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Jimenez-Sainz J, Mathew J, Moore G, Lahiri S, Garbarino J, Eder JP, Rothenberg E, Jensen RB. BRCA2 BRC missense variants disrupt RAD51-dependent DNA repair. eLife 2022; 11:e79183. [PMID: 36098506 PMCID: PMC9545528 DOI: 10.7554/elife.79183] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 09/12/2022] [Indexed: 11/24/2022] Open
Abstract
Pathogenic mutations in the BRCA2 tumor suppressor gene predispose to breast, ovarian, pancreatic, prostate, and other cancers. BRCA2 maintains genome stability through homology-directed repair (HDR) of DNA double-strand breaks (DSBs) and replication fork protection. Nonsense or frameshift mutations leading to truncation of the BRCA2 protein are typically considered pathogenic; however, missense mutations resulting in single amino acid substitutions can be challenging to functionally interpret. The majority of missense mutations in BRCA2 have been classified as Variants of Uncertain Significance (VUS) with unknown functional consequences. In this study, we identified three BRCA2 VUS located within the BRC repeat region to determine their impact on canonical HDR and fork protection functions. We provide evidence that S1221P and T1980I, which map to conserved residues in the BRC2 and BRC7 repeats, compromise the cellular response to chemotherapeutics and ionizing radiation, and display deficits in fork protection. We further demonstrate biochemically that S1221P and T1980I disrupt RAD51 binding and diminish the ability of BRCA2 to stabilize RAD51-ssDNA complexes. The third variant, T1346I, located within the spacer region between BRC2 and BRC3 repeats, is fully functional. We conclude that T1346I is a benign allele, whereas S1221P and T1980I are hypomorphic disrupting the ability of BRCA2 to fully engage and stabilize RAD51 nucleoprotein filaments. Our results underscore the importance of correctly classifying BRCA2 VUS as pathogenic variants can impact both future cancer risk and guide therapy selection during cancer treatment.
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Affiliation(s)
| | - Joshua Mathew
- Department of Therapeutic Radiology, Yale UniversityNew HavenUnited States
| | - Gemma Moore
- Department of Therapeutic Radiology, Yale UniversityNew HavenUnited States
| | - Sudipta Lahiri
- Department of Therapeutic Radiology, Yale UniversityNew HavenUnited States
| | - Jennifer Garbarino
- Department of Therapeutic Radiology, Yale UniversityNew HavenUnited States
| | - Joseph P Eder
- Department of Medical Oncology, Yale University School of Medicine, Yale Cancer CenterNew HavenUnited States
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, New York UniversityNew YorkUnited States
| | - Ryan B Jensen
- Department of Therapeutic Radiology, Yale UniversityNew HavenUnited States
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Singh JK, Noordermeer SM, Jimenez-Sainz J, Maranon DG, Altmeyer M. Editorial: Protecting the code: DNA double-strand break repair pathway choice. Front Genet 2022; 13:993889. [PMID: 36035119 PMCID: PMC9413145 DOI: 10.3389/fgene.2022.993889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 07/19/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- Jenny Kaur Singh
- Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands
- Institut Curie, PSL University, CNRS, Orsay, France
| | - Sylvie M. Noordermeer
- Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands
- Oncode Institute, Utrecht, Netherlands
| | - Judit Jimenez-Sainz
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, United States
| | - David G. Maranon
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
- *Correspondence: Matthias Altmeyer,
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Jimenez-Sainz J, Krysztofiak A, Garbarino J, Rogers F, Jensen RB. The Pathogenic R3052W BRCA2 Variant Disrupts Homology-Directed Repair by Failing to Localize to the Nucleus. Front Genet 2022; 13:884210. [PMID: 35711920 PMCID: PMC9197106 DOI: 10.3389/fgene.2022.884210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/22/2022] [Indexed: 12/04/2022] Open
Abstract
The BRCA2 germline missense variant, R3052W, resides in the DNA binding domain and has been previously classified as a pathogenic allele. In this study, we sought to determine how R3052W alters the cellular functions of BRCA2 in the DNA damage response. The BRCA2 R3052W mutated protein exacerbates genome instability, is unable to rescue homology-directed repair, and fails to complement cell survival following exposure to PARP inhibitors and crosslinking drugs. Surprisingly, despite anticipated defects in DNA binding or RAD51-mediated DNA strand exchange, the BRCA2 R3052W protein mislocalizes to the cytoplasm precluding its ability to perform any DNA repair functions. Rather than acting as a simple loss-of-function mutation, R3052W behaves as a dominant negative allele, likely by sequestering RAD51 in the cytoplasm.
