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Liu J, Gore S, Heyer WD. Local structural dynamics of Rad51 protomers revealed by cryo-electron microscopy of Rad51-ssDNA filaments. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.06.592824. [PMID: 38766236 PMCID: PMC11100689 DOI: 10.1101/2024.05.06.592824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Homologous recombination (HR) is a high-fidelity repair mechanism for double-strand breaks. Rad51 is the key enzyme that forms filaments on single-stranded DNA (ssDNA) to catalyze homology search and DNA strand exchange in recombinational DNA repair. In this study, we employed single-particle cryo-electron microscopy (cryo-EM) to ascertain the density map of the budding yeast Rad51-ssDNA filament bound to ADP-AlF 3 , achieving a resolution of 2.35 Å without imposing helical symmetry. The model assigned 6 Rad51 protomers, 24 nt of DNA, and 6 bound ADP-AlF 3 . It shows 6-fold symmetry implying monomeric building blocks, unlike the structure of the Rad51-I345T mutant filament with three-fold symmetry implying dimeric building blocks, for which the structural comparisons provide a satisfying mechanistic explanation. This image analysis enables comprehensive comparisons of individual Rad51 protomers within the filament and reveals local conformational movements of amino acid side chains. Notably, Arg293 in Loop1 adopts multiple conformations to facilitate Leu296 and Val331 in separating and twisting the DNA triplets. We also analyzed the predicted structures of yeast Rad51-K342E and two tumor-derived human RAD51 variants, RAD51-Q268P and RAD51-Q272L, using the Rad51-ssDNA structure from this study as a reference.
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Antoniuk-Majchrzak J, Enkhbaatar T, Długajczyk A, Kaminska J, Skoneczny M, Klionsky DJ, Skoneczna A. Stability of Rad51 recombinase and persistence of Rad51 DNA repair foci depends on post-translational modifiers, ubiquitin and SUMO. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119526. [PMID: 37364618 DOI: 10.1016/j.bbamcr.2023.119526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 06/02/2023] [Accepted: 06/19/2023] [Indexed: 06/28/2023]
Abstract
The DNA double-strand breaks are particularly deleterious, especially when an error-free repair pathway is unavailable, enforcing the error-prone recombination pathways to repair the lesion. Cells can resume the cell cycle but at the expense of decreased viability due to genome rearrangements. One of the major players involved in recombinational repair of DNA damage is Rad51 recombinase, a protein responsible for presynaptic complex formation. We previously showed that an increased level of this protein promotes the usage of illegitimate recombination. Here we show that the level of Rad51 is regulated via the ubiquitin-dependent proteolytic pathway. The ubiquitination of Rad51 depends on multiple E3 enzymes, including SUMO-targeted ubiquitin ligases. We also demonstrate that Rad51 can be modified by both ubiquitin and SUMO. Moreover, its modification with ubiquitin may lead to opposite effects: degradation dependent on Rad6, Rad18, Slx8, Dia2, and the anaphase-promoting complex, or stabilization dependent on Rsp5. We also show that post-translational modifications with SUMO and ubiquitin affect Rad51's ability to form and disassemble DNA repair foci, respectively, influencing cell cycle progression and cell viability in genotoxic stress conditions. Our data suggest the existence of a complex E3 ligases network that regulates Rad51 recombinase's turnover, its molecular activity, and access to DNA, limiting it to the proportions optimal for the actual cell cycle stage and growth conditions, e.g., stress. Dysregulation of this network would result in a drop in cell viability due to uncontrolled genome rearrangement in the yeast cells. In mammals would promote the development of genetic diseases and cancer.
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Affiliation(s)
| | - Tuguldur Enkhbaatar
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Anna Długajczyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Joanna Kaminska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Marek Skoneczny
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Daniel J Klionsky
- Life Sciences Institute, Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Adrianna Skoneczna
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland.
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Benjamin M, Malakar P, Sinha RA, Nasser MW, Batra SK, Siddiqui JA, Chakravarti B. Molecular signaling network and therapeutic developments in breast cancer brain metastasis. ADVANCES IN CANCER BIOLOGY - METASTASIS 2023; 7:100079. [PMID: 36536947 PMCID: PMC7613958 DOI: 10.1016/j.adcanc.2022.100079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Breast cancer (BC) is one of the most frequently diagnosed cancers in women worldwide. It has surpassed lung cancer as the leading cause of cancer-related death. Breast cancer brain metastasis (BCBM) is becoming a major clinical concern that is commonly associated with ER-ve and HER2+ve subtypes of BC patients. Metastatic lesions in the brain originate when the cancer cells detach from a primary breast tumor and establish metastatic lesions and infiltrate near and distant organs via systemic blood circulation by traversing the BBB. The colonization of BC cells in the brain involves a complex interplay in the tumor microenvironment (TME), metastatic cells, and brain cells like endothelial cells, microglia, and astrocytes. BCBM is a significant cause of morbidity and mortality and presents a challenge to developing successful cancer therapy. In this review, we discuss the molecular mechanism of BCBM and novel therapeutic strategies for patients with brain metastatic BC.
