groningen 9713 GZ, the Netherlands
| | - Dana Koerse
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Elsa Callen
- Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jasper Boom
- Sequencing Analysis Support Core, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Hailiang Mei
- Sequencing Analysis Support Core, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Edwin Cuppen
- Oncode Institute, Utrecht 3521 AL, the Netherlands; Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht 3584 CG, the Netherlands; Hartwig Medical Foundation, Amsterdam 1098 XH, the Netherlands
| | - Martijn S Luijsterburg
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Marcel A T M van Vugt
- Department of Medical Oncology, University Medical Center Groningen, Groningen 9713 GZ, the Netherlands
| | - André Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Haico van Attikum
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands.
| | - Sylvie M Noordermeer
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands.
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4
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Chen Y, Wu J, Zhai L, Zhang T, Yin H, Gao H, Zhao F, Wang Z, Yang X, Jin M, Huang B, Ding X, Li R, Yang J, He Y, Wang Q, Wang W, Kloeber JA, Li Y, Hao B, Zhang Y, Wang J, Tan M, Li K, Wang P, Lou Z, Yuan J. Metabolic regulation of homologous recombination repair by MRE11 lactylation. Cell 2024; 187:294-311.e21. [PMID: 38128537 DOI: 10.1016/j.cell.2023.11.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 08/09/2023] [Accepted: 11/18/2023] [Indexed: 12/23/2023]
Abstract
Lactylation is a lactate-induced post-translational modification best known for its roles in epigenetic regulation. Herein, we demonstrate that MRE11, a crucial homologous recombination (HR) protein, is lactylated at K673 by the CBP acetyltransferase in response to DNA damage and dependent on ATM phosphorylation of the latter. MRE11 lactylation promotes its binding to DNA, facilitating DNA end resection and HR. Inhibition of CBP or LDH downregulated MRE11 lactylation, impaired HR, and enhanced chemosensitivity of tumor cells in patient-derived xenograft and organoid models. A cell-penetrating peptide that specifically blocks MRE11 lactylation inhibited HR and sensitized cancer cells to cisplatin and PARPi. These findings unveil lactylation as a key regulator of HR, providing fresh insights into the ways in which cellular metabolism is linked to DSB repair. They also imply that the Warburg effect can confer chemoresistance through enhancing HR and suggest a potential therapeutic strategy of targeting MRE11 lactylation to mitigate the effects.
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Affiliation(s)
- Yuping Chen
- State Key Laboratory of Cardiology and Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China; Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai 200120, China
| | - Jinhuan Wu
- State Key Laboratory of Cardiology and Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China; Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai 200120, China
| | - Linhui Zhai
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing, China
| | - Tingting Zhang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Hui Yin
- Department of Thoracic Surgery, The First Affiliated Hospital of Shaoyang University, Shaoyang 422001, China
| | - Huanyao Gao
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA
| | - Fei Zhao
- Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Zhe Wang
- State Key Laboratory of Cardiology and Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China; Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai 200120, China
| | - Xiaoning Yang
- Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Mingpeng Jin
- State Key Laboratory of Cardiology and Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China; Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai 200120, China
| | - Bingsong Huang
- State Key Laboratory of Cardiology and Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China; Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai 200120, China
| | - Xin Ding
- State Key Laboratory of Cardiology and Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China; Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai 200120, China
| | - Rui Li
- State Key Laboratory of Cardiology and Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China; Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai 200120, China
| | - Jie Yang
- Department of Thoracic Surgery, The First Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Yiming He
- State Key Laboratory of Cardiology and Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China; Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai 200120, China
| | - Qianwen Wang
- State Key Laboratory of Cardiology and Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China; Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai 200120, China
| | - Weibin Wang
- Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Jake A Kloeber
- Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA; Mayo Clinic Medical Scientist Training Program, Mayo Clinic Alix School of Medicine and Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55905, USA
| | - Yunxuan Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Bingbing Hao
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yuanyuan Zhang
- State Key Laboratory of Cardiology and Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Jiadong Wang
- Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Minjia Tan
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing, China
| | - Ke Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Ping Wang
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, School of Medicine, Shanghai 200072, China
| | - Zhenkun Lou
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA; Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Jian Yuan
- State Key Laboratory of Cardiology and Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China; Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai 200120, China.
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5
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van de Kooij B, Kruswick A, van Attikum H, Yaffe MB. Multi-pathway DNA-repair reporters reveal competition between end-joining, single-strand annealing and homologous recombination at Cas9-induced DNA double-strand breaks. Nat Commun 2022; 13:5295. [PMID: 36075911 PMCID: PMC9458747 DOI: 10.1038/s41467-022-32743-w] [Citation(s) in RCA: 20] [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: 02/09/2021] [Accepted: 08/11/2022] [Indexed: 11/25/2022] Open
Abstract
DNA double-strand breaks (DSB) are repaired by multiple distinct pathways, with outcomes ranging from error-free repair to mutagenesis and genomic loss. DSB-repair pathway cross-talk and compensation is incompletely understood, despite its importance for genomic stability, oncogenesis, and genome editing using CRISPR/Cas9. To address this, we constructed and validated three fluorescent Cas9-based reporters, named DSB-Spectrum, that simultaneously quantify the contribution of multiple DNA repair pathways at a DSB. DSB-Spectrum reporters distinguish between DSB-repair by error-free canonical non-homologous end-joining (c-NHEJ) versus homologous recombination (HR; reporter 1), mutagenic repair versus HR (reporter 2), and mutagenic end-joining versus single strand annealing (SSA) versus HR (reporter 3). Using these reporters, we show that inhibiting the c-NHEJ factor DNA-PKcs increases repair by HR, but also substantially increases mutagenic SSA. Our data indicate that SSA-mediated DSB-repair also occurs at endogenous genomic loci, driven by Alu elements or homologous gene regions. Finally, we demonstrate that long-range end-resection factors DNA2 and Exo1 promote SSA and reduce HR, when both pathways compete for the same substrate. These new Cas9-based DSB-Spectrum reporters facilitate the comprehensive analysis of repair pathway crosstalk and DSB-repair outcome.
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Affiliation(s)
- Bert van de Kooij
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, the Netherlands
- Koch Institute for Integrative Cancer Research, MIT Center for Precision Cancer Medicine, Departments of Biology and Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Alex Kruswick
- Koch Institute for Integrative Cancer Research, MIT Center for Precision Cancer Medicine, Departments of Biology and Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Haico van Attikum
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, the Netherlands.
| | - Michael B Yaffe
- Koch Institute for Integrative Cancer Research, MIT Center for Precision Cancer Medicine, Departments of Biology and Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Surgery, Beth Israel Deaconess Medical Center, Divisions of Acute Care Surgery, Trauma, and Critical Care and Surgical Oncology, Harvard Medical School, Boston, MA, USA.
- Surgical Oncology Program, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
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6
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Kudlova N, De Sanctis JB, Hajduch M. Cellular Senescence: Molecular Targets, Biomarkers, and Senolytic Drugs. Int J Mol Sci 2022; 23:ijms23084168. [PMID: 35456986 PMCID: PMC9028163 DOI: 10.3390/ijms23084168] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 03/31/2022] [Accepted: 04/05/2022] [Indexed: 11/16/2022] Open
Abstract
Cellular senescence is defined as irreversible cell cycle arrest caused by various processes that render viable cells non-functional, hampering normal tissue homeostasis. It has many endogenous and exogenous inducers, and is closely connected with age, age-related pathologies, DNA damage, degenerative disorders, tumor suppression and activation, wound healing, and tissue repair. However, the literature is replete with contradictory findings concerning its triggering mechanisms, specific biomarkers, and detection protocols. This may be partly due to the wide range of cellular and in vivo animal or human models of accelerated aging that have been used to study senescence and test senolytic drugs. This review summarizes recent findings concerning senescence, presents some widely used cellular and animal senescence models, and briefly describes the best-known senolytic agents.
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Affiliation(s)
- Natalie Kudlova
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 77147 Olomouc, Czech Republic; (N.K.); (J.B.D.S.)
| | - Juan Bautista De Sanctis
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 77147 Olomouc, Czech Republic; (N.K.); (J.B.D.S.)
- Institute of Molecular and Translational Medicine Czech Advanced Technologies and Research Institute, Palacky University, 77147 Olomouc, Czech Republic
| | - Marian Hajduch
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 77147 Olomouc, Czech Republic; (N.K.); (J.B.D.S.)
- Institute of Molecular and Translational Medicine Czech Advanced Technologies and Research Institute, Palacky University, 77147 Olomouc, Czech Republic
- Correspondence: ; Tel.: +42-0-585632082
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7
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Harris C, Savas J, Ray S, Shanle EK. Yeast-based screening of cancer mutations in the DNA damage response protein Mre11 demonstrates importance of conserved capping domain residues. Mol Biol Rep 2021; 48:4107-4119. [PMID: 34075539 DOI: 10.1007/s11033-021-06424-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 05/20/2021] [Indexed: 10/21/2022]
Abstract
DNA damage response (DDR) pathways are initiated to prevent mutations from being passed on in the event of DNA damage. Mutations in DDR proteins can contribute to the development and maintenance of cancer cells, but many mutations observed in human tumors have not been functionally characterized. Because a proper response to DNA damage is fundamental to living organisms, DDR proteins and processes are often highly conserved. The goal of this project was to use Saccharomyces cerevisiae as a model for functional screening of human cancer mutations in conserved DDR proteins. After comparing the cancer mutation frequency and conservation of DDR proteins, Mre11 was selected for functional screening. A subset of mutations in conserved residues was analyzed by structural modeling and screened for functional effects in yeast Mre11. Yeast expressing wild type or mutant Mre11 were then assessed for DNA damage sensitivity using hydroxyurea (HU) and methyl methanesulfonate (MMS). The results were further validated in human cancer cells. The N-terminal point mutations tested in yeast Mre11 do not confer sensitivity to DNA damage sensitivity, suggesting that these residues are dispensable for yeast Mre11 function and may have conserved sequence without conserved function. However, a mutation near the capping domain associated with breast and colorectal cancers compromises Mre11 function in both yeast and human cells. These results provide novel insight into the function of this conserved capping domain residue and demonstrate a framework for yeast-based screening of cancer mutations.
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Affiliation(s)
- Caitlin Harris
- Department of Biological and Environmental Sciences, Longwood University, Farmville, VA, 23901, USA
| | - Jessica Savas
- Department of Biological and Environmental Sciences, Longwood University, Farmville, VA, 23901, USA
| | - Sreerupa Ray
- Department of Biology, Linfield University, McMinnville, OR, 97128, USA
| | - Erin K Shanle
- Department of Biological and Environmental Sciences, Longwood University, Farmville, VA, 23901, USA.
