1
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Gao F, Dong JH, Xue C, Lu XX, Cai Y, Tang ZY, Ou CJ. Tumor-Targeting Multiple Metabolic Regulations for Bursting Antitumor Efficacy of Chemodynamic Therapy. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2310248. [PMID: 38234145 DOI: 10.1002/smll.202310248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/04/2024] [Indexed: 01/19/2024]
Abstract
Interfering with intratumoral metabolic processes is proven to effectively sensitize different antitumor treatments. Here, a tumor-targeting catalytic nanoplatform (CQ@MIL-GOX@PB) loading with autophagy inhibitor (chloroquine, CQ) and glucose oxidase (GOX) is fabricated to interfere with the metabolisms of tumor cells and tumor-associated macrophages (TAMs), then realizing effective antitumor chemodynamic therapy (CDT). Once accumulating in the tumor site with the navigation of external biotin, CQ@MIL-GOX@PB will release Fe ions and CQ in the acid lysosomes of tumor cells, the latter can sensitize Fe ions-involved antitumor CDT by blocking the autophagy-dependent cell repair. Meanwhile, the GOX component will consume glucose, which not only generates many H2O2 for CDT but also once again decelerates the tumor repair process by reducing energy metabolism. What is more, the release of CQ can also drive the NO anabolism of TAMs to further sensitize CDT. This strategy of multiple metabolic regulations is evidenced to significantly improve the antitumor effect of traditional CDT nanoagents and might provide a new sight to overcome the bottlenecks of different antitumor treatments.
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Affiliation(s)
- Fan Gao
- Institute of Advanced Materials and Flexible Electronics (IAMFE), School of Chemistry and Materials Science, Nanjing University of Information Science & Technology, Nanjing, 210044, P. R. China
| | - Jian-Hui Dong
- Institute of Advanced Materials and Flexible Electronics (IAMFE), School of Chemistry and Materials Science, Nanjing University of Information Science & Technology, Nanjing, 210044, P. R. China
| | - Chun Xue
- Institute of Advanced Materials and Flexible Electronics (IAMFE), School of Chemistry and Materials Science, Nanjing University of Information Science & Technology, Nanjing, 210044, P. R. China
| | - Xin-Xin Lu
- Institute of Advanced Materials and Flexible Electronics (IAMFE), School of Chemistry and Materials Science, Nanjing University of Information Science & Technology, Nanjing, 210044, P. R. China
| | - Yu Cai
- Center for Rehabilitation Medicine, Rehabilitation & Sports Medicine Research Institute of Zhejiang Province, Department of Rehabilitation Medicine, Cancer Center, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, 310014, P. R. China
| | - Zi-Yang Tang
- Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, The Clinical College of Nanjing Medical University, Nanjing, 210008, P. R. China
| | - Chang-Jin Ou
- Institute of Advanced Materials and Flexible Electronics (IAMFE), School of Chemistry and Materials Science, Nanjing University of Information Science & Technology, Nanjing, 210044, P. R. China
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2
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Son MY, Belan O, Spirek M, Cibulka J, Nikulenkov F, Kim YY, Hwang S, Myung K, Montagna C, Kim TM, Krejci L, Hasty P. RAD51 separation of function mutation disables replication fork maintenance but preserves DSB repair. iScience 2024; 27:109524. [PMID: 38577109 PMCID: PMC10993188 DOI: 10.1016/j.isci.2024.109524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 03/01/2023] [Accepted: 03/14/2024] [Indexed: 04/06/2024] Open
Abstract
Homologous recombination (HR) protects replication forks (RFs) and repairs DNA double-strand breaks (DSBs). Within HR, BRCA2 regulates RAD51 via two interaction regions: the BRC repeats to form filaments on single-stranded DNA and exon 27 (Ex27) to stabilize the filament. Here, we identified a RAD51 S181P mutant that selectively disrupted the RAD51-Ex27 association while maintaining interaction with BRC repeat and proficiently forming filaments capable of DNA binding and strand invasion. Interestingly, RAD51 S181P was defective for RF protection/restart but proficient for DSB repair. Our data suggest that Ex27-mediated stabilization of RAD51 filaments is required for the protection of RFs, while it seems dispensable for the repair of DSBs.
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Affiliation(s)
- Mi Young Son
- Department of Molecular Medicine, The Barshop Institute for Longevity and Aging Studies, The Cancer Therapy Research Center, UT Health San Antonio, San Antonio, TX 78229, USA
| | - Ondrej Belan
- Department of Biology, Masaryk University, 625 00 Brno, Czech Republic
| | - Mario Spirek
- Department of Biology, Masaryk University, 625 00 Brno, Czech Republic
- National Centre for Biomolecular Research, Masaryk University, 625 00 Brno, Czech Republic
| | - Jakub Cibulka
- Department of Biology, Masaryk University, 625 00 Brno, Czech Republic
| | - Fedor Nikulenkov
- Department of Biology, Masaryk University, 625 00 Brno, Czech Republic
| | - You Young Kim
- Center for Genomic Integrity Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Sunyoung Hwang
- Center for Genomic Integrity Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Kyungjae Myung
- Center for Genomic Integrity Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Cristina Montagna
- Department of Genetics, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461, USA
| | - Tae Moon Kim
- Department of Molecular Medicine, The Barshop Institute for Longevity and Aging Studies, The Cancer Therapy Research Center, UT Health San Antonio, San Antonio, TX 78229, USA
- Center for Genomic Integrity Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Lumir Krejci
- Department of Biology, Masaryk University, 625 00 Brno, Czech Republic
- National Centre for Biomolecular Research, Masaryk University, 625 00 Brno, Czech Republic
| | - Paul Hasty
- Department of Molecular Medicine, The Barshop Institute for Longevity and Aging Studies, The Cancer Therapy Research Center, UT Health San Antonio, San Antonio, TX 78229, USA
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3
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Liu S, Shinohara A, Furukohri A. Fanconi anemia-associated mutation in RAD51 compromises the coordinated action of DNA-binding and ATPase activities. J Biol Chem 2023; 299:105424. [PMID: 37924868 PMCID: PMC10716581 DOI: 10.1016/j.jbc.2023.105424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 10/16/2023] [Accepted: 10/25/2023] [Indexed: 11/06/2023] Open
Abstract
Fanconi anemia (FA) is a rare genetic disease caused by a defect in DNA repair pathway for DNA interstrand crosslinks. These crosslinks can potentially impede the progression of the DNA replication fork, consequently leading to DNA double-strand breaks. Heterozygous RAD51-Q242R mutation has been reported to cause FA-like symptoms. However, the molecular defect of RAD51 underlying the disease is largely unknown. In this study, we conducted a biochemical analysis of RAD51-Q242R protein, revealing notable deficiencies in its DNA-dependent ATPase activity and its ATP-dependent regulation of DNA-binding activity. Interestingly, although RAD51-Q242R exhibited the filament instability and lacked the ability to form displacement loop, it efficiently stimulated the formation of displacement loops mediated by wild-type RAD51. These findings facilitate understanding of the biochemical properties of the mutant protein and how RAD51 works in the FA patient cells.
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Affiliation(s)
- Sijia Liu
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Akira Shinohara
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Asako Furukohri
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan.
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4
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Matos‐Rodrigues G, Barroca V, Muhammad A, Dardillac E, Allouch A, Koundrioukoff S, Lewandowski D, Despras E, Guirouilh‐Barbat J, Frappart L, Kannouche P, Dupaigne P, Le Cam E, Perfettini J, Romeo P, Debatisse M, Jasin M, Livera G, Martini E, Lopez BS. In vivo reduction of RAD51-mediated homologous recombination triggers aging but impairs oncogenesis. EMBO J 2023; 42:e110844. [PMID: 37661798 PMCID: PMC10577633 DOI: 10.15252/embj.2022110844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 06/06/2023] [Accepted: 08/21/2023] [Indexed: 09/05/2023] Open
Abstract
Homologous recombination (HR) is a prominent DNA repair pathway maintaining genome integrity. Mutations in many HR genes lead to cancer predisposition. Paradoxically, the implication of the pivotal HR factor RAD51 on cancer development remains puzzling. Particularly, no RAD51 mouse models are available to address the role of RAD51 in aging and carcinogenesis in vivo. We engineered a mouse model with an inducible dominant-negative form of RAD51 (SMRad51) that suppresses RAD51-mediated HR without stimulating alternative mutagenic repair pathways. We found that in vivo expression of SMRad51 led to replicative stress, systemic inflammation, progenitor exhaustion, premature aging and reduced lifespan, but did not trigger tumorigenesis. Expressing SMRAD51 in a breast cancer predisposition mouse model (PyMT) decreased the number and the size of tumors, revealing an anti-tumor activity of SMRAD51. We propose that these in vivo phenotypes result from chronic endogenous replication stress caused by HR decrease, which preferentially targets progenitors and tumor cells. Our work underlines the importance of RAD51 activity for progenitor cell homeostasis, preventing aging and more generally for the balance between cancer and aging.
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Affiliation(s)
- Gabriel Matos‐Rodrigues
- Université de Paris, INSERM U1016, UMR 8104 CNRS, Institut CochinEquipe Labellisée Ligue Contre le CancerParisFrance
- Université de Paris and Université Paris‐Saclay, Laboratory of Development of the Gonads, IRCM/IBFJ CEA, UMR Genetic Stability Stem Cells and RadiationFontenay aux RosesFrance
| | - Vilma Barroca
- Université de Paris and Université Paris‐Saclay, Inserm, IRCM/IBFJ CEAUMR Genetic Stability Stem Cells and RadiationFontenay aux RosesFrance
| | - Ali‐Akbar Muhammad
- Genome Maintenance and Molecular Microscopy UMR8126 CNRSUniversité Paris‐Sud, Université Paris‐Saclay, Gustave RoussyVillejuif CedexFrance
| | - Elodie Dardillac
- Université de Paris, INSERM U1016, UMR 8104 CNRS, Institut CochinEquipe Labellisée Ligue Contre le CancerParisFrance
| | - Awatef Allouch
- Cell Death and Aging Team, INSERM U1030, Laboratory of Molecular RadiotherapyUniversity Paris‐Sud and Gustave RoussyVillejuifFrance
| | - Stephane Koundrioukoff
- CNRS UMR8200 Sorbonne UniversitésUPMC UniversityParisFrance
- Institut Gustave RoussyVillejuifFrance
| | - Daniel Lewandowski
- Université de Paris and Université Paris‐Saclay, Inserm, IRCM/IBFJ CEAUMR Genetic Stability Stem Cells and RadiationFontenay aux RosesFrance
| | - Emmanuelle Despras
- CNRS UMR8200, Laboratory of Genetic Instability and OncogenesisUniversity Paris‐Sud and Gustave RoussyVillejuifFrance
| | - Josée Guirouilh‐Barbat
- Université de Paris, INSERM U1016, UMR 8104 CNRS, Institut CochinEquipe Labellisée Ligue Contre le CancerParisFrance
| | - Lucien Frappart
- Leibniz Institute on Aging‐Fritz Lipmann InstituteJenaGermany
| | - Patricia Kannouche
- CNRS UMR8200, Laboratory of Genetic Instability and OncogenesisUniversity Paris‐Sud and Gustave RoussyVillejuifFrance
| | - Pauline Dupaigne
- Genome Maintenance and Molecular Microscopy UMR8126 CNRSUniversité Paris‐Sud, Université Paris‐Saclay, Gustave RoussyVillejuif CedexFrance
| | - Eric Le Cam
- Genome Maintenance and Molecular Microscopy UMR8126 CNRSUniversité Paris‐Sud, Université Paris‐Saclay, Gustave RoussyVillejuif CedexFrance
| | - Jean‐Luc Perfettini
- Cell Death and Aging Team, INSERM U1030, Laboratory of Molecular RadiotherapyUniversity Paris‐Sud and Gustave RoussyVillejuifFrance
| | - Paul‐Henri Romeo
- Université de Paris and Université Paris‐Saclay, Inserm, IRCM/IBFJ CEAUMR Genetic Stability Stem Cells and RadiationFontenay aux RosesFrance
| | - Michelle Debatisse
- CNRS UMR8200 Sorbonne UniversitésUPMC UniversityParisFrance
- Institut Gustave RoussyVillejuifFrance
| | - Maria Jasin
- Developmental Biology ProgramMemorial Sloan Kettering Cancer CenterNew YorkNYUSA
| | - Gabriel Livera
- Université de Paris and Université Paris‐Saclay, Laboratory of Development of the Gonads, IRCM/IBFJ CEA, UMR Genetic Stability Stem Cells and RadiationFontenay aux RosesFrance
| | - Emmanuelle Martini
- Université de Paris and Université Paris‐Saclay, Laboratory of Development of the Gonads, IRCM/IBFJ CEA, UMR Genetic Stability Stem Cells and RadiationFontenay aux RosesFrance
| | - Bernard S Lopez
- Université de Paris, INSERM U1016, UMR 8104 CNRS, Institut CochinEquipe Labellisée Ligue Contre le CancerParisFrance
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5
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Adolph MB, Garje AS, Balakrishnan S, Morati F, Modesti M, Chazin WJ, Cortez D. CRISPR-dependent Base Editing Screens Identify Separation of Function Mutants of RADX with Altered RAD51 Regulatory Activity. J Mol Biol 2023; 435:168236. [PMID: 37572935 PMCID: PMC10530557 DOI: 10.1016/j.jmb.2023.168236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/01/2023] [Accepted: 08/04/2023] [Indexed: 08/14/2023]
Abstract
RAD51 forms nucleoprotein filaments to promote homologous recombination, replication fork reversal, and fork protection. Numerous factors regulate the stability of these filaments and improper regulation leads to genomic instability and ultimately disease including cancer. RADX is a single stranded DNA binding protein that modulates RAD51 filament stability. Here, we utilize a CRISPR-dependent base editing screen to tile mutations across RADX to delineate motifs required for RADX function. We identified separation of function mutants of RADX that bind DNA and RAD51 but have a reduced ability to stimulate its ATP hydrolysis activity. Cells expressing these RADX mutants accumulate RAD51 on chromatin, exhibit replication defects, have reduced growth, accumulate DNA damage, and are hypersensitive to DNA damage and replication stress. These results indicate that RADX must promote RAD51 ATP turnover to regulate RAD51 and genome stability during DNA replication.