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Affiliation(s)
- Mercilena Benjamin
- Lab Oncology, Dr. B.R.A.I.R.C.H. All India Institute of Medical Sciences, New Delhi, India
| | - Pushkar Malakar
- Department of Biomedical Science and Technology, School of Biological Sciences, Ramakrishna Mission Vivekananda Educational and Research Institute, Narendrapur, West Bengal, 700103, India
| | - Rohit Anthony Sinha
- Department of Endocrinology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, 226014, India
| | - Mohd Wasim Nasser
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, 68198, USA
- Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68108, USA
| | - Surinder K. Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, 68198, USA
- Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68108, USA
| | - Jawed Akhtar Siddiqui
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, 68198, USA
- Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68108, USA
| | - Bandana Chakravarti
- Department of Endocrinology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, 226014, India
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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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Liu H, Weng J. A Pan-Cancer Bioinformatic Analysis of RAD51 Regarding the Values for Diagnosis, Prognosis, and Therapeutic Prediction. Front Oncol 2022; 12:858756. [PMID: 35359409 PMCID: PMC8960930 DOI: 10.3389/fonc.2022.858756] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/17/2022] [Indexed: 12/21/2022] Open
Abstract
Background RAD51, a critical protein for DNA repairment, has been found to associate with multiple cancer types, but, so far, a systematic pan-cancer analysis of RAD51 has not been done yet. Methods Data were obtained from multiple open databases and genetic alteration, gene expression, survival association, functional enrichment, stemness, mutation association, immunity association, and drug therapy association of RAD51were analyzed. A prognostic model of RAD51 for overall glioma was constructed as an example application of RAD51 as a biomarker. Results RAD51 was overexpressed in 28 types of cancers and was associated with worse overall survival in 11 cancer types. RAD51 correlated genes were enriched in cell cycle terms. RAD51 was associated with cancer stemness, tumor mutational burden, and multiple immunomodulators in different cancer types. RAD51 expression was different across immune subtypes in 11 cancer types. RAD51 was closely associated with cancer immune microenvironments in some cancer types. Proliferating T cells was the cell type that expressed highest RAD51 across most of the cancer samples analyzed. RAD51 expression had an AUC of over 0.5 in 12 of the 23 ICB subcohorts. The Tumor Immune Dysfunction and Exclusion of 9 cancer types were different between RAD51 high and low groups. RAD51 expression showed negative correlations with the sensitivity of most drugs. A prognostic nomogram was constructed with a high confidence. Conclusion RAD51 is a clinical valuable biomarker for multiple cancer types, regarding its potential power for diagnosis, prognosis, and therapeutic prediction.
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Affiliation(s)
| | - Jieling Weng
- Department of Pathology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
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Toh M, Ngeow J. Homologous Recombination Deficiency: Cancer Predispositions and Treatment Implications. Oncologist 2021; 26:e1526-e1537. [PMID: 34021944 PMCID: PMC8417864 DOI: 10.1002/onco.13829] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 12/03/2020] [Indexed: 12/19/2022] Open
Abstract
Homologous recombination (HR) is a highly accurate DNA repair mechanism. Several HR genes are established cancer susceptibility genes with clinically actionable pathogenic variants (PVs). Classically, BRCA1 and BRCA2 germline PVs are associated with significant breast and ovarian cancer risks. Patients with BRCA1 or BRCA2 PVs display worse clinical outcomes but respond better to platinum-based chemotherapies and poly-ADP ribose polymerase inhibitors, a trait termed "BRCAness." With the advent of whole-exome sequencing and multigene panels, PVs in other HR genes are increasingly identified among familial cancers. As such, several genes such as PALB2 are reclassified as cancer predisposition genes. But evidence for cancer risks remains unclear for many others. In this review, we will discuss cancer predispositions and treatment implications beyond BRCA1 and BRCA2, with a focus on 24 HR genes: 53BP1, ATM, ATR, ATRIP, BARD1, BLM, BRIP1, DMC1, MRE11A, NBN, PALB2, RAD50, RAD51, RAD51B, RAD51C, RAD51D, RIF1, RMI1, RMI2, RPA1, TOP3A, TOPBP1, XRCC2, and XRCC3. IMPLICATIONS FOR PRACTICE: This review provides a comprehensive reference for readers to quickly identify potential cancer predisposing homologous recombination (HR) genes, and to generate research questions for genes with inconclusive evidence. This review also evaluates the "BRCAness" of each HR member. Clinicians can refer to these discussions to identify potential candidates for future clinical trials.