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8
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Whelan DR, Lee WTC, Marks F, Kong YT, Yin Y, Rothenberg E. Super-resolution visualization of distinct stalled and broken replication fork structures. PLoS Genet 2020; 16:e1009256. [PMID: 33370257 PMCID: PMC7793303 DOI: 10.1371/journal.pgen.1009256] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 01/08/2021] [Accepted: 11/03/2020] [Indexed: 12/25/2022] Open
Abstract
Endogenous genotoxic stress occurs in healthy cells due to competition between DNA replication machinery, and transcription and topographic relaxation processes. This causes replication fork stalling and regression, which can further collapse to form single-ended double strand breaks (seDSBs). Super-resolution microscopy has made it possible to directly observe replication stress and DNA damage inside cells, however new approaches to sample preparation and analysis are required. Here we develop and apply multicolor single molecule microscopy to visualize individual replication forks under mild stress from the trapping of Topoisomerase I cleavage complexes, a damage induction which closely mimics endogenous replicative stress. We observe RAD51 and RAD52, alongside RECQ1, as the first responder proteins to stalled but unbroken forks, whereas Ku and MRE11 are initially recruited to seDSBs. By implementing novel super-resolution imaging assays, we are thus able to discern closely related replication fork stress motifs and their repair pathways.
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Affiliation(s)
- Donna R. Whelan
- Department of Pharmacy and Biomedical Sciences, La Trobe Institute for Molecular Science, La Trobe University, Bendigo, Victoria, Australia
- * E-mail: (DRW); (ER)
| | - Wei Ting C. Lee
- Department of Biochemistry and Molecular Pharmacology, Perlmutter Cancer Center, New York University School of Medicine, New York, New York, United States of America
| | - Frances Marks
- Department of Biochemistry and Molecular Pharmacology, Perlmutter Cancer Center, New York University School of Medicine, New York, New York, United States of America
| | - Yu Tina Kong
- Department of Biochemistry and Molecular Pharmacology, Perlmutter Cancer Center, New York University School of Medicine, New York, New York, United States of America
| | - Yandong Yin
- Department of Biochemistry and Molecular Pharmacology, Perlmutter Cancer Center, New York University School of Medicine, New York, New York, United States of America
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, Perlmutter Cancer Center, New York University School of Medicine, New York, New York, United States of America
- * E-mail: (DRW); (ER)
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9
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Modes of action of the archaeal Mre11/Rad50 DNA-repair complex revealed by fast-scan atomic force microscopy. Proc Natl Acad Sci U S A 2020; 117:14936-14947. [PMID: 32541055 PMCID: PMC7334584 DOI: 10.1073/pnas.1915598117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The Mre11/Rad50 (M/R) complex forms the core of an essential DNA-repair complex, conserved in all divisions of life. Here we investigate this complex from the thermophilic archaeon Sulfolobus acidocaldarius using real-time atomic force microscopy. We demonstrate that the coiled-coil regions of Rad50 facilitate M/R interaction with DNA and permit substrate translocation until a free end is encountered. We also observe that the M/R complex drives unprecedented unwinding of the DNA duplexes. Taking these findings together, we provide a model for how the M/R complex can identify DNA double-strand breaks and orchestrate repair events. Mre11 and Rad50 (M/R) proteins are part of an evolutionarily conserved macromolecular apparatus that maintains genomic integrity through repair pathways. Prior structural studies have revealed that this apparatus is extremely dynamic, displaying flexibility in the long coiled-coil regions of Rad50, a member of the structural maintenance of chromosome (SMC) superfamily of ATPases. However, many details of the mechanics of M/R chromosomal manipulation during DNA-repair events remain unclear. Here, we investigate the properties of the thermostable M/R complex from the archaeon Sulfolobus acidocaldarius using atomic force microscopy (AFM) to understand how this macromolecular machinery orchestrates DNA repair. While previous studies have observed canonical interactions between the globular domains of M/R and DNA, we observe transient interactions between DNA substrates and the Rad50 coiled coils. Fast-scan AFM videos (at 1–2 frames per second) of M/R complexes reveal that these interactions result in manipulation and translocation of the DNA substrates. Our study also shows dramatic and unprecedented ATP-dependent DNA unwinding events by the M/R complex, which extend hundreds of base pairs in length. Supported by molecular dynamic simulations, we propose a model for M/R recognition at DNA breaks in which the Rad50 coiled coils aid movement along DNA substrates until a DNA end is encountered, after which the DNA unwinding activity potentiates the downstream homologous recombination (HR)-mediated DNA repair.
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10
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Hu M, Li L, Liu S, Lou Y, Wang L, Le F, Li H, Wang Q, Lou H, Wang N, Jin F. Decreased expression of MRE11 and RAD50 in testes from humans with spermatogenic failure. J Assist Reprod Genet 2020; 37:331-340. [PMID: 31983050 PMCID: PMC7056783 DOI: 10.1007/s10815-019-01686-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 12/27/2019] [Indexed: 12/31/2022] Open
Abstract
PURPOSE To assess testicular mRNA and protein expression levels of MRE11 and RAD50 in human azoospermia patients. METHODS Patients diagnosed with maturation arrest at the spermatocyte stage (MA) and Sertoli cell-only syndrome (SCOS) were recruited through diagnostic testicular biopsy. Patients with normal spermatogenesis were studied as controls. In addition, knockdown of MRE11 and RAD50 was performed in GC-2spd(ts) cells to investigate their roles in cellular proliferation and apoptosis. RESULTS mRNA and protein expression levels of MRE11 and RAD50 were measured using quantitative polymerase chain reaction, western blotting, and immunohistochemistry, respectively. Knockdown of both MRE11 and RAD50 utilized transfection with small interfering RNAs. CONCLUSION Our findings demonstrated altered expression levels of MRE11 and RAD50 in human testes with MA and SCOS, and showed that these alterations might be associated with impaired spermatogenesis. These results offer valuable new perspectives into the molecular mechanisms of male infertility.
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Affiliation(s)
- Minhao Hu
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, 1 Xueshi Road, Hangzhou, 310006, Zhejiang, China
| | - Lejun Li
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, 1 Xueshi Road, Hangzhou, 310006, Zhejiang, China
| | - Shuyuan Liu
- Department of Gynecology, Weifang Maternal and Child Health Hospital, Weifang, 261000, China
| | - Yiyun Lou
- Department of Gynecology, Hangzhou Hospital of Traditional Chinese Medicine, Hangzhou, 310007, China
| | - Liya Wang
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, 1 Xueshi Road, Hangzhou, 310006, Zhejiang, China
| | - Fang Le
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, 1 Xueshi Road, Hangzhou, 310006, Zhejiang, China
| | - Hongping Li
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, 1 Xueshi Road, Hangzhou, 310006, Zhejiang, China
| | - Qijing Wang
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, 1 Xueshi Road, Hangzhou, 310006, Zhejiang, China
| | - Hangying Lou
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, 1 Xueshi Road, Hangzhou, 310006, Zhejiang, China
| | - Ning Wang
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, 1 Xueshi Road, Hangzhou, 310006, Zhejiang, China
| | - Fan Jin
- Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, 1 Xueshi Road, Hangzhou, 310006, Zhejiang, China.
- Women's Reproductive Health Laboratory of Zhejiang Province, Key Laboratory of Reproductive Genetics, Ministry of Education, Hangzhou, 310006, China.
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11
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Ferreira S, Dutreix M. DNA repair inhibitors to enhance radiotherapy: Progresses and limitations. Cancer Radiother 2019; 23:883-890. [PMID: 31615730 DOI: 10.1016/j.canrad.2019.08.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 08/29/2019] [Accepted: 08/31/2019] [Indexed: 02/08/2023]
Abstract
Radiotherapy is one of the most common form of treatment in oncology care. Indeed, radiotherapy proved to be very effective in treating a wide range of malignancies. Nevertheless, certain tumours are intrinsically radioresistant or may evolve to become radioresistant. Resistance to radiotherapy is often associated with dysregulated DNA damage response and repair. Recently, a number of strategies have been developed to improve radiotherapy efficacy by targeting the DNA damage response and repair pathways. Ongoing clinical trials showed the potential of some of these approaches in enhancing radiotherapy, but also highlighted the possible limitations. Here, we will describe (i) the main mechanisms involved in double-strand break repair; (ii) available strategies that target these DNA repair processes to improve radiotherapy and (iii) the clinical outcomes and challenges that have emerged so far.
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Affiliation(s)
- S Ferreira
- Centre universitaire, institut Curie, UMR « Etic », bâtiment 110, 91405 Orsay cedex, France; Université PSL, 91405 Orsay, France; CNRS, UMR 3347, 91405 Orsay, France; Inserm, UMR 3347, 91405 Orsay, France; Université Paris-Sud université Paris-Saclay, 91405 Orsay, France
| | - M Dutreix
- Centre universitaire, institut Curie, UMR « Etic », bâtiment 110, 91405 Orsay cedex, France; Université PSL, 91405 Orsay, France; CNRS, UMR 3347, 91405 Orsay, France; Inserm, UMR 3347, 91405 Orsay, France; Université Paris-Sud université Paris-Saclay, 91405 Orsay, France.
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12
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Mechanistic link between DNA damage sensing, repairing and signaling factors and immune signaling. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 115:297-324. [PMID: 30798935 DOI: 10.1016/bs.apcsb.2018.11.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Previously, DNA damage sensing, repairing and signaling machineries were thought to mainly suppress genomic instability in response to genotoxic stress. Emerging evidence indicates a crosstalk between DNA repair machinery and the immune system. In this chapter, we attempt to decipher the molecular choreography of how factors, including ATM, BRCA1, DNA-PK, FANCA/D2, MRE11, MUS81, NBS1, RAD51 and TREX1, of multiple DNA metabolic processes are directly or indirectly involved in suppressing cytosolic DNA sensing pathway-mediated immune signaling. We provide systematic details showing how different DDR factors' roles in modulating immune signaling are not direct, but are rather a consequence of their inherent ability to sense, repair and signal in response to DNA damage. Unexpectedly, most DDR factors negatively impact the immune system; that is, the immune system shows defective signaling if there are defects in DNA repair pathways. Thus, in addition to their known DNA repair and replication functions, DDR factors help prevent erroneous activation of immune signaling. A more precise understanding of the mechanisms by which different DDR factors function in immune signaling can be exploited to redirect the immune system for both preventing and treating autoimmunity, cellular senescence and cancer in humans.