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Affiliation(s)
- Madison B Adolph
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Atharv S Garje
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Swati Balakrishnan
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Florian Morati
- Cancer Research Center of Marseille, Department of Genome Integrity, CNRS UMR7258, Inserm U1068, Institut Paoli-Calmettes, Aix Marseille Univ, Marseille, France
| | - Mauro Modesti
- Cancer Research Center of Marseille, Department of Genome Integrity, CNRS UMR7258, Inserm U1068, Institut Paoli-Calmettes, Aix Marseille Univ, Marseille, France
| | - Walter J Chazin
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - David Cortez
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA.
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6
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Liu W, Saito Y, Jackson J, Bhowmick R, Kanemaki MT, Vindigni A, Cortez D. RAD51 bypasses the CMG helicase to promote replication fork reversal. Science 2023; 380:382-387. [PMID: 37104614 PMCID: PMC10302453 DOI: 10.1126/science.add7328] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 03/25/2023] [Indexed: 04/29/2023]
Abstract
Replication fork reversal safeguards genome integrity as a replication stress response. DNA translocases and the RAD51 recombinase catalyze reversal. However, it remains unknown why RAD51 is required and what happens to the replication machinery during reversal. We find that RAD51 uses its strand exchange activity to circumvent the replicative helicase, which remains bound to the stalled fork. RAD51 is not required for fork reversal if the helicase is unloaded. Thus, we propose that RAD51 creates a parental DNA duplex behind the helicase that is used as a substrate by the DNA translocases for branch migration to create a reversed fork structure. Our data explain how fork reversal happens while maintaining the helicase in a position poised to restart DNA synthesis and complete genome duplication.
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Affiliation(s)
- Wenpeng Liu
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37237 USA
| | - Yuichiro Saito
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Yata 1111, Mishima, Shizuoka, 411-8540, Japan
| | - Jessica Jackson
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Rahul Bhowmick
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37237 USA
| | - Masato T. Kanemaki
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Yata 1111, Mishima, Shizuoka, 411-8540, Japan
- Department of Biological Science, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Alessandro Vindigni
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - David Cortez
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37237 USA
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7
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Thomas M, Dubacq C, Rabut E, Lopez BS, Guirouilh-Barbat J. Noncanonical Roles of RAD51. Cells 2023; 12:cells12081169. [PMID: 37190078 DOI: 10.3390/cells12081169] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/07/2023] [Accepted: 04/12/2023] [Indexed: 05/17/2023] Open
Abstract
Homologous recombination (HR), an evolutionary conserved pathway, plays a paramount role(s) in genome plasticity. The pivotal HR step is the strand invasion/exchange of double-stranded DNA by a homologous single-stranded DNA (ssDNA) covered by RAD51. Thus, RAD51 plays a prime role in HR through this canonical catalytic strand invasion/exchange activity. The mutations in many HR genes cause oncogenesis. Surprisingly, despite its central role in HR, the invalidation of RAD51 is not classified as being cancer prone, constituting the "RAD51 paradox". This suggests that RAD51 exercises other noncanonical roles that are independent of its catalytic strand invasion/exchange function. For example, the binding of RAD51 on ssDNA prevents nonconservative mutagenic DNA repair, which is independent of its strand exchange activity but relies on its ssDNA occupancy. At the arrested replication forks, RAD51 plays several noncanonical roles in the formation, protection, and management of fork reversal, allowing for the resumption of replication. RAD51 also exhibits noncanonical roles in RNA-mediated processes. Finally, RAD51 pathogenic variants have been described in the congenital mirror movement syndrome, revealing an unexpected role in brain development. In this review, we present and discuss the different noncanonical roles of RAD51, whose presence does not automatically result in an HR event, revealing the multiple faces of this prominent actor in genomic plasticity.
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Affiliation(s)
- Mélissa Thomas
- INSERM U1016, UMR 8104 CNRS, Institut Cochin, Université de Paris Cité, 24 rue du Faubourg St. Jacques, F-75014 Paris, France
| | - Caroline Dubacq
- Institut de Biologie Paris Seine, IBPS, Neuroscience Paris Seine, NPS, INSERM, CNRS, Sorbonne Université, F-75005 Paris, France
| | - Elise Rabut
- INSERM U1016, UMR 8104 CNRS, Institut Cochin, Université de Paris Cité, 24 rue du Faubourg St. Jacques, F-75014 Paris, France
| | - Bernard S Lopez
- INSERM U1016, UMR 8104 CNRS, Institut Cochin, Université de Paris Cité, 24 rue du Faubourg St. Jacques, F-75014 Paris, France
| | - Josée Guirouilh-Barbat
- INSERM U1016, UMR 8104 CNRS, Institut Cochin, Université de Paris Cité, 24 rue du Faubourg St. Jacques, F-75014 Paris, France
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8
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So A, Dardillac E, Muhammad A, Chailleux C, Sesma-Sanz L, Ragu S, Le Cam E, Canitrot Y, Masson J, Dupaigne P, Lopez BS, Guirouilh-Barbat J. OUP accepted manuscript. Nucleic Acids Res 2022; 50:2651-2666. [PMID: 35137208 PMCID: PMC8934640 DOI: 10.1093/nar/gkac073] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 01/18/2022] [Accepted: 01/25/2022] [Indexed: 11/23/2022] Open
Abstract
Selection of the appropriate DNA double-strand break (DSB) repair pathway is decisive for genetic stability. It is proposed to act according to two steps: 1-canonical nonhomologous end-joining (C-NHEJ) versus resection that generates single-stranded DNA (ssDNA) stretches; 2-on ssDNA, gene conversion (GC) versus nonconservative single-strand annealing (SSA) or alternative end-joining (A-EJ). Here, we addressed the mechanisms by which RAD51 regulates this second step, preventing nonconservative repair in human cells. Silencing RAD51 or BRCA2 stimulated both SSA and A-EJ, but not C-NHEJ, validating the two-step model. Three different RAD51 dominant-negative forms (DN-RAD51s) repressed GC and stimulated SSA/A-EJ. However, a fourth DN-RAD51 repressed SSA/A-EJ, although it efficiently represses GC. In living cells, the three DN-RAD51s that stimulate SSA/A-EJ failed to load efficiently onto damaged chromatin and inhibited the binding of endogenous RAD51, while the fourth DN-RAD51, which inhibits SSA/A-EJ, efficiently loads on damaged chromatin. Therefore, the binding of RAD51 to DNA, rather than its ability to promote GC, is required for SSA/A-EJ inhibition by RAD51. We showed that RAD51 did not limit resection of endonuclease-induced DSBs, but prevented spontaneous and RAD52-induced annealing of complementary ssDNA in vitro. Therefore, RAD51 controls the selection of the DSB repair pathway, protecting genome integrity from nonconservative DSB repair through ssDNA occupancy, independently of the promotion of CG.
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Affiliation(s)
- Ayeong So
- Université de Paris, INSERM U1016, UMR 8104 CNRS, Institut Cochin, Equipe Labellisée Ligue Contre le Cancer, France
- CNRS UMR 8200, Gustave-Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, 94805 Villejuif, France
| | - Elodie Dardillac
- Université de Paris, INSERM U1016, UMR 8104 CNRS, Institut Cochin, Equipe Labellisée Ligue Contre le Cancer, France
- CNRS UMR 8200, Gustave-Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, 94805 Villejuif, France
| | - Ali Muhammad
- Genome Maintenance and Molecular Microscopy UMR 9019 CNRS, Université Paris-Saclay, Gustave Roussy, F-94805, Villejuif Cedex, France
| | | | - Laura Sesma-Sanz
- Genome Stability Laboratory, CHU de Québec Research Center (Oncology Division), Quebec City, QC, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Quebec City, QC, Canada
| | - Sandrine Ragu
- Université de Paris, INSERM U1016, UMR 8104 CNRS, Institut Cochin, Equipe Labellisée Ligue Contre le Cancer, France
- CNRS UMR 8200, Gustave-Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, 94805 Villejuif, France
| | - Eric Le Cam
- Genome Maintenance and Molecular Microscopy UMR 9019 CNRS, Université Paris-Saclay, Gustave Roussy, F-94805, Villejuif Cedex, France
| | - Yvan Canitrot
- CBI, CNRS UMR5088, LBCMCP, Toulouse University, Toulouse, France
| | - Jean Yves Masson
- Genome Stability Laboratory, CHU de Québec Research Center (Oncology Division), Quebec City, QC, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Quebec City, QC, Canada
| | - Pauline Dupaigne
- Genome Maintenance and Molecular Microscopy UMR 9019 CNRS, Université Paris-Saclay, Gustave Roussy, F-94805, Villejuif Cedex, France
| | - Bernard S Lopez
- To whom correspondence should be addressed. Tel: +33 1 53 73 27 40;
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9
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Vu TV, Das S, Nguyen CC, Kim J, Kim JY. Single-strand annealing: Molecular mechanisms and potential applications in CRISPR-Cas-based precision genome editing. Biotechnol J 2021; 17:e2100413. [PMID: 34846104 DOI: 10.1002/biot.202100413] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 11/22/2021] [Accepted: 11/29/2021] [Indexed: 12/24/2022]
Abstract
BACKGROUND Spontaneous double-stranded DNA breaks (DSBs) frequently occur within the genome of all living organisms and must be well repaired for survival. Recently, more important roles of the DSB repair pathways that were previously thought to be minor pathways, such as single-strand annealing (SSA), have been shown. Nevertheless, the biochemical mechanisms and applications of the SSA pathway in genome editing have not been updated. PURPOSE AND SCOPE Understanding the molecular mechanism of SSA is important to design potential applications in gene editing. This review provides insights into the recent progress of SSA studies and establishes a model for their potential applications in precision genome editing. SUMMARY AND CONCLUSION The SSA mechanism involved in DNA DSB repair appears to be activated by a complex signaling cascade starting with broken end sensing and 5'-3' resection to reveal homologous repeats on the 3' ssDNA overhangs that flank the DSB. Annealing the repeats would help to amend the discontinuous ends and restore the intact genome, resulting in the missing of one repeat and the intervening sequence between the repeats. We proposed a model for CRISPR-Cas-based precision insertion or replacement of DNA fragments to take advantage of the characteristics. The proposed model can add a tool to extend the choice for precision gene editing. Nevertheless, the model needs to be experimentally validated and optimized with SSA-favorable conditions for practical applications.