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Affiliation(s)
- MingRen Toh
- Duke–National University of Singapore Medical SchoolSingapore
| | - Joanne Ngeow
- Cancer Genetics Service, Division of Medical Oncology, National Cancer CenterSingapore
- Lee Kong Chian School of Medicine, Nanyang Technological UniversitySingapore
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Wilde JJ, Aida T, Del Rosario RCH, Kaiser T, Qi P, Wienisch M, Zhang Q, Colvin S, Feng G. Efficient embryonic homozygous gene conversion via RAD51-enhanced interhomolog repair. Cell 2021; 184:3267-3280.e18. [PMID: 34043941 PMCID: PMC8240950 DOI: 10.1016/j.cell.2021.04.035] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 03/03/2021] [Accepted: 04/19/2021] [Indexed: 12/20/2022]
Abstract
Searching for factors to improve knockin efficiency for therapeutic applications, biotechnology, and generation of non-human primate models of disease, we found that the strand exchange protein RAD51 can significantly increase Cas9-mediated homozygous knockin in mouse embryos through an interhomolog repair (IHR) mechanism. IHR is a hallmark of meiosis but only occurs at low frequencies in somatic cells, and its occurrence in zygotes is controversial. Using multiple approaches, we provide evidence for an endogenous IHR mechanism in the early embryo that can be enhanced by RAD51. This process can be harnessed to generate homozygotes from wild-type zygotes using exogenous donors and to convert heterozygous alleles into homozygous alleles without exogenous templates. Furthermore, we identify additional IHR-promoting factors and describe features of IHR events. Together, our findings show conclusive evidence for IHR in mouse embryos and describe an efficient method for enhanced gene conversion.
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Affiliation(s)
- Jonathan J Wilde
- Department of Brain & Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.
| | - Tomomi Aida
- Department of Brain & Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Ricardo C H Del Rosario
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Tobias Kaiser
- Department of Brain & Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Peimin Qi
- Department of Brain & Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Martin Wienisch
- Department of Brain & Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Qiangge Zhang
- Department of Brain & Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Steven Colvin
- Department of Brain & Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Guoping Feng
- Department of Brain & Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
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8
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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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Huang F, Tang W, Lei Y. MicroRNA-107 promotes apoptosis of acute myelocytic leukemia cells by targeting RAD51. Arch Med Sci 2021; 17:1044-1055. [PMID: 34336032 PMCID: PMC8314419 DOI: 10.5114/aoms.2020.92860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 06/11/2018] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION This study aimed to investigate the role of microRNA (miRNA) that affects acute myelocytic leukemia (AML) and its potential molecular mechanism by constructing a miRNA-mRNA interaction network using bioinformatics methods. MATERIAL AND METHODS MicroRNA expression data of AML were retrieved from Gene Expression Omnibus (GEO) and analyzed by microarray analysis. Expression levels of miR-107 and RAD51 mRNA were detected by quantitative real time polymerase chain reaction (qRT-PCR). Protein expression of RAD51, pro-apoptotic protein Bax, apoptosis related protein CytC and anti-apoptotic protein Bcl-2 were determined by Western blot. The rate of cell apoptosis was detected by Annexin-V/PI. The predicted targeting relationship between miR-107 and the 3'UTR of RAD51 was first predicted by the online application TargetScan and then verified by dual-luciferase assay. RESULTS Acute myelocytic leukemia-associated genes (n = 197) and miRNAs (n = 1701) were retrieved from the database, the interaction network of miRNA-mRNA was constructed and the core position was occupied by RAD51. miR-107 exhibited a regulatory effect on RAD51 in which the mRNA and protein expression of RAD51 were both significantly inhibited by miR-107 mimics in vitro. Additionally, down-regulated expression of miR107 as well as up-regulated expression of RAD51 were detected not only in the plasma of AML patients compared to healthy volunteers, but also in AML cell lines compared to the normal bone marrow stromal cell line. Further study found that increased expression of miR-107 and the consequent down-regulation of RAD51 could aggravate the apoptosis of AML cells in vitro. CONCLUSIONS Our present results showed that the crucial role of RAD51 and miR-107 in the apoptosis of AML cells, i.e., miR-107 promotes the apoptosis of AML cells through down-regulating the expression of RAD51.