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Affiliation(s)
| | | | | | | | - Ryan B. Jensen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, United States
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Jimenez-Sainz J, Jensen RB. Imprecise Medicine: BRCA2 Variants of Uncertain Significance (VUS), the Challenges and Benefits to Integrate a Functional Assay Workflow with Clinical Decision Rules. Genes (Basel) 2021; 12:genes12050780. [PMID: 34065235 PMCID: PMC8161351 DOI: 10.3390/genes12050780] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 12/20/2022] Open
Abstract
Pathological mutations in homology-directed repair (HDR) genes impact both future cancer risk and therapeutic options for patients. HDR is a high-fidelity DNA repair pathway for resolving DNA double-strand breaks throughout the genome. BRCA2 is an essential protein that mediates the loading of RAD51 onto resected DNA breaks, a key step in HDR. Germline mutations in BRCA2 are associated with an increased risk for breast, ovarian, prostate, and pancreatic cancer. Clinical findings of germline or somatic BRCA2 mutations in tumors suggest treatment with platinum agents or PARP inhibitors. However, when genetic analysis reveals a variant of uncertain significance (VUS) in the BRCA2 gene, precision medicine-based decisions become complex. VUS are genetic changes with unknown pathological impact. Current statistics indicate that between 10–20% of BRCA sequencing results are VUS, and of these, more than 50% are missense mutations. Functional assays to determine the pathological outcome of VUS are urgently needed to provide clinical guidance regarding cancer risk and treatment options. In this review, we provide a brief overview of BRCA2 functions in HDR, describe how BRCA2 VUS are currently assessed in the clinic, and how genetic and biochemical functional assays could be integrated into the clinical decision process. We suggest a multi-step workflow composed of robust and accurate functional assays to correctly evaluate the potential pathogenic or benign nature of BRCA2 VUS. Success in this precision medicine endeavor will offer actionable information to patients and their physicians.
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Affiliation(s)
- Judit Jimenez-Sainz
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Correspondence: (J.J.-S.); (R.B.J.); Tel.:+1-203-737-6456 (R.B.J.)
| | - Ryan B. Jensen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA
- Correspondence: (J.J.-S.); (R.B.J.); Tel.:+1-203-737-6456 (R.B.J.)
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Jimenez-Sainz J, Jensen R. Abstract GMM-033: CONDITIONAL BRCA2 SWITCH IN HUMAN CELLS TO STUDY TUMOR PROGRESSION. Clin Cancer Res 2019. [DOI: 10.1158/1557-3265.ovcasymp18-gmm-033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The BRCA2 (Breast Cancer Susceptibility 2) gene is a caretaker of genome integrity. Germline mutations in BRCA2 predispose individuals to a high risk for ovarian and breast cancer. The BRCA2 protein plays an important role in repair of DNA double-strand breaks (DSBs) by homologous recombination. The hallmarks found in BRCA2 mutant tumors involve: genome instability including chromosome aberrations, sensitivity to cross-linking agents, presence of micronuclei, an abnormal number of centrosomes, and severe defects in homologous recombination. However, the initial steps of tumor progression in BRCA2 carriers remain elusive as the majority of cellular models are derived from tumor cell lines that have undergone prior selection in an environment of genomic instability. Here, we present the generation of isogenic, inducible BRCA2