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Affiliation(s)
- Tien Van Vu
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea.,National Key Laboratory for Plant Cell Biotechnology, Agricultural Genetics Institute, Bac Tu Liem, Hanoi, Vietnam
| | - Swati Das
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea
| | - Cam Chau Nguyen
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea
| | - Jihae Kim
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea
| | - Jae-Yean Kim
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea.,Division of Life Science, Gyeongsang National University, Jinju, Republic of Korea
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10
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Le HP, Heyer WD, Liu J. Guardians of the Genome: BRCA2 and Its Partners. Genes (Basel) 2021; 12:genes12081229. [PMID: 34440403 PMCID: PMC8394001 DOI: 10.3390/genes12081229] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/04/2021] [Accepted: 08/06/2021] [Indexed: 12/28/2022] Open
Abstract
The tumor suppressor BRCA2 functions as a central caretaker of genome stability, and individuals who carry BRCA2 mutations are predisposed to breast, ovarian, and other cancers. Recent research advanced our mechanistic understanding of BRCA2 and its various interaction partners in DNA repair, DNA replication support, and DNA double-strand break repair pathway choice. In this review, we discuss the biochemical and structural properties of BRCA2 and examine how these fundamental properties contribute to DNA repair and replication fork stabilization in living cells. We highlight selected BRCA2 binding partners and discuss their role in BRCA2-mediated homologous recombination and fork protection. Improved mechanistic understanding of how BRCA2 functions in genome stability maintenance can enable experimental evidence-based evaluation of pathogenic BRCA2 mutations and BRCA2 pseudo-revertants to support targeted therapy.
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Affiliation(s)
- Hang Phuong Le
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA; (H.P.L.); (W.-D.H.)
| | - Wolf-Dietrich Heyer
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA; (H.P.L.); (W.-D.H.)
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Jie Liu
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA; (H.P.L.); (W.-D.H.)
- Correspondence: ; Tel.: +1-530-752-3016
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11
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Prakash R, Sandoval T, Morati F, Zagelbaum JA, Lim PX, White T, Taylor B, Wang R, Desclos ECB, Sullivan MR, Rein HL, Bernstein KA, Krawczyk PM, Gautier J, Modesti M, Vanoli F, Jasin M. Distinct pathways of homologous recombination controlled by the SWS1-SWSAP1-SPIDR complex. Nat Commun 2021; 12:4255. [PMID: 34253720 PMCID: PMC8275761 DOI: 10.1038/s41467-021-24205-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 06/04/2021] [Indexed: 02/06/2023] Open
Abstract
Homology-directed repair (HDR), a critical DNA repair pathway in mammalian cells, is complex, leading to multiple outcomes with different impacts on genomic integrity. However, the factors that control these different outcomes are often not well understood. Here we show that SWS1-SWSAP1-SPIDR controls distinct types of HDR. Despite their requirement for stable assembly of RAD51 recombinase at DNA damage sites, these proteins are not essential for intra-chromosomal HDR, providing insight into why patients and mice with mutations are viable. However, SWS1-SWSAP1-SPIDR is critical for inter-homolog HDR, the first mitotic factor identified specifically for this function. Furthermore, SWS1-SWSAP1-SPIDR drives the high level of sister-chromatid exchange, promotes long-range loss of heterozygosity often involved with cancer initiation, and impels the poor growth of BLM helicase-deficient cells. The relevance of these genetic interactions is evident as SWSAP1 loss prolongs Blm-mutant embryo survival, suggesting a possible druggable target for the treatment of Bloom syndrome.
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Affiliation(s)
- Rohit Prakash
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
| | - Thomas Sandoval
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Florian Morati
- Cancer Research Center of Marseille, CNRS, Inserm, Institut Paoli-Calmettes, Aix-Marseille Université, Marseille, France
| | - Jennifer A Zagelbaum
- Department of Genetics and Development and Institute for Cancer Genetics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Pei-Xin Lim
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Travis White
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Brett Taylor
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Raymond Wang
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Emilie C B Desclos
- Department of Medical Biology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Meghan R Sullivan
- Department of Microbiology and Molecular Genetics, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Hayley L Rein
- Department of Microbiology and Molecular Genetics, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Kara A Bernstein
- Department of Microbiology and Molecular Genetics, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Przemek M Krawczyk
- Department of Medical Biology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Jean Gautier
- Department of Genetics and Development and Institute for Cancer Genetics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Mauro Modesti
- Cancer Research Center of Marseille, CNRS, Inserm, Institut Paoli-Calmettes, Aix-Marseille Université, Marseille, France
| | - Fabio Vanoli
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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12
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Matos-Rodrigues G, Guirouilh-Barbat J, Martini E, Lopez BS. Homologous recombination, cancer and the 'RAD51 paradox'. NAR Cancer 2021; 3:zcab016. [PMID: 34316706 PMCID: PMC8209977 DOI: 10.1093/narcan/zcab016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/08/2021] [Accepted: 04/20/2021] [Indexed: 01/22/2023] Open
Abstract
Genetic instability is a hallmark of cancer cells. Homologous recombination (HR) plays key roles in genome stability and variability due to its roles in DNA double-strand break and interstrand crosslink repair, and in the protection and resumption of arrested replication forks. HR deficiency leads to genetic instability, and, as expected, many HR genes are downregulated in cancer cells. The link between HR deficiency and cancer predisposition is exemplified by familial breast and ovarian cancers and by some subgroups of Fanconi anaemia syndromes. Surprisingly, although RAD51 plays a pivotal role in HR, i.e., homology search and in strand exchange with a homologous DNA partner, almost no inactivating mutations of RAD51 have been associated with cancer predisposition; on the contrary, overexpression of RAD51 is associated with a poor prognosis in different types of tumours. Taken together, these data highlight the fact that RAD51 differs from its HR partners with regard to cancer susceptibility and expose what we call the ‘RAD51 paradox’. Here, we catalogue the dysregulations of HR genes in human pathologies, including cancer and Fanconi anaemia or congenital mirror movement syndromes, and we discuss the RAD51 paradox.
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Affiliation(s)
- Gabriel Matos-Rodrigues
- Université de Paris, INSERM U1016, UMR 8104 CNRS, Institut Cochin, Equipe Labellisée Ligue Contre le Cancer, F-75014, France
| | - Josée Guirouilh-Barbat
- Université de Paris, INSERM U1016, UMR 8104 CNRS, Institut Cochin, Equipe Labellisée Ligue Contre le Cancer, F-75014, France
| | - Emmanuelle Martini
- Université de Paris and Université Paris-Saclay, Laboratory of Development of the Gonads, IRCM/IBFJ CEA, UMR Genetic Stability, Stem Cells and Radiation, F-92265 Fontenay aux Roses, France
| | - Bernard S Lopez
- Université de Paris, INSERM U1016, UMR 8104 CNRS, Institut Cochin, Equipe Labellisée Ligue Contre le Cancer, F-75014, France
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13
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Wassing IE, Esashi F. RAD51: Beyond the break. Semin Cell Dev Biol 2020; 113:38-46. [PMID: 32938550 PMCID: PMC8082279 DOI: 10.1016/j.semcdb.2020.08.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/14/2020] [Accepted: 08/28/2020] [Indexed: 01/30/2023]
Abstract
As the primary catalyst of homologous recombination (HR) in vertebrates, RAD51 has been extensively studied in the context of repair of double-stranded DNA breaks (DSBs). With recent advances in the understanding of RAD51 function extending beyond DSBs, the importance of RAD51 throughout DNA metabolism has become increasingly clear. Here we review the suggested roles of RAD51 beyond HR, specifically focusing on their interplay with DNA replication and the maintenance of genomic stability, in which RAD51 function emerges as a double-edged sword.
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Affiliation(s)
- Isabel E Wassing
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Fumiko Esashi
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
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14
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Abstract
Accurate DNA repair and replication are critical for genomic stability and cancer prevention. RAD51 and its gene family are key regulators of DNA fidelity through diverse roles in double-strand break repair, replication stress, and meiosis. RAD51 is an ATPase that forms a nucleoprotein filament on single-stranded DNA. RAD51 has the function of finding and invading homologous DNA sequences to enable accurate and timely DNA repair. Its paralogs, which arose from ancient gene duplications of RAD51, have evolved to regulate and promote RAD51 function. Underscoring its importance, misregulation of RAD51, and its paralogs, is associated with diseases such as cancer and Fanconi anemia. In this review, we focus on the mammalian RAD51 structure and function and highlight the use of model systems to enable mechanistic understanding of RAD51 cellular roles. We also discuss how misregulation of the RAD51 gene family members contributes to disease and consider new approaches to pharmacologically inhibit RAD51.
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Affiliation(s)
- Braulio Bonilla
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA;
| | - Sarah R Hengel
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA;
| | - McKenzie K Grundy
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA;
| | - Kara A Bernstein
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA;
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15
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Bosshard S, Duroy PO, Mermod N. A role for alternative end-joining factors in homologous recombination and genome editing in Chinese hamster ovary cells. DNA Repair (Amst) 2019; 82:102691. [PMID: 31476574 DOI: 10.1016/j.dnarep.2019.102691] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 08/13/2019] [Accepted: 08/14/2019] [Indexed: 12/22/2022]
Abstract
CRISPR technologies greatly foster genome editing in mammalian cells through site-directed DNA double strand breaks (DSBs). However, precise editing outcomes, as mediated by homologous recombination (HR) repair, are typically infrequent and outnumbered by undesired genome alterations. By using knockdown and overexpression studies in Chinese hamster ovary (CHO) cells as well as characterizing repaired DNA junctions, we found that efficient HR-mediated genome editing depends on alternative end-joining (alt-EJ) DNA repair activities, a family of incompletely characterized DNA repair pathways traditionally considered to oppose HR. This dependency was influenced by the CRISPR nuclease type and the DSB-to-mutation distance, but not by the DNA sequence surrounding the DSBs or reporter cell line. We also identified elevated Mre11 and Pari, and low Rad51 expression levels as the most rate-limiting factors for HR in CHO cells. Counteracting these three bottlenecks improved precise genome editing by up to 75%. Altogether, our study provides novel insights into the complex interplay of alt-EJ and HR repair pathways, highlighting their relevance for developing improved genome editing strategies.
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Affiliation(s)
- Sandra Bosshard
- Institute of Biotechnology and Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Pierre-Olivier Duroy
- Institute of Biotechnology and Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Nicolas Mermod
- Institute of Biotechnology and Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland.