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Affiliation(s)
- Fengxia Huang
- Department of Medical Technology Clinical and Hematological Laboratory Office, Xi’an Medical University, Xi’an, Shaanxi, China
| | - Wei Tang
- Department of Radiology, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, China
| | - Yan Lei
- Department of Laboratory Medicine, North Sichuan Medical College, Nanchong, Sichuan, China
- Department of Clinical Laboratory, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, China
- Translational Medical Research Center, North Sichuan Medical College, Nanchong, Sichuan, China
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10
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Grundy MK, Buckanovich RJ, Bernstein KA. Regulation and pharmacological targeting of RAD51 in cancer. NAR Cancer 2020; 2:zcaa024. [PMID: 33015624 PMCID: PMC7520849 DOI: 10.1093/narcan/zcaa024] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/25/2020] [Accepted: 09/03/2020] [Indexed: 01/06/2023] Open
Abstract
Regulation of homologous recombination (HR) is central for cancer prevention. However, too little HR can increase cancer incidence, whereas too much HR can drive cancer resistance to therapy. Importantly, therapeutics targeting HR deficiency have demonstrated a profound efficacy in the clinic improving patient outcomes, particularly for breast and ovarian cancer. RAD51 is central to DNA damage repair in the HR pathway. As such, understanding the function and regulation of RAD51 is essential for cancer biology. This review will focus on the role of RAD51 in cancer and beyond and how modulation of its function can be exploited as a cancer therapeutic.
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Affiliation(s)
- McKenzie K Grundy
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Ronald J Buckanovich
- Division of Hematology Oncology, Department of Internal Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Kara A Bernstein
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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11
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Role of Rad51 and DNA repair in cancer: A molecular perspective. Pharmacol Ther 2020; 208:107492. [PMID: 32001312 DOI: 10.1016/j.pharmthera.2020.107492] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/13/2020] [Accepted: 01/22/2020] [Indexed: 12/24/2022]
Abstract
The maintenance of genome integrity is essential for any organism survival and for the inheritance of traits to offspring. To the purpose, cells have developed a complex DNA repair system to defend the genetic information against both endogenous and exogenous sources of damage. Accordingly, multiple repair pathways can be aroused from the diverse forms of DNA lesions, which can be effective per se or via crosstalk with others to complete the whole DNA repair process. Deficiencies in DNA healing resulting in faulty repair and/or prolonged DNA damage can lead to genes mutations, chromosome rearrangements, genomic instability, and finally carcinogenesis and/or cancer progression. Although it might seem paradoxical, at the same time such defects in DNA repair pathways may have therapeutic implications for potential clinical practice. Here we provide an overview of the main DNA repair pathways, with special focus on the role played by homologous repair and the RAD51 recombinase protein in the cellular DNA damage response. We next discuss the recombinase structure and function per se and in combination with all its principal mediators and regulators. Finally, we conclude with an analysis of the manifold roles that RAD51 plays in carcinogenesis, cancer progression and anticancer drug resistance, and conclude this work with a survey of the most promising therapeutic strategies aimed at targeting RAD51 in experimental oncology.
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12
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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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13
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Ghodke H, Paudel BP, Lewis JS, Jergic S, Gopal K, Romero ZJ, Wood EA, Woodgate R, Cox MM, van Oijen AM. Spatial and temporal organization of RecA in the Escherichia coli DNA-damage response. eLife 2019; 8:42761. [PMID: 30717823 PMCID: PMC6363387 DOI: 10.7554/elife.42761] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 01/22/2019] [Indexed: 12/14/2022] Open
Abstract
The RecA protein orchestrates the cellular response to DNA damage via its multiple roles in the bacterial SOS response. Lack of tools that provide unambiguous access to the various RecA states within the cell have prevented understanding of the spatial and temporal changes in RecA structure/function that underlie control of the damage response. Here, we develop a monomeric C-terminal fragment of the λ repressor as a novel fluorescent probe that specifically interacts with RecA filaments on single-stranded DNA (RecA*). Single-molecule imaging techniques in live cells demonstrate that RecA is largely sequestered in storage structures during normal metabolism. Upon DNA damage, the storage structures dissolve and the cytosolic pool of RecA rapidly nucleates to form early SOS-signaling complexes, maturing into DNA-bound RecA bundles at later time points. Both before and after SOS induction, RecA* largely appears at locations distal from replisomes. Upon completion of repair, RecA storage structures reform.