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13
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Reichman R, Shi Z, Malone R, Smolikove S. Mitotic and Meiotic Functions for the SUMOylation Pathway in the Caenorhabditis elegans Germline. Genetics 2018; 208:1421-1441. [PMID: 29472245 PMCID: PMC5887140 DOI: 10.1534/genetics.118.300787] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 02/19/2018] [Indexed: 02/07/2023] Open
Abstract
Meiosis is a highly regulated process, partly due to the need to break and then repair DNA as part of the meiotic program. Post-translational modifications are widely used during meiotic events to regulate steps such as protein complex formation, checkpoint activation, and protein attenuation. In this paper, we investigate how proteins that are obligatory components of the SUMO (small ubiquitin-like modifier) pathway, one such post-translational modification, affect the Caenorhabditis elegans germline. We show that UBC-9, the E2 conjugation enzyme, and the C. elegans homolog of SUMO, SMO-1, localize to germline nuclei throughout prophase I. Mutant analysis of smo-1 and ubc-9 revealed increased recombination intermediates throughout the germline, originating during the mitotic divisions. SUMOylation mutants also showed late meiotic defects including defects in the restructuring of oocyte bivalents and endomitotic oocytes. Increased rates of noninterfering crossovers were observed in ubc-9 heterozygotes, even though interfering crossovers were unaffected. We have also identified a physical interaction between UBC-9 and DNA repair protein MRE-11 ubc-9 and mre-11 null mutants exhibited similar phenotypes at germline mitotic nuclei and were synthetically sick. These phenotypes and genetic interactions were specific to MRE-11 null mutants as opposed to RAD-50 or resection-defective MRE-11 We propose that the SUMOylation pathway acts redundantly with MRE-11, and in this process MRE-11 likely plays a structural role.
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Affiliation(s)
- Rachel Reichman
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
| | - Zhuoyue Shi
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
| | - Robert Malone
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
| | - Sarit Smolikove
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
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14
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Moiani D, Ronato DA, Brosey CA, Arvai AS, Syed A, Masson JY, Petricci E, Tainer JA. Targeting Allostery with Avatars to Design Inhibitors Assessed by Cell Activity: Dissecting MRE11 Endo- and Exonuclease Activities. Methods Enzymol 2018. [PMID: 29523233 DOI: 10.1016/bs.mie.2017.11.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
For inhibitor design, as in most research, the best system is question dependent. We suggest structurally defined allostery to design specific inhibitors that target regions beyond active sites. We choose systems allowing efficient quality structures with conformational changes as optimal for structure-based design to optimize inhibitors. We maintain that evolutionarily related targets logically provide molecular avatars, where this Sanskrit term for descent includes ideas of functional relationships and of being a physical embodiment of the target's essential features without requiring high sequence identity. Appropriate biochemical and cell assays provide quantitative measurements, and for biomedical impacts, any inhibitor's activity should be validated in human cells. Specificity is effectively shown empirically by testing if mutations blocking target activity remove cellular inhibitor impact. We propose this approach to be superior to experiments testing for lack of cross-reactivity among possible related enzymes, which is a challenging negative experiment. As an exemplary avatar system for protein and DNA allosteric conformational controls, we focus here on developing separation-of-function inhibitors for meiotic recombination 11 nuclease activities. This was achieved not by targeting the active site but rather by geometrically impacting loop motifs analogously to ribosome antibiotics. These loops are neighboring the dimer interface and active site act in sculpting dsDNA and ssDNA into catalytically competent complexes. One of our design constraints is to preserve DNA substrate binding to geometrically block competing enzymes and pathways from the damaged site. We validate our allosteric approach to controlling outcomes in human cells by reversing the radiation sensitivity and genomic instability in BRCA mutant cells.
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Affiliation(s)
- Davide Moiani
- The University of Texas, M.D. Anderson Cancer Center, Houston, TX, United States
| | - Daryl A Ronato
- Genome Stability Laboratory, CHU de Québec Research Center, Québec City, QC, Canada; Laval University Cancer Research Center, Québec City, QC, Canada
| | - Chris A Brosey
- The University of Texas, M.D. Anderson Cancer Center, Houston, TX, United States
| | - Andrew S Arvai
- The Scripps Research Institute, La Jolla, CA, United States
| | - Aleem Syed
- The University of Texas, M.D. Anderson Cancer Center, Houston, TX, United States
| | - Jean-Yves Masson
- Genome Stability Laboratory, CHU de Québec Research Center, Québec City, QC, Canada; Laval University Cancer Research Center, Québec City, QC, Canada
| | | | - John A Tainer
- The University of Texas, M.D. Anderson Cancer Center, Houston, TX, United States; Lawrence Berkeley National Laboratory, Berkeley, CA, United States.
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15
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Myler LR, Gallardo IF, Soniat MM, Deshpande RA, Gonzalez XB, Kim Y, Paull TT, Finkelstein IJ. Single-Molecule Imaging Reveals How Mre11-Rad50-Nbs1 Initiates DNA Break Repair. Mol Cell 2017; 67:891-898.e4. [PMID: 28867292 PMCID: PMC5609712 DOI: 10.1016/j.molcel.2017.08.002] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 06/07/2017] [Accepted: 08/04/2017] [Indexed: 11/21/2022]
Abstract
DNA double-strand break (DSB) repair is essential for maintaining our genomes. Mre11-Rad50-Nbs1 (MRN) and Ku70-Ku80 (Ku) direct distinct DSB repair pathways, but the interplay between these complexes at a DSB remains unclear. Here, we use high-throughput single-molecule microscopy to show that MRN searches for free DNA ends by one-dimensional facilitated diffusion, even on nucleosome-coated DNA. Rad50 binds homoduplex DNA and promotes facilitated diffusion, whereas Mre11 is required for DNA end recognition and nuclease activities. MRN gains access to occluded DNA ends by removing Ku or other DNA adducts via an Mre11-dependent nucleolytic reaction. Next, MRN loads exonuclease 1 (Exo1) onto the free DNA ends to initiate DNA resection. In the presence of replication protein A (RPA), MRN acts as a processivity factor for Exo1, retaining the exonuclease on DNA for long-range resection. Our results provide a mechanism for how MRN promotes homologous recombination on nucleosome-coated DNA.
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Affiliation(s)
- Logan R Myler
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Howard Hughes Medical Institute, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Ignacio F Gallardo
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Michael M Soniat
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Rajashree A Deshpande
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Howard Hughes Medical Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Xenia B Gonzalez
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Yoori Kim
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Tanya T Paull
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Howard Hughes Medical Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA.
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16
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Seeber A, Hegnauer AM, Hustedt N, Deshpande I, Poli J, Eglinger J, Pasero P, Gut H, Shinohara M, Hopfner KP, Shimada K, Gasser SM. RPA Mediates Recruitment of MRX to Forks and Double-Strand Breaks to Hold Sister Chromatids Together. Mol Cell 2016; 64:951-966. [PMID: 27889450 DOI: 10.1016/j.molcel.2016.10.032] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 09/29/2016] [Accepted: 10/21/2016] [Indexed: 10/20/2022]
Abstract
The Mre11-Rad50-Xrs2 (MRX) complex is related to SMC complexes that form rings capable of holding two distinct DNA strands together. MRX functions at stalled replication forks and double-strand breaks (DSBs). A mutation in the N-terminal OB fold of the 70 kDa subunit of yeast replication protein A, rfa1-t11, abrogates MRX recruitment to both types of DNA damage. The rfa1 mutation is functionally epistatic with loss of any of the MRX subunits for survival of replication fork stress or DSB recovery, although it does not compromise end-resection. High-resolution imaging shows that either the rfa1-t11 or the rad50Δ mutation lets stalled replication forks collapse and allows the separation not only of opposing ends but of sister chromatids at breaks. Given that cohesin loss does not provoke visible sister separation as long as the RPA-MRX contacts are intact, we conclude that MRX also serves as a structural linchpin holding sister chromatids together at breaks.
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Affiliation(s)
- Andrew Seeber
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; University of Basel, Faculty of Natural Sciences, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Anna Maria Hegnauer
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Nicole Hustedt
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Ishan Deshpande
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; University of Basel, Faculty of Natural Sciences, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Jérôme Poli
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Jan Eglinger
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Philippe Pasero
- Institute of Human Genetics, CNRS UPR 1142, 34090 Montpellier, France
| | - Heinz Gut
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Miki Shinohara
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
| | | | - Kenji Shimada
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; University of Basel, Faculty of Natural Sciences, Klingelbergstrasse 50, 4056 Basel, Switzerland.
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17
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Yamamoto K, Wang J, Sprinzen L, Xu J, Haddock CJ, Li C, Lee BJ, Loredan DG, Jiang W, Vindigni A, Wang D, Rabadan R, Zha S. Kinase-dead ATM protein is highly oncogenic and can be preferentially targeted by Topo-isomerase I inhibitors. eLife 2016; 5. [PMID: 27304073 PMCID: PMC4957979 DOI: 10.7554/elife.14709] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 06/14/2016] [Indexed: 12/20/2022] Open
Abstract
Missense mutations in ATM kinase, a master regulator of DNA damage responses, are found in many cancers, but their impact on ATM function and implications for cancer therapy are largely unknown. Here we report that 72% of cancer-associated ATM mutations are missense mutations that are enriched around the kinase domain. Expression of kinase-dead ATM (Atm(KD/-)) is more oncogenic than loss of ATM (Atm(-/-)) in mouse models, leading to earlier and more frequent lymphomas with Pten deletions. Kinase-dead ATM protein (Atm-KD), but not loss of ATM (Atm-null), prevents replication-dependent removal of Topo-isomerase I-DNA adducts at the step of strand cleavage, leading to severe genomic instability and hypersensitivity to Topo-isomerase I inhibitors. Correspondingly, Topo-isomerase I inhibitors effectively and preferentially eliminate Atm(KD/-), but not Atm-proficientor Atm(-/-) leukemia in animal models. These findings identify ATM kinase-domain missense mutations as a potent oncogenic event and a biomarker for Topo-isomerase I inhibitor based therapy.