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16
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Mack EA, Xiao YP, Allred DR. Knockout of Babesia bovis rad51 ortholog and its complementation by expression from the BbACc3 artificial chromosome platform. PLoS One 2019; 14:e0215882. [PMID: 31386669 PMCID: PMC6684078 DOI: 10.1371/journal.pone.0215882] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 07/21/2019] [Indexed: 11/18/2022] Open
Abstract
Babesia bovis establishes persistent infections of long duration in cattle, despite the development of effective anti-disease immunity. One mechanism used by the parasite to achieve persistence is rapid antigenic variation of the VESA1 cytoadhesion ligand through segmental gene conversion (SGC), a phenomenon thought to be a form of homologous recombination (HR). To begin investigation of the enzymatic basis for SGC we initially identified and knocked out the Bbrad51 gene encoding the B. bovis Rad51 ortholog. BbRad51 was found to be non-essential for in vitro growth of asexual-stage parasites. However, its loss resulted in hypersensitivity to methylmethane sulfonate (MMS) and an apparent defect in HR. This defect rendered attempts to complement the knockout phenotype by reinsertion of the Bbrad51 gene into the genome unsuccessful. To circumvent this difficulty, we constructed an artificial chromosome, BbACc3, into which the complete Bbrad51 locus was inserted, for expression of BbRad51 under regulation by autologous elements. Maintenance of BbACc3 makes use of centromeric sequences from chromosome 3 and telomeric ends from chromosome 1 of the B. bovis C9.1 line. A selection cassette employing human dihydrofolate reductase enables recovery of transformants by selection with pyrimethamine. We demonstrate that the BbACc3 platform is stably maintained once established, assembles nucleosomes to form native chromatin, and expands in telomere length over time. Significantly, the MMS-sensitivity phenotype observed in the absence of Bbrad51 was successfully complemented at essentially normal levels. We provide cautionary evidence, however, that in HR-competent parasites BbACc3 can recombine with native chromosomes, potentially resulting in crossover. We propose that, under certain circumstances this platform can provide a useful alternative for the genetic manipulation of this group of parasites, particularly when regulated gene expression under the control of autologous elements may be important.
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Affiliation(s)
- Erin A. Mack
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Yu-Ping Xiao
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
| | - David R. Allred
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
- Genetics Institute, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
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17
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Kelso AA, Lopezcolorado FW, Bhargava R, Stark JM. Distinct roles of RAD52 and POLQ in chromosomal break repair and replication stress response. PLoS Genet 2019; 15:e1008319. [PMID: 31381562 PMCID: PMC6695211 DOI: 10.1371/journal.pgen.1008319] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 08/15/2019] [Accepted: 07/18/2019] [Indexed: 12/18/2022] Open
Abstract
Disrupting either the DNA annealing factor RAD52 or the A-family DNA polymerase POLQ can cause synthetic lethality with defects in BRCA1 and BRCA2, which are tumor suppressors important for homology-directed repair of DNA double-strand breaks (DSBs), and protection of stalled replication forks. A likely mechanism of this synthetic lethality is that RAD52 and/or POLQ are important for backup pathways for DSB repair and/or replication stress responses. The features of DSB repair events that require RAD52 vs. POLQ, and whether combined disruption of these factors causes distinct effects on genome maintenance, have been unclear. Using human U2OS cells, we generated a cell line with POLQ mutations upstream of the polymerase domain, a RAD52 knockout cell line, and a line with combined disruption of both genes. We also examined RAD52 and POLQ using RNA-interference. We find that combined disruption of RAD52 and POLQ causes at least additive hypersensitivity to cisplatin, and a synthetic reduction in replication fork restart velocity. We also examined the influence of RAD52 and POLQ on several DSB repair events. We find that RAD52 is particularly important for repair using ≥ 50 nt repeat sequences that flank the DSB, and that also involve removal of non-homologous sequences flanking the repeats. In contrast, POLQ is important for repair events using 6 nt (but not ≥ 18 nt) of flanking repeats that are at the edge of the break, as well as oligonucleotide microhomology-templated (i.e., 12-20 nt) repair events requiring nascent DNA synthesis. Finally, these factors show key distinctions with BRCA2, regarding effects on DSB repair events and response to stalled replication forks. These findings indicate that RAD52 and POLQ have distinct roles in genome maintenance, including for specific features of DSB repair events, such that combined disruption of these factors may be effective for genotoxin sensitization and/or synthetic lethal strategies.
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Affiliation(s)
- Andrew A. Kelso
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, California, United States of America
| | - Felicia Wednesday Lopezcolorado
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, California, United States of America
| | - Ragini Bhargava
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, California, United States of America
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, California, United States of America
| | - Jeremy M. Stark
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, California, United States of America
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, California, United States of America
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18
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Rees HA, Yeh WH, Liu DR. Development of hRad51-Cas9 nickase fusions that mediate HDR without double-stranded breaks. Nat Commun 2019; 10:2212. [PMID: 31101808 PMCID: PMC6525190 DOI: 10.1038/s41467-019-09983-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 04/04/2019] [Indexed: 12/20/2022] Open
Abstract
In mammalian cells, double-stranded DNA breaks (DSBs) are preferentially repaired through end-joining processes that generally lead to mixtures of insertions and deletions (indels) or other rearrangements at the cleavage site. In the presence of homologous DNA, homology-directed repair (HDR) can generate specific mutations, albeit typically with modest efficiency and a low ratio of HDR products:indels. Here, we develop hRad51 mutants fused to Cas9(D10A) nickase (RDN) that mediate HDR while minimizing indels. We use RDN to install disease-associated point mutations in HEK293T cells with comparable or better efficiency than Cas9 nuclease and a 2.7-to-53-fold higher ratio of desired HDR product:undesired byproducts. Across five different human cell types, RDN variants generally result in higher HDR:indel ratios and lower off-target activity than Cas9 nuclease, although HDR efficiencies remain strongly site- and cell type-dependent. RDN variants provide precision editing options in cell types amenable to HDR, especially when byproducts of DSBs must be minimized.
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Affiliation(s)
- Holly A Rees
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, 02142, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Wei-Hsi Yeh
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, 02142, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA
- Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA, 02115, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, 02142, USA.
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, 02142, USA.
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA.
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19
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Sutherland JH, Holloman WK. Characterization of a potent dominant negative mutant variant of Rad51 in Ustilago maydis. DNA Repair (Amst) 2019; 78:91-101. [PMID: 31005682 DOI: 10.1016/j.dnarep.2019.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 03/08/2019] [Accepted: 04/09/2019] [Indexed: 11/26/2022]
Abstract
Rad51 serves to maintain and protect integrity of the genome through its actions in DNA repair and replication fork protection. The active form of Rad51 is a nucleoprotein filament consisting of chains of protomer units arranged linearly along single-stranded DNA. In a mutant screen using Ustilago maydis as an experimental system we identified a novel variant of Rad51, in which an amino acid change near the protomer-protomer interaction interface confers a strong trans dominant inhibitory effect on resistance to DNA damaging agents and proficiency in homologous recombination. Modeling studies of the mutated residue D161Y suggested that steric interference with surrounding residues was the likely cause of the inhibitory effect. Changes of two nearby residues, predicted from the modeling to minimize steric clashes, mitigated the inhibition of DNA repair. Direct testing of purified Rad51D161Y protein in defined biochemical reactions revealed it to be devoid of DNA-binding activity itself, but capable of interfering with Rad51WT in formation and maintenance of nucleoprotein filaments on single-stranded DNA and in DNA strand exchange. Rad51D161Y protein appears to be unable to self-associate in solution and defective in forming complexes with the U. maydis BRCA2 ortholog.
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Affiliation(s)
- Jeanette H Sutherland
- Department of Microbiology and Immunology, Cornell University, Weill Medical College, New York, NY 10065, USA
| | - William K Holloman
- Department of Microbiology and Immunology, Cornell University, Weill Medical College, New York, NY 10065, USA.
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20
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Son MY, Hasty P. Homologous recombination defects and how they affect replication fork maintenance. AIMS GENETICS 2019; 5:192-211. [PMID: 31435521 PMCID: PMC6690234 DOI: 10.3934/genet.2018.4.192] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 03/18/2019] [Indexed: 01/07/2023]
Abstract
Homologous recombination (HR) repairs DNA double strand breaks (DSBs) and stabilizes replication forks (RFs). RAD51 is the recombinase for the HR pathway. To preserve genomic integrity, RAD51 forms a filament on the 3' end of a DSB and on a single-stranded DNA (ssDNA) gap. But unregulated HR results in undesirable chromosomal rearrangements. This review describes the multiple mechanisms that regulate HR with a focus on those mechanisms that promote and contain RAD51 filaments to limit chromosomal rearrangements. If any of these pathways break down and HR becomes unregulated then disease, primarily cancer, can result.
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Affiliation(s)
- Mi Young Son
- Department of Molecular Medicine and Institute of Biotechnology, UT Health San Antonio, 15355 Lambda Drive, San Antonio, USA
| | - Paul Hasty
- Department of Molecular Medicine and Institute of Biotechnology, UT Health San Antonio, 15355 Lambda Drive, San Antonio, USA
- The Mays Cancer Center, USA
- Sam and Ann Barshop Institute for Longevity and Aging Studies, USA
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21
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Vydyam P, Dutta D, Sutram N, Bhattacharyya S, Bhattacharyya MK. A small-molecule inhibitor of the DNA recombinase Rad51 from Plasmodium falciparum synergizes with the antimalarial drugs artemisinin and chloroquine. J Biol Chem 2019; 294:8171-8183. [PMID: 30936202 DOI: 10.1074/jbc.ra118.005009] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 03/27/2019] [Indexed: 11/06/2022] Open
Abstract
Malaria parasites repair DNA double-strand breaks (DSBs) primarily through homologous recombination (HR). Here, because the unrepaired DSBs lead to the death of the unicellular parasite Plasmodium falciparum, we investigated its recombinase, PfRad51, as a potential drug target. Undertaking an in silico screening approach, we identified a compound, B02, that docks to the predicted tertiary structure of PfRad51 with high affinity. B02 inhibited a drug-sensitive P. falciparum strain (3D7) and multidrug-resistant parasite (Dd2) in culture, with IC50 values of 8 and 3 μm, respectively. We found that B02 is more potent against these P. falciparum strains than against mammalian cell lines. Our findings also revealed that the antimalarial activity of B02 synergizes with those of two first-line malaria drugs, artemisinin (ART) and chloroquine (CQ), lowering the IC50 values of ART and CQ by 15- and 8-fold, respectively. Our results also provide mechanistic insights into the anti-parasitic activity of B02, indicating that it blocks the ATPase and strand-exchange activities of PfRad51 and abrogates the formation of PfRad51 foci on damaged DNA at chromosomal sites, probably by blocking homomeric interactions of PfRad51 proteins. The B02-mediated PfRad51 disruption led to the accumulation of unrepaired parasitic DNA and rendered parasites more sensitive to DNA-damaging agents, including ART. Our findings provide a rationale for targeting the Plasmodium DSB repair pathway in combination with ART. We propose that identification of a specific inhibitor of HR in Plasmodium may enable investigations of HR's role in Plasmodium biology, including generation of antigenic diversity.