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Affiliation(s)
- Harshad Ghodke
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Bishnu P Paudel
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Jacob S Lewis
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Slobodan Jergic
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Kamya Gopal
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Zachary J Romero
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Elizabeth A Wood
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Roger Woodgate
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
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14
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Asan A, Skoko JJ, Woodcock CSC, Wingert BM, Woodcock SR, Normolle D, Huang Y, Stark JM, Camacho CJ, Freeman BA, Neumann CA. Electrophilic fatty acids impair RAD51 function and potentiate the effects of DNA-damaging agents on growth of triple-negative breast cells. J Biol Chem 2018; 294:397-404. [PMID: 30478172 DOI: 10.1074/jbc.ac118.005899] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/15/2018] [Indexed: 01/24/2023] Open
Abstract
Homologous recombination (HR)-directed DNA double-strand break (DSB) repair enables template-directed DNA repair to maintain genomic stability. RAD51 recombinase (RAD51) is a critical component of HR and facilitates DNA strand exchange in DSB repair. We report here that treating triple-negative breast cancer (TNBC) cells with the fatty acid nitroalkene 10-nitro-octadec-9-enoic acid (OA-NO2) in combination with the antineoplastic DNA-damaging agents doxorubicin, cisplatin, olaparib, and γ-irradiation (IR) enhances the antiproliferative effects of these agents. OA-NO2 inhibited IR-induced RAD51 foci formation and enhanced H2A histone family member X (H2AX) phosphorylation in TNBC cells. Analyses of fluorescent DSB reporter activity with both static-flow cytometry and kinetic live-cell studies enabling temporal resolution of recombination revealed that OA-NO2 inhibits HR and not nonhomologous end joining (NHEJ). OA-NO2 alkylated Cys-319 in RAD51, and this alkylation depended on the Michael acceptor properties of OA-NO2 because nonnitrated and saturated nonelectrophilic analogs of OA-NO2, octadecanoic acid and 10-nitro-octadecanoic acid, did not react with Cys-319. Of note, OA-NO2 alkylation of RAD51 inhibited its binding to ssDNA. RAD51 Cys-319 resides within the SH3-binding site of ABL proto-oncogene 1, nonreceptor tyrosine kinase (ABL1), so we investigated the effect of OA-NO2-mediated Cys-319 alkylation on ABL1 binding and found that OA-NO2 inhibits RAD51-ABL1 complex formation both in vitro and in cell-based immunoprecipitation assays. The inhibition of the RAD51-ABL1 complex also suppressed downstream RAD51 Tyr-315 phosphorylation. In conclusion, RAD51 Cys-319 is a functionally significant site for adduction of soft electrophiles such as OA-NO2 and suggests further investigation of lipid electrophile-based combinational therapies for TNBC.
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Affiliation(s)
- Alparslan Asan
- From the Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261.,Women's Cancer Research Center, University of Pittsburgh Medical Center (UPMC) Hillman Cancer Center, Pittsburgh, Pennsylvania 15213.,Magee-Womens Research Institute, Magee-Womens Research Hospital of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213
| | - John J Skoko
- From the Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, .,Women's Cancer Research Center, University of Pittsburgh Medical Center (UPMC) Hillman Cancer Center, Pittsburgh, Pennsylvania 15213.,Magee-Womens Research Institute, Magee-Womens Research Hospital of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213
| | - Chen-Shan Chen Woodcock
- From the Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | | | - Steven R Woodcock
- From the Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Daniel Normolle
- Biostatistics, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Yi Huang
- From the Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261.,Women's Cancer Research Center, University of Pittsburgh Medical Center (UPMC) Hillman Cancer Center, Pittsburgh, Pennsylvania 15213.,Magee-Womens Research Institute, Magee-Womens Research Hospital of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213
| | - Jeremy M Stark
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, California 91010
| | | | - Bruce A Freeman
- From the Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Carola A Neumann
- From the Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, .,Women's Cancer Research Center, University of Pittsburgh Medical Center (UPMC) Hillman Cancer Center, Pittsburgh, Pennsylvania 15213.,Magee-Womens Research Institute, Magee-Womens Research Hospital of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213
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15
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van der Zon NL, Kanaar R, Wyman C. Variation in RAD51 details a hub of functions: opportunities to advance cancer diagnosis and therapy. F1000Res 2018; 7. [PMID: 30271574 PMCID: PMC6137408 DOI: 10.12688/f1000research.15650.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/29/2018] [Indexed: 11/30/2022] Open
Abstract
Loss of genome stability is one of the hallmarks of the enabling characteristics of cancer development. Homologous recombination is a DNA repair process that often breaks down as a prelude to developing cancer. Conversely, homologous recombination can be the Achilles’ heel in common anti-cancer therapies, which are effective by inducing irreparable DNA damage. Here, we review recent structural and functional studies of RAD51, the protein that catalyzes the defining step of homologous recombination: homology recognition and DNA strand exchange. Specific mutations can be linked to structural changes and known essential functions. Additional RAD51 interactions and functions may be revealed. The identification of viable mutations in this essential protein may help define the range of activity and interactions needed. All of this information provides opportunities to fine-tune existing therapies based on homologous recombination status, guide diagnosis, and hopefully develop new clinical tools.
