51
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Verma P, Dilley RL, Zhang T, Gyparaki MT, Li Y, Greenberg RA. RAD52 and SLX4 act nonepistatically to ensure telomere stability during alternative telomere lengthening. Genes Dev 2019; 33:221-235. [PMID: 30692206 PMCID: PMC6362809 DOI: 10.1101/gad.319723.118] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 12/05/2018] [Indexed: 11/25/2022]
Abstract
Approximately 15% of cancers use homologous recombination for alternative lengthening of telomeres (ALT). How the initiating genomic lesions invoke homology-directed telomere synthesis remains enigmatic. Here, we show that distinct dependencies exist for telomere synthesis in response to replication stress or DNA double-strand breaks (DSBs). RAD52 deficiency reduced spontaneous telomeric DNA synthesis and replication stress-associated recombination in G2, concomitant with telomere shortening and damage. However, viability and proliferation remained unaffected, suggesting that alternative telomere recombination mechanisms compensate in the absence of RAD52. In agreement, RAD52 was dispensable for DSB-induced telomere synthesis. Moreover, a targeted CRISPR screen revealed that loss of the structure-specific endonuclease scaffold SLX4 reduced the proliferation of RAD52-null ALT cells. While SLX4 was dispensable for RAD52-mediated ALT telomere synthesis in G2, combined SLX4 and RAD52 loss resulted in elevated telomere loss, unresolved telomere recombination intermediates, and mitotic infidelity. These findings establish that RAD52 and SLX4 mediate distinct postreplicative DNA repair processes that maintain ALT telomere stability and cancer cell viability.
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Affiliation(s)
- Priyanka Verma
- Department of Cancer Biology, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Robert L Dilley
- Department of Cancer Biology, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Tianpeng Zhang
- Department of Cancer Biology, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Melina T Gyparaki
- Department of Cancer Biology, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Yiwen Li
- Department of Cancer Biology, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Roger A Greenberg
- Department of Cancer Biology, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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52
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Chen H, Zhou K, Wang Y, Zang J, Zhao G. Self-assembly of engineered protein nanocages into reversible ordered 3D superlattices mediated by zinc ions. Chem Commun (Camb) 2019; 55:11299-11302. [DOI: 10.1039/c9cc06262a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Zinc ion triggered self-assembly of re-engineered Dps nanocages into highly ordered architectures with a bcc structure.
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Affiliation(s)
- H. Chen
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Food Science & Nutritional Engineering
- China Agricultural University
- Beijing Key Laboratory of Functional Food from Plant Resources
- Beijing
| | - K. Zhou
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Food Science & Nutritional Engineering
- China Agricultural University
- Beijing Key Laboratory of Functional Food from Plant Resources
- Beijing
| | - Y. Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Food Science & Nutritional Engineering
- China Agricultural University
- Beijing Key Laboratory of Functional Food from Plant Resources
- Beijing
| | - J. Zang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Food Science & Nutritional Engineering
- China Agricultural University
- Beijing Key Laboratory of Functional Food from Plant Resources
- Beijing
| | - G. Zhao
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Food Science & Nutritional Engineering
- China Agricultural University
- Beijing Key Laboratory of Functional Food from Plant Resources
- Beijing
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53
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Shinohara T, Arai N, Iikura Y, Kasagi M, Masuda-Ozawa T, Yamaguchi Y, Suzuki-Nagata K, Shibata T, Mikawa T. Nonfilament-forming RecA dimer catalyzes homologous joint formation. Nucleic Acids Res 2018; 46:10855-10869. [PMID: 30285153 PMCID: PMC6237804 DOI: 10.1093/nar/gky877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 09/19/2018] [Indexed: 01/18/2023] Open
Abstract
Homologous recombination is essential to genome maintenance, and also to genome diversification. In virtually all organisms, homologous recombination depends on the RecA/Rad51-family recombinases, which catalyze ATP-dependent formation of homologous joints—critical intermediates in homologous recombination. RecA/Rad51 binds first to single-stranded (ss) DNA at a damaged site to form a spiral nucleoprotein filament, after which double-stranded (ds) DNA interacts with the filament to search for sequence homology and to form consecutive base pairs with ssDNA (‘pairing’). How sequence homology is recognized and what exact role filament formation plays remain unknown. We addressed the question of whether filament formation is a prerequisite for homologous joint formation. To this end we constructed a nonpolymerizing (np) head-to-tail-fused RecA dimer (npRecA dimer) and an npRecA monomer. The npRecA dimer bound to ssDNA, but did not form continuous filaments upon binding to DNA; it formed beads-on-string structures exclusively. Although its efficiency was lower, the npRecA dimer catalyzed the formation of D-loops (a type of homologous joint), whereas the npRecA monomer was completely defective. Thus, filament formation contributes to efficiency, but is not essential to sequence-homology recognition and pairing, for which a head-to-tail dimer form of RecA protomer is required and sufficient.
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Affiliation(s)
- Takeshi Shinohara
- Cellular & Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- Department of Supramolecular Biology, Graduate School of Nanobiosciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Naoto Arai
- Department of Applied Biological Science, Nihon University College of Bioresource Sciences, 1866 Kameino, Fujisawa-shi, Kanagawa 252-0880, Japan
| | - Yukari Iikura
- Cellular & Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Motochika Kasagi
- Cellular & Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- Department of Supramolecular Biology, Graduate School of Nanobiosciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Tokiha Masuda-Ozawa
- Cellular & Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- Department of Supramolecular Biology, Graduate School of Nanobiosciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Yuuki Yamaguchi
- Cellular & Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- Department of Supramolecular Biology, Graduate School of Nanobiosciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Kayo Suzuki-Nagata
- RIKEN Quantitative Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Takehiko Shibata
- Cellular & Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- Department of Supramolecular Biology, Graduate School of Nanobiosciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minami-Osawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
- To whom correspondence should be addressed. Takehiko Shibata. Tel: +81 3 3950 2534; . Correspondence may also be addressed to Tsutomu Mikawa. Tel: +81 45 633 8013;
| | - Tsutomu Mikawa
- Cellular & Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- Department of Supramolecular Biology, Graduate School of Nanobiosciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- RIKEN Quantitative Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- To whom correspondence should be addressed. Takehiko Shibata. Tel: +81 3 3950 2534; . Correspondence may also be addressed to Tsutomu Mikawa. Tel: +81 45 633 8013;
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Sutherland JH, Holloman WK. Loss of Cohesin Subunit Rec8 Switches Rad51 Mediator Dependence in Resistance to Formaldehyde Toxicity in Ustilago maydis. Genetics 2018; 210:559-572. [PMID: 30082279 PMCID: PMC6216591 DOI: 10.1534/genetics.118.301439] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 08/03/2018] [Indexed: 01/08/2023] Open
Abstract
DNA-protein cross-links (DPCs) are frequently occurring lesions that provoke continual threats to the integrity of the genome by interference with replication and transcription. Reactive aldehydes generated from endogenous metabolic processes or produced in the environment are sources that trigger cross-linking of DNA with associated proteins. DNA repair pathways in place for removing DPCs, or for bypassing them to enable completion of replication, include homologous recombination (HR) and replication fork remodeling (FR) systems. Here, we surveyed a set of mutants defective in known HR and FR components to determine their contribution toward maintaining resistance to chronic formaldehyde (FA) exposure in Ustilago maydis, a fungus that relies on the BRCA2-family member Brh2 as the principal Rad51 mediator in repair of DNA strand breaks. We found that, in addition to Brh2, Rad52 was also vital for resistance to FA. Deleting the gene for Rec8, a kleisin subunit of cohesin, eliminated the requirement for Brh2, but not Rad52, in FA resistance. The Rad51K133R mutant variant that is able to bind DNA but unable to dissociate from it was able to support resistance to FA. These findings suggest a model for DPC repair and tolerance that features a specialized role for Rad52, enabling Rad51 to access DNA in its noncanonical capacity of replication fork protection rather than DNA strand transfer.
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Affiliation(s)
- Jeanette H Sutherland
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York 10065
| | - William K Holloman
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York 10065
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55
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Abstract
Homologous recombination (HR) is a universally conserved mechanism used to maintain genomic integrity. In eukaryotes, HR is used to repair the spontaneous double strand breaks (DSBs) that arise during mitotic growth, and the programmed DSBs that form during meiosis. The mechanisms that govern mitotic and meiotic HR share many similarities, however, there are also several key differences, which reflect the unique attributes of each process. For instance, even though many of the proteins involved in mitotic and meiotic HR are the same, DNA target specificity is not: mitotic DSBs are repaired primarily using the sister chromatid as a template, whereas meiotic DBSs are repaired primarily through targeting of the homologous chromosome. These changes in template specificity are induced by expression of meiosis-specific HR proteins, down-regulation of mitotic HR proteins, and the formation of meiosis-specific chromosomal structures. Here, we compare and contrast the biochemical properties of key recombination intermediates formed during the pre-synapsis phase of mitotic and meiotic HR. Throughout, we try to highlight unanswered questions that will shape our understanding of how homologous recombination contributes to human cancer biology and sexual reproduction.
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56
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Leland BA, Chen AC, Zhao AY, Wharton RC, King MC. Rev7 and 53BP1/Crb2 prevent RecQ helicase-dependent hyper-resection of DNA double-strand breaks. eLife 2018; 7:33402. [PMID: 29697047 PMCID: PMC5945276 DOI: 10.7554/elife.33402] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 04/11/2018] [Indexed: 12/15/2022] Open
Abstract
Poly(ADP ribose) polymerase inhibitors (PARPi) target cancer cells deficient in homology-directed repair of DNA double-strand breaks (DSBs). In preclinical models, PARPi resistance is tied to altered nucleolytic processing (resection) at the 5’ ends of a DSB. For example, loss of either 53BP1 or Rev7/MAD2L2/FANCV derepresses resection to drive PARPi resistance, although the mechanisms are poorly understood. Long-range resection can be catalyzed by two machineries: the exonuclease Exo1, or the combination of a RecQ helicase and Dna2. Here, we develop a single-cell microscopy assay that allows the distinct phases and machineries of resection to be interrogated simultaneously in living S. pombe cells. Using this assay, we find that the 53BP1 orthologue and Rev7 specifically repress long-range resection through the RecQ helicase-dependent pathway, thereby preventing hyper-resection. These results suggest that ‘rewiring’ of BRCA1-deficient cells to employ an Exo1-independent hyper-resection pathway is a driver of PARPi resistance. Healthy cells can typically repair damage to their DNA with high accuracy, keeping their genetic code intact. In contrast, cancer cells often lose this ability. Inaccurate repair leads to more frequent DNA mutations, which can make a tumor more aggressive. However, DNA repair-deficient tumors can be targeted with cancer therapies, such as PARP inhibitors, which kill cells that do not have working DNA repair mechanisms. PARP inhibitors show great promise clinically, but unfortunately some tumor cells can become resistant to these treatments over time. Recent work has shown that resistance to PARP inhibitors is often caused by further alternations to DNA repair machineries. Being able to visualize DNA repair in living cells is crucial to understanding this process and to find ways to improve cancer treatments. Previous studies have used repetitive DNA sequences called Lac operators (LacO) to visualize the dynamic behavior of DNA in live cells. Leland et al. have now adapted this system to watch individual DNA repair events in living yeast cells under the microscope. Their experiments reveal that when cells lose a single protein called Rev7, an early phase of DNA repair becomes hyperactive. Leland et al. traced the cause of this hyperactivity to an enzyme in the RecQ helicase family. A RecQ helicase becoming hyperactive in cells lacking Rev7 could explain how some cancer cells become resistant to PARP inhibitor treatments. This information could help fine-tune future approaches to treating cancer. For example, using an inhibitor of RecQ helicase alongside PARP inhibitors may help block this type of resistance from developing in the first place. As well as potentially paving the way for better cancer treatments, this method of visualization could improve scientists’ understanding of the basic processes of DNA repair.