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Affiliation(s)
- Pratap Vydyam
- Department of Biochemistry, University of Hyderabad, Gachibowli, Hyderabad 500046, TS, India
| | - Dibyendu Dutta
- Department of Biochemistry, University of Hyderabad, Gachibowli, Hyderabad 500046, TS, India
| | - Niranjan Sutram
- Department of Biochemistry, University of Hyderabad, Gachibowli, Hyderabad 500046, TS, India
| | - Sunanda Bhattacharyya
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500046, TS, India
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22
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Chromatin control in double strand break repair. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019. [PMID: 30798938 DOI: 10.1016/bs.apcsb.2018.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2023]
Abstract
DNA double strand breaks (DSB) are the most deleterious type of damage inflicted on DNA by various environmental factors and as consequences of normal cellular metabolism. The multistep nature of DSB repair and the need to assemble large protein complexes at repair sites necessitate multiple chromatin changes there. This review focuses on the key findings of how chromatin regulators exert temporal and spatial control on DSB repair. These mechanisms coordinate repair with cell cycle progression, lead to DSB repair pathway choice, provide accessibility of repair machinery to damaged sites and move the lesions to nuclear environments permissive for repair.
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23
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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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24
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Fanconi-Anemia-Associated Mutations Destabilize RAD51 Filaments and Impair Replication Fork Protection. Cell Rep 2018; 21:333-340. [PMID: 29020621 DOI: 10.1016/j.celrep.2017.09.062] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 08/25/2017] [Accepted: 09/18/2017] [Indexed: 12/13/2022] Open
Abstract
Fanconi anemia (FA) is a genetic disorder characterized by a defect in DNA interstrand crosslink (ICL) repair, chromosomal instability, and a predisposition to cancer. Recently, two RAD51 mutations were reported to cause an FA-like phenotype. Despite the tight association of FA/HR proteins with replication fork (RF) stabilization during normal replication, it remains unknown how FA-associated RAD51 mutations affect replication beyond ICL lesions. Here, we report that these mutations fail to protect nascent DNA from MRE11-mediated degradation during RF stalling in Xenopus laevis egg extracts. Reconstitution of DNA protection in vitro revealed that the defect arises directly due to altered RAD51 properties. Both mutations induce pronounced structural changes and RAD51 filament destabilization that is not rescued by prevention of ATP hydrolysis due to aberrant ATP binding. Our results further interconnect the FA pathway with DNA replication and provide mechanistic insight into the role of RAD51 in recombination-independent mechanisms of genome maintenance.
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25
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Moreb EA, Hoover B, Yaseen A, Valyasevi N, Roecker Z, Menacho-Melgar R, Lynch MD. Managing the SOS Response for Enhanced CRISPR-Cas-Based Recombineering in E. coli through Transient Inhibition of Host RecA Activity. ACS Synth Biol 2017; 6:2209-2218. [PMID: 28915012 DOI: 10.1021/acssynbio.7b00174] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Phage-derived "recombineering" methods are utilized for bacterial genome editing. Recombineering results in a heterogeneous population of modified and unmodified chromosomes, and therefore selection methods, such as CRISPR-Cas9, are required to select for edited clones. Cells can evade CRISPR-Cas-induced cell death through recA-mediated induction of the SOS response. The SOS response increases RecA dependent repair as well as mutation rates through induction of the umuDC error prone polymerase. As a result, CRISPR-Cas selection is more efficient in recA mutants. We report an approach to inhibiting the SOS response and RecA activity through the expression of a mutant dominant negative form of RecA, which incorporates into wild type RecA filaments and inhibits activity. Using a plasmid-based system in which Cas9 and recA mutants are coexpressed, we can achieve increased efficiency and consistency of CRISPR-Cas9-mediated selection and recombineering in E. coli, while reducing the induction of the SOS response. To date, this approach has been shown to be independent of recA genotype and host strain lineage. Using this system, we demonstrate increased CRISPR-Cas selection efficacy with over 10 000 guides covering the E. coli chromosome. The use of dominant negative RecA or homologues may be of broad use in bacterial CRISPR-Cas-based genome editing where the SOS pathways are present.
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Affiliation(s)
- Eirik Adim Moreb
- Department of Biomedical
Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Benjamin Hoover
- Department of Biomedical
Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Adam Yaseen
- Department of Biomedical
Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Nisakorn Valyasevi
- Department of Biomedical
Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Zoe Roecker
- Department of Biomedical
Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Romel Menacho-Melgar
- Department of Biomedical
Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Michael D. Lynch
- Department of Biomedical
Engineering, Duke University, Durham, North Carolina 27708, United States
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26
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Fujii N. Potential Strategies to Target Protein-Protein Interactions in the DNA Damage Response and Repair Pathways. J Med Chem 2017; 60:9932-9959. [PMID: 28654754 DOI: 10.1021/acs.jmedchem.7b00358] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This review article discusses some insights about generating novel mechanistic inhibitors of the DNA damage response and repair (DDR) pathways by focusing on protein-protein interactions (PPIs) of the key DDR components. General requirements for PPI strategies, such as selecting the target PPI site on the basis of its functionality, are discussed first. Next, on the basis of functional rationale and biochemical feasibility to identify a PPI inhibitor, 26 PPIs in DDR pathways (BER, MMR, NER, NHEJ, HR, TLS, and ICL repair) are specifically discussed for inhibitor discovery to benefit cancer therapies using a DNA-damaging agent.
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Affiliation(s)
- Naoaki Fujii
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital , 262 Danny Thomas Place, MS1000, Memphis, Tennessee 38105, United States
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27
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The Tumor-Associated Variant RAD51 G151D Induces a Hyper-Recombination Phenotype. PLoS Genet 2016; 12:e1006208. [PMID: 27513445 PMCID: PMC4981402 DOI: 10.1371/journal.pgen.1006208] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 06/29/2016] [Indexed: 12/20/2022] Open
Abstract
The RAD51 protein plays a key role in the homology-directed repair of DNA double-strand breaks and is important for maintaining genome stability. Here we report on a novel human RAD51 variant found in an aggressive and therapy-refractive breast carcinoma. Expression of the RAD51 G151D variant in human breast epithelial cells increases the levels of homology-directed repair. Expression of RAD51 G151D in cells also promotes high levels of chromosomal aberrations and sister chromatid exchanges. In vitro, the purified RAD51 G151D protein directly and significantly enhances DNA strand exchange activity in the presence of RPA. In concordance with this result, co-incubation of G151D with BRCA2 resulted in a much higher level of strand-exchange activity compared to WT RAD51. Strikingly, the RAD51 G151D variant confers resistance to multiple DNA damaging agents, including ionizing radiation, mitomycin C, and doxorubicin. Our findings demonstrate that the RAD51 G151D somatic variant has a novel hyper-recombination phenotype and suggest that this property of the protein is important for the repair of DNA damage, leading to drug resistance. Therapeutic resistance is a major hurdle for the treatment and eradication of cancer. Furthermore, the development of therapeutic resistance significantly decreases patient survival and negatively impacts the quality of life of patients battling cancer. Cancer cells utilize a number of previously described mechanisms in order to overcome sensitivity to cancer therapeutics, including overexpression of RAD51. However, in this study we report a novel gain-of-function heterozygous somatic variant, RAD51 G151D, identified in a highly refractory and aggressive breast adenocarcinoma. RAD51 G151D induces a hyper-recombination phenotype in human cells resulting in increased resistance to therapeutics via enhanced HDR of DSBs. We further demonstrate enhanced DNA strand exchange activity in the presence of RPA, providing a possible mechanism for the hyper-recombination phenotype observed in cells. Our study presents a novel hyper-recombinant RAD51 tumor-associated variant (RAD51 G151D), providing the first evidence that links altered RAD51 function with therapeutic resistance as well as a novel genetic marker to identify patients at high risk for aggressive and refractory disease.
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28
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Bhargava R, Onyango DO, Stark JM. Regulation of Single-Strand Annealing and its Role in Genome Maintenance. Trends Genet 2016; 32:566-575. [PMID: 27450436 DOI: 10.1016/j.tig.2016.06.007] [Citation(s) in RCA: 311] [Impact Index Per Article: 38.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 06/28/2016] [Accepted: 06/29/2016] [Indexed: 01/19/2023]
Abstract
Single-strand annealing (SSA) is a DNA double-strand break (DSB) repair pathway that uses homologous repeats to bridge DSB ends. SSA involving repeats that flank a single DSB causes a deletion rearrangement between the repeats, and hence is relatively mutagenic. Nevertheless, this pathway is conserved, in that SSA events have been found in several organisms. In this review, we describe the mechanism of SSA and its regulation, including the cellular conditions that may favor SSA versus other DSB repair events. We will also evaluate the potential contribution of SSA to cancer-associated genome rearrangements, and to DSB-induced gene targeting.
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Affiliation(s)
- Ragini Bhargava
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA, USA; Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - David O Onyango
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - Jeremy M Stark
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA, USA; Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, CA, USA.
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29
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Vriend LEM, Prakash R, Chen CC, Vanoli F, Cavallo F, Zhang Y, Jasin M, Krawczyk PM. Distinct genetic control of homologous recombination repair of Cas9-induced double-strand breaks, nicks and paired nicks. Nucleic Acids Res 2016; 44:5204-17. [PMID: 27001513 PMCID: PMC4914091 DOI: 10.1093/nar/gkw179] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 03/05/2016] [Accepted: 03/07/2016] [Indexed: 12/29/2022] Open
Abstract
DNA double-strand breaks (DSBs) are known to be powerful inducers of homologous recombination (HR), but single-strand breaks (nicks) have also been shown to trigger HR. Both DSB- and nick-induced HR ((nick)HR) are exploited in advanced genome-engineering approaches based on the bacterial RNA-guided nuclease Cas9. However, the mechanisms of (nick)HR are largely unexplored. Here, we applied Cas9 nickases to study (nick)HR in mammalian cells. We find that (nick)HR is unaffected by inhibition of major damage signaling kinases and that it is not suppressed by nonhomologous end-joining (NHEJ) components, arguing that nick processing does not require a DSB intermediate to trigger HR. Relative to a single nick, nicking both strands enhances HR, consistent with a DSB intermediate, even when nicks are induced up to ∼1kb apart. Accordingly, HR and NHEJ compete for repair of these paired nicks, but, surprisingly, only when 5' overhangs or blunt ends can be generated. Our study advances the understanding of molecular mechanisms driving nick and paired-nick repair in mammalian cells and clarify phenomena associated with Cas9-mediated genome editing.
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Affiliation(s)
- Lianne E M Vriend
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, Amsterdam, 1105 AZ, The Netherlands Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Rohit Prakash
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Chun-Chin Chen
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA Weill Cornell Graduate School of Medical Sciences, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Fabio Vanoli
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Francesca Cavallo
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Yu Zhang
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA Weill Cornell Graduate School of Medical Sciences, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Przemek M Krawczyk
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, Amsterdam, 1105 AZ, The Netherlands Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
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30
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Marsh ME, Scott DE, Ehebauer MT, Abell C, Blundell TL, Hyvönen M. ATP half-sites in RadA and RAD51 recombinases bind nucleotides. FEBS Open Bio 2016; 6:372-85. [PMID: 27419043 PMCID: PMC4856416 DOI: 10.1002/2211-5463.12052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 12/20/2022] Open
Abstract
Homologous recombination is essential for repair of DNA double-strand breaks. Central to this process is a family of recombinases, including archeal RadA and human RAD51, which form nucleoprotein filaments on damaged single-stranded DNA ends and facilitate their ATP-dependent repair. ATP binding and hydrolysis are dependent on the formation of a nucleoprotein filament comprising RadA/RAD51 and single-stranded DNA, with ATP bound between adjacent protomers. We demonstrate that truncated, monomeric Pyrococcus furiosus RadA and monomerised human RAD51 retain the ability to bind ATP and other nucleotides with high affinity. We present crystal structures of both apo and nucleotide-bound forms of monomeric RadA. These structures reveal that while phosphate groups are tightly bound, RadA presents a shallow, poorly defined binding surface for the nitrogenous bases of nucleotides. We suggest that RadA monomers would be constitutively bound to nucleotides in the cell and that the bound nucleotide might play a structural role in filament assembly.