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Affiliation(s)
- Nick Ll van der Zon
- Department of Molecular Genetics, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
| | - Roland Kanaar
- Department of Molecular Genetics, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands.,Oncode Institute, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
| | - Claire Wyman
- Department of Molecular Genetics, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands.,Department of Radiation Oncology, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
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16
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van der Zon NLL, Kanaar R, Wyman C. Variation in RAD51 details a hub of functions: opportunities to advance cancer diagnosis and therapy. F1000Res 2018; 7:F1000 Faculty Rev-1453. [PMID: 30271574 PMCID: PMC6137408 DOI: 10.12688/f1000research.15650.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/29/2018] [Indexed: 11/06/2023] Open
Abstract
Loss of genome stability is one of the hallmarks of the enabling characteristics of cancer development. Homologous recombination is a DNA repair process that often breaks down as a prelude to developing cancer. Conversely, homologous recombination can be the Achilles' heel in common anti-cancer therapies, which are effective by inducing irreparable DNA damage. Here, we review recent structural and functional studies of RAD51, the protein that catalyzes the defining step of homologous recombination: homology recognition and DNA strand exchange. Specific mutations can be linked to structural changes and known essential functions. Additional RAD51 interactions and functions may be revealed. The identification of viable mutations in this essential protein may help define the range of activity and interactions needed. All of this information provides opportunities to fine-tune existing therapies based on homologous recombination status, guide diagnosis, and hopefully develop new clinical tools.
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Affiliation(s)
- Nick LL van der Zon
- Department of Molecular Genetics, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
| | - Roland Kanaar
- Department of Molecular Genetics, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
- Oncode Institute, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
| | - Claire Wyman
- Department of Molecular Genetics, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
- Department of Radiation Oncology, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
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17
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Ding YC, Adamson AW, Steele L, Bailis AM, John EM, Tomlinson G, Neuhausen SL. Discovery of mutations in homologous recombination genes in African-American women with breast cancer. Fam Cancer 2018; 17:187-195. [PMID: 28864920 PMCID: PMC5834346 DOI: 10.1007/s10689-017-0036-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
African-American women are more likely to develop aggressive breast cancer at younger ages and experience poorer cancer prognoses than non-Hispanic Caucasians. Deficiency in repair of DNA by homologous recombination (HR) is associated with cancer development, suggesting that mutations in genes that affect this process may cause breast cancer. Inherited pathogenic mutations have been identified in genes involved in repairing DNA damage, but few studies have focused on African-Americans. We screened for germline mutations in seven HR repair pathway genes in DNA of 181 African-American women with breast cancer, evaluated the potential effects of identified missense variants using in silico prediction software, and functionally characterized a set of missense variants by yeast two-hybrid assays. We identified five likely-damaging variants, including two PALB2 truncating variants (Q151X and W1038X) and three novel missense variants (RAD51C C135R, and XRCC3 L297P and V337E) that abolish protein-protein interactions in yeast two-hybrid assays. Our results add to evidence that HR gene mutations account for a proportion of the genetic risk for developing breast cancer in African-Americans. Identifying additional mutations that diminish HR may provide a tool for better assessing breast cancer risk and improving approaches for targeted treatment.
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Affiliation(s)
- Yuan Chun Ding
- Department of Population Sciences, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Aaron W Adamson
- Department of Population Sciences, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Linda Steele
- Department of Population Sciences, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Adam M Bailis
- Department of Molecular and Cellular Biology, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Esther M John
- Cancer Prevention Institute of California, Fremont, CA, USA
- Department of Health Research & Policy (Epidemiology), and Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Gail Tomlinson
- Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
- Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Susan L Neuhausen
- Department of Population Sciences, Beckman Research Institute of City of Hope, Duarte, CA, USA.
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18
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Turchick A, Hegan DC, Jensen RB, Glazer PM. A cell-penetrating antibody inhibits human RAD51 via direct binding. Nucleic Acids Res 2017; 45:11782-11799. [PMID: 29036688 PMCID: PMC5714174 DOI: 10.1093/nar/gkx871] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 09/16/2017] [Indexed: 12/11/2022] Open
Abstract
RAD51, a key factor in homology-directed repair (HDR), has long been considered an attractive target for cancer therapy, but few specific inhibitors have been found. A cell-penetrating, anti-DNA, lupus autoantibody, 3E10, was previously shown to inhibit HDR, sensitize tumors to radiation, and mediate synthetic lethal killing of BRCA2-deficient cancer cells, effects that were initially attributed to its affinity for DNA. However, as the molecular basis for its ability to inhibit DNA repair, we report that 3E10 directly binds to the N-terminus of RAD51, sequesters RAD51 in the cytoplasm, and impedes RAD51 binding to DNA. Further, we generate separation-of-function mutations in the complementarity-determining regions of 3E10 revealing that inhibition of HDR tracks with binding to RAD51 but not to DNA, whereas cell penetration is linked to DNA binding. The consequences of these mutations on putative 3E10 interactions with RAD51 and DNA are correlated with in silico molecular modeling. Taken together, the results identify 3E10 as a novel inhibitor of RAD51 by direct binding, accounting for its ability to suppress HDR and providing the molecular basis to guide pre-clinical development of 3E10 as an anti-cancer agent.