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Affiliation(s)
- Kenta Yamamoto
- Institute for Cancer Genetics, Columbia Unviersity, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States.,College of Physicians and Surgeons, Columbia University, New York, United States.,Pathobiology and Molecular Medicine Graduate Program, Columbia University, New York, United States
| | - Jiguang Wang
- Department of Biomedical Informatics, Columbia University, New York, United States.,Department of Systems Biology, Columbia University, New York, United States.,College of Physicians & Surgeons, Columbia University, New York, United States
| | - Lisa Sprinzen
- Institute for Cancer Genetics, Columbia Unviersity, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States.,College of Physicians and Surgeons, Columbia University, New York, United States.,Pathobiology and Molecular Medicine Graduate Program, Columbia University, New York, United States
| | - Jun Xu
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, United States
| | - Christopher J Haddock
- Edward A Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, United States
| | - Chen Li
- Institute for Cancer Genetics, Columbia Unviersity, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States.,College of Physicians and Surgeons, Columbia University, New York, United States
| | - Brian J Lee
- Institute for Cancer Genetics, Columbia Unviersity, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States.,College of Physicians and Surgeons, Columbia University, New York, United States
| | - Denis G Loredan
- Institute for Cancer Genetics, Columbia Unviersity, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States.,College of Physicians and Surgeons, Columbia University, New York, United States
| | - Wenxia Jiang
- Institute for Cancer Genetics, Columbia Unviersity, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States.,College of Physicians and Surgeons, Columbia University, New York, United States
| | - Alessandro Vindigni
- Edward A Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, United States
| | - Dong Wang
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, United States
| | - Raul Rabadan
- Department of Biomedical Informatics, Columbia University, New York, United States.,Department of Systems Biology, Columbia University, New York, United States.,College of Physicians & Surgeons, Columbia University, New York, United States
| | - Shan Zha
- Institute for Cancer Genetics, Columbia Unviersity, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States.,College of Physicians and Surgeons, Columbia University, New York, United States.,Division of Pediatric Oncology, Hematology and Stem Cell Transplantation, Columbia University, New York, United States.,Department of Pediatrics, Columbia University, New York, United States.,College of Physicians & Surgeons, Columbia University, New York, United States
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18
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Kish A, Gaillard JC, Armengaud J, Elie C. Post-translational methylations of the archaeal Mre11:Rad50 complex throughout the DNA damage response. Mol Microbiol 2016; 100:362-78. [PMID: 26724682 DOI: 10.1111/mmi.13322] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2015] [Indexed: 12/31/2022]
Abstract
The Mre11:Rad50 complex is central to DNA double strand break repair in the Archaea and Eukarya, and acts through mechanical and nuclease activities regulated by conformational changes induced by ATP binding and hydrolysis. Despite the widespread use of Mre11 and Rad50 from hyperthermophilic archaea for structural studies, little is known in the regulation of these proteins in the Archaea. Using purification and mass spectrometry approaches allowing nearly full sequence coverage of both proteins from the species Sulfolobus acidocaldarius, we show for the first time post-translational methylation of the archaeal Mre11:Rad50 complex. Under basal growth conditions, extensive lysine methylations were identified in Mre11 and Rad50 dynamic domains, as well as methylation of a few aspartates and glutamates, including a key Mre11 aspartate involved in nuclease activity. Upon γ-irradiation induced DNA damage, additional methylated residues were identified in Rad50, notably methylation of Walker B aspartate and glutamate residues involved in ATP hydrolysis. These findings strongly suggest a key role for post-translational methylation in the regulation of the archaeal Mre11:Rad50 complex and in the DNA damage response.
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Affiliation(s)
- Adrienne Kish
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Jean-Charles Gaillard
- CEA-Marcoule, DSV/IBITEC-S/SPI/Li2D, Laboratory "Innovative technologies for Detection and Diagnostic", BP 17171, F-30200, Bagnols-sur-Cèze, France
| | - Jean Armengaud
- CEA-Marcoule, DSV/IBITEC-S/SPI/Li2D, Laboratory "Innovative technologies for Detection and Diagnostic", BP 17171, F-30200, Bagnols-sur-Cèze, France
| | - Christiane Elie
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
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19
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Kim YJ, Kim TW, Park SR, Kim HT, Jung DY, Ryu SY, Jung JY. Deletion of NAD(P)H:quinone oxidoreductase 1 represses Mre11-Rad50-Nbs1 complex protein expression in cisplatin-induced nephrotoxicity. Toxicol Lett 2016; 243:22-30. [PMID: 26723870 DOI: 10.1016/j.toxlet.2015.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 12/13/2015] [Accepted: 12/21/2015] [Indexed: 01/02/2023]
Abstract
The Mre11, Rad50, and Nbs1 (MRN) complex is a DNA double-strand break sensor involved in DNA damage repair. Herein, we explored whether deletion of NAD(P)H quinone oxidoreductase 1 (NQO1), a cytoprotective gene, affected MRN complex expression in the kidney after cisplatin-induced acute kidney injury (AKI). In vitro, cisplatin increased the expression of MRN complex proteins and NQO1 in NQO1-expressing ACHN cells in a time- and concentration-dependent manner. The expression of MRN complex proteins was relatively inhibited in NQO1-knockdown cells. In vivo, increased expression of renal MRN complex proteins was accompanied by upregulation of γ-H2A histone member X, a DNA damage marker, in cisplatin-treated wild-type mice. Although the NQO1-knockout (NQO1(-/-)) mice showed more severe cisplatin-induced renal damage, the renal expression of MRN complex proteins was lower than in NQO1-expressing mice; expression of poly[ADP-ribose] polymerase 1, which promotes MRN complex accumulation, was also lower in these animals. In addition, cisplatin-induced expression of DNA damage repair-related proteins, ataxia telangiectasia mutated and sirtuin1, markedly decreased in the NQO1(-/-) group, relative to the NQO1-expressing mice. These findings suggest that NQO1 deletion might be associated with decreased MRN complex expression, which might be partially responsible for the exacerbation of cisplatin-induced AKI in the absence of NQO1.
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Affiliation(s)
- Young-Jung Kim
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, Daejeon 305-764, Republic of Korea
| | - Tae-Won Kim
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, Daejeon 305-764, Republic of Korea
| | - So-Ra Park
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, Daejeon 305-764, Republic of Korea
| | - Hyun-Tae Kim
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, Daejeon 305-764, Republic of Korea
| | - Da-Young Jung
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, Daejeon 305-764, Republic of Korea
| | - Si-Yun Ryu
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, Daejeon 305-764, Republic of Korea
| | - Ju-Young Jung
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, Daejeon 305-764, Republic of Korea.
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20
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DNA Damage Signalling and Repair Inhibitors: The Long-Sought-After Achilles' Heel of Cancer. Biomolecules 2015; 5:3204-59. [PMID: 26610585 PMCID: PMC4693276 DOI: 10.3390/biom5043204] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 11/09/2015] [Indexed: 12/16/2022] Open
Abstract
For decades, radiotherapy and chemotherapy were the two only approaches exploiting DNA repair processes to fight against cancer. Nowadays, cancer therapeutics can be a major challenge when it comes to seeking personalized targeted medicine that is both effective and selective to the malignancy. Over the last decade, the discovery of new targeted therapies against DNA damage signalling and repair has offered the possibility of therapeutic improvements in oncology. In this review, we summarize the current knowledge of DNA damage signalling and repair inhibitors, their molecular and cellular effects, and future therapeutic use.
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21
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Chung D, Dellaire G. The Role of the COP9 Signalosome and Neddylation in DNA Damage Signaling and Repair. Biomolecules 2015; 5:2388-416. [PMID: 26437438 PMCID: PMC4693240 DOI: 10.3390/biom5042388] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 09/18/2015] [Accepted: 09/21/2015] [Indexed: 01/28/2023] Open
Abstract
The maintenance of genomic integrity is an important process in organisms as failure to sense and repair damaged DNA can result in a variety of diseases. Eukaryotic cells have developed complex DNA repair response (DDR) mechanisms to accurately sense and repair damaged DNA. Post-translational modifications by ubiquitin and ubiquitin-like proteins, such as SUMO and NEDD8, have roles in coordinating the progression of DDR. Proteins in the neddylation pathway have also been linked to regulating DDR. Of interest is the COP9 signalosome (CSN), a multi-subunit metalloprotease present in eukaryotes that removes NEDD8 from cullins and regulates the activity of cullin-RING ubiquitin ligases (CRLs). This in turn regulates the stability and turnover of a host of CRL-targeted proteins, some of which have established roles in DDR. This review will summarize the current knowledge on the role of the CSN and neddylation in DNA repair.
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Affiliation(s)
- Dudley Chung
- Department of Pathology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
| | - Graham Dellaire
- Department of Pathology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
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22
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Kim YJ, Kim TW, Park SR, Kim HT, Ryu SY, Jung JY. Expression of the Mre11-Rad50-Nbs1 complex in cisplatin nephrotoxicity. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2015; 40:12-17. [PMID: 26056972 DOI: 10.1016/j.etap.2015.04.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 04/22/2015] [Accepted: 04/28/2015] [Indexed: 06/04/2023]
Abstract
The aim of this study was to explore whether the Mre11, Rad50, and Nbs1 (MRN) complex is associated with DNA repair mechanisms in cisplatin-induced acute renal failure. Rats were randomly allocated into three groups: control, sacrificed 5 days (5D), and 10 days (10D) after 5mg/kg of cisplatin injection. The 5D group showed disrupted renal function together with enhanced MRN complex- and DNA repair-related protein expression. Meanwhile, in the 10D group, recovery from cisplatin-induced damage was accompanied by the reduced MRN expression, although the expression was still distinctive in proximal tubular cells and higher than the control group. Moreover, pretreatment with mirin, an MRN complex inhibitor, decreased cell viability and inhibited proliferating cell nuclear antigen expression in cisplatin-treated human embryonic kidney 293 cells. Taken together, cisplatin treatment could trigger the MRN complex expression in the kidney and inhibition of the complex might aggravate damage recovery processes.
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Affiliation(s)
- Young-Jung Kim
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, 99 Daehak-ro, Yusung-gu, Daejeon 305-764, Republic of Korea
| | - Tae-Won Kim
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, 99 Daehak-ro, Yusung-gu, Daejeon 305-764, Republic of Korea
| | - So-Ra Park
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, 99 Daehak-ro, Yusung-gu, Daejeon 305-764, Republic of Korea
| | - Hyun-Tae Kim
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, 99 Daehak-ro, Yusung-gu, Daejeon 305-764, Republic of Korea
| | - Si-Yun Ryu
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, 99 Daehak-ro, Yusung-gu, Daejeon 305-764, Republic of Korea
| | - Ju-Young Jung
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, 99 Daehak-ro, Yusung-gu, Daejeon 305-764, Republic of Korea.
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23
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Xu G, Chapman JR, Brandsma I, Yuan J, Mistrik M, Bouwman P, Bartkova J, Gogola E, Warmerdam D, Barazas M, Jaspers JE, Watanabe K, Pieterse M, Kersbergen A, Sol W, Celie PHN, Schouten PC, van den Broek B, Salman A, Nieuwland M, de Rink I, de Ronde J, Jalink K, Boulton SJ, Chen J, van Gent DC, Bartek J, Jonkers J, Borst P, Rottenberg S. REV7 counteracts DNA double-strand break resection and affects PARP inhibition. Nature 2015; 521:541-544. [PMID: 25799992 PMCID: PMC4671316 DOI: 10.1038/nature14328] [Citation(s) in RCA: 435] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 02/13/2015] [Indexed: 01/01/2023]
Abstract
Error-free repair of DNA double-strand breaks (DSBs) is achieved by homologous recombination (HR), and BRCA1 is an important factor for this repair pathway. In the absence of BRCA1-mediated HR, the administration of PARP inhibitors induces synthetic lethality of tumour cells of patients with breast or ovarian cancers. Despite the benefit of this tailored therapy, drug resistance can occur by HR restoration. Genetic reversion of BRCA1-inactivating mutations can be the underlying mechanism of drug resistance, but this does not explain resistance in all cases. In particular, little is known about BRCA1-independent restoration of HR. Here we show that loss of REV7 (also known as MAD2L2) in mouse and human cell lines re-establishes CTIP-dependent end resection of DSBs in BRCA1-deficient cells, leading to HR restoration and PARP inhibitor resistance, which is reversed by ATM kinase inhibition. REV7 is recruited to DSBs in a manner dependent on the H2AX-MDC1-RNF8-RNF168-53BP1 chromatin pathway, and seems to block HR and promote end joining in addition to its regulatory role in DNA damage tolerance. Finally, we establish that REV7 blocks DSB resection to promote non-homologous end-joining during immunoglobulin class switch recombination. Our results reveal an unexpected crucial function of REV7 downstream of 53BP1 in coordinating pathological DSB repair pathway choices in BRCA1-deficient cells.
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Affiliation(s)
- Guotai Xu
- Division of Molecular Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - J Ross Chapman
- The Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, OX3 7BN, United Kingdom
| | - Inger Brandsma
- Department of Genetics, Erasmus, University Medical Center, Rotterdam, The Netherlands
| | - Jingsong Yuan
- Department of Experimental Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Martin Mistrik
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic
| | - Peter Bouwman
- Division of Molecular Pathology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | | | - Ewa Gogola
- Division of Molecular Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Daniël Warmerdam
- Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Marco Barazas
- Division of Molecular Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Janneke E Jaspers
- Division of Molecular Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Kenji Watanabe
- Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Mark Pieterse
- Department of Experimental Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Ariena Kersbergen
- Division of Molecular Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Wendy Sol
- Division of Molecular Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Patrick H N Celie
- Protein Facility, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Philip C Schouten
- Division of Molecular Pathology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Bram van den Broek
- Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Ahmed Salman
- The Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, OX3 7BN, United Kingdom
| | - Marja Nieuwland
- Deep Sequencing Core Facility, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Iris de Rink
- Deep Sequencing Core Facility, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Jorma de Ronde
- Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Kees Jalink
- Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Simon J Boulton
- DNA Damage Response Laboratory, London Research Institute, Cancer Research UK, Clare Hall, South Mimms EN6 3LD, UK
| | - Junjie Chen
- Department of Experimental Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Dik C van Gent
- Department of Genetics, Erasmus, University Medical Center, Rotterdam, The Netherlands
| | - Jiri Bartek
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic
- Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Jos Jonkers
- Division of Molecular Pathology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Piet Borst
- Division of Molecular Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Sven Rottenberg
- Division of Molecular Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
- Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Laengassstrasse 122, 3012 Bern, Switzerland
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24
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Bais MV, Ozdener GB, Sonenshein GE, Trackman PC. Effects of tumor-suppressor lysyl oxidase propeptide on prostate cancer xenograft growth and its direct interactions with DNA repair pathways. Oncogene 2015; 34:1928-37. [PMID: 24882580 PMCID: PMC4254378 DOI: 10.1038/onc.2014.147] [Citation(s) in RCA: 32] [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: 06/09/2013] [Revised: 04/01/2014] [Accepted: 04/18/2014] [Indexed: 01/27/2023]
Abstract
Lysyl oxidase (LOX) is a multifunctional protein required for normal collagen and elastin biosynthesis and maturation. In addition, LOX has complex roles in cancer in which the lysyl oxidase propeptide (LOX-PP) domain of secreted pro-LOX has tumor-suppressor activity, while the active enzyme promotes metastasis. In prostate cancer cell lines, recombinant LOX-PP (rLOX-PP) inhibits the growth of PC3 cells in vitro by mechanisms that were not characterized, while in DU145 cells rLOX-PP targeted fibroblast growth factor signaling. Because rLOX-PP can enhance effects of a genotoxic chemotherapeutic on breast cancer cell apoptosis, we reasoned that rLOX-PP could target DNA repair pathways typically elevated in cancer. Here we demonstrate for the first time that rLOX-PP inhibits prostate xenograft growth in vivo and that activating phosphorylations of the key DNA repair molecules ataxia-telangiectasia mutated (ATM) and checkpoint kinase 2 (CHK2) are inhibited by rLOX-PP expression in vivo. In addition, in vitro studies showed that rLOX-PP inhibits radiation-induced activating phosphorylations of ATM and CHK2 and that exogenously added rLOX-PP protein can localize to the nucleus in both DU145 and PC3 cells. rLOX-PP pull-down studies resulted in detection of a protein complex with the nuclear DNA repair regulator MRE11 in both cell lines, and rLOX-PP localized to radiation-induced nuclear DNA repair foci. Finally, rLOX-PP was shown to sensitize both DU145 and PC3 cells to radiation-induced cell death determined in colony-formation assays. These data provide evidence that rLOX-PP has a nuclear mechanism of action in which it directly interacts with DNA repair proteins to sensitize prostate cancer cells to the effects of ionizing radiation.
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Affiliation(s)
- Manish V. Bais
- Boston University Henry M. Goldman School of Dental Medicine, Department of Periodontology and Oral Biology, Boston, MA 02118
| | - Gokhan Baris Ozdener
- Boston University Henry M. Goldman School of Dental Medicine, Department of Periodontology and Oral Biology, Boston, MA 02118
| | - Gail E. Sonenshein
- Tufts University School of Medicine, Department of Biochemistry, Boston, MA 02111
| | - Philip C. Trackman
- Boston University Henry M. Goldman School of Dental Medicine, Department of Periodontology and Oral Biology, Boston, MA 02118
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25
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Brown JS, Jackson SP. Ubiquitylation, neddylation and the DNA damage response. Open Biol 2015; 5:150018. [PMID: 25833379 PMCID: PMC4422126 DOI: 10.1098/rsob.150018] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/09/2015] [Indexed: 12/19/2022] Open
Abstract
Failure of accurate DNA damage sensing and repair mechanisms manifests as a variety of human diseases, including neurodegenerative disorders, immunodeficiency, infertility and cancer. The accuracy and efficiency of DNA damage detection and repair, collectively termed the DNA damage response (DDR), requires the recruitment and subsequent post-translational modification (PTM) of a complex network of proteins. Ubiquitin and the ubiquitin-like protein (UBL) SUMO have established roles in regulating the cellular response to DNA double-strand breaks (DSBs). A role for other UBLs, such as NEDD8, is also now emerging. This article provides an overview of the DDR, discusses our current understanding of the process and function of PTM by ubiquitin and NEDD8, and reviews the literature surrounding the role of ubiquitylation and neddylation in DNA repair processes, focusing particularly on DNA DSB repair.
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Affiliation(s)
- Jessica S Brown
- The Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
| | - Stephen P Jackson
- The Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
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26
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Lentz TB, Samulski RJ. Insight into the mechanism of inhibition of adeno-associated virus by the Mre11/Rad50/Nbs1 complex. J Virol 2015; 89:181-94. [PMID: 25320294 PMCID: PMC4301101 DOI: 10.1128/jvi.01990-14] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 10/03/2014] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Adeno-associated virus (AAV) is a dependent virus of the family Parvoviridae. The gene expression and replication of AAV and derived recombinant AAV (rAAV) vectors are severely limited (>10-fold) by the cellular DNA damage-sensing complex made up of Mre11, Rad50, and Nbs1 (MRN). The AAV genome does not encode the means to circumvent this block to productive infection but relies on coinfecting helper virus to do so. Using adenovirus helper proteins E1B55k and E4orf6, which enhance the transduction of AAV via degradation of MRN, we investigated the mechanism through which this DNA damage complex inhibits gene expression from rAAV. We tested the substrate specificity of inhibition and the contribution of different functions of the MRN complex. Our results demonstrate that both single- and double-stranded rAAV vectors are inhibited by MRN, which is in contrast to the predominant model that inhibition is the result of a block to second-strand synthesis. Exploring the contribution of known functions of MRN, we found that inhibition of rAAV does not require downstream DNA damage response factors, including signaling kinases ATM and ATR. The nuclease domain of Mre11 appears to play only a minor role in inhibition, while the DNA binding domain makes a greater contribution. Additionally, mutation of the inverted terminal repeat of the rAAV genome, which has been proposed to be the signal for interaction with MRN, is tolerated by the mechanism of inhibition. These results articulate a model of inhibition of gene expression in which physical interaction is more important than enzymatic activity and several key downstream damage repair factors are dispensable. IMPORTANCE Many viruses modulate the host DNA damage response (DDR) in order to create a cellular environment permissive for infection. The MRN complex is a primary sensor of damage in the cell but also responds to invading viral genomes, often posing a block to infection. AAV is greatly inhibited by MRN and dependent on coinfecting helper virus, such as adenovirus, to remove this factor. Currently, the mechanism through which MRN inhibits AAV and other viruses is poorly understood. Our results reform the predominant model that inhibition of rAAV by MRN is due to limiting second-strand DNA synthesis. Instead, a novel mechanism of inhibition of gene expression independent of a block in rAAV DNA synthesis or downstream damage factors is indicated. These findings have clear implications for understanding this restriction to transduction of AAV and rAAV vectors, which have high therapeutic relevance and likely translate to other viruses that must navigate the DDR.
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Affiliation(s)
- Thomas B Lentz
- Gene Therapy Center, University of North Carolina, Chapel Hill, North Carolina, USA
| | - R Jude Samulski
- Gene Therapy Center, University of North Carolina, Chapel Hill, North Carolina, USA Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina, USA
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27
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Schröder-Heurich B, Wieland B, Lavin MF, Schindler D, Dörk T. Protective role of RAD50 on chromatin bridges during abnormal cytokinesis. FASEB J 2013; 28:1331-41. [PMID: 24344331 DOI: 10.1096/fj.13-236984] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Faithful chromosome segregation is required for preserving genomic integrity. Failure of this process may entail chromatin bridges preventing normal cytokinesis. To test whether RAD50, a protein normally involved in DNA double-strand break repair, is involved in abnormal cytokinesis and formation of chromatin bridges, we used immunocytochemical and protein interaction assays. RAD50 localizes to chromatin bridges during aberrant cytokinesis and subsequent stages of the cell cycle, either decorating the entire bridge or focally accumulating at the midbody zone. Ionizing radiation led to an ∼4-fold increase in the rate of chromatin bridges in an ataxia telangiectatica mutated (ATM)-dependent manner in human RAD50-proficient fibroblasts but not in RAD50-deficient cells. Cells with a RAD50-positive chromatin bridge were able to continue cell cycling and to progress through S phase (44%), whereas RAD50 knockdown caused a deficiency in chromatin bridges as well as an ∼4-fold prolonged duration of mitosis. RAD50 colocalized and directly interacted with Aurora B kinase and phospho-histone H3, and Aurora B kinase inhibition led to a deficiency in RAD50-positive bridges. Based on these observations, we propose that RAD50 is a crucial factor for the stabilization and shielding of chromatin bridges. Our study provides evidence for a hitherto unknown role of RAD50 in abnormal cytokinesis.
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Affiliation(s)
- Bianca Schröder-Heurich
- 1Hannover Medical School, Gynaecology Research Unit (OE 6411), Carl-Neuberg-Str. 1, D-30625 Hannover, Germany.
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28
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Zhang J, Cui F, Li L, Yang J, Zhang L, Chen Q, Tian Y. Contrasting effects of Krüppel-like factor 4 on X-ray-induced double-strand and single-strand DNA breaks in mouse astrocytes. Cell Biochem Funct 2013; 32:241-8. [PMID: 24114958 DOI: 10.1002/cbf.3007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 07/26/2013] [Accepted: 08/28/2013] [Indexed: 11/06/2022]
Abstract
Astrocytes, the most common cell type in the brain, play a principal role in the repair of damaged brain tissues during external radiotherapy of brain tumours. As a downstream gene of p53, the effects of Krüppel-like factor 4 (KLF4) in response to X-ray-induced DNA damage in astrocytes are unclear. In the present study, KLF4 expression was upregulated after the exposure of astrocytes isolated from the murine brain. Inhibition of KLF4 expression using lentiviral transduction produced less double-strand DNA breaks (DSB) determined by a neutral comet assay and flow cytometric analysis of phosphorylated histone family 2A variant and more single-strand DNA breaks (SSB) determined by a basic comet assay when the astrocytes were exposed to 4 Gy of X-ray radiation. These data suggest that radiation exposure of the tissues around brain tumour during radiation therapy causes KLF4 overexpression in astrocytes, which induces more DSB and reduces SSB. This causes the adverse effects of radiation therapy in the treatment of brain tumours.
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Affiliation(s)
- Ji Zhang
- The second affiliated hospital of Soochow University, Suzhou, China
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29
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Coordination and processing of DNA ends during double-strand break repair: the role of the bacteriophage T4 Mre11/Rad50 (MR) complex. Genetics 2013; 195:739-55. [PMID: 23979587 DOI: 10.1534/genetics.113.154872] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The in vivo functions of the bacteriophage T4 Mre11/Rad50 (MR) complex (gp46/47) in double-strand-end processing, double-strand break repair, and recombination-dependent replication were investigated. The complex is essential for T4 growth, but we wanted to investigate the in vivo function during productive infections. We therefore generated a suppressed triple amber mutant in the Rad50 subunit to substantially reduce the level of complex and thereby reduce phage growth. Growth-limiting amounts of the complex caused a concordant decrease in phage genomic recombination-dependent replication. However, the efficiencies of double-strand break repair and of plasmid-based recombination-dependent replication remained relatively normal. Genetic analyses of linked markers indicated that double-strand ends were less protected from nuclease erosion in the depleted infection and also that end coordination during repair was compromised. We discuss models for why phage genomic recombination-dependent replication is more dependent on Mre11/Rad50 levels when compared to plasmid recombination-dependent replication. We also tested the importance of the conserved histidine residue in nuclease motif I of the T4 Mre11 protein. Substitution with multiple different amino acids (including serine) failed to support phage growth, completely blocked plasmid recombination-dependent replication, and led to the stabilization of double-strand ends. We also constructed and expressed an Mre11 mutant protein with the conserved histidine changed to serine. The mutant protein was found to be completely defective for nuclease activities, but retained the ability to bind the Rad50 subunit and double-stranded DNA. These results indicate that the nuclease activity of Mre11 is critical for phage growth and recombination-dependent replication during T4 infections.
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30
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The role of arginine methylation in the DNA damage response. DNA Repair (Amst) 2013; 12:459-65. [DOI: 10.1016/j.dnarep.2013.04.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 04/13/2013] [Indexed: 12/20/2022]
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31
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Currall BB, Chiang C, Talkowski ME, Morton CC. Mechanisms for Structural Variation in the Human Genome. CURRENT GENETIC MEDICINE REPORTS 2013; 1:81-90. [PMID: 23730541 DOI: 10.1007/s40142-013-0012-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
It has been known for several decades that genetic variation involving changes to chromosomal structure (i.e., structural variants) can contribute to disease; however this relationship has been brought into acute focus in recent years largely based on innovative new genomics approaches and technology. Structural variants (SVs) arise from improperly repaired DNA double-strand breaks (DSB). DSBs are a frequent occurrence in all cells and two major pathways are involved in their repair: homologous recombination and non-homologous end joining. Errors during these repair mechanisms can result in SVs that involve losses, gains and rearrangements ranging from a few nucleotides to entire chromosomal arms. Factors such as rearrangements, hotspots and induced DSBs are implicated in the formation of SVs. While de novo SVs are often associated with disease, some SVs are conserved within human subpopulations and may have had a meaningful influence on primate evolution. As the ability to sequence the whole human genome rapidly evolves, the diversity of SVs is illuminated, including very complex rearrangements involving multiple DSBs in a process recently designated as "chromothripsis". Elucidating mechanisms involved in the etiology of SVs informs disease pathogenesis as well as the dynamic function associated with the biology and evolution of human genomes.
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Affiliation(s)
- Benjamin B Currall
- Departments of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women's Hospital and Harvard Medical School, New Research Building, Room 160D, 77 Avenue Louis Pasteur, Boston, MA 02115, USA. Harvard Medical School, Boston, MA, USA
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32
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Ghodke I, Muniyappa K. Processing of DNA double-stranded breaks and intermediates of recombination and repair by Saccharomyces cerevisiae Mre11 and its stimulation by Rad50, Xrs2, and Sae2 proteins. J Biol Chem 2013; 288:11273-86. [PMID: 23443654 DOI: 10.1074/jbc.m112.439315] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Saccharomyces cerevisiae RAD50, MRE11, and XRS2 genes are essential for telomere length maintenance, cell cycle checkpoint signaling, meiotic recombination, and DNA double-stranded break (DSB) repair via nonhomologous end joining and homologous recombination. The DSB repair pathways that draw upon Mre11-Rad50-Xrs2 subunits are complex, so their mechanistic features remain poorly understood. Moreover, the molecular basis of DSB end resection in yeast mre11-nuclease deficient mutants and Mre11 nuclease-independent activation of ATM in mammals remains unknown and adds a new dimension to many unanswered questions about the mechanism of DSB repair. Here, we demonstrate that S. cerevisiae Mre11 (ScMre11) exhibits higher binding affinity for single- over double-stranded DNA and intermediates of recombination and repair and catalyzes robust unwinding of substrates possessing a 3' single-stranded DNA overhang but not of 5' overhangs or blunt-ended DNA fragments. Additional evidence disclosed that ScMre11 nuclease activity is dispensable for its DNA binding and unwinding activity, thus uncovering the molecular basis underlying DSB end processing in mre11 nuclease deficient mutants. Significantly, Rad50, Xrs2, and Sae2 potentiate the DNA unwinding activity of Mre11, thus underscoring functional interaction among the components of DSB end repair machinery. Our results also show that ScMre11 by itself binds to DSB ends, then promotes end bridging of duplex DNA, and directly interacts with Sae2. We discuss the implications of these results in the context of an alternative mechanism for DSB end processing and the generation of single-stranded DNA for DNA repair and homologous recombination.
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Affiliation(s)
- Indrajeet Ghodke
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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33
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Mason PA, Cox LS. The role of DNA exonucleases in protecting genome stability and their impact on ageing. AGE (DORDRECHT, NETHERLANDS) 2012; 34:1317-1340. [PMID: 21948156 PMCID: PMC3528374 DOI: 10.1007/s11357-011-9306-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 08/19/2011] [Indexed: 05/30/2023]
Abstract
Exonucleases are key enzymes involved in many aspects of cellular metabolism and maintenance and are essential to genome stability, acting to cleave DNA from free ends. Exonucleases can act as proof-readers during DNA polymerisation in DNA replication, to remove unusual DNA structures that arise from problems with DNA replication fork progression, and they can be directly involved in repairing damaged DNA. Several exonucleases have been recently discovered, with potentially critical roles in genome stability and ageing. Here we discuss how both intrinsic and extrinsic exonuclease activities contribute to the fidelity of DNA polymerases in DNA replication. The action of exonucleases in processing DNA intermediates during normal and aberrant DNA replication is then assessed, as is the importance of exonucleases in repair of double-strand breaks and interstrand crosslinks. Finally we examine how exonucleases are involved in maintenance of mitochondrial genome stability. Throughout the review, we assess how nuclease mutation or loss predisposes to a range of clinical diseases and particularly ageing.
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Affiliation(s)
- Penelope A. Mason
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Lynne S. Cox
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
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Tittel-Elmer M, Lengronne A, Davidson MB, Bacal J, François P, Hohl M, Petrini JHJ, Pasero P, Cobb JA. Cohesin association to replication sites depends on rad50 and promotes fork restart. Mol Cell 2012; 48:98-108. [PMID: 22885006 PMCID: PMC3904740 DOI: 10.1016/j.molcel.2012.07.004] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 05/21/2012] [Accepted: 07/05/2012] [Indexed: 01/19/2023]
Abstract
The cohesin complex holds together newly replicated chromatids and is involved in diverse pathways that preserve genome integrity. We show that in budding yeast, cohesin is transiently recruited to active replication origins, and it spreads along DNA as forks progress. When DNA synthesis is impeded, cohesin accumulates at replication sites and is critical for the recovery of stalled forks. Cohesin enrichment at replication forks does not depend on γH2A(X) formation, which differs from its loading requirements at DNA double-strand breaks (DSBs). However, cohesin localization is largely reduced in rad50Δ mutants and in cells lacking both Mec1 and Tel1 checkpoint kinases. Interestingly, cohesin loading at replication sites depends on the structural features of Rad50 that are important for bridging sister chromatids, including the CXXC hook domain and the length of the coiled-coil extensions. Together, these data reveal a function for cohesin in the maintenance of genome integrity during S phase.
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Affiliation(s)
- Mireille Tittel-Elmer
- Department of Biochemistry and Molecular Biology, Southern Alberta Cancer Research Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB Canada T2N 4N1
- Institute of Human Genetics, Centre National de la Recherche Scientifique, Unité Propre de Recherche 1142, Montpellier, France
| | - Armelle Lengronne
- Institute of Human Genetics, Centre National de la Recherche Scientifique, Unité Propre de Recherche 1142, Montpellier, France
| | - Marta B Davidson
- Department of Biochemistry and Molecular Biology, Southern Alberta Cancer Research Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB Canada T2N 4N1
| | - Julien Bacal
- Institute of Human Genetics, Centre National de la Recherche Scientifique, Unité Propre de Recherche 1142, Montpellier, France
| | - Philippe François
- Institute of Human Genetics, Centre National de la Recherche Scientifique, Unité Propre de Recherche 1142, Montpellier, France
| | - Marcel Hohl
- Laboratory of Chromosome Biology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - John H J Petrini
- Laboratory of Chromosome Biology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - Philippe Pasero
- Institute of Human Genetics, Centre National de la Recherche Scientifique, Unité Propre de Recherche 1142, Montpellier, France
| | - Jennifer A Cobb
- Department of Biochemistry and Molecular Biology, Southern Alberta Cancer Research Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB Canada T2N 4N1
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35
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Unwinding and rewinding: double faces of helicase? J Nucleic Acids 2012; 2012:140601. [PMID: 22888405 PMCID: PMC3409536 DOI: 10.1155/2012/140601] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 05/28/2012] [Indexed: 12/29/2022] Open
Abstract
Helicases are enzymes that use ATP-driven motor force to unwind double-stranded DNA or RNA. Recently, increasing evidence demonstrates that some helicases also possess rewinding activity—in other words, they can anneal two complementary single-stranded nucleic acids. All five members of the human RecQ helicase family, helicase PIF1, mitochondrial helicase TWINKLE, and helicase/nuclease Dna2 have been shown to possess strand-annealing activity. Moreover, two recently identified helicases—HARP and AH2 have only ATP-dependent rewinding activity. These findings not only enhance our understanding of helicase enzymes but also establish the presence of a new type of protein: annealing helicases. This paper discusses what is known about these helicases, focusing on their biochemical activity to zip and unzip double-stranded DNA and/or RNA, their possible regulation mechanisms, and biological functions.
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36
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Taleei R, Weinfeld M, Nikjoo H. Single strand annealing mathematical model for double strand break repair. ACTA ACUST UNITED AC 2012. [DOI: 10.7243/2050-1412-1-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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37
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Tankimanova M, Capper R, Letsolo BT, Rowson J, Jones RE, Britt-Compton B, Taylor AMR, Baird DM. Mre11 modulates the fidelity of fusion between short telomeres in human cells. Nucleic Acids Res 2011; 40:2518-26. [PMID: 22139912 PMCID: PMC3315324 DOI: 10.1093/nar/gkr1117] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The loss of telomere function can result in the fusion of telomeres with other telomeric loci, or non-telomeric double-stranded DNA breaks. Sequence analysis of fusion events between short dysfunctional telomeres in human cells has revealed that fusion is characterized by a distinct molecular signature consisting of extensive deletions and micro-homology at the fusion points. This signature is consistent with alternative error-prone end-joining processes. We have examined the role that Mre11 may play in the fusion of short telomeres in human cells; to do this, we have analysed telomere fusion events in cells derived from ataxia-telangiectasia-like disorder (ATLD) patients that exhibit hypomorphic mutations in MRE11. The telomere dynamics of ATLD fibroblasts were indistinguishable from wild-type fibroblasts and they were proficient in the fusion of short telomeres. However, we observed a high frequency of insertion of DNA sequences at the fusion points that created localized sequence duplications. These data indicate that Mre11 plays a role in the fusion of short dysfunctional telomeres in human cells and are consistent with the hypothesis that as part of the MRN complex it serves to stabilize the joining complex, thereby controlling the fidelity of the fusion reaction.
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Affiliation(s)
- Maira Tankimanova
- Department of Pathology, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK
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Wyman C, Lebbink J, Kanaar R. Mre11-Rad50 complex crystals suggest molecular calisthenics. DNA Repair (Amst) 2011; 10:1066-70. [PMID: 21893433 PMCID: PMC3185151 DOI: 10.1016/j.dnarep.2011.07.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 07/25/2011] [Indexed: 10/17/2022]
Abstract
Recently published crystal structures of different Mre11 and Rad50 complexes show the arrangement of these proteins and imply dramatic ligand-induced rearrangements with important functional consequences.
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Affiliation(s)
- Claire Wyman
- Department of Radiation Oncology, Department of Genetics and Cancer, Erasmus University Medical Center, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
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The MRE11 GAR motif regulates DNA double-strand break processing and ATR activation. Cell Res 2011; 22:305-20. [PMID: 21826105 DOI: 10.1038/cr.2011.128] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The MRE11/RAD50/NBS1 complex is the primary sensor rapidly recruited to DNA double-strand breaks (DSBs). MRE11 is known to be arginine methylated by PRMT1 within its glycine-arginine-rich (GAR) motif. In this study, we report a mouse knock-in allele of Mre11 that substitutes the arginines with lysines in the GAR motif and generates the MRE11(RK) protein devoid of methylated arginines. The Mre11(RK/RK) mice were hypersensitive to γ-irradiation (IR) and the cells from these mice displayed cell cycle checkpoint defects and chromosome instability. Moreover, the Mre11(RK/RK) MEFs exhibited ATR/CHK1 signaling defects and impairment in the recruitment of RPA and RAD51 to the damaged sites. The M(RK)RN complex formed and localized to the sites of DNA damage and normally activated the ATM pathway in response to IR. The M(RK)RN complex exhibited exonuclease and DNA-binding defects in vitro responsible for the impaired DNA end resection and ATR activation observed in vivo in response to IR. Our findings provide genetic evidence for the critical role of the MRE11 GAR motif in DSB repair, and demonstrate a mechanistic link between post-translational modifications at the MRE11 GAR motif and DSB processing, as well as the ATR/CHK1 checkpoint signaling.
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40
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Dynlacht JR, Batuello CN, Lopez JT, Kim KK, Turchi JJ. Identification of Mre11 as a target for heat radiosensitization. Radiat Res 2011; 176:323-32. [PMID: 21699368 DOI: 10.1667/rr2594.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Thermal radiosensitization is believed to be mediated by an inhibition of double-strand break (DSB) repair, but the exact mechanism of radiosensitization remains to be elucidated. Previously, we demonstrated that proteins of the Mre11/Rad50/Nbs1 complex (MRN) translocate from the nucleus to the cytoplasm in cells have that been heated or heated and then irradiated; this finding led us to propose that heat radiosensitization was due at least in part to translocation of MRN. In the current study, we used leptomycin B to inhibit MRN translocation in heated, irradiated cells, but we found that heat radiosensitization was not altered. Thus enhanced radiosensitivity was not attributed to translocation of MRN proteins. To determine which of the MRN subunits contributed to heat radiosensitization, we compared the extent of heat radiosensitization in wild-type cells with that of cells hypomorphic for Mre11 or Nbs1 or cells in which the level of Rad50 was suppressed. We found that neither Nbs1 nor Rad50 is involved in heat radiosensitization, because a similar amount of heat radiosensitization was observed in cells deficient in those proteins compared to cells expressing normal levels. However, heat radiosensitization was not observed in A-TLD1 cells deficient in Mre11. Measurement of exonuclease activity of purified Mre11 heated at 42.5°C or 45.5°C indicated that the protein is very heat-labile. Immunoprecipitation of Mre11 from heated HeLa cells also revealed that hsp70 associates with Mre11 and that this association is maintained long after heating. Taken together, these findings implicate Mre11 as a target for heat radiosensitization and suggest that heat radiosensitization and inhibition of DSB repair may be mediated by heat-induced conformational changes in Mre11.
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Affiliation(s)
- Joseph R Dynlacht
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
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41
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Kaiser GS, Germann SM, Westergaard T, Lisby M. Phenylbutyrate inhibits homologous recombination induced by camptothecin and methyl methanesulfonate. Mutat Res 2011; 713:64-75. [PMID: 21658395 DOI: 10.1016/j.mrfmmm.2011.05.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 05/15/2011] [Accepted: 05/23/2011] [Indexed: 01/05/2023]
Abstract
Homologous recombination is accompanied by extensive changes to chromatin organization at the site of DNA damage. Some of these changes are mediated through acetylation/deacetylation of histones. Here, we show that recombinational repair of DNA damage induced by the anti-cancer drug camptothecin (CPT) and the alkylating agent methyl methanesulfonate (MMS) is blocked by sodium phenylbutyrate (PBA) in the budding yeast Saccharomyces cerevisiae. In particular, PBA suppresses CPT- and MMS-induced genetic recombination as well as DNA double-strand break repair during mating-type interconversion. Treatment with PBA is accompanied by a dramatic reduction in histone H4 lysine 8 acetylation. Live cell imaging of homologous recombination proteins indicates that repair of CPT-induced DNA damage is redirected to a non-recombinogenic pathway in the presence of PBA without loss in cell viability. In contrast, the suppression of MMS-induced recombination by PBA is accompanied by a dramatic loss in cell viability. Taken together, our results demonstrate that PBA inhibits DNA damage-induced homologous recombination likely by mediating changes in chromatin acetylation. Moreover, the combination of PBA with genotoxic agents can lead to different cell fates depending on the type of DNA damage inflicted.
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Affiliation(s)
- Gitte S Kaiser
- Department of Biology, University of Copenhagen, Ole Maaloeesvej 5, DK-2200 Copenhagen N, Denmark
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42
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Mild hyperthermia inhibits homologous recombination, induces BRCA2 degradation, and sensitizes cancer cells to poly (ADP-ribose) polymerase-1 inhibition. Proc Natl Acad Sci U S A 2011; 108:9851-6. [PMID: 21555554 DOI: 10.1073/pnas.1101053108] [Citation(s) in RCA: 251] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Defective homologous recombination (HR) DNA repair imposed by BRCA1 or BRCA2 deficiency sensitizes cells to poly (ADP-ribose) polymerase (PARP)-1 inhibition and is currently exploited in clinical treatment of HR-deficient tumors. Here we show that mild hyperthermia (41-42.5 °C) induces degradation of BRCA2 and inhibits HR. We demonstrate that hyperthermia can be used to sensitize innately HR-proficient tumor cells to PARP-1 inhibitors and that this effect can be enhanced by heat shock protein inhibition. Our results, obtained from cell lines and in vivo tumor models, enable the design of unique therapeutic strategies involving localized on-demand induction of HR deficiency, an approach that we term induced synthetic lethality.
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43
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Mir SE, De Witt Hamer PC, Krawczyk PM, Balaj L, Claes A, Niers JM, Van Tilborg AA, Zwinderman AH, Geerts D, Kaspers GJ, Vandertop WP, Cloos J, Tannous BA, Wesseling P, Aten JA, Noske DP, Van Noorden CJ, Würdinger T. In silico analysis of kinase expression identifies WEE1 as a gatekeeper against mitotic catastrophe in glioblastoma. Cancer Cell 2010; 18:244-57. [PMID: 20832752 PMCID: PMC3115571 DOI: 10.1016/j.ccr.2010.08.011] [Citation(s) in RCA: 228] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2009] [Revised: 03/29/2010] [Accepted: 08/03/2010] [Indexed: 12/12/2022]
Abstract
Kinases execute pivotal cellular functions and are therefore widely investigated as potential targets in anticancer treatment. Here we analyze the kinase gene expression profiles of various tumor types and reveal the wee1 kinase to be overexpressed in glioblastomas. We demonstrate that WEE1 is a major regulator of the G(2) checkpoint in glioblastoma cells. Inhibition of WEE1 by siRNA or small molecular compound in cells exposed to DNA damaging agents results in abrogation of the G(2) arrest, premature termination of DNA repair, and cell death. Importantly, we show that the small-molecule inhibitor of WEE1 sensitizes glioblastoma to ionizing radiation in vivo. Our results suggest that inhibition of WEE1 kinase holds potential as a therapeutic approach in treatment of glioblastoma.