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Affiliation(s)
- Bryan A Leland
- Department of Cell Biology, Yale School of Medicine, New Haven, United States
| | - Angela C Chen
- Department of Cell Biology, Yale School of Medicine, New Haven, United States
| | - Amy Y Zhao
- Department of Cell Biology, Yale School of Medicine, New Haven, United States
| | - Robert C Wharton
- Department of Cell Biology, Yale School of Medicine, New Haven, United States
| | - Megan C King
- Department of Cell Biology, Yale School of Medicine, New Haven, United States
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57
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Structural Basis of Homology-Directed DNA Repair Mediated by RAD52. iScience 2018; 3:50-62. [PMID: 30428330 PMCID: PMC6137706 DOI: 10.1016/j.isci.2018.04.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 03/07/2018] [Accepted: 03/20/2018] [Indexed: 11/21/2022] Open
Abstract
RAD52 mediates homologous recombination by annealing cDNA strands. However, the detailed mechanism of DNA annealing promoted by RAD52 has remained elusive. Here we report two crystal structures of human RAD52 single-stranded DNA (ssDNA) complexes that probably represent key reaction intermediates of RAD52-mediated DNA annealing. The first structure revealed a "wrapped" conformation of ssDNA around the homo-oligomeric RAD52 ring, in which the edges of the bases involved in base pairing are exposed to the solvent. The ssDNA conformation is close to B-form and appears capable of engaging in Watson-Crick base pairing with the cDNA strand. The second structure revealed a "trapped" conformation of ssDNA between two RAD52 rings. This conformation is stabilized by a different RAD52 DNA binding site, which promotes the accumulation of multiple RAD52 rings on ssDNA and the aggregation of ssDNA. These structures provide a structural framework for understanding the mechanism of RAD52-mediated DNA annealing.
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58
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Yasuda T, Kagawa W, Ogi T, Kato TA, Suzuki T, Dohmae N, Takizawa K, Nakazawa Y, Genet MD, Saotome M, Hama M, Konishi T, Nakajima NI, Hazawa M, Tomita M, Koike M, Noshiro K, Tomiyama K, Obara C, Gotoh T, Ui A, Fujimori A, Nakayama F, Hanaoka F, Sugasawa K, Okayasu R, Jeggo PA, Tajima K. Novel function of HATs and HDACs in homologous recombination through acetylation of human RAD52 at double-strand break sites. PLoS Genet 2018; 14:e1007277. [PMID: 29590107 PMCID: PMC5891081 DOI: 10.1371/journal.pgen.1007277] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 04/09/2018] [Accepted: 02/26/2018] [Indexed: 11/18/2022] Open
Abstract
The p300 and CBP histone acetyltransferases are recruited to DNA double-strand break (DSB) sites where they induce histone acetylation, thereby influencing the chromatin structure and DNA repair process. Whether p300/CBP at DSB sites also acetylate non-histone proteins, and how their acetylation affects DSB repair, remain unknown. Here we show that p300/CBP acetylate RAD52, a human homologous recombination (HR) DNA repair protein, at DSB sites. Using in vitro acetylated RAD52, we identified 13 potential acetylation sites in RAD52 by a mass spectrometry analysis. An immunofluorescence microscopy analysis revealed that RAD52 acetylation at DSBs sites is counteracted by SIRT2- and SIRT3-mediated deacetylation, and that non-acetylated RAD52 initially accumulates at DSB sites, but dissociates prematurely from them. In the absence of RAD52 acetylation, RAD51, which plays a central role in HR, also dissociates prematurely from DSB sites, and hence HR is impaired. Furthermore, inhibition of ataxia telangiectasia mutated (ATM) protein by siRNA or inhibitor treatment demonstrated that the acetylation of RAD52 at DSB sites is dependent on the ATM protein kinase activity, through the formation of RAD52, p300/CBP, SIRT2, and SIRT3 foci at DSB sites. Our findings clarify the importance of RAD52 acetylation in HR and its underlying mechanism.
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Affiliation(s)
- Takeshi Yasuda
- Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences (NIRS), Anagawa, Inage-ku, Chiba, Japan
- * E-mail: (TY); (KT)
| | - Wataru Kagawa
- Program in Chemistry and Life Science, Department of Interdisciplinary Science and Engineering, School of Science and Engineering, Meisei University, Hodokubo, Hino-shi, Tokyo, Japan
| | - Tomoo Ogi
- Department of Genetics, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan
| | - Takamitsu A. Kato
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States of America
| | - Takehiro Suzuki
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Hirosawa, Wako, Saitama, Japan
| | - Naoshi Dohmae
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Hirosawa, Wako, Saitama, Japan
| | - Kazuya Takizawa
- Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences (NIRS), Anagawa, Inage-ku, Chiba, Japan
| | - Yuka Nakazawa
- Department of Genetics, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan
- Department of Genome Repair, Atomic Bomb Disease Institute, Nagasaki University, Sakamoto, Nagasaki, Japan
| | - Matthew D. Genet
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States of America
| | - Mika Saotome
- Program in Chemistry and Life Science, Department of Interdisciplinary Science and Engineering, School of Science and Engineering, Meisei University, Hodokubo, Hino-shi, Tokyo, Japan
| | - Michio Hama
- Department of Basic Medical Sciences for Radiation Damage, NIRS, National Institutes for Quantum and Radiation Sciences and Technology (QST), Anagawa, Inage-ku, Chiba, Japan
| | - Teruaki Konishi
- Department of Basic Medical Sciences for Radiation Damage, NIRS, National Institutes for Quantum and Radiation Sciences and Technology (QST), Anagawa, Inage-ku, Chiba, Japan
| | | | - Masaharu Hazawa
- Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences (NIRS), Anagawa, Inage-ku, Chiba, Japan
- Cell-Bionomics Research Unit, Innovative Integrated Bio-Research Core, Institute for Frontier Science Initiative, Kanazawa University, Kakuma-machi, Kanazawa, Japan
| | - Masanori Tomita
- Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry, Iwado Kita, Komae-shi, Tokyo, Japan
| | - Manabu Koike
- Research Center for Radiation Protection, NIRS, 4-9-1 Anagawa, Inage-ku, Chiba, Japan
| | - Katsuko Noshiro
- Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences (NIRS), Anagawa, Inage-ku, Chiba, Japan
| | - Kenichi Tomiyama
- Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences (NIRS), Anagawa, Inage-ku, Chiba, Japan
| | - Chizuka Obara
- Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences (NIRS), Anagawa, Inage-ku, Chiba, Japan
| | - Takaya Gotoh
- Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences (NIRS), Anagawa, Inage-ku, Chiba, Japan
| | - Ayako Ui
- Genome regulation and Molecular pharmacogenomics, School of Bioscience and Biotechnology, Tokyo University of Technology, Katakuramachi, Hachioji City, Tokyo, Japan
| | - Akira Fujimori
- Research Center for Charged Particle Therapy, NIRS, Anagawa, Inage-ku, Chiba, Japan
- International Open Laboratory (IOL), NIRS, Anagawa, Inage-ku, Chiba, Japan
| | - Fumiaki Nakayama
- Department of Basic Medical Sciences for Radiation Damage, NIRS, National Institutes for Quantum and Radiation Sciences and Technology (QST), Anagawa, Inage-ku, Chiba, Japan
| | - Fumio Hanaoka
- Faculty of Science, Gakushuin University, Mejiro, Toshima-ku, Tokyo, Japan
| | - Kaoru Sugasawa
- Biosignal Research Center, and Graduate School of Science, Kobe University, Rokkodai-cho, Nada-ku, Kobe, Japan
| | - Ryuichi Okayasu
- International Open Laboratory (IOL), NIRS, Anagawa, Inage-ku, Chiba, Japan
| | - Penny A. Jeggo
- International Open Laboratory (IOL), NIRS, Anagawa, Inage-ku, Chiba, Japan
- Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Katsushi Tajima
- Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences (NIRS), Anagawa, Inage-ku, Chiba, Japan
- * E-mail: (TY); (KT)
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59
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Galanos P, Pappas G, Polyzos A, Kotsinas A, Svolaki I, Giakoumakis NN, Glytsou C, Pateras IS, Swain U, Souliotis VL, Georgakilas AG, Geacintov N, Scorrano L, Lukas C, Lukas J, Livneh Z, Lygerou Z, Chowdhury D, Sørensen CS, Bartek J, Gorgoulis VG. Mutational signatures reveal the role of RAD52 in p53-independent p21-driven genomic instability. Genome Biol 2018; 19:37. [PMID: 29548335 PMCID: PMC5857109 DOI: 10.1186/s13059-018-1401-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/30/2018] [Indexed: 02/07/2023] Open
Abstract
Background Genomic instability promotes evolution and heterogeneity of tumors. Unraveling its mechanistic basis is essential for the design of appropriate therapeutic strategies. In a previous study, we reported an unexpected oncogenic property of p21WAF1/Cip1, showing that its chronic expression in a p53-deficient environment causes genomic instability by deregulation of the replication licensing machinery. Results We now demonstrate that p21WAF1/Cip1 can further fuel genomic instability by suppressing the repair capacity of low- and high-fidelity pathways that deal with nucleotide abnormalities. Consequently, fewer single nucleotide substitutions (SNSs) occur, while formation of highly deleterious DNA double-strand breaks (DSBs) is enhanced, crafting a characteristic mutational signature landscape. Guided by the mutational signatures formed, we find that the DSBs are repaired by Rad52-dependent break-induced replication (BIR) and single-strand annealing (SSA) repair pathways. Conversely, the error-free synthesis-dependent strand annealing (SDSA) repair route is deficient. Surprisingly, Rad52 is activated transcriptionally in an E2F1-dependent manner, rather than post-translationally as is common for DNA repair factor activation. Conclusions Our results signify the importance of mutational signatures as guides to disclose the repair history leading to genomic instability. We unveil how chronic p21WAF1/Cip1 expression rewires the repair process and identifies Rad52 as a source of genomic instability and a candidate therapeutic target. Electronic supplementary material The online version of this article (10.1186/s13059-018-1401-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Panagiotis Galanos
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National Kapodistrian University of Athens, 75 Mikras Asias Str, GR-11527, Athens, Greece.,Danish Cancer Society Research Centre, Strandboulevarden 49, DK-2100, Copenhagen, Denmark
| | - George Pappas
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National Kapodistrian University of Athens, 75 Mikras Asias Str, GR-11527, Athens, Greece.,Danish Cancer Society Research Centre, Strandboulevarden 49, DK-2100, Copenhagen, Denmark
| | - Alexander Polyzos
- Biomedical Research Foundation of the Academy of Athens, 4 Soranou Ephessiou Str, GR-11527, Athens, Greece
| | - Athanassios Kotsinas
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National Kapodistrian University of Athens, 75 Mikras Asias Str, GR-11527, Athens, Greece
| | - Ioanna Svolaki
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National Kapodistrian University of Athens, 75 Mikras Asias Str, GR-11527, Athens, Greece
| | | | | | - Ioannis S Pateras
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National Kapodistrian University of Athens, 75 Mikras Asias Str, GR-11527, Athens, Greece
| | - Umakanta Swain
- Department of Biomolecular Sciences, Weizmann Institute of Science, 76100, Rehovot, Israel
| | - Vassilis L Souliotis
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave, GR-11635, Athens, Greece
| | - Alexandros G Georgakilas
- Physics Department, School of Applied Mathematical and Physical Sciences, National Technical University of Athens (NTUA), 15780, Zografou, Athens, Greece
| | | | - Luca Scorrano
- Department of Biology, University of Padova, 35121, Padova, Italy
| | - Claudia Lukas
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jiri Lukas
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Zvi Livneh
- Department of Biomolecular Sciences, Weizmann Institute of Science, 76100, Rehovot, Israel
| | - Zoi Lygerou
- Laboratory of Biology, School of Medicine, University of Patras, 26505, Patras, Rio, Greece
| | - Dipanjan Chowdhury
- Department of Radiation Oncology, Dana-Farber Cancer Institute, 450 Brookline Ave, Boston, MA, 02215, USA.,Harvard Medical School, 25 Shattuck St, Boston, MA, 02115, USA
| | - Claus Storgaard Sørensen
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaloes Vej 5, DK-2200, Copenhagen, Denmark
| | - Jiri Bartek
- Danish Cancer Society Research Centre, Strandboulevarden 49, DK-2100, Copenhagen, Denmark. .,Science for Life Laboratory, Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, SE-171 77, Stockholm, Sweden.
| | - Vassilis G Gorgoulis
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National Kapodistrian University of Athens, 75 Mikras Asias Str, GR-11527, Athens, Greece. .,Biomedical Research Foundation of the Academy of Athens, 4 Soranou Ephessiou Str, GR-11527, Athens, Greece. .,Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Wilmslow Road, Manchester, M20 4QL, UK.
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60
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Li Q, Folly da Silva Constantino L, Spies MA. Integrating Experimental and In Silico HTS in the Discovery of Inhibitors of Protein-Nucleic Acid Interactions. Methods Enzymol 2018. [PMID: 29523234 DOI: 10.1016/bs.mie.2017.11.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Discovery of novel tool compounds and drug leads against a range of unorthodox protein targets has pushed both experimental screening methodologies as well as the field of structure-based design to the limit in recent years. Increasingly, it has been recognized that some of the most desirable targets for the development of small-molecule effectors are actually protein-protein and protein-nucleic acid interactions. There are numerous nontrivial challenges to pursuing small-molecule lead compounds directed toward PPIs and PNIs: relatively shallow cavities, large surface areas that are natively complexed to macromolecules, complex patterns of interstitial waters, a paucity of "hot spots," large conformational changes upon ligand binding, etc. Although there have been some notable successes targeting PPIs in the last decade, there has been distinctly less success in the realm of targeting PNIs. This chapter focuses on an approach, successfully applied by our group to address the challenge of gaining traction on the PPI target RAD52, which is a protein that binds both single-stranded and double-stranded DNA, and is an anticancer target for certain types of cancer. There are many approaches to tackling the difficult problems of finding effective small molecules that disrupt PPIs and PNIs, but the methods presented here offer a series of elegant solutions, which integrate experimental HTS, biophysical methods, docking, and molecular dynamics in a powerful way. Additionally, the structural knowledge gained from these studies provides a means for rationally understanding what features lead to ligand affinity in these fascinating and highly unorthodox pockets.
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Affiliation(s)
- Quinn Li
- The University of Iowa, Iowa City, IA, United States
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61
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Yang G, Wu L, Chen G, Jiang M. Precise protein assembly of array structures. Chem Commun (Camb) 2018; 52:10595-605. [PMID: 27384233 DOI: 10.1039/c6cc04190f] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The assembly of proteins into various nano-objects with regular and periodic microstructures, i.e. protein arrays, is a fast-growing field in materials science. Due to the structural complexity of proteins, reports in this field are still quite limited. In this review, we summarize the recent developments in protein array construction by different driving forces, including electrostatic interactions, metal-ligand interactions, molecular recognition and protein-protein interactions. In line with our particular interest, assemblies driven by molecular recognition are particularly explored. Finally, functionalities of the obtained protein arrays are briefly discussed.
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Affiliation(s)
- Guang Yang
- State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University, Shanghai 200433, China.
| | - Libin Wu
- State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University, Shanghai 200433, China.
| | - Guosong Chen
- State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University, Shanghai 200433, China.
| | - Ming Jiang
- State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University, Shanghai 200433, China.
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62
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Li J, Yang Q, Zhang Y, Huang K, Sun R, Zhao Q. Compound F779-0434 causes synthetic lethality in BRCA2-deficient cancer cells by disrupting RAD52–ssDNA association. RSC Adv 2018; 8:18859-18869. [PMID: 35539677 PMCID: PMC9080615 DOI: 10.1039/c8ra01919c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/04/2018] [Indexed: 11/21/2022] Open
Abstract
A novel compound named F779-0434 caused synthetic lethality in BRCA2-deficient cancer cells by disrupting RAD52–ssDNA associations.
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Affiliation(s)
- Jian Li
- School of Medicine
- Chengdu University
- Chengdu 610106
- China
- Sichuan Industrial Institute of Antibiotics
| | - Qianye Yang
- Sichuan Industrial Institute of Antibiotics
- Chengdu University
- Chengdu 610052
- China
| | - Yang Zhang
- Sichuan Industrial Institute of Antibiotics
- Chengdu University
- Chengdu 610052
- China
| | - Kejia Huang
- Sichuan Industrial Institute of Antibiotics
- Chengdu University
- Chengdu 610052
- China
| | - Rong Sun
- College of Life Sciences and Key Laboratory for Bio-Resources of Ministry of Education
- Sichuan University
- Chengdu 610064
- China
| | - Qi Zhao
- Sichuan Industrial Institute of Antibiotics
- Chengdu University
- Chengdu 610052
- China
- College of Pharmacy and Biological Engineering
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63
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Zafar F, Okita AK, Onaka AT, Su J, Katahira Y, Nakayama JI, Takahashi TS, Masukata H, Nakagawa T. Regulation of mitotic recombination between DNA repeats in centromeres. Nucleic Acids Res 2017; 45:11222-11235. [PMID: 28977643 PMCID: PMC5737691 DOI: 10.1093/nar/gkx763] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 08/17/2017] [Indexed: 12/18/2022] Open
Abstract
Centromeres that are essential for faithful segregation of chromosomes consist of unique DNA repeats in many eukaryotes. Although recombination is under-represented around centromeres during meiosis, little is known about recombination between centromere repeats in mitotic cells. Here, we compared spontaneous recombination that occurs between ade6B/ade6X inverted repeats integrated at centromere 1 (cen1) or at a non-centromeric ura4 locus in fission yeast. Remarkably, distinct mechanisms of homologous recombination (HR) were observed in centromere and non-centromere regions. Rad51-dependent HR that requires Rad51, Rad54 and Rad52 was predominant in the centromere, whereas Rad51-independent HR that requires Rad52 also occurred in the arm region. Crossovers between inverted repeats (i.e. inversions) were under-represented in the centromere as compared to the arm region. While heterochromatin was dispensable, Mhf1/CENP–S, Mhf2/CENP–X histone-fold proteins and Fml1/FANCM helicase were required to suppress crossovers. Furthermore, Mhf1 and Fml1 were found to prevent gross chromosomal rearrangements mediated by centromere repeats. These data uncovered the regulation of mitotic recombination between DNA repeats in centromeres and its physiological role in maintaining genome integrity.
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Affiliation(s)
- Faria Zafar
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Akiko K Okita
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Atsushi T Onaka
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Jie Su
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Yasuhiro Katahira
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Jun-Ichi Nakayama
- Division of Chromatin Regulation, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 44-8585, Japan
| | - Tatsuro S Takahashi
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Hisao Masukata
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Takuro Nakagawa
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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64
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Rad52 phosphorylation by Ipl1 and Mps1 contributes to Mps1 kinetochore localization and spindle assembly checkpoint regulation. Proc Natl Acad Sci U S A 2017; 114:E9261-E9270. [PMID: 29078282 DOI: 10.1073/pnas.1705261114] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Rad52 is well known as a key factor in homologous recombination. Here, we report that Rad52 has functions unrelated to homologous recombination in Saccharomyces cerevisiae; it plays a role in the recruitment of Mps1 to the kinetochores and the maintenance of spindle assembly checkpoint (SAC) activity. Deletion of RAD52 causes various phenotypes related to the dysregulation of chromosome biorientation. Rad52 directly affects efficient operation of the SAC and accurate chromosome segregation. Remarkably, by using an in vitro kinase assay, we found that Rad52 is a substrate of Ipl1/Aurora and Mps1 in yeast and humans. Ipl1-dependent phosphorylation of Rad52 facilitates the kinetochore accumulation of Mps1, and Mps1-dependent phosphorylation of Rad52 is important for the accurate regulation of the SAC under spindle damage conditions. Taken together, our data provide detailed insights into the regulatory mechanism of chromosome biorientation by mitotic kinases.
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65
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Manthey GM, Clear AD, Liddell LC, Negritto MC, Bailis AM. Homologous recombination in budding yeast expressing the human RAD52 gene reveals a Rad51-independent mechanism of conservative double-strand break repair. Nucleic Acids Res 2017; 45:1879-1888. [PMID: 27923995 PMCID: PMC5389729 DOI: 10.1093/nar/gkw1228] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Accepted: 11/24/2016] [Indexed: 11/12/2022] Open
Abstract
RAD52 is a homologous recombination (HR) protein that is conserved from bacteriophage to humans. Simultaneously attenuating expression of both the RAD52 gene, and the HR and tumor suppressor gene, BRCA2, in human cells synergistically reduces HR – indicating that RAD52 and BRCA2 control independent mechanisms of HR. We have expressed the human RAD52 gene (HsRAD52) in budding yeast strains lacking the endogenous RAD52 gene and found that HsRAD52 supports repair of DNA double-strand breaks (DSB) by a mechanism of HR that conserves genome structure. Importantly, this mechanism of HR is independent of RAD51, which encodes the central strand exchange protein in yeast required for conservative HR. In contrast, BRCA2 exerts its effect on HR in human cells together with HsRAD51, potentially explaining the synergistic effect of attenuating the expression of both HsRAD52 and BRCA2. This suggests that multiple mechanisms of conservative DSB repair may contribute to tumor suppression in human cells.
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Affiliation(s)
- Glenn M Manthey
- Department of Molecular and Cellular Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Alissa D Clear
- Department of Molecular and Cellular Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.,Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Lauren C Liddell
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | - Adam M Bailis
- Department of Molecular and Cellular Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.,Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
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66
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Bhowmick R, Minocherhomji S, Hickson ID. RAD52 Facilitates Mitotic DNA Synthesis Following Replication Stress. Mol Cell 2017; 64:1117-1126. [PMID: 27984745 DOI: 10.1016/j.molcel.2016.10.037] [Citation(s) in RCA: 266] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/06/2016] [Accepted: 10/28/2016] [Indexed: 11/16/2022]
Abstract
Homologous recombination (HR) is necessary to counteract DNA replication stress. Common fragile site (CFS) loci are particularly sensitive to replication stress and undergo pathological rearrangements in tumors. At these loci, replication stress frequently activates DNA repair synthesis in mitosis. This mitotic DNA synthesis, termed MiDAS, requires the MUS81-EME1 endonuclease and a non-catalytic subunit of the Pol-delta complex, POLD3. Here, we examine the contribution of HR factors in promoting MiDAS in human cells. We report that RAD51 and BRCA2 are dispensable for MiDAS but are required to counteract replication stress at CFS loci during S-phase. In contrast, MiDAS is RAD52 dependent, and RAD52 is required for the timely recruitment of MUS81 and POLD3 to CFSs in early mitosis. Our results provide further mechanistic insight into MiDAS and define a specific function for human RAD52. Furthermore, selective inhibition of MiDAS may comprise a potential therapeutic strategy to sensitize cancer cells undergoing replicative stress.
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Affiliation(s)
- Rahul Bhowmick
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Sheroy Minocherhomji
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Ian D Hickson
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen N, Denmark.
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67
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Sotiriou SK, Kamileri I, Lugli N, Evangelou K, Da-Ré C, Huber F, Padayachy L, Tardy S, Nicati NL, Barriot S, Ochs F, Lukas C, Lukas J, Gorgoulis VG, Scapozza L, Halazonetis TD. Mammalian RAD52 Functions in Break-Induced Replication Repair of Collapsed DNA Replication Forks. Mol Cell 2017; 64:1127-1134. [PMID: 27984746 PMCID: PMC5179496 DOI: 10.1016/j.molcel.2016.10.038] [Citation(s) in RCA: 194] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 10/08/2016] [Accepted: 10/28/2016] [Indexed: 02/01/2023]
Abstract
Human cancers are characterized by the presence of oncogene-induced DNA replication stress (DRS), making them dependent on repair pathways such as break-induced replication (BIR) for damaged DNA replication forks. To better understand BIR, we performed a targeted siRNA screen for genes whose depletion inhibited G1 to S phase progression when oncogenic cyclin E was overexpressed. RAD52, a gene dispensable for normal development in mice, was among the top hits. In cells in which fork collapse was induced by oncogenes or chemicals, the Rad52 protein localized to DRS foci. Depletion of Rad52 by siRNA or knockout of the gene by CRISPR/Cas9 compromised restart of collapsed forks and led to DNA damage in cells experiencing DRS. Furthermore, in cancer-prone, heterozygous APC mutant mice, homozygous deletion of the Rad52 gene suppressed tumor growth and prolonged lifespan. We therefore propose that mammalian RAD52 facilitates repair of collapsed DNA replication forks in cancer cells. Mammalian RAD52 is involved in the oncogene-induced DNA replication stress response Mammalian RAD52 functions in the repair of collapsed DNA replication forks Rad52 deficiency prolongs the lifespan of Apcmin/+ mice
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Affiliation(s)
- Sotirios K Sotiriou
- Department of Molecular Biology, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - Irene Kamileri
- Department of Molecular Biology, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - Natalia Lugli
- Department of Molecular Biology, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - Konstantinos Evangelou
- Department of Histology and Embryology, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias Street, 11527 Athens, Greece
| | - Caterina Da-Ré
- Department of Molecular Biology, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - Florian Huber
- Department of Molecular Biology, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - Laura Padayachy
- Department of Molecular Biology, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - Sebastien Tardy
- School of Pharmaceutical Sciences, Department of Pharmaceutical Biochemistry, CMU, University of Geneva and University of Lausanne, Rue Michel-Servet 1, 1211 Geneva, Switzerland
| | - Noemie L Nicati
- Department of Molecular Biology, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva, Switzerland; School of Pharmaceutical Sciences, Department of Pharmaceutical Biochemistry, CMU, University of Geneva and University of Lausanne, Rue Michel-Servet 1, 1211 Geneva, Switzerland
| | - Samia Barriot
- Department of Molecular Biology, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - Fena Ochs
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Claudia Lukas
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Jiri Lukas
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Vassilis G Gorgoulis
- Department of Histology and Embryology, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias Street, 11527 Athens, Greece; Faculty Institute for Cancer Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Manchester M13 9PL, UK; Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece
| | - Leonardo Scapozza
- School of Pharmaceutical Sciences, Department of Pharmaceutical Biochemistry, CMU, University of Geneva and University of Lausanne, Rue Michel-Servet 1, 1211 Geneva, Switzerland
| | - Thanos D Halazonetis
- Department of Molecular Biology, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva, Switzerland.
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68
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Ma CJ, Kwon Y, Sung P, Greene EC. Human RAD52 interactions with replication protein A and the RAD51 presynaptic complex. J Biol Chem 2017; 292:11702-11713. [PMID: 28551686 PMCID: PMC5512066 DOI: 10.1074/jbc.m117.794545] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 05/24/2017] [Indexed: 11/06/2022] Open
Abstract
Rad52 is a highly conserved protein involved in the repair of DNA damage. Human RAD52 has been shown to mediate single-stranded DNA (ssDNA) and is synthetic lethal with mutations in other key recombination proteins. For this study, we used single-molecule imaging and ssDNA curtains to examine the binding interactions of human RAD52 with replication protein A (RPA)-coated ssDNA, and we monitored the fate of RAD52 during assembly of the presynaptic complex. We show that RAD52 binds tightly to the RPA-ssDNA complex and imparts an inhibitory effect on RPA turnover. We also found that during presynaptic complex assembly, most of the RPA and RAD52 was displaced from the ssDNA, but some RAD52-RPA-ssDNA complexes persisted as interspersed clusters surrounded by RAD51 filaments. Once assembled, the presence of RAD51 restricted formation of new RAD52-binding events, but additional RAD52 could bind once RAD51 dissociated from the ssDNA. Together, these results provide new insights into the behavior and dynamics of human RAD52 during presynaptic complex assembly and disassembly.
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Affiliation(s)
- Chu Jian Ma
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, New York 10032
| | - Youngho Kwon
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Eric C Greene
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, New York 10032.
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69
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Mazina OM, Keskin H, Hanamshet K, Storici F, Mazin AV. Rad52 Inverse Strand Exchange Drives RNA-Templated DNA Double-Strand Break Repair. Mol Cell 2017; 67:19-29.e3. [PMID: 28602639 DOI: 10.1016/j.molcel.2017.05.019] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 05/09/2017] [Accepted: 05/19/2017] [Indexed: 12/20/2022]
Abstract
RNA can serve as a template for DNA double-strand break repair in yeast cells, and Rad52, a member of the homologous recombination pathway, emerged as an important player in this process. However, the exact mechanism of how Rad52 contributes to RNA-dependent DSB repair remained unknown. Here, we report an unanticipated activity of yeast and human Rad52: inverse strand exchange, in which Rad52 forms a complex with dsDNA and promotes strand exchange with homologous ssRNA or ssDNA. We show that in eukaryotes, inverse strand exchange between homologous dsDNA and RNA is a distinctive activity of Rad52; neither Rad51 recombinase nor the yeast Rad52 paralog Rad59 has this activity. In accord with our in vitro results, our experiments in budding yeast provide evidence that Rad52 inverse strand exchange plays an important role in RNA-templated DSB repair in vivo.
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Affiliation(s)
- Olga M Mazina
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Havva Keskin
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Kritika Hanamshet
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Francesca Storici
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Alexander V Mazin
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA.
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70
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Martínez-Miguel RM, Sandoval-Cabrera A, Bazán-Tejeda ML, Torres-Huerta AL, Martínez-Reyes DA, Bermúdez-Cruz RM. Giardia duodenalis Rad52 protein: biochemical characterization and response upon DNA damage. J Biochem 2017; 162:123-135. [DOI: 10.1093/jb/mvx009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 01/10/2017] [Indexed: 11/13/2022] Open
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71
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Ghosh S, Hönscheid A, Dückers G, Ginzel S, Gohlke H, Gombert M, Kempkes B, Klapper W, Kuhlen M, Laws HJ, Linka RM, Meisel R, Mielke C, Niehues T, Schindler D, Schneider D, Schuster FR, Speckmann C, Borkhardt A. Human RAD52 - a novel player in DNA repair in cancer and immunodeficiency. Haematologica 2016; 102:e69-e72. [PMID: 27979922 DOI: 10.3324/haematol.2016.155838] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Sujal Ghosh
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Center of Child and Adolescent Health, Heinrich-Heine-University, Düsseldorf, Germany .,Infection, Immunity, Inflammation, Molecular and Cellular Immunology Section, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Andrea Hönscheid
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Center of Child and Adolescent Health, Heinrich-Heine-University, Düsseldorf, Germany
| | - Gregor Dückers
- Department of Pediatrics, Helios Hospital Krefeld, Germany
| | - Sebastian Ginzel
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Center of Child and Adolescent Health, Heinrich-Heine-University, Düsseldorf, Germany
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-University, Düsseldorf, Germany
| | - Michael Gombert
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Center of Child and Adolescent Health, Heinrich-Heine-University, Düsseldorf, Germany
| | - Bettina Kempkes
- Department of Gene Vectors, Helmholtz Center Munich, German Research Center for Environmental Health, Germany
| | - Wolfram Klapper
- Department of Pathology, Haematopathology Section and Lymph Node Registry, University Medical Centre Schleswig-Holstein, Kiel, Germany
| | - Michaela Kuhlen
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Center of Child and Adolescent Health, Heinrich-Heine-University, Düsseldorf, Germany
| | - Hans-Jürgen Laws
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Center of Child and Adolescent Health, Heinrich-Heine-University, Düsseldorf, Germany
| | - René Martin Linka
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Center of Child and Adolescent Health, Heinrich-Heine-University, Düsseldorf, Germany
| | - Roland Meisel
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Center of Child and Adolescent Health, Heinrich-Heine-University, Düsseldorf, Germany
| | - Christian Mielke
- Institute of Clinical Chemistry and Laboratory Diagnostics, Heinrich-Heine-University, Düsseldorf, GermanyMedical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Tim Niehues
- Department of Pediatrics, Helios Hospital Krefeld, Germany
| | | | | | - Friedhelm R Schuster
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Center of Child and Adolescent Health, Heinrich-Heine-University, Düsseldorf, Germany
| | - Carsten Speckmann
- Centre for Chronic Immunodeficiency (CCI) and Centre of Pediatrics, University of Freiburg, Germany
| | - Arndt Borkhardt
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Center of Child and Adolescent Health, Heinrich-Heine-University, Düsseldorf, Germany
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72
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Korolev S. Advances in structural studies of recombination mediator proteins. Biophys Chem 2016; 225:27-37. [PMID: 27974172 DOI: 10.1016/j.bpc.2016.12.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 12/01/2016] [Accepted: 12/01/2016] [Indexed: 12/25/2022]
Abstract
Recombination mediator proteins (RMPs) are critical for genome integrity in all organisms. They include phage UvsY, prokaryotic RecF, -O, -R (RecFOR) and eukaryotic Rad52, Breast Cancer susceptibility 2 (BRCA2) and Partner and localizer of BRCA2 (PALB2) proteins. BRCA2 and PALB2 are tumor suppressors implicated in cancer. RMPs regulate binding of RecA-like recombinases to sites of DNA damage to initiate the most efficient non-mutagenic repair of broken chromosome and other deleterious DNA lesions. Mechanistically, RMPs stimulate a single-stranded DNA (ssDNA) hand-off from ssDNA binding proteins (ssbs) such as gp32, SSB and RPA, to recombinases, activating DNA repair only at the time and site of the damage event. This review summarizes structural studies of RMPs and their implications for understanding mechanism and function. Comparative analysis of RMPs is complicated due to their convergent evolution. In contrast to the evolutionary conserved ssbs and recombinases, RMPs are extremely diverse in sequence and structure. Structural studies are particularly important in such cases to reveal common features of the entire family and specific features of regulatory mechanisms for each member. All RMPs are characterized by specific DNA-binding domains and include variable protein interaction motifs. The complexity of such RMPs corresponds to the ever-growing number of DNA metabolism events they participate in under normal and pathological conditions and requires additional comprehensive structure-functional studies.
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Affiliation(s)
- S Korolev
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1100 S Grand Blvd., St. Louis, MO 63104, USA.
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73
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Seetoh WG, Abell C. Disrupting the Constitutive, Homodimeric Protein-Protein Interface in CK2β Using a Biophysical Fragment-Based Approach. J Am Chem Soc 2016; 138:14303-14311. [PMID: 27726344 PMCID: PMC5257173 DOI: 10.1021/jacs.6b07440] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
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Identifying small molecules that
induce the disruption of constitutive
protein–protein interfaces is a challenging objective. Here,
a targeted biophysical screening cascade was employed to specifically
identify small molecules that could disrupt the constitutive, homodimeric
protein–protein interface within CK2β. This approach
could potentially be applied to achieve subunit disassembly of other
homo-oligomeric proteins as a means of modulating protein function.
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Affiliation(s)
- Wei-Guang Seetoh
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Chris Abell
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
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74
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Subramaniam S, Erler A, Fu J, Kranz A, Tang J, Gopalswamy M, Ramakrishnan S, Keller A, Grundmeier G, Müller D, Sattler M, Stewart AF. DNA annealing by Redβ is insufficient for homologous recombination and the additional requirements involve intra- and inter-molecular interactions. Sci Rep 2016; 6:34525. [PMID: 27708411 PMCID: PMC5052646 DOI: 10.1038/srep34525] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 08/15/2016] [Indexed: 01/09/2023] Open
Abstract
Single strand annealing proteins (SSAPs) like Redβ initiate homologous recombination by annealing complementary DNA strands. We show that C-terminally truncated Redβ, whilst still able to promote annealing and nucleoprotein filament formation, is unable to mediate homologous recombination. Mutations of the C-terminal domain were evaluated using both single- and double stranded (ss and ds) substrates in recombination assays. Mutations of critical amino acids affected either dsDNA recombination or both ssDNA and dsDNA recombination indicating two separable functions, one of which is critical for dsDNA recombination and the second for recombination per se. As evaluated by co-immunoprecipitation experiments, the dsDNA recombination function relates to the Redα-Redβ protein-protein interaction, which requires not only contacts in the C-terminal domain but also a region near the N-terminus. Because the nucleoprotein filament formed with C-terminally truncated Redβ has altered properties, the second C-terminal function could be due to an interaction required for functional filaments. Alternatively the second C-terminal function could indicate a requirement for a Redβ-host factor interaction. These data further advance the model for Red recombination and the proposition that Redβ and RAD52 SSAPs share ancestral and mechanistic roots.
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Affiliation(s)
| | - Axel Erler
- Genomics, Biotechnology Center, TU Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Jun Fu
- Genomics, Biotechnology Center, TU Dresden, Tatzberg 47/49, 01307 Dresden, Germany.,Shandong University-Helmholtz Joint Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Shanda Nanlu 27, 250100 Jinan, People's Republic of China
| | - Andrea Kranz
- Genomics, Biotechnology Center, TU Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Jing Tang
- Genomics, Biotechnology Center, TU Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Mohanraj Gopalswamy
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany and Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technische Universität München, Lichtenbergstr.4, 85747 Garching, Germany
| | - Saminathan Ramakrishnan
- Technical and Macromolecular Chemistry, University of Paderborn, Warburger Str. 100 33098 Paderborn, Germany
| | - Adrian Keller
- Technical and Macromolecular Chemistry, University of Paderborn, Warburger Str. 100 33098 Paderborn, Germany
| | - Guido Grundmeier
- Technical and Macromolecular Chemistry, University of Paderborn, Warburger Str. 100 33098 Paderborn, Germany
| | - Daniel Müller
- Department of Biosystems Science and Engineering (D-BSSE), ETH Zürich, Mattenstraße 26, 4058 Basel, Switzerland
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany and Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technische Universität München, Lichtenbergstr.4, 85747 Garching, Germany
| | - A Francis Stewart
- Genomics, Biotechnology Center, TU Dresden, Tatzberg 47/49, 01307 Dresden, Germany
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75
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Reappearance from Obscurity: Mammalian Rad52 in Homologous Recombination. Genes (Basel) 2016; 7:genes7090063. [PMID: 27649245 PMCID: PMC5042393 DOI: 10.3390/genes7090063] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/06/2016] [Accepted: 09/09/2016] [Indexed: 01/28/2023] Open
Abstract
Homologous recombination (HR) plays an important role in maintaining genomic integrity. It is responsible for repair of the most harmful DNA lesions, DNA double-strand breaks and inter-strand DNA cross-links. HR function is also essential for proper segregation of homologous chromosomes in meiosis, maintenance of telomeres, and resolving stalled replication forks. Defects in HR often lead to genetic diseases and cancer. Rad52 is one of the key HR proteins, which is evolutionarily conserved from yeast to humans. In yeast, Rad52 is important for most HR events; Rad52 mutations disrupt repair of DNA double-strand breaks and targeted DNA integration. Surprisingly, in mammals, Rad52 knockouts showed no significant DNA repair or recombination phenotype. However, recent work demonstrated that mutations in human RAD52 are synthetically lethal with mutations in several other HR proteins including BRCA1 and BRCA2. These new findings indicate an important backup role for Rad52, which complements the main HR mechanism in mammals. In this review, we focus on the Rad52 activities and functions in HR and the possibility of using human RAD52 as therapeutic target in BRCA1 and BRCA2-deficient familial breast cancer and ovarian cancer.
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76
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Nair A, Agarwal R, Chittela RK. Biochemical characterization of plant Rad52 protein from rice (Oryza sativa). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 106:108-117. [PMID: 27156135 DOI: 10.1016/j.plaphy.2016.04.048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 04/28/2016] [Accepted: 04/28/2016] [Indexed: 06/05/2023]
Abstract
DNA damage in living cells is repaired by two main pathways, homologous recombination (HR) and non-homologous end joining (NHEJ). Of all the genes promoting HR, Rad52 (Radiation sensitive 52) is an important gene which is found to be highly conserved across different species. It was believed that RAD52 is absent in plant systems until lately. However, recent genetic studies have shown the presence of RAD52 homologues in plants. Rad52 homologues in plant systems have not yet been characterized biochemically. In the current study, we bring out the biochemical properties of rice Rad52-2a protein. OsRad52-2a was over-expressed in Escherichia coli BL21 (DE3) cells and the protein was purified. The identity of purified OsRad52-2a protein was confirmed via peptide mass fingerprinting. Gel filtration and native PAGE analysis indicated that the OsRad52-2a protein in its native state probably formed an undecameric structure. Purified OsRad52-2a protein showed binding to single stranded DNA, double stranded DNA. Protein also mediated the renaturation of complementary single strands into duplex DNA in both agarose gel and FRET based assays. Put together, OsRad52-2a forms oligomeric structures and binds to ssDNA/dsDNA for mediating an important function like renaturation during homologous recombination. This study represents the first report on biochemical properties of OsRad52-2a protein from important crop like rice. This information will help in dissecting the recombination and repair machinery in plant systems.
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Affiliation(s)
- Anuradha Nair
- Bio-molecular Damage and Repair Section, Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Rachna Agarwal
- Bio-molecular Damage and Repair Section, Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Rajani Kant Chittela
- Bio-molecular Damage and Repair Section, Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India.
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77
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Saotome M, Saito K, Onodera K, Kurumizaka H, Kagawa W. Structure of the human DNA-repair protein RAD52 containing surface mutations. Acta Crystallogr F Struct Biol Commun 2016; 72:598-603. [PMID: 27487923 PMCID: PMC4973300 DOI: 10.1107/s2053230x1601027x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Accepted: 06/24/2016] [Indexed: 11/10/2022] Open
Abstract
The Rad52 protein is a eukaryotic single-strand DNA-annealing protein that is involved in the homologous recombinational repair of DNA double-strand breaks. The isolated N-terminal half of the human RAD52 protein (RAD52(1-212)) forms an undecameric ring structure with a surface that is mostly positively charged. In the present study, it was found that RAD52(1-212) containing alanine mutations of the charged surface residues (Lys102, Lys133 and Glu202) is highly amenable to crystallization. The structure of the mutant RAD52(1-212) was solved at 2.4 Å resolution. The structure revealed an association between the symmetry-related RAD52(1-212) rings, in which a partially unfolded, C-terminal region of RAD52 extended into the DNA-binding groove of the neighbouring ring in the crystal. The alanine mutations probably reduced the surface entropy of the RAD52(1-212) ring and stabilized the ring-ring association observed in the crystal.
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Affiliation(s)
- Mika Saotome
- Department of Interdisciplinary Science and Engineering, Program in Chemistry and Life Science, School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino-shi, Tokyo 191-8506, Japan
| | - Kengo Saito
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Keiichi Onodera
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Wataru Kagawa
- Department of Interdisciplinary Science and Engineering, Program in Chemistry and Life Science, School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino-shi, Tokyo 191-8506, Japan
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78
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Hengel SR, Malacaria E, Folly da Silva Constantino L, Bain FE, Diaz A, Koch BG, Yu L, Wu M, Pichierri P, Spies MA, Spies M. Small-molecule inhibitors identify the RAD52-ssDNA interaction as critical for recovery from replication stress and for survival of BRCA2 deficient cells. eLife 2016; 5. [PMID: 27434671 PMCID: PMC4982760 DOI: 10.7554/elife.14740] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 07/18/2016] [Indexed: 12/20/2022] Open
Abstract
The DNA repair protein RAD52 is an emerging therapeutic target of high importance for BRCA-deficient tumors. Depletion of RAD52 is synthetically lethal with defects in tumor suppressors BRCA1, BRCA2 and PALB2. RAD52 also participates in the recovery of the stalled replication forks. Anticipating that ssDNA binding activity underlies the RAD52 cellular functions, we carried out a high throughput screening campaign to identify compounds that disrupt the RAD52-ssDNA interaction. Lead compounds were confirmed as RAD52 inhibitors in biochemical assays. Computational analysis predicted that these inhibitors bind within the ssDNA-binding groove of the RAD52 oligomeric ring. The nature of the inhibitor-RAD52 complex was validated through an in silico screening campaign, culminating in the discovery of an additional RAD52 inhibitor. Cellular studies with our inhibitors showed that the RAD52-ssDNA interaction enables its function at stalled replication forks, and that the inhibition of RAD52-ssDNA binding acts additively with BRCA2 or MUS81 depletion in cell killing. DOI:http://dx.doi.org/10.7554/eLife.14740.001 Cells are constantly in danger of losing or scrambling critical genetic information because of DNA damage. To cope with this stress, cells have numerous DNA repair systems. One of these systems – homology-directed DNA repair – involves the proteins BRCA1 and BRCA2, which are often missing or defective in breast and ovarian cancers. The BRCA-deficient cancer cells can still survive, but become “addicted” to other DNA repair proteins – among them a protein called RAD52. It might be possible to kill these cancer cells using drugs that stop RAD52 from working. Such treatments would have the benefit of not harming normal healthy cells, as these cells contain working BRCA proteins and can survive without RAD52. It is not currently known exactly how RAD52 allows the BRCA-deficient cells to survive, but this probably depends on RAD52’s ability to bind to single strands of DNA. Small molecules that block the interaction between the RAD52 protein and DNA might therefore help to kill cancer cells. Hengel et al. developed a high throughput biophysical method to search through a large collection of small molecules to find those that prevent RAD52 from binding to DNA. The best potential drug leads were then tested in laboratory-grown human cells and using biophysical and biochemical techniques. Computational approaches were also used to model how these molecules block the interaction between RAD52 and DNA at the atomistic level. Hengel et al. then used the information about how the small molecules bind to RAD52 to perform further computational screening. This identified a natural compound that competes with single-stranded DNA to bind to RAD52. The activity of this molecule was then validated using biophysical methods. The methods used by Hengel et al. provide the foundation for further searches for new anticancer drugs. Future studies that employ the small molecule drugs identified so far will also help to determine exactly how RAD52 works in human cells and how it helps cancer cells to survive. DOI:http://dx.doi.org/10.7554/eLife.14740.002
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Affiliation(s)
- Sarah R Hengel
- Department of Biochemistry, University of Iowa, Iowa City, United States
| | - Eva Malacaria
- Department of Environment and Health, Section of Experimental and Computational Carcinogenesis, Istituto Superiore di Sanita, Rome, Italy
| | - Laura Folly da Silva Constantino
- Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, United States
| | - Fletcher E Bain
- Department of Biochemistry, University of Iowa, Iowa City, United States
| | - Andrea Diaz
- Department of Biochemistry, University of Iowa, Iowa City, United States
| | - Brandon G Koch
- Department of Biochemistry, University of Iowa, Iowa City, United States
| | - Liping Yu
- Department of Biochemistry, University of Iowa, Iowa City, United States.,NMR Core Facility, Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Meng Wu
- Department of Biochemistry, University of Iowa, Iowa City, United States.,Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, United States.,High Throughput Screening Facility, University of Iowa, Iowa City, United States
| | - Pietro Pichierri
- Department of Environment and Health, Section of Experimental and Computational Carcinogenesis, Istituto Superiore di Sanita, Rome, Italy
| | - M Ashley Spies
- Department of Biochemistry, University of Iowa, Iowa City, United States.,Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, United States
| | - Maria Spies
- Department of Biochemistry, University of Iowa, Iowa City, United States
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79
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Roles of C-Terminal Region of Yeast and Human Rad52 in Rad51-Nucleoprotein Filament Formation and ssDNA Annealing. PLoS One 2016; 11:e0158436. [PMID: 27362509 PMCID: PMC4928909 DOI: 10.1371/journal.pone.0158436] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 06/15/2016] [Indexed: 11/19/2022] Open
Abstract
Yeast Rad52 (yRad52) has two important functions at homologous DNA recombination (HR); annealing complementary single-strand DNA (ssDNA) molecules and recruiting Rad51 recombinase onto ssDNA (recombination mediator activity). Its human homolog (hRAD52) has a lesser role in HR, and apparently lacks mediator activity. Here we show that yRad52 can load human Rad51 (hRAD51) onto ssDNA complexed with yeast RPA in vitro. This is biochemically equivalent to mediator activity because it depends on the C-terminal Rad51-binding region of yRad52 and on functional Rad52-RPA interaction. It has been reported that the N-terminal two thirds of both yRad52 and hRAD52 is essential for binding to and annealing ssDNA. Although a second DNA binding region has been found in the C-terminal region of yRad52, its role in ssDNA annealing is not clear. In this paper, we also show that the C-terminal region of yRad52, but not of hRAD52, is involved in ssDNA annealing. This suggests that the second DNA binding site is required for the efficient ssDNA annealing by yRad52. We propose an updated model of Rad52-mediated ssDNA annealing.
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80
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Mechanism for accurate, protein-assisted DNA annealing by Deinococcus radiodurans DdrB. Proc Natl Acad Sci U S A 2016; 113:4308-13. [PMID: 27044084 DOI: 10.1073/pnas.1520847113] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Accurate pairing of DNA strands is essential for repair of DNA double-strand breaks (DSBs). How cells achieve accurate annealing when large regions of single-strand DNA are unpaired has remained unclear despite many efforts focused on understanding proteins, which mediate this process. Here we report the crystal structure of a single-strand annealing protein [DdrB (DNA damage response B)] in complex with a partially annealed DNA intermediate to 2.2 Å. This structure and supporting biochemical data reveal a mechanism for accurate annealing involving DdrB-mediated proofreading of strand complementarity. DdrB promotes high-fidelity annealing by constraining specific bases from unauthorized association and only releases annealed duplex when bound strands are fully complementary. To our knowledge, this mechanism provides the first understanding for how cells achieve accurate, protein-assisted strand annealing under biological conditions that would otherwise favor misannealing.
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81
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Structure and mechanism of the phage T4 recombination mediator protein UvsY. Proc Natl Acad Sci U S A 2016; 113:3275-80. [PMID: 26951671 DOI: 10.1073/pnas.1519154113] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The UvsY recombination mediator protein is critical for efficient homologous recombination in bacteriophage T4 and is the functional analog of the eukaryotic Rad52 protein. During T4 homologous recombination, the UvsX recombinase has to compete with the prebound gp32 single-stranded binding protein for DNA-binding sites and UvsY stimulates this filament nucleation event. We report here the crystal structure of UvsY in four similar open-barrel heptameric assemblies and provide structural and biophysical insights into its function. The UvsY heptamer was confirmed in solution by centrifugation and light scattering, and thermodynamic analyses revealed that the UvsY-ssDNA interaction occurs within the assembly via two distinct binding modes. Using surface plasmon resonance, we also examined the binding of UvsY to both ssDNA and the ssDNA-gp32 complex. These analyses confirmed that ssDNA can bind UvsY and gp32 independently and also as a ternary complex. They also showed that residues located on the rim of the heptamer are required for optimal binding to ssDNA, thus identifying the putative ssDNA-binding surface. We propose a model in which UvsY promotes a helical ssDNA conformation that disfavors the binding of gp32 and initiates the assembly of the ssDNA-UvsX filament.
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82
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Huang F, Goyal N, Sullivan K, Hanamshet K, Patel M, Mazina OM, Wang CX, An WF, Spoonamore J, Metkar S, Emmitte KA, Cocklin S, Skorski T, Mazin AV. Targeting BRCA1- and BRCA2-deficient cells with RAD52 small molecule inhibitors. Nucleic Acids Res 2016; 44:4189-99. [PMID: 26873923 PMCID: PMC4872086 DOI: 10.1093/nar/gkw087] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 02/03/2016] [Indexed: 12/20/2022] Open
Abstract
RAD52 is a member of the homologous recombination (HR) pathway that is important for maintenance of genome integrity. While single RAD52 mutations show no significant phenotype in mammals, their combination with mutations in genes that cause hereditary breast cancer and ovarian cancer like BRCA1, BRCA2, PALB2 and RAD51C are lethal. Consequently, RAD52 may represent an important target for cancer therapy. In vitro, RAD52 has ssDNA annealing and DNA strand exchange activities. Here, to identify small molecule inhibitors of RAD52 we screened a 372,903-compound library using a fluorescence-quenching assay for ssDNA annealing activity of RAD52. The obtained 70 putative inhibitors were further characterized using biochemical and cell-based assays. As a result, we identified compounds that specifically inhibit the biochemical activities of RAD52, suppress growth of BRCA1- and BRCA2-deficient cells and inhibit RAD52-dependent single-strand annealing (SSA) in human cells. We will use these compounds for development of novel cancer therapy and as a probe to study mechanisms of DNA repair.
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Affiliation(s)
- Fei Huang
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Nadish Goyal
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Katherine Sullivan
- Department of Microbiology and Immunology, and Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 10140, USA
| | - Kritika Hanamshet
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Mikir Patel
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Olga M Mazina
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Charles X Wang
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - W Frank An
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - James Spoonamore
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Shailesh Metkar
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Kyle A Emmitte
- Vanderbilt Specialized Chemistry Center for Accelerated Probe Development, Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology and Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Simon Cocklin
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Tomasz Skorski
- Department of Microbiology and Immunology, and Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 10140, USA
| | - Alexander V Mazin
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
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83
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Sullivan K, Cramer-Morales K, McElroy DL, Ostrov DA, Haas K, Childers W, Hromas R, Skorski T. Identification of a Small Molecule Inhibitor of RAD52 by Structure-Based Selection. PLoS One 2016; 11:e0147230. [PMID: 26784987 PMCID: PMC4718542 DOI: 10.1371/journal.pone.0147230] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/30/2015] [Indexed: 11/18/2022] Open
Abstract
It has been reported that inhibition of RAD52 either by specific shRNA or a small peptide aptamer induced synthetic lethality in tumor cell lines carrying BRCA1 and BRCA2 inactivating mutations. Molecular docking was used to screen two chemical libraries: 1) 1,217 FDA approved drugs, and 2) 139,735 drug-like compounds to identify candidates for interacting with DNA binding domain of human RAD52. Thirty six lead candidate compounds were identified that were predicted to interfere with RAD52 –DNA binding. Further biological testing confirmed that 9 of 36 candidate compounds were able to inhibit the binding of RAD52 to single-stranded DNA in vitro. Based on molecular binding combined with functional assays, we propose a model in which the active compounds bind to a critical “hotspot” in RAD52 DNA binding domain 1. In addition, one of the 9 active compounds, adenosine 5’-monophosphate (A5MP), and also its mimic 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) 5’ phosphate (ZMP) inhibited RAD52 activity in vivo and exerted synthetic lethality against BRCA1 and BRCA2–mutated carcinomas. These data suggest that active, inhibitory RAD52 binding compounds could be further refined for efficacy and safety to develop drugs inducing synthetic lethality in tumors displaying deficiencies in BRCA1/2-mediated homologous recombination.
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Affiliation(s)
- Katherine Sullivan
- Department of Microbiology and Immunology and Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, United States of America
| | - Kimberly Cramer-Morales
- Department of Microbiology and Immunology and Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, United States of America
| | - Daniel L. McElroy
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida & Shands, Gainesville, Florida 32610, United States of America
| | - David A. Ostrov
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida & Shands, Gainesville, Florida 32610, United States of America
| | - Kimberly Haas
- Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, Pennsylvania 19140, United States of America
| | - Wayne Childers
- Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, Pennsylvania 19140, United States of America
| | - Robert Hromas
- Department of Medicine, College of Medicine, University of Florida & Shands, Gainesville, Florida 32610, United States of America
| | - Tomasz Skorski
- Department of Microbiology and Immunology and Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, United States of America
- * E-mail:
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84
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Smith CE, Bell CE. Domain Structure of the Redβ Single-Strand Annealing Protein: the C-terminal Domain is Required for Fine-Tuning DNA-binding Properties, Interaction with the Exonuclease Partner, and Recombination in vivo. J Mol Biol 2016; 428:561-578. [PMID: 26780547 DOI: 10.1016/j.jmb.2016.01.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 12/19/2015] [Accepted: 01/12/2016] [Indexed: 11/28/2022]
Abstract
Redβ is a component of the Red recombination system of bacteriophage λ that promotes a single strand annealing (SSA) reaction to generate end-to-end concatemers of the phage genome for packaging. Redβ interacts with λ exonuclease (λexo), the other component of the Red system, to form a "synaptosome" complex that somehow integrates the end resection and annealing steps of the reaction. Previous work using limited proteolysis and chemical modification revealed that Redβ consists of an N-terminal DNA binding domain, residues 1-177, and a flexible C-terminal "tail", residues 178-261. Here, we quantitatively compare the binding of the full-length protein (Redβ(FL)) and the N-terminal domain (Redβ(177)) to different lengths of ssDNA substrate and annealed duplex product. We find that in general, Redβ(FL) binds more tightly to annealed duplex product than to ssDNA substrate, while Redβ(177) binds more tightly to ssDNA. In addition, the C-terminal region of Redβ corresponding to residues 182-261 was purified and found to fold into an α-helical domain that is required for the interaction with λexo to form the synaptosome complex. Deletion analysis of Redβ revealed that removal of just eleven residues from the C-terminus disrupts the interaction with λexo as well as ssDNA and dsDNA recombination in vivo. By contrast, the determinants for self-oligomerization of Redβ appear to reside solely within the N-terminal domain. The subtle but significant differences in the relative binding of Redβ(FL) and Redβ(177) to ssDNA substrate and annealed duplex product may be important for Redβ to function as a SSA protein in vivo.
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Affiliation(s)
- Christopher E Smith
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA; Department of Biological Chemistry and Pharmacology, The Ohio State University College of Medicine, Columbus, Ohio 43210
| | - Charles E Bell
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA; Department of Biological Chemistry and Pharmacology, The Ohio State University College of Medicine, Columbus, Ohio 43210; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210.
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85
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Mekkawy MK, Mazen IM, Kamel AK, Vater I, Zaki MS. Genotype/phenotype correlation in a female patient with 21q22.3 and 12p13.33 duplications. Am J Med Genet A 2016; 170A:1050-8. [PMID: 26749249 DOI: 10.1002/ajmg.a.37523] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Accepted: 11/25/2015] [Indexed: 01/10/2023]
Abstract
Many chromosomal rearrangements that lead to copy-number gains or losses have been shown to cause distinctive and recognizable clinical phenotypes. Conventional cytogenetic analysis can detect many, but not all, rearrangements depending on its power of resolution. The wide use of whole-genome array-based comparative genomic hybridization (array-CGH) techniques has allowed the detection of novel syndromes and to establish genotype-phenotype correlations by delineating at high resolution the regions involved in specific chromosomal aberrations. We report on a two and half-year-old female patient with intellectual disability and distinctive phenotypic features resulting from a de novo duplication of about 0.3 Mb in 21q22.3 associated with duplication of about 0.3 Mb in 12p13.33. The patient's chromosomal abnormalities were identified at the cytogenetic molecular level, using SNP array analysis, while GTG banding technique revealed a normal karyotype. Clinical findings of the patient were compared with Down syndrome and 12p duplication syndrome. This study suggests that an area of contiguous genes on the distal part of chromosome 21 (21q22.3) contribute to the Down syndrome phenotype and indicates that genes in the distal region of 12p (12p13.33) account for many facial characteristics and hypotonia of trisomy 12p syndrome.
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Affiliation(s)
- Mona K Mekkawy
- Division of Human Genetics and Genome Research, Department of Human Cytogenetics, National Research Centre, Cairo, Egypt
| | - Inas M Mazen
- Division of Human Genetics and Genome Research, Department of Clinical Genetics, National Research Centre, Cairo, Egypt
| | - Alaa K Kamel
- Division of Human Genetics and Genome Research, Department of Human Cytogenetics, National Research Centre, Cairo, Egypt
| | - Inga Vater
- Institute of Human Genetics, Christian-Albrechts-University Kiel and University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Maha S Zaki
- Division of Human Genetics and Genome Research, Department of Clinical Genetics, National Research Centre, Cairo, Egypt
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86
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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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87
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Chandramouly G, McDevitt S, Sullivan K, Kent T, Luz A, Glickman JF, Andrake M, Skorski T, Pomerantz RT. Small-Molecule Disruption of RAD52 Rings as a Mechanism for Precision Medicine in BRCA-Deficient Cancers. ACTA ACUST UNITED AC 2015; 22:1491-1504. [PMID: 26548611 DOI: 10.1016/j.chembiol.2015.10.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 09/08/2015] [Accepted: 10/04/2015] [Indexed: 11/27/2022]
Abstract
Suppression of RAD52 causes synthetic lethality in BRCA-deficient cells. Yet pharmacological inhibition of RAD52, which binds single-strand DNA (ssDNA) and lacks enzymatic activity, has not been demonstrated. Here, we identify the small molecule 6-hydroxy-DL-dopa (6-OH-dopa) as a major allosteric inhibitor of the RAD52 ssDNA binding domain. For example, we find that multiple small molecules bind to and completely transform RAD52 undecamer rings into dimers, which abolishes the ssDNA binding channel observed in crystal structures. 6-OH-Dopa also disrupts RAD52 heptamer and undecamer ring superstructures, and suppresses RAD52 recruitment and recombination activity in cells with negligible effects on other double-strand break repair pathways. Importantly, we show that 6-OH-dopa selectively inhibits the proliferation of BRCA-deficient cancer cells, including those obtained from leukemia patients. Taken together, these data demonstrate small-molecule disruption of RAD52 rings as a promising mechanism for precision medicine in BRCA-deficient cancers.
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Affiliation(s)
- Gurushankar Chandramouly
- Department of Medical Genetics and Molecular Biochemistry, Fels Institute for Cancer Research, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Shane McDevitt
- Department of Medical Genetics and Molecular Biochemistry, Fels Institute for Cancer Research, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Katherine Sullivan
- Department of Microbiology and Immunology, Fels Institute for Cancer Research, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Tatiana Kent
- Department of Medical Genetics and Molecular Biochemistry, Fels Institute for Cancer Research, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Antonio Luz
- High-Throughput and Spectroscopy Resource Center, The Rockefeller University, New York, NY 10065, USA
| | - J Fraser Glickman
- High-Throughput and Spectroscopy Resource Center, The Rockefeller University, New York, NY 10065, USA
| | - Mark Andrake
- Institute for Cancer Research, Fox Chase Cancer Center, Temple Health, Philadelphia, PA 19111, USA
| | - Tomasz Skorski
- Department of Microbiology and Immunology, Fels Institute for Cancer Research, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Richard T Pomerantz
- Department of Medical Genetics and Molecular Biochemistry, Fels Institute for Cancer Research, Temple University School of Medicine, Philadelphia, PA 19140, USA.
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88
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Ander M, Subramaniam S, Fahmy K, Stewart AF, Schäffer E. A Single-Strand Annealing Protein Clamps DNA to Detect and Secure Homology. PLoS Biol 2015; 13:e1002213. [PMID: 26271032 PMCID: PMC4535883 DOI: 10.1371/journal.pbio.1002213] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 06/26/2015] [Indexed: 11/24/2022] Open
Abstract
Repair of DNA breaks by single-strand annealing (SSA) is a major mechanism for the maintenance of genomic integrity. SSA is promoted by proteins (single-strand-annealing proteins [SSAPs]), such as eukaryotic RAD52 and λ phage Redβ. These proteins use a short single-stranded region to find sequence identity and initiate homologous recombination. However, it is unclear how SSAPs detect homology and catalyze annealing. Using single-molecule experiments, we provide evidence that homology is recognized by Redβ monomers that weakly hold single DNA strands together. Once annealing begins, dimerization of Redβ clamps the double-stranded region and nucleates nucleoprotein filament growth. In this manner, DNA clamping ensures and secures a successful detection for DNA sequence homology. The clamp is characterized by a structural change of Redβ and a remarkable stability against force up to 200 pN. Our findings not only present a detailed explanation for SSAP action but also identify the DNA clamp as a very stable, noncovalent, DNA-protein interaction.
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Affiliation(s)
- Marcel Ander
- Nanomechanics Group, Biotechnology Center, TU Dresden, Dresden, Germany
| | | | - Karim Fahmy
- Division of Biophysics, Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - A. Francis Stewart
- Department of Genomics, Biotechnology Center, TU Dresden, Dresden, Germany
| | - Erik Schäffer
- Nanomechanics Group, Biotechnology Center, TU Dresden, Dresden, Germany
- Cellular Nanoscience, Center for Plant Molecular Biology (ZMBP), Universität Tübingen, Tübingen, Germany
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89
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Abstract
Homology-dependent exchange of genetic information between DNA molecules has a profound impact on the maintenance of genome integrity by facilitating error-free DNA repair, replication, and chromosome segregation during cell division as well as programmed cell developmental events. This chapter will focus on homologous mitotic recombination in budding yeast Saccharomyces cerevisiae. However, there is an important link between mitotic and meiotic recombination (covered in the forthcoming chapter by Hunter et al. 2015) and many of the functions are evolutionarily conserved. Here we will discuss several models that have been proposed to explain the mechanism of mitotic recombination, the genes and proteins involved in various pathways, the genetic and physical assays used to discover and study these genes, and the roles of many of these proteins inside the cell.
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90
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Gleghorn ML, Maquat LE. 'Black sheep' that don't leave the double-stranded RNA-binding domain fold. Trends Biochem Sci 2014; 39:328-40. [PMID: 24954387 DOI: 10.1016/j.tibs.2014.05.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 05/19/2014] [Accepted: 05/19/2014] [Indexed: 12/28/2022]
Abstract
The canonical double-stranded RNA (dsRNA)-binding domain (dsRBD) is composed of an α1-β1-β2-β3-α2 secondary structure that folds in three dimensions to recognize dsRNA. Recently, structural and functional studies of divergent dsRBDs revealed adaptations that include intra- and/or intermolecular protein interactions, sometimes in the absence of detectable dsRNA-binding ability. We describe here how discrete dsRBD components can accommodate pronounced amino-acid sequence changes while maintaining the core fold. We exemplify the growing importance of divergent dsRBDs in mRNA decay by discussing Dicer, Staufen (STAU)1 and 2, trans-activation responsive RNA-binding protein (TARBP)2, protein activator of protein kinase RNA-activated (PKR) (PACT), DiGeorge syndrome critical region (DGCR)8, DEAH box helicase proteins (DHX) 9 and 30, and dsRBD-like fold-containing proteins that have ribosome-related functions. We also elaborate on the computational limitations to discovering yet-to-be-identified divergent dsRBDs.
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Affiliation(s)
- Michael L Gleghorn
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA.
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91
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Mechanism of homologous recombination and implications for aging-related deletions in mitochondrial DNA. Microbiol Mol Biol Rev 2014; 77:476-96. [PMID: 24006472 DOI: 10.1128/mmbr.00007-13] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Homologous recombination is a universal process, conserved from bacteriophage to human, which is important for the repair of double-strand DNA breaks. Recombination in mitochondrial DNA (mtDNA) was documented more than 4 decades ago, but the underlying molecular mechanism has remained elusive. Recent studies have revealed the presence of a Rad52-type recombination system of bacteriophage origin in mitochondria, which operates by a single-strand annealing mechanism independent of the canonical RecA/Rad51-type recombinases. Increasing evidence supports the notion that, like in bacteriophages, mtDNA inheritance is a coordinated interplay between recombination, repair, and replication. These findings could have profound implications for understanding the mechanism of mtDNA inheritance and the generation of mtDNA deletions in aging cells.
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92
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Matsubara K, Malay AD, Curtis FA, Sharples GJ, Heddle JG. Structural and functional characterization of the Redβ recombinase from bacteriophage λ. PLoS One 2013; 8:e78869. [PMID: 24244379 PMCID: PMC3823998 DOI: 10.1371/journal.pone.0078869] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 09/23/2013] [Indexed: 11/18/2022] Open
Abstract
The Red system of bacteriophage λ is responsible for the genetic rearrangements that contribute to its rapid evolution and has been successfully harnessed as a research tool for genome manipulation. The key recombination component is Redβ, a ring-shaped protein that facilitates annealing of complementary DNA strands. Redβ shares functional similarities with the human Rad52 single-stranded DNA (ssDNA) annealing protein although their evolutionary relatedness is not well established. Alignment of Rad52 and Redβ sequences shows an overall low level of homology, with 15% identity in the N-terminal core domains as well as important similarities with the Rad52 homolog Sak from phage ul36. Key conserved residues were chosen for mutagenesis and their impact on oligomer formation, ssDNA binding and annealing was probed. Two conserved regions were identified as sites important for binding ssDNA; a surface basic cluster and an intersubunit hydrophobic patch, consistent with findings for Rad52. Surprisingly, mutation of Redβ residues in the basic cluster that in Rad52 are involved in ssDNA binding disrupted both oligomer formation and ssDNA binding. Mutations in the equivalent of the intersubunit hydrophobic patch in Rad52 did not affect Redβ oligomerization but did impair DNA binding and annealing. We also identified a single amino acid substitution which had little effect on oligomerization and DNA binding but which inhibited DNA annealing, indicating that these two functions of Redβ can be separated. Taken together, the results provide fresh insights into the structural basis for Redβ function and the important role of quaternary structure.
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Affiliation(s)
| | - Ali D. Malay
- Heddle Initiative Research Unit, RIKEN, Wako, Saitama, Japan
| | - Fiona A. Curtis
- School of Biological and Biomedical Sciences, Department of Chemistry, Durham University, Durham, United Kingdom
| | - Gary J. Sharples
- School of Biological and Biomedical Sciences, Department of Chemistry, Durham University, Durham, United Kingdom
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93
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Sugiman-Marangos SN, Peel JK, Weiss YM, Ghirlando R, Junop MS. Crystal structure of the DdrB/ssDNA complex from Deinococcus radiodurans reveals a DNA binding surface involving higher-order oligomeric states. Nucleic Acids Res 2013; 41:9934-44. [PMID: 23975200 PMCID: PMC3834827 DOI: 10.1093/nar/gkt759] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The ability of Deinococcus radiodurans to recover from extensive DNA damage is due in part to its ability to efficiently repair its genome, even following severe fragmentation by hundreds of double-strand breaks. The single-strand annealing pathway plays an important role early during the recovery process, making use of a protein, DdrB, shown to greatly stimulate ssDNA annealing. Here, we report the structure of DdrB bound to ssDNA to 2.3 Å. Pentameric DdrB was found to assemble into higher-order structures that coat ssDNA. To gain further mechanistic insight into the protein's function, a number of point mutants were generated altering both DNA binding and higher order oligomerization. This work not only identifies higher-order DdrB associations but also suggests the presence of an extended DNA binding surface running along the 'top' surface of a DdrB pentamer and continuing down between two individual subunits of the ring structure. Together this work sheds new insight into possible mechanisms for DdrB function in which higher-order assemblies of DdrB pentamers assist in the pairing of complementary ssDNA using an extended DNA binding surface.
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Affiliation(s)
- Seiji N. Sugiman-Marangos
- Department of Biochemistry and Biomedical Sciences and M. G. DeGroote Institute for Infectious Disease Research, McMaster University, 1200 Main Street West, Hamilton, Ontario L8N 3Z5, Canada and Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Center Drive, Bethesda, MD 20892, USA
| | - John K. Peel
- Department of Biochemistry and Biomedical Sciences and M. G. DeGroote Institute for Infectious Disease Research, McMaster University, 1200 Main Street West, Hamilton, Ontario L8N 3Z5, Canada and Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Center Drive, Bethesda, MD 20892, USA
| | - Yoni M. Weiss
- Department of Biochemistry and Biomedical Sciences and M. G. DeGroote Institute for Infectious Disease Research, McMaster University, 1200 Main Street West, Hamilton, Ontario L8N 3Z5, Canada and Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Center Drive, Bethesda, MD 20892, USA
| | - Rodolfo Ghirlando
- Department of Biochemistry and Biomedical Sciences and M. G. DeGroote Institute for Infectious Disease Research, McMaster University, 1200 Main Street West, Hamilton, Ontario L8N 3Z5, Canada and Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Center Drive, Bethesda, MD 20892, USA
| | - Murray S. Junop
- Department of Biochemistry and Biomedical Sciences and M. G. DeGroote Institute for Infectious Disease Research, McMaster University, 1200 Main Street West, Hamilton, Ontario L8N 3Z5, Canada and Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Center Drive, Bethesda, MD 20892, USA,*To whom correspondence should be addressed. Tel: +1 905 525 9140 (ext 22912); Fax: +1 905 522 9033;
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94
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Kagawa W, Arai N, Ichikawa Y, Saito K, Sugiyama S, Saotome M, Shibata T, Kurumizaka H. Functional analyses of the C-terminal half of the Saccharomyces cerevisiae Rad52 protein. Nucleic Acids Res 2013; 42:941-51. [PMID: 24163251 PMCID: PMC3902949 DOI: 10.1093/nar/gkt986] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Saccharomyces cerevisiae Rad52 protein is essential for efficient homologous recombination (HR). An important role of Rad52 in HR is the loading of Rad51 onto replication protein A-coated single-stranded DNA (ssDNA), which is referred to as the recombination mediator activity. In vitro, Rad52 displays additional activities, including self-association, DNA binding and ssDNA annealing. Although Rad52 has been a subject of extensive genetic, biochemical and structural studies, the mechanisms by which these activities are coordinated in the various roles of Rad52 in HR remain largely unknown. In the present study, we found that an isolated C-terminal half of Rad52 disrupted the Rad51 oligomer and formed a heterodimeric complex with Rad51. The Rad52 fragment inhibited the binding of Rad51 to double-stranded DNA, but not to ssDNA. The phenylalanine-349 and tyrosine-409 residues present in the C-terminal half of Rad52 were critical for the interaction with Rad51, the disruption of Rad51 oligomers, the mediator activity of the full-length protein and for DNA repair in vivo in the presence of methyl methanesulfonate. Our studies suggested that phenylalanine-349 and tyrosine-409 are key residues in the C-terminal half of Rad52 and probably play an important role in the mediator activity.
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Affiliation(s)
- Wataru Kagawa
- Department of Interdisciplinary Science and Engineering, Program in Chemistry and Life Science, School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino-shi, Tokyo 191-8506, Japan, Department of Applied Biological Science, Nihon University College of Bioresource Sciences, Fujisawa-shi, Kanagawa 252-0880, Japan, Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan and Cellular and Molecular Biology Laboratory, RIKEN, Wako-shi, Saitama 351-0198, Japan
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95
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Liddell LC, Manthey GM, Owens SN, Fu BXH, Bailis AM. Alleles of the homologous recombination gene, RAD59, identify multiple responses to disrupted DNA replication in Saccharomyces cerevisiae. BMC Microbiol 2013; 13:229. [PMID: 24125552 PMCID: PMC3852934 DOI: 10.1186/1471-2180-13-229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 10/04/2013] [Indexed: 11/26/2022] Open
Abstract
Background In Saccharomyces cerevisiae, Rad59 is required for multiple homologous recombination mechanisms and viability in DNA replication-defective rad27 mutant cells. Recently, four rad59 missense alleles were found to have distinct effects on homologous recombination that are consistent with separation-of-function mutations. The rad59-K166A allele alters an amino acid in a conserved α-helical domain, and, like the rad59 null allele diminishes association of Rad52 with double-strand breaks. The rad59-K174A and rad59-F180A alleles alter amino acids in the same domain and have genetically similar effects on homologous recombination. The rad59-Y92A allele alters a conserved amino acid in a separate domain, has genetically distinct effects on homologous recombination, and does not diminish association of Rad52 with double-strand breaks. Results In this study, rad59 mutant strains were crossed with a rad27 null mutant to examine the effects of the rad59 alleles on the link between viability, growth and the stimulation of homologous recombination in replication-defective cells. Like the rad59 null allele, rad59-K166A was synthetically lethal in combination with rad27. The rad59-K174A and rad59-F180A alleles were not synthetically lethal in combination with rad27, had effects on growth that coincided with decreased ectopic gene conversion, but did not affect mutation, unequal sister-chromatid recombination, or loss of heterozygosity. The rad59-Y92A allele was not synthetically lethal when combined with rad27, stimulated ectopic gene conversion and heteroallelic recombination independently from rad27, and was mutually epistatic with srs2. Unlike rad27, the stimulatory effect of rad59-Y92A on homologous recombination was not accompanied by effects on growth rate, cell cycle distribution, mutation, unequal sister-chromatid recombination, or loss of heterozygosity. Conclusions The synthetic lethality conferred by rad59 null and rad59-K166A alleles correlates with their inhibitory effect on association of Rad52 with double-strand breaks, suggesting that this may be essential for rescuing replication lesions in rad27 mutant cells. The rad59-K174A and rad59-F180A alleles may fractionally reduce this same function, which proportionally reduced repair of replication lesions by homologous recombination and growth rate. In contrast, rad59-Y92A stimulates homologous recombination, perhaps by affecting association of replication lesions with the Rad51 recombinase. This suggests that Rad59 influences the rescue of replication lesions by multiple recombination factors.
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Affiliation(s)
- Lauren C Liddell
- Department of Molecular and Cellular Biology, Beckman Research Institute of the City of Hope, 91010 Duarte, CA, USA.
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96
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Personalized synthetic lethality induced by targeting RAD52 in leukemias identified by gene mutation and expression profile. Blood 2013; 122:1293-304. [PMID: 23836560 DOI: 10.1182/blood-2013-05-501072] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Homologous recombination repair (HRR) protects cells from the lethal effect of spontaneous and therapy-induced DNA double-stand breaks. HRR usually depends on BRCA1/2-RAD51, and RAD52-RAD51 serves as back-up. To target HRR in tumor cells, a phenomenon called "synthetic lethality" was applied, which relies on the addiction of cancer cells to a single DNA repair pathway, whereas normal cells operate 2 or more mechanisms. Using mutagenesis and a peptide aptamer approach, we pinpointed phenylalanine 79 in RAD52 DNA binding domain I (RAD52-phenylalanine 79 [F79]) as a valid target to induce synthetic lethality in BRCA1- and/or BRCA2-deficient leukemias and carcinomas without affecting normal cells and tissues. Targeting RAD52-F79 disrupts the RAD52-DNA interaction, resulting in the accumulation of toxic DNA double-stand breaks in malignant cells, but not in normal counterparts. In addition, abrogation of RAD52-DNA interaction enhanced the antileukemia effect of already-approved drugs. BRCA-deficient status predisposing to RAD52-dependent synthetic lethality could be predicted by genetic abnormalities such as oncogenes BCR-ABL1 and PML-RAR, mutations in BRCA1 and/or BRCA2 genes, and gene expression profiles identifying leukemias displaying low levels of BRCA1 and/or BRCA2. We believe this work may initiate a personalized therapeutic approach in numerous patients with tumors displaying encoded and functional BRCA deficiency.
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97
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Tolun G, Makhov AM, Ludtke SJ, Griffith JD. Details of ssDNA annealing revealed by an HSV-1 ICP8-ssDNA binary complex. Nucleic Acids Res 2013; 41:5927-37. [PMID: 23605044 PMCID: PMC3675482 DOI: 10.1093/nar/gkt266] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Infected cell protein 8 (ICP8) from herpes simplex virus 1 was first identified as a single-strand (ss) DNA-binding protein. It is essential for, and abundant during, viral replication. Studies in vitro have shown that ICP8 stimulates model replication reactions, catalyzes annealing of complementary ssDNAs and, in combination with UL12 exonuclease, will catalyze ssDNA annealing homologous recombination. DNA annealing and strand transfer occurs within large oligomeric filaments of ssDNA-bound ICP8. We present the first 3D reconstruction of a novel ICP8-ssDNA complex, which seems to be the basic unit of the DNA annealing machine. The reconstructed volume consists of two nonameric rings containing ssDNA stacked on top of each other, corresponding to a molecular weight of 2.3 MDa. Fitting of the ICP8 crystal structure suggests a mechanism for the annealing reaction catalyzed by ICP8, which is most likely a general mechanism for protein-driven DNA annealing.
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Affiliation(s)
- Gökhan Tolun
- Lineberger Comprehensive Cancer Center, and Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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98
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Mbantenkhu M, Wierzbicki S, Wang X, Guo S, Wilkens S, Chen XJ. A short carboxyl-terminal tail is required for single-stranded DNA binding, higher-order structural organization, and stability of the mitochondrial single-stranded annealing protein Mgm101. Mol Biol Cell 2013; 24:1507-18. [PMID: 23536705 PMCID: PMC3655812 DOI: 10.1091/mbc.e13-01-0006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Mgm101 is a Rad52-type single-stranded annealing protein (SSAP) required for mitochondrial DNA (mtDNA) repair and maintenance. Structurally, Mgm101 forms large oligomeric rings. Here we determine the function(s) of a 32-amino acid carboxyl-terminal tail (Mgm101(238-269)) conserved in the Mgm101 family of proteins. Mutagenic analysis shows that Lys-253, Trp-257, Arg-259, and Tyr-268 are essential for mtDNA maintenance. Mutations in Lys-251, Arg-252, Lys-260, and Tyr-266 affect mtDNA stability at 37°C and under oxidative stress. The Y268A mutation severely affects single-stranded DNA (ssDNA) binding without altering the ring structure. Mutations in the Lys-251-Arg-252-Lys-253 positive triad also affect ssDNA binding. Moreover, the C-tail alone is sufficient to mediate ssDNA binding. Finally, we find that the W257A and R259A mutations dramatically affect the conformation and oligomeric state of Mgm101. These structural alterations correlate with protein degradation in vivo. The data thus indicate that the C-tail of Mgm101, likely displayed on the ring surface, is required for ssDNA binding, higher-order structural organization, and protein stability. We speculate that an initial electrostatic and base-stacking interaction with ssDNA could remodel ring organization. This may facilitate the formation of nucleoprotein filaments competent for mtDNA repair. These findings could have broad implications for understanding how SSAPs promote DNA repair and genome maintenance.
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Affiliation(s)
- MacMillan Mbantenkhu
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
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There and back again: new single-molecule insights in the motion of DNA repair proteins. Curr Opin Struct Biol 2012; 23:154-60. [PMID: 23260129 DOI: 10.1016/j.sbi.2012.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 11/26/2012] [Accepted: 11/27/2012] [Indexed: 11/24/2022]
Abstract
Cellular DNA repair machines are constantly at work supporting the integrity of our genomes. Numerous proteins cooperate to form a complex and adaptive system dedicated to detection and timely processing of DNA damage. The molecular underpinnings of how these proteins locate and discriminate DNA lesions, match homologous sequences, mend the DNA and attend to a replication in distress are of a paramount biomedical importance, but in many cases remain unclear. Combined with more conventional tools, single-molecule biochemistry has been stepping in to address the age-old problems in the DNA repair field. This review will address new insights into diffusive properties of three DNA repair systems: I will discuss the emerging model of how MutS homologues locate and respond to mismatches in the dsDNA; the mechanism by which RAD52 promotes annealing of complementary DNA strands coated with ssDNA binding protein RPA; and how the nucleoprotein filament formed by RecA recombinase on ssDNA searches for homology within duplex DNA. These three distinct DNA repair factors exemplify the dynamic nature of cellular DNA repair machines revealed by single-molecule studies.
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Lok BH, Powell SN. Molecular pathways: understanding the role of Rad52 in homologous recombination for therapeutic advancement. Clin Cancer Res 2012; 18:6400-6. [PMID: 23071261 PMCID: PMC3513650 DOI: 10.1158/1078-0432.ccr-11-3150] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The Rad52 protein was largely ignored in humans and other mammals when the mouse knockout revealed a largely "no-effect" phenotype. However, using synthetic lethal approaches to investigate context-dependent function, new studies have shown that Rad52 plays a key survival role in cells lacking the function of the breast cancer type 1 susceptibility protein (BRCA1)-BRCA2 pathway of homologous recombination. Biochemical studies also showed significant differences between yeast and human Rad52 (hRad52), in which yeast Rad52 can promote strand invasion of replication protein A (RPA)-coated single-stranded DNA (ssDNA) in the presence of Rad51 but hRad52 cannot. This results in the paradox of how is hRad52 providing Rad51 function: presumably there is something missing in the biochemical assays that exists in vivo, but the nature of this missing factor is currently unknown. Recent studies have suggested that Rad52 provides back-up Rad51 function for all members of the BRCA1-BRCA2 pathway, suggesting that Rad52 may be a target for therapy in BRCA pathway-deficient cancers. Screening for ways to inhibit Rad52 would potentially provide a complementary strategy for targeting BRCA-deficient cancers in addition to poly (ADP-ribose) polymerase (PARP) inhibitors.
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Affiliation(s)
- Benjamin H. Lok
- Memorial Sloan-Kettering Cancer Center, New York, NY
- New York University School of Medicine, New York, NY
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