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Affiliation(s)
- Audrey Turchick
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Denise C Hegan
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Ryan B Jensen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06510, USA.,Department of Pathology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Peter M Glazer
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06510, USA.,Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06510, USA
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19
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Silva MC, Bryan KE, Morrical MD, Averill AM, Dragon J, Wiegmans AP, Morrical SW. Defects in recombination activity caused by somatic and germline mutations in the multimerization/BRCA2 binding region of human RAD51 protein. DNA Repair (Amst) 2017; 60:64-76. [PMID: 29100040 DOI: 10.1016/j.dnarep.2017.10.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 09/10/2017] [Accepted: 10/19/2017] [Indexed: 10/18/2022]
Abstract
The human RAD51 recombinase possesses DNA pairing and strand exchange activities that are essential for the error-free, homology-directed repair of DNA double-strand breaks. The recombination activities of RAD51 are activated upon its assembly into presynaptic filaments on single-stranded DNA at resected DSB ends. Defects in filament assembly caused by mutations in RAD51 or its regulators such as BRCA2 are associated with human cancer. Here we describe two novel RAD51 missense variants located in the multimerization/BRCA2 binding region of RAD51. F86L is a breast tumor-derived somatic variant that affects the interface between adjacent RAD51 protomers in the presynaptic filament. E258A is a germline variant that maps to the interface region between the N-terminal and RecA homology domains of RAD51. Both variants exhibit abnormal biochemistry including altered DNA strand exchange activity. Both variants inhibit the DNA strand exchange activity of wild-type RAD51, suggesting a mechanism for negative dominance. The inhibitory effect of F86L on wild-type RAD51 is surprising since F86L alone exhibits robust DNA strand exchange activity. Our findings indicate that even DNA strand exchange-proficient variants can have negative functional interactions with wild-type RAD51. Thus heterozygous F86L or E258 mutations in RAD51 could promote genomic instability, and thereby contribute to tumor progression.
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Affiliation(s)
- Michelle C Silva
- Department of Biochemistry, Larner College of Medicine at the University of Vermont, Burlington, VT 05405, United States
| | - Katie E Bryan
- Department of Biochemistry, Larner College of Medicine at the University of Vermont, Burlington, VT 05405, United States
| | - Milagros D Morrical
- Department of Biochemistry, Larner College of Medicine at the University of Vermont, Burlington, VT 05405, United States
| | - April M Averill
- Department of Microbiology & Molecular Genetics, Larner College of Medicine at the University of Vermont, Burlington, VT 05405, United States
| | - Julie Dragon
- Department of Microbiology & Molecular Genetics, Larner College of Medicine at the University of Vermont, Burlington, VT 05405, United States; University of Vermont Cancer Center, Burlington, VT 05405, United States
| | - Adrian P Wiegmans
- Tumor Microenvironment Laboratory, QIMR Berghofer, Herston Rd., Herston, QLD 4006, Australia
| | - Scott W Morrical
- Department of Biochemistry, Larner College of Medicine at the University of Vermont, Burlington, VT 05405, United States; Department of Microbiology & Molecular Genetics, Larner College of Medicine at the University of Vermont, Burlington, VT 05405, United States; University of Vermont Cancer Center, Burlington, VT 05405, United States.