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Affiliation(s)
- Shahryar E. Mir
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
| | - Philip C. De Witt Hamer
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
| | | | - Leonora Balaj
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
| | - An Claes
- Department of Pathology, Radboud University Nijmegen Medical Centre, 6525 GA, Nijmegen, the Netherlands
| | - Johanna M. Niers
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
- Molecular Neurogenetics Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02113, USA
| | | | - Aeilko H. Zwinderman
- Department of Clinical Epidemiology and Biostatistics, Academic Medical Center, University of Amsterdam, 1100 DD, Amsterdam, the Netherlands
| | | | - Gertjan J.L. Kaspers
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
| | - W. Peter Vandertop
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
| | - Jacqueline Cloos
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
| | - Bakhos A. Tannous
- Molecular Neurogenetics Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02113, USA
| | - Pieter Wesseling
- Department of Pathology, Radboud University Nijmegen Medical Centre, 6525 GA, Nijmegen, the Netherlands
| | | | - David P. Noske
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
| | | | - Thomas Würdinger
- Neuro-oncology Research Group, Departments of Neurosurgery and Pediatric Oncology/Hematology, VU University Medical Center, 1081 HV, Amsterdam, the Netherlands
- Molecular Neurogenetics Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02113, USA
- Correspondence:
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Lamarche BJ, Orazio NI, Weitzman MD. The MRN complex in double-strand break repair and telomere maintenance. FEBS Lett 2010; 584:3682-95. [PMID: 20655309 DOI: 10.1016/j.febslet.2010.07.029] [Citation(s) in RCA: 301] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 07/16/2010] [Accepted: 07/19/2010] [Indexed: 10/25/2022]
Abstract
Genomes are subject to constant threat by damaging agents that generate DNA double-strand breaks (DSBs). The ends of linear chromosomes need to be protected from DNA damage recognition and end-joining, and this is achieved through protein-DNA complexes known as telomeres. The Mre11-Rad50-Nbs1 (MRN) complex plays important roles in detection and signaling of DSBs, as well as the repair pathways of homologous recombination (HR) and non-homologous end-joining (NHEJ). In addition, MRN associates with telomeres and contributes to their maintenance. Here, we provide an overview of MRN functions at DSBs, and examine its roles in telomere maintenance and dysfunction.
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Affiliation(s)
- Brandon J Lamarche
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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45
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Blunt-ended DNA double-strand breaks induced by endonucleases PvuII and EcoRV are poor substrates for repair in Saccharomyces cerevisiae. DNA Repair (Amst) 2010; 9:617-26. [PMID: 20356803 DOI: 10.1016/j.dnarep.2010.02.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 01/11/2010] [Accepted: 02/12/2010] [Indexed: 12/26/2022]
Abstract
Most mechanistic studies of repair of DNA double-strand breaks (DSBs) produced by in vivo expression of endonucleases have utilized enzymes that produce cohesive-ended DSBs such as HO, I-SceI and EcoRI. We have developed systems for expression of PvuII and EcoRV, nucleases that produce DSBs containing blunt ends, using a modified GAL1 promoter that has reduced basal activity. Expression of PvuII and EcoRV caused growth inhibition and strong cell killing in both haploid and diploid yeast cells. Surprisingly, there was little difference in sensitivities of wildtype cells and mutants defective in homologous recombination, nonhomologous end-joining (NHEJ), or both pathways. Physical analysis using standard and pulsed field gel electrophoresis demonstrated time-dependent breakage of chromosomal DNA within cells. Although ionizing radiation-induced DSBs were largely repaired within 4h, no repair of PvuII-induced breaks could be detected in diploid cells, even after arrest in G2/M. Rare survivors of PvuII expression had an increased frequency of chromosome XII deletions, an indication that a fraction of the induced DSBs could be repaired by an error-prone process. These results indicate that, unlike DSBs with complementary single-stranded DNA overhangs, blunt-ended DSBs in yeast chromosomes are poor substrates for repair by either NHEJ or recombination.
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46
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Stavnezer J, Björkman A, Du L, Cagigi A, Pan-Hammarström Q. Mapping of Switch Recombination Junctions, a Tool for Studying DNA Repair Pathways during Immunoglobulin Class Switching. Adv Immunol 2010; 108:45-109. [DOI: 10.1016/b978-0-12-380995-7.00003-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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47
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Cell cycle-dependent role of MRN at dysfunctional telomeres: ATM signaling-dependent induction of nonhomologous end joining (NHEJ) in G1 and resection-mediated inhibition of NHEJ in G2. Mol Cell Biol 2009; 29:5552-63. [PMID: 19667071 DOI: 10.1128/mcb.00476-09] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Here, we address the role of the MRN (Mre11/Rad50/Nbs1) complex in the response to telomeres rendered dysfunctional by deletion of the shelterin component TRF2. Using conditional NBS1/TRF2 double-knockout MEFs, we show that MRN is required for ATM signaling in response to telomere dysfunction. This establishes that MRN is the only sensor for the ATM kinase and suggests that TRF2 might block ATM signaling by interfering with MRN binding to the telomere terminus, possibly by sequestering the telomere end in the t-loop structure. We also examined the role of the MRN/ATM pathway in nonhomologous end joining (NHEJ) of damaged telomeres. NBS1 deficiency abrogated the telomere fusions that occur in G(1), consistent with the requirement for ATM and its target 53BP1 in this setting. Interestingly, NBS1 and ATM, but not H2AX, repressed NHEJ at dysfunctional telomeres in G(2), specifically at telomeres generated by leading-strand DNA synthesis. Leading-strand telomere ends were not prone to fuse in the absence of either TRF2 or MRN/ATM, indicating redundancy in their protection. We propose that MRN represses NHEJ by promoting the generation of a 3' overhang after completion of leading-strand DNA synthesis. TRF2 may ensure overhang formation by recruiting MRN (and other nucleases) to newly generated telomere ends. The activation of the MRN/ATM pathway by the dysfunctional telomeres is proposed to induce resection that protects the leading-strand ends from NHEJ when TRF2 is absent. Thus, the role of MRN at dysfunctional telomeres is multifaceted, involving both repression of NHEJ in G(2) through end resection and induction of NHEJ in G(1) through ATM-dependent signaling.
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48
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van der Linden E, Sanchez H, Kinoshita E, Kanaar R, Wyman C. RAD50 and NBS1 form a stable complex functional in DNA binding and tethering. Nucleic Acids Res 2009; 37:1580-8. [PMID: 19151086 PMCID: PMC2655673 DOI: 10.1093/nar/gkn1072] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Revised: 12/19/2008] [Accepted: 12/22/2008] [Indexed: 11/24/2022] Open
Abstract
The RAD50/MRE11/NBS1 protein complex (RMN) plays an essential role during the early steps of DNA double-strand break (DSB) repair by homologous recombination. Previous data suggest that one important role for RMN in DSB repair is to provide a link between DNA ends. The striking architecture of the complex, a globular domain from which two extended coiled coils protrude, is essential for this function. Due to its DNA-binding activity, ability to form dimers and interact with both RAD50 and NBS1, MRE11 is considered to be crucial for formation and function of RMN. Here, we show the successful expression and purification of a stable complex containing only RAD50 and NBS1 (RN). The characteristic architecture of the complex was not affected by absence of MRE11. Although MRE11 is a DNA-binding protein it was not required for DNA binding per se or DNA-tethering activity of the complex. The stoichiometry of NBS1 in RMN and RN complexes was estimated by SFM-based volume analysis. These data show that in vitro, R, M and N form a variety of stable complexes with variable subunit composition and stoichiometry, which may be physiologically relevant in different aspects of RMN function.
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Affiliation(s)
- Eddy van der Linden
- Department of Cell Biology and Genetics, Cancer Genomics Center and Department of Radiation Oncology, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Humberto Sanchez
- Department of Cell Biology and Genetics, Cancer Genomics Center and Department of Radiation Oncology, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Eri Kinoshita
- Department of Cell Biology and Genetics, Cancer Genomics Center and Department of Radiation Oncology, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Roland Kanaar
- Department of Cell Biology and Genetics, Cancer Genomics Center and Department of Radiation Oncology, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Claire Wyman
- Department of Cell Biology and Genetics, Cancer Genomics Center and Department of Radiation Oncology, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands
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49
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The MRX complex stabilizes the replisome independently of the S phase checkpoint during replication stress. EMBO J 2009; 28:1142-56. [PMID: 19279665 DOI: 10.1038/emboj.2009.60] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Accepted: 02/11/2009] [Indexed: 12/21/2022] Open
Abstract
The Mre11-Rad50-Xrs2 (MRX) complex has an important function in the maintenance of genomic integrity by contributing to the detection and repair of chromosome breaks. Here we show that the complex is recruited to sites of paused forks where it stabilizes the association of essential replisome components. Interestingly, this function is not dependent on the S phase checkpoint or the nuclease activity of Mre11. We find that disruption of the MRX complex leads to a loss of fork recovery and a failure to properly complete DNA replication when cells are exposed to replication stress. Our data suggest that one critical function of the MRX complex during replication is to promote the cohesion of sister chromatids at paused forks, offering an explanation for why MRX deficiency leads to a loss of cell viability and high levels of chromosome rearrangements under conditions of replication stress.
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Nelson SW, Perumal SK, Benkovic SJ. Processive and unidirectional translocation of monomeric UvsW helicase on single-stranded DNA. Biochemistry 2009; 48:1036-46. [PMID: 19154117 DOI: 10.1021/bi801792q] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
UvsW protein from bacteriophage T4 controls the transition from origin-dependent to origin-independent initiation of replication through the unwinding of R-loops bound to the T4 origins of replication. UvsW has also been implicated through genetic and biochemical experiments to play a role in DNA repair processes such as replication fork regression and Holliday junction branch migration. UvsW is capable of unwinding a wide variety of substrates, many of which contain only duplex DNA without single-stranded regions. Based on this observation, it has been suggested that UvsW is a dsDNA translocase. In this work we examine the ability of UvsW to translocate on ssDNA. Kinetic analysis indicates that the rate of ATP hydrolysis is strongly dependent on the length of the ssDNA lattice, whereas the K(M)-DNA remains relatively constant, demonstrating that UvsW translocates on ssDNA in an ATP-dependent fashion. Experiments using streptavidin blocks or poly dT sequences located at either end of the ssDNA substrate indicate that UvsW translocates in a 3' to 5' direction. Mutant competition and heparin trapping experiments reveal that UvsW is extremely processive during ATP-driven translocation with a half-life on the order of several minutes. Finally, functional assays provide evidence that UvsW is monomeric while translocating on ssDNA. The ability of UvsW to unwind DNA duplexes is likely to be mechanistically linked to its ability to processively translocate on ssDNA in a 3' to 5' unidirectional fashion.
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Affiliation(s)
- Scott W Nelson
- Department of Chemistry, 414 Wartik Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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