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Affiliation(s)
- May E Marsh
- Department of Biochemistry University of Cambridge UK; Present address: Paul Scherrer Institut Villingen Switzerland
| | | | - Matthias T Ehebauer
- Department of Biochemistry University of Cambridge UK; Present address: Target Discovery Institute Nuffield Department of Medicine University of Oxford UK
| | - Chris Abell
- Department of Chemistry University of Cambridge UK
| | | | - Marko Hyvönen
- Department of Biochemistry University of Cambridge UK
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31
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Kitange GJ, Mladek AC, Schroeder MA, Pokorny JC, Carlson BL, Zhang Y, Nair AA, Lee JH, Yan H, Decker PA, Zhang Z, Sarkaria JN. Retinoblastoma Binding Protein 4 Modulates Temozolomide Sensitivity in Glioblastoma by Regulating DNA Repair Proteins. Cell Rep 2016; 14:2587-98. [PMID: 26972001 DOI: 10.1016/j.celrep.2016.02.045] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 12/22/2015] [Accepted: 02/04/2016] [Indexed: 01/18/2023] Open
Abstract
Here we provide evidence that RBBP4 modulates temozolomide (TMZ) sensitivity through coordinate regulation of two key DNA repair genes critical for recovery from TMZ-induced DNA damage: methylguanine-DNA-methyltransferase (MGMT) and RAD51. Disruption of RBBP4 enhanced TMZ sensitivity, induced synthetic lethality to PARP inhibition, and increased DNA damage signaling in response to TMZ. Moreover, RBBP4 silencing enhanced TMZ-induced H2AX phosphorylation and apoptosis in GBM cells. Intriguingly, RBBP4 knockdown suppressed the expression of MGMT, RAD51, and other genes in association with decreased promoter H3K9 acetylation (H3K9Ac) and increased H3K9 tri-methylation (H3K9me3). Consistent with these data, RBBP4 interacts with CBP/p300 to form a chromatin-modifying complex that binds within the promoter of MGMT, RAD51, and perhaps other genes. Globally, RBBP4 positively and negatively regulates genes involved in critical cellular functions including tumorigenesis. The RBBP4/CBP/p300 complex may provide an interesting target for developing therapy-sensitizing strategies for GBM and other tumors.
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Affiliation(s)
- Gaspar J Kitange
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN 55905, USA.
| | - Ann C Mladek
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Mark A Schroeder
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Jenny C Pokorny
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Brett L Carlson
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Yuji Zhang
- Department of Biostatistics and Bioinformatics, Mayo Clinic, Rochester, MN 55905, USA
| | - Asha A Nair
- Department of Biostatistics and Bioinformatics, Mayo Clinic, Rochester, MN 55905, USA
| | - Jeong-Heon Lee
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Huihuang Yan
- Department of Biostatistics and Bioinformatics, Mayo Clinic, Rochester, MN 55905, USA
| | - Paul A Decker
- Department of Biostatistics and Bioinformatics, Mayo Clinic, Rochester, MN 55905, USA
| | - Zhiguo Zhang
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Jann N Sarkaria
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN 55905, USA
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32
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Cho NW, Dilley RL, Lampson MA, Greenberg RA. Interchromosomal homology searches drive directional ALT telomere movement and synapsis. Cell 2015; 159:108-121. [PMID: 25259924 DOI: 10.1016/j.cell.2014.08.030] [Citation(s) in RCA: 261] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Revised: 06/16/2014] [Accepted: 08/25/2014] [Indexed: 12/17/2022]
Abstract
Telomere length maintenance is a requisite feature of cellular immortalization and a hallmark of human cancer. While most human cancers express telomerase activity, ∼10%-15% employ a recombination-dependent telomere maintenance pathway known as alternative lengthening of telomeres (ALT) that is characterized by multitelomere clusters and associated promyelocytic leukemia protein bodies. Here, we show that a DNA double-strand break (DSB) response at ALT telomeres triggers long-range movement and clustering between chromosome termini, resulting in homology-directed telomere synthesis. Damaged telomeres initiate increased random surveillance of nuclear space before displaying rapid directional movement and association with recipient telomeres over micron-range distances. This phenomenon required Rad51 and the Hop2-Mnd1 heterodimer, which are essential for homologous chromosome synapsis during meiosis. These findings implicate a specialized homology searching mechanism in ALT-dependent telomere maintenance and provide a molecular basis underlying the preference for recombination between nonsister telomeres during ALT.
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Affiliation(s)
- Nam Woo Cho
- Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104-6160, USA
| | - Robert L Dilley
- Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104-6160, USA
| | - Michael A Lampson
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Roger A Greenberg
- Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104-6160, USA; Department of Pathology, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104-6160, USA; Abramson Family Cancer Research Institute, Basser Research Center for BRCA, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104-6160, USA.
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33
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Prakash R, Zhang Y, Feng W, Jasin M. Homologous recombination and human health: the roles of BRCA1, BRCA2, and associated proteins. Cold Spring Harb Perspect Biol 2015; 7:a016600. [PMID: 25833843 DOI: 10.1101/cshperspect.a016600] [Citation(s) in RCA: 561] [Impact Index Per Article: 62.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Homologous recombination (HR) is a major pathway for the repair of DNA double-strand breaks in mammalian cells, the defining step of which is homologous strand exchange directed by the RAD51 protein. The physiological importance of HR is underscored by the observation of genomic instability in HR-deficient cells and, importantly, the association of cancer predisposition and developmental defects with mutations in HR genes. The tumor suppressors BRCA1 and BRCA2, key players at different stages of HR, are frequently mutated in familial breast and ovarian cancers. Other HR proteins, including PALB2 and RAD51 paralogs, have also been identified as tumor suppressors. This review summarizes recent findings on BRCA1, BRCA2, and associated proteins involved in human disease with an emphasis on their molecular roles and interactions.
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Affiliation(s)
- Rohit Prakash
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Yu Zhang
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Weiran Feng
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065 Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065 Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York 10065
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34
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Reuter M, Zelensky A, Smal I, Meijering E, van Cappellen WA, de Gruiter HM, van Belle GJ, van Royen ME, Houtsmuller AB, Essers J, Kanaar R, Wyman C. BRCA2 diffuses as oligomeric clusters with RAD51 and changes mobility after DNA damage in live cells. ACTA ACUST UNITED AC 2015; 207:599-613. [PMID: 25488918 PMCID: PMC4259808 DOI: 10.1083/jcb.201405014] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Nuclear BRCA2 is oligomeric and associated with RAD51, possibly sequestering it until it is delivered to DNA damage sites. Genome maintenance by homologous recombination depends on coordinating many proteins in time and space to assemble at DNA break sites. To understand this process, we followed the mobility of BRCA2, a critical recombination mediator, in live cells at the single-molecule level using both single-particle tracking and fluorescence correlation spectroscopy. BRCA2-GFP and -YFP were compared to distinguish diffusion from fluorophore behavior. Diffusive behavior of fluorescent RAD51 and RAD54 was determined for comparison. All fluorescent proteins were expressed from endogenous loci. We found that nuclear BRCA2 existed in oligomeric clusters, and exhibited heterogeneous mobility. DNA damage increased BRCA2 transient binding, presumably including binding to damaged sites. Despite its very different size, RAD51 displayed mobility similar to BRCA2, which indicates physical interaction between these proteins both before and after induction of DNA damage. We propose that BRCA2-mediated sequestration of nuclear RAD51 serves to prevent inappropriate DNA interactions and that all RAD51 is delivered to DNA damage sites in association with BRCA2.
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Affiliation(s)
- Marcel Reuter
- Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands
| | - Alex Zelensky
- Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands
| | - Ihor Smal
- Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands
| | - Erik Meijering
- Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands
| | - Wiggert A van Cappellen
- Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands
| | - H Martijn de Gruiter
- Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands
| | - Gijsbert J van Belle
- Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands
| | - Martin E van Royen
- Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands
| | - Adriaan B Houtsmuller
- Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands
| | - Jeroen Essers
- Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands
| | - Roland Kanaar
- Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands
| | - Claire Wyman
- Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands Department of Genetics, Cancer Genomics Centre Netherlands, Department of Medical Informatics, Department of Radiology, Erasmus Optical Imaging Centre, Department of Pathology, Department of Vascular Surgery, and Department of Radiation Oncology, Erasmus University Medical Centre, 3000 CA Rotterdam, Netherlands
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Roy N, Bhattacharyya S, Chakrabarty S, Laskar S, Babu SM, Bhattacharyya MK. Dominant negative mutant of Plasmodium Rad51 causes reduced parasite burden in host by abrogating DNA double-strand break repair. Mol Microbiol 2014; 94:353-66. [PMID: 25145341 DOI: 10.1111/mmi.12762] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2014] [Indexed: 01/05/2023]
Abstract
Malaria parasites survive through repairing a plethora of DNA double-stranded breaks (DSBs) experienced during their asexual growth. In Plasmodium Rad51 mediated homologous recombination (HR) mechanism and homology-independent alternative end-joining mechanism have been identified. Here we address whether loss of HR activity can be compensated by other DSB repair mechanisms. Creating a transgenic Plasmodium line defective in HR function, we demonstrate that HR is the most important DSB repair pathway in malarial parasite. Using mouse malaria model we have characterized the dominant negative effect of PfRad51(K143R) mutant on Plasmodium DSB repair and host-parasite interaction. Our work illustrates that Plasmodium berghei harbouring the mutant protein (PfRad51(K143R)) failed to repair DSBs as evidenced by hypersensitivity to DNA-damaging agent. Mice infected with mutant parasites lived significantly longer with markedly reduced parasite burden. To better understand the effect of mutant PfRad51(K143R) on HR, we used yeast as a surrogate model and established that the presence of PfRad51(K143R) completely inhibited DNA repair, gene conversion and gene targeting. Biochemical experiment confirmed that very low level of mutant protein was sufficient for complete disruption of wild-type PfRad51 activity. Hence our work provides evidence that HR pathway of Plasmodium could be efficiently targeted to curb malaria.
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Affiliation(s)
- Nabamita Roy
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, 500046, Andhra Pradesh, India
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Homology-directed repair of DNA nicks via pathways distinct from canonical double-strand break repair. Proc Natl Acad Sci U S A 2014; 111:E924-32. [PMID: 24556991 DOI: 10.1073/pnas.1400236111] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
DNA nicks are the most common form of DNA damage, and if unrepaired can give rise to genomic instability. In human cells, nicks are efficiently repaired via the single-strand break repair pathway, but relatively little is known about the fate of nicks not processed by that pathway. Here we show that homology-directed repair (HDR) at nicks occurs via a mechanism distinct from HDR at double-strand breaks (DSBs). HDR at nicks, but not DSBs, is associated with transcription and is eightfold more efficient at a nick on the transcribed strand than at a nick on the nontranscribed strand. HDR at nicks can proceed by a pathway dependent upon canonical HDR factors RAD51 and BRCA2; or by an efficient alternative pathway that uses either ssDNA or nicked dsDNA donors and that is strongly inhibited by RAD51 and BRCA2. Nicks generated by either I-AniI or the CRISPR/Cas9(D10A) nickase are repaired by the alternative HDR pathway with little accompanying mutagenic end-joining, so this pathway may be usefully applied to genome engineering. These results suggest that alternative HDR at nicks may be stimulated in physiological contexts in which canonical RAD51/BRCA2-dependent HDR is compromised or down-regulated, which occurs frequently in tumors.
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Park JY, Singh TR, Nassar N, Zhang F, Freund M, Hanenberg H, Meetei AR, Andreassen PR. Breast cancer-associated missense mutants of the PALB2 WD40 domain, which directly binds RAD51C, RAD51 and BRCA2, disrupt DNA repair. Oncogene 2013; 33:4803-12. [PMID: 24141787 PMCID: PMC3994186 DOI: 10.1038/onc.2013.421] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 08/29/2013] [Accepted: 09/05/2013] [Indexed: 12/13/2022]
Abstract
Heterozygous carriers of germ-line mutations in the BRCA2/FANCD1, PALB2/FANCN and RAD51C/FANCO DNA repair genes have an increased lifetime risk of developing breast, ovarian and other cancers; bi-allelic mutations in these genes clinically manifest as Fanconi anemia (FA). Here, we demonstrate that RAD51C is part of a novel protein complex that contains PALB2 and BRCA2. Further, the PALB2 WD40 domain can directly and independently bind RAD51C and BRCA2. To understand the role of these homologous recombination (HR) proteins in DNA repair, we functionally characterize effects of missense mutants of the PALB2 WD40 domain that have been reported in breast cancer patients. In contrast to large truncations of PALB2, which display a complete loss of interaction, the L939W, T1030I and L1143P missense mutants/variants of the PALB2 WD40 domain are associated with altered patterns of direct binding to the RAD51C, RAD51 and BRCA2 HR proteins in biochemical assays. Further, the T1030I missense mutant is unstable, whereas the L939W and L1143P proteins are stable but partially disrupt the PALB2-RAD51C-BRCA2 complex in cells. Functionally, the L939W and L1143P mutants display a decreased capacity for DNA double-strand break-induced HR and an increased cellular sensitivity to ionizing radiation. As further evidence for the functional importance of the HR complex, RAD51C mutants that are associated with cancer susceptibility and FA also display decreased complex formation with PALB2. Together, our results suggest that three different cancer susceptibility and FA proteins function in a DNA repair pathway based upon the PALB2 WD40 domain binding to RAD51C and BRCA2.
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Affiliation(s)
- J-Y Park
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Research Foundation, Cincinnati, OH, USA
| | - T R Singh
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Research Foundation, Cincinnati, OH, USA
| | - N Nassar
- 1] Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Research Foundation, Cincinnati, OH, USA [2] Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - F Zhang
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Research Foundation, Cincinnati, OH, USA
| | - M Freund
- Department of Otorhinolaryngology and Head/Neck Surgery, Heinrich Heine University School of Medicine, Duesseldorf, Germany
| | - H Hanenberg
- 1] Department of Otorhinolaryngology and Head/Neck Surgery, Heinrich Heine University School of Medicine, Duesseldorf, Germany [2] Unit of Pediatric Hematology/Oncology, Wells Center for Pediatric Research, Department of Pediatrics, The Riley Hospital, Indiana University School of Medicine, Indianapolis, IN, USA [3] Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A R Meetei
- 1] Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Research Foundation, Cincinnati, OH, USA [2] Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - P R Andreassen
- 1] Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Research Foundation, Cincinnati, OH, USA [2] Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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Interaction of FUS and HDAC1 regulates DNA damage response and repair in neurons. Nat Neurosci 2013; 16:1383-91. [PMID: 24036913 DOI: 10.1038/nn.3514] [Citation(s) in RCA: 306] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 08/14/2013] [Indexed: 12/11/2022]
Abstract
Defects in DNA repair have been extensively linked to neurodegenerative diseases, but the exact mechanisms remain poorly understood. We found that FUS, an RNA/DNA-binding protein that has been linked to amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration, is important for the DNA damage response (DDR). The function of FUS in DDR involved a direct interaction with histone deacetylase 1 (HDAC1), and the recruitment of FUS to double-stranded break sites was important for proper DDR signaling. Notably, FUS proteins carrying familial ALS mutations were defective in DDR and DNA repair and showed a diminished interaction with HDAC1. Moreover, we observed increased DNA damage in human ALS patients harboring FUS mutations. Our findings suggest that an impaired DDR and DNA repair may contribute to the pathogenesis of neurodegenerative diseases linked to FUS mutations.
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Gospodinov A, Herceg Z. Chromatin structure in double strand break repair. DNA Repair (Amst) 2013; 12:800-10. [PMID: 23919923 DOI: 10.1016/j.dnarep.2013.07.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 07/11/2013] [Indexed: 12/16/2022]
Abstract
Cells are under constant assault by endogenous and environmental DNA damaging agents. DNA double strand breaks (DSBs) sever entire chromosomes and pose a major threat to genome integrity as a result of chromosomal fragment loss or chromosomal rearrangements. Exogenous factors such as ionizing radiation, crosslinking agents, and topoisomerase poisons, contribute to break formation. DSBs are associated with oxidative metabolism, form during the normal S phase, when replication forks collapse and are generated during physiological processes such as V(D)J recombination, yeast mating type switching and meiosis. It is estimated that in mammalian cells ∼10 DSBs per cell are formed daily. If left unrepaired DSBs can lead to cell death or deregulated growth, and cancer development. Cellular response to DSB damage includes mechanisms to halt the progression of the cell cycle and to restore the structure of the broken chromosome. Changes in chromatin adjacent to DNA break sites are instrumental to the DNA damage response (DDR) with two apparent ends: to control compaction and to bind repair and signaling molecules to the lesion. Here, we review the key findings related to each of these functions and examine their cross-talk.
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Affiliation(s)
- Anastas Gospodinov
- Institute of Molecular Biology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. 21, 1113 Sofia, Bulgaria.
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Abstract
Mutations of the breast and ovarian cancer susceptibility gene 1 (BRCA1) account for about 40-45% of hereditary breast cancer cases. Moreover, a significant fraction of sporadic (non-hereditary) breast and ovarian cancers exhibit reduced or absent expression of the BRCA1 protein, suggesting an additional role for BRCA1 in sporadic cancers. BRCA1 follows the classic pattern of a highly penetrant Knudsen-type tumor suppressor gene in which one allele is inactivated through a germ-line mutation and the other is mutated or deleted within the tumor. BRCA1 is a multi-functional protein but it is not fully understood which function(s) is (are) most important for tumor suppression, nor is it clear why BRCA1-mutations confer a high risk for breast and ovarian cancers and not a broad spectrum of tumor types. Here, we will review BRCA1 functions in the DNA damage response (DDR), which are likely to contribute to tumor suppression. In the process, we will highlight some of the controversies and unresolved issues in the field. We will also describe a recently identified and under-investigated role for BRCA1 in the regulation of telomeres and the implications of this role in the DDR and cancer suppression.
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Affiliation(s)
- Eliot M Rosen
- Department of Oncology, Georgetown University School of Medicine Washington, DC, USA ; Department of Biochemistry, Molecular and Cellular Biology, Georgetown University School of Medicine Washington, DC, USA ; Department of Radiation Medicine, Georgetown University School of Medicine Washington, DC, USA
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Kim TM, Rebel VI, Hasty P. Defining a genotoxic profile with mouse embryonic stem cells. Exp Biol Med (Maywood) 2013; 238:285-93. [PMID: 23598974 DOI: 10.1177/1535370213480700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Many genotoxins are found in the environment from synthetic to natural, yet very few have been studied in depth. This means we fail to understand many molecules that damage DNA, we do not understand the type of damage they cause and the repair pathways required to correct their lesions. It is surprising so little is known about the vast majority of genotoxins since they have potential to cause disease from developmental defects to cancer to degenerative ailments. By contrast, some of these molecules have commercial and medical potential and some can be weaponized. Therefore, we need a systematic method to efficiently generate a genotoxic profile for these agents. A genotoxic profile would include the type of damage the genotoxin causes, the pathways used to repair the damage and the resultant mutations if repair fails. Mouse embryonic stem (ES) cells are well suited for identifying pathways and mutations. Mouse ES cells are genetically tractable and many DNA repair mutant cells are available. ES cells have a high mitotic index and form colonies so experiments can be completed quickly and easily. Furthermore, ES cells have robust DNA repair pathways to minimize genetic mutations at a particularly vulnerable time in life, early development when a mutation in a single cell could ultimately contribute to a large fraction of the individual. After an initial screen, other types of cells and mouse models can be used to complement the analysis. This review discusses the merging field of genotoxic screens in mouse ES cells that can be used to discover and study potential genotoxic activity for chemicals commonly found in our environment.
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Affiliation(s)
- Tae Moon Kim
- Department of Molecular Medicine and Institute of Biotechnology, University of Texas Health Science Center, San Antonio, TX 78245, USA
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Verma S, Rao BJ. p53 suppresses BRCA2-stimulated ATPase and strand exchange functions of human RAD51. J Biochem 2013; 154:237-48. [PMID: 23678008 DOI: 10.1093/jb/mvt040] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Although homologous recombination (HR) is an important pathway for DNA repair, it can also be a cause for deleterious genomic rearrangements leading to carcinogenesis. Therefore, cells have evolved elaborate mechanisms to regulate HR, positively as well as negatively. Among many molecular components that regulate HR are tumour suppressors p53, a negative regulator and breast cancer early-onset (BRCA)2, a positive regulator. Both the players not only interact with each other but also directly interact with human RAD51 (hRAD51), the key recombinase in HR. Here, for the first time we studied HR regulation by the combined action of p53 and BRCA2, in vitro. While BRC4 peptide inhibits ATP hydrolysis by hRAD51, BRCA2(BRC1-8) stimulates DNA-independent and double-stranded DNA-dependent ATPase several fold and only marginally single-stranded DNA-dependent ATPase. Pull down assays demonstrated the occurrence of complex comprising of all three proteins and DNA, where p53 tends to compete out hRAD51 and BRCA2(BRC1-8), leading to not only the decline in ATP hydrolysis but also the strand exchange function of hRAD51 that was stimulated by BRCA2(BRC1-8). Our findings suggest a rigorous p53-mediated regulation on hRAD51 functions in HR even in the presence of BRCA2.
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Affiliation(s)
- Shalini Verma
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, Maharashtra, India
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43
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I-SceI-based assays to examine distinct repair outcomes of mammalian chromosomal double strand breaks. Methods Mol Biol 2013; 920:379-91. [PMID: 22941618 DOI: 10.1007/978-1-61779-998-3_27] [Citation(s) in RCA: 252] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Chromosomal double strand breaks (DSBs) can be repaired by a number of mechanisms that result in diverse genetic outcomes. To examine distinct outcomes of chromosomal DSB repair, a panel of human cell lines has been developed that contain GFP-based reporters with recognition sites for the rare-cutting endonuclease I-SceI. One set of reporters is used to measure DSB repair events that require access to homology: homology-directed repair, homology-directed repair that requires the removal of a nonhomologous insertion, single strand annealing, and alternative end joining. An additional reporter (EJ5-GFP) is used to measure end joining (EJ) between distal DSB ends of two tandem I-SceI sites. These Distal-EJ events do not require access to homology, and thus are distinct from the repair events described above. Indeed, this assay provides a measure of DSB end protection during EJ, via physical analysis of Distal-EJ products to determine the frequency of I-SceI-restoration. The EJ5-GFP reporter can also be adapted to examine EJ of non-cohesive DSB ends, using co-expression of I-SceI with a non-processive 3' exonuclease (Trex2), which can cause partial degradation of the 4 nucleotide 3' cohesive overhangs generated by I-SceI. Such co-expression of I-SceI and Trex2 leads to measurable I-SceI-resistant EJ products that use proximal DSB ends (Proximal-EJ), as well as distal DSB ends (Distal-EJ). Therefore, this co-expression approach can be used to examine the relative frequency of Proximal-EJ versus Distal-EJ, and hence provide a measure of the fidelity of end utilization during repair of multiple DSBs. In this report, the repair outcomes examined by each reporter are described, along with methods for cell culture, transient expression of I-SceI and Trex2, and repair product analysis.
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Howell EK, Gaschak SP, Griffith KDW, Rodgers BE. Radioadaptive Response Following In Utero Low-Dose Irradiation. Radiat Res 2012. [DOI: 10.1667/rr3029.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Eric K. Howell
- Department of Biological Sciences and the Center for Environmental Radiation Studies, Texas Tech University, Lubbock, Texas; and
| | - Sergey P. Gaschak
- International Radioecology Laboratory, Slavutych, Kyiv Region 07100, Ukraine
| | - Kenneth D. W. Griffith
- Department of Biological Sciences and the Center for Environmental Radiation Studies, Texas Tech University, Lubbock, Texas; and
| | - Brenda E. Rodgers
- Department of Biological Sciences and the Center for Environmental Radiation Studies, Texas Tech University, Lubbock, Texas; and
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Gospodinov A, Herceg Z. Shaping chromatin for repair. Mutat Res 2012; 752:45-60. [PMID: 23085398 DOI: 10.1016/j.mrrev.2012.10.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Revised: 10/08/2012] [Accepted: 10/09/2012] [Indexed: 12/19/2022]
Abstract
To counteract the adverse effects of various DNA lesions, cells have evolved an array of diverse repair pathways to restore DNA structure and to coordinate repair with cell cycle regulation. Chromatin changes are an integral part of the DNA damage response, particularly with regard to the types of repair that involve assembly of large multiprotein complexes such as those involved in double strand break (DSB) repair and nucleotide excision repair (NER). A number of phosphorylation, acetylation, methylation, ubiquitylation and chromatin remodeling events modulate chromatin structure at the lesion site. These changes demarcate chromatin neighboring the lesion, afford accessibility and binding surfaces to repair factors and provide on-the-spot means to coordinate repair and damage signaling. Thus, the hierarchical assembly of repair factors at a double strand break is mostly due to their regulated interactions with posttranslational modifications of histones. A large number of chromatin remodelers are required at different stages of DSB repair and NER. Remodelers physically interact with proteins involved in repair processes, suggesting that chromatin remodeling is a requisite for repair factors to access the damaged site. Together, recent findings define the roles of histone post-translational modifications and chromatin remodeling in the DNA damage response and underscore possible differences in the requirements for these events in relation to the chromatin context.
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Affiliation(s)
- Anastas Gospodinov
- Institute of Molecular Biology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. 21, 1113 Sofia, Bulgaria
| | - Zdenko Herceg
- Epigenetics Group, International Agency for Research on Cancer (IARC), 150 Cours Albert Thomas, 69008, Lyon, France.
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Schumacher AJ, Mohni KN, Kan Y, Hendrickson EA, Stark JM, Weller SK. The HSV-1 exonuclease, UL12, stimulates recombination by a single strand annealing mechanism. PLoS Pathog 2012; 8:e1002862. [PMID: 22912580 PMCID: PMC3415443 DOI: 10.1371/journal.ppat.1002862] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 07/01/2012] [Indexed: 11/19/2022] Open
Abstract
Production of concatemeric DNA is an essential step during HSV infection, as the packaging machinery must recognize longer-than-unit-length concatemers; however, the mechanism by which they are formed is poorly understood. Although it has been proposed that the viral genome circularizes and rolling circle replication leads to the formation of concatemers, several lines of evidence suggest that HSV DNA replication involves recombination-dependent replication reminiscent of bacteriophages λ and T4. Similar to λ, HSV-1 encodes a 5′-to-3′ exonuclease (UL12) and a single strand annealing protein [SSAP (ICP8)] that interact with each other and can perform strand exchange in vitro. By analogy with λ phage, HSV may utilize viral and/or cellular recombination proteins during DNA replication. At least four double strand break repair pathways are present in eukaryotic cells, and HSV-1 is known to manipulate several components of these pathways. Chromosomally integrated reporter assays were used to measure the repair of double strand breaks in HSV-infected cells. Single strand annealing (SSA) was increased in HSV-infected cells, while homologous recombination (HR), non-homologous end joining (NHEJ) and alternative non-homologous end joining (A-NHEJ) were decreased. The increase in SSA was abolished when cells were infected with a viral mutant lacking UL12. Moreover, expression of UL12 alone caused an increase in SSA, which was completely eliminated when a UL12 mutant lacking exonuclease activity was expressed. UL12-mediated stimulation of SSA was decreased in cells lacking the cellular SSAP, Rad52, and could be restored by coexpressing the viral SSAP, ICP8, indicating that an SSAP is also required. These results demonstrate that UL12 can specifically stimulate SSA and that either ICP8 or Rad52 can function as an SSAP. We suggest that SSA is the homology-mediated repair pathway utilized during HSV infection. The repair of DNA damage is essential to maintain genomic stability. Cells have at least four distinct DNA repair pathways, and defects in any of them can lead to tumor formation and cancer progression. Herpes Simplex Virus-1 (HSV-1) manipulates components of the host DNA repair pathways. In this paper we showed that DNA repair by the single strand annealing (SSA) pathway was increased during HSV infection and that other pathways were inhibited. We also show that a viral nuclease in conjunction with either a viral or cellular single strand annealing protein can stimulate the SSA pathway. We suggest that viral DNA synthesis occurs via an SSAdependent mechanism that is reminiscent of that used by bacterial viruses such as λ. Interestingly, λ has evolved an SSA-mediated repair mechanism to exchange genetic information that has also been used to enhance gene targeting in bacteria. It is thus possible that HSV proteins could be similarly used as tools to stimulate gene targeting in human cells leading to more effective strategies for gene therapy. Furthermore, the diversity of HSV reported in human populations, combined with the high rate of genetic exchange during infection, suggests that SSA may play a role in viral evolution and pathogenesis.
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Affiliation(s)
- April J. Schumacher
- Molecular, Microbial and Structural Biology Department, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Kareem N. Mohni
- Molecular, Microbial and Structural Biology Department, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Yinan Kan
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Eric A. Hendrickson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Jeremy M. Stark
- Department of Cancer Biology, Beckman Research Institute of the City of Hope, Duarte, California, United States of America
| | - Sandra K. Weller
- Molecular, Microbial and Structural Biology Department, University of Connecticut Health Center, Farmington, Connecticut, United States of America
- * E-mail:
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47
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Abstract
RAD51 is important for restarting stalled replication forks and for repairing DNA double-strand breaks (DSBs) through a pathway called homology-directed repair (HDR). However, analysis of the consequences of specific RAD51 mutants has been difficult since they are toxic. Here we report on the dominant effects of two human RAD51 mutants defective for ATP binding (K133A) or ATP hydrolysis (K133R) expressed in mouse embryonic stem (ES) cells that also expressed normal mouse RAD51 from the other chromosome. These cells were defective for restarting stalled replication forks and repairing breaks. They were also hypersensitive to camptothecin, a genotoxin that generates breaks specifically at the replication fork. In addition, these cells exhibited a wide range of structural chromosomal changes that included multiple breakpoints within the same chromosome. Thus, ATP binding and hydrolysis are essential for chromosomal maintenance. Fusion of RAD51 to a fluorescent tag (enhanced green fluorescent protein [eGFP]) allowed visualization of these proteins at sites of replication and repair. We found very low levels of mutant protein present at these sites compared to normal protein, suggesting that low levels of mutant protein were sufficient for disruption of RAD51 activity and generation of chromosomal rearrangements.
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48
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Huang F, Mazina OM, Zentner IJ, Cocklin S, Mazin AV. Inhibition of homologous recombination in human cells by targeting RAD51 recombinase. J Med Chem 2012; 55:3011-20. [PMID: 22380680 DOI: 10.1021/jm201173g] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The homologous recombination (HR) pathway plays a crucial role in the repair of DNA double-strand breaks (DSBs) and interstrand cross-links (ICLs). RAD51, a key protein of HR, possesses a unique activity: DNA strand exchange between homologous DNA sequences. Recently, using a high-throughput screening (HTS), we identified compound 1 (B02), which specifically inhibits the DNA strand exchange activity of human RAD51. Here, we analyzed the mechanism of inhibition and found that 1 disrupts RAD51 binding to DNA. We then examined the effect of 1 on HR and DNA repair in the cell. The results show that 1 inhibits HR and increases cell sensitivity to DNA damage. We propose to use 1 for analysis of cellular functions of RAD51. Because DSB- and ICL-inducing agents are commonly used in anticancer therapy, specific inhibitors of RAD51 may also help to increase killing of cancer cells.
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Affiliation(s)
- Fei Huang
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA
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49
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Amunugama R, Fishel R. Homologous Recombination in Eukaryotes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 110:155-206. [DOI: 10.1016/b978-0-12-387665-2.00007-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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50
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Siaud N, Barbera MA, Egashira A, Lam I, Christ N, Schlacher K, Xia B, Jasin M. Plasticity of BRCA2 function in homologous recombination: genetic interactions of the PALB2 and DNA binding domains. PLoS Genet 2011; 7:e1002409. [PMID: 22194698 PMCID: PMC3240595 DOI: 10.1371/journal.pgen.1002409] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 10/15/2011] [Indexed: 11/30/2022] Open
Abstract
The breast cancer suppressor BRCA2 is essential for the maintenance of genomic integrity in mammalian cells through its role in DNA repair by homologous recombination (HR). Human BRCA2 is 3,418 amino acids and is comprised of multiple domains that interact with the RAD51 recombinase and other proteins as well as with DNA. To gain insight into the cellular function of BRCA2 in HR, we created fusions consisting of various BRCA2 domains and also introduced mutations into these domains to disrupt specific protein and DNA interactions. We find that a BRCA2 fusion peptide deleted for the DNA binding domain and active in HR is completely dependent on interaction with the PALB2 tumor suppressor for activity. Conversely, a BRCA2 fusion peptide deleted for the PALB2 binding domain is dependent on an intact DNA binding domain, providing a role for this conserved domain in vivo; mutagenesis suggests that both single-stranded and double-stranded DNA binding activities in the DNA binding domain are required for its activity. Given that PALB2 itself binds DNA, these results suggest alternative mechanisms to deliver RAD51 to DNA. In addition, the BRCA2 C terminus contains both RAD51-dependent and -independent activities which are essential to HR in some contexts. Finally, binding the small peptide DSS1 is essential for activity when its binding domain is present, but not when it is absent. Our results reveal functional redundancy within the BRCA2 protein and emphasize the plasticity of this large protein built for optimal HR function in mammalian cells. The occurrence of disease-causing mutations throughout BRCA2 suggests sub-optimal HR from a variety of domain modulations. The breast tumor suppressor BRCA2 has a major role in DNA repair by homologous recombination (HR). BRCA2 is a large protein with multiple domains that interact with several proteins as well as with DNA, complicating our understanding of how the protein functions in cells. To investigate the mechanism by which BRCA2 functions in HR in cells, we created fusions consisting of various BRCA2 domains and also introduced mutations into these domains to disrupt specific protein and DNA interactions. We find that DNA binding by BRCA2 is critical when a BRCA2 peptide is deficient in binding another breast cancer suppressor, PALB2, but not when the peptide can bind PALB2, suggesting alternative mechanisms of activity. Binding the small peptide DSS1 is also essential for HR only in some contexts, as are activities in the BRCA2 C terminus. Our results reveal redundancy of BRCA2 domains and emphasize plasticity within this large protein built for optimal HR function in mammalian cells. The occurrence of disease-causing mutations throughout BRCA2 suggests sub-optimal HR from a variety of domain modulations.
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Affiliation(s)
- Nicolas Siaud
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Maria A. Barbera
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Akinori Egashira
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Isabel Lam
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Louis V. Gerstner Sloan-Kettering Graduate School of Biomedical Sciences, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Nicole Christ
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Katharina Schlacher
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Bing Xia
- Department of Radiation Oncology, The Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, New Jersey, United States of America
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Louis V. Gerstner Sloan-Kettering Graduate School of Biomedical Sciences, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- * E-mail:
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