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20
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Short JM, Liu Y, Chen S, Soni N, Madhusudhan MS, Shivji MKK, Venkitaraman AR. High-resolution structure of the presynaptic RAD51 filament on single-stranded DNA by electron cryo-microscopy. Nucleic Acids Res 2016; 44:9017-9030. [PMID: 27596592 PMCID: PMC5100573 DOI: 10.1093/nar/gkw783] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 08/24/2016] [Indexed: 12/21/2022] Open
Abstract
Homologous DNA recombination (HR) by the RAD51 recombinase enables error-free DNA break repair. To execute HR, RAD51 first forms a presynaptic filament on single-stranded (ss) DNA, which catalyses pairing with homologous double-stranded (ds) DNA. Here, we report a structure for the presynaptic human RAD51 filament at 3.5–5.0Å resolution using electron cryo-microscopy. RAD51 encases ssDNA in a helical filament of 103Å pitch, comprising 6.4 protomers per turn, with a rise of 16.1Å and a twist of 56.2°. Inter-protomer distance correlates with rotation of an α-helical region in the core catalytic domain that is juxtaposed to ssDNA, suggesting how the RAD51–DNA interaction modulates protomer spacing and filament pitch. We map Fanconi anaemia-like disease-associated RAD51 mutations, clarifying potential phenotypes. We predict binding sites on the presynaptic filament for two modules present in each BRC repeat of the BRCA2 tumour suppressor, a critical HR mediator. Structural modelling suggests that changes in filament pitch mask or expose one binding site with filament-inhibitory potential, rationalizing the paradoxical ability of the BRC repeats to either stabilize or inhibit filament formation at different steps during HR. Collectively, our findings provide fresh insight into the structural mechanism of HR and its dysregulation in human disease.
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Affiliation(s)
- Judith M Short
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Yang Liu
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Shaoxia Chen
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Neelesh Soni
- Indian Institute of Science, Education & Research, Dr Homi Babha Road, Pune 411 008, India
| | - Mallur S Madhusudhan
- Indian Institute of Science, Education & Research, Dr Homi Babha Road, Pune 411 008, India.,Bioinformatics Institute, A*STAR, 30 Biopolis Drive, 138671 Singapore
| | - Mahmud K K Shivji
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Ashok R Venkitaraman
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
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21
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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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22
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Torres-Huerta AL, Martínez-Miguel RM, Bazán-Tejeda ML, Bermúdez-Cruz RM. Characterization of recombinase DMC1B and its functional role as Rad51 in DNA damage repair in Giardia duodenalis trophozoites. Biochimie 2016; 127:173-86. [DOI: 10.1016/j.biochi.2016.05.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 05/22/2016] [Indexed: 01/08/2023]
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23
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Silva MC, Morrical MD, Bryan KE, Averill AM, Dragon J, Bond JP, Morrical SW. RAD51 variant proteins from human lung and kidney tumors exhibit DNA strand exchange defects. DNA Repair (Amst) 2016; 42:44-55. [PMID: 27153211 DOI: 10.1016/j.dnarep.2016.02.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 02/16/2016] [Accepted: 02/29/2016] [Indexed: 02/05/2023]
Abstract
In human cells, error-free repair of DNA double-strand breaks requires the DNA pairing and strand exchange activities of RAD51 recombinase. Activation of RAD51 recombination activities requires the assembly of RAD51 presynaptic filaments on the single-stranded DNA that forms at resected DSB ends. Mutations in proteins that control presynaptic filament assembly, such as BRCA2, and in RAD51 itself, are associated with human breast cancer. Here we describe the properties of two mutations in RAD51 protein that derive from human lung and kidney tumors, respectively. Sequence variants Q268P and Q272L both map to the DNA binding loop 2 (L2) region of RAD51, a motif that is involved in DNA binding and in the allosteric activation of ATP hydrolysis and DNA strand exchange activities. Both mutations alter the thermal stability, DNA binding, and ATPase properties of RAD51, however both variants retain intrinsic DNA strand exchange activity towards oligonucleotide substrates under optimized conditions. In contrast, both Q268P and Q272L variants exhibit drastically reduced DNA strand exchange activity in reaction mixtures containing long homologous ssDNA and dsDNA substrates and human RPA protein. Mixtures of wild-type and variant proteins also exhibit reduced DNA strand exchange activity, suggesting that heterozygous mutations could negatively affect DNA recombination and repair processes in vivo. Together, the findings of this study suggest that hypomorphic missense mutations in RAD51 protein could be drivers of genomic instability in cancer cells, and thereby contribute to the etiology of metastatic disease.
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Affiliation(s)
- Michelle C Silva
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, VT 05405, United States
| | - Milagros D Morrical
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, VT 05405, United States
| | - Katie E Bryan
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, VT 05405, United States
| | - April M Averill
- Department of Microbiology & Molecular Genetics, University of Vermont College of Medicine, Burlington, VT, 05405 United States
| | - Julie Dragon
- Department of Microbiology & Molecular Genetics, University of Vermont College of Medicine, Burlington, VT, 05405 United States
| | - Jeffrey P Bond
- Department of Microbiology & Molecular Genetics, University of Vermont College of Medicine, Burlington, VT, 05405 United States; University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT 05405 United States
| | - Scott W Morrical
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, VT 05405, United States; Department of Microbiology & Molecular Genetics, University of Vermont College of Medicine, Burlington, VT, 05405 United States; University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT 05405 United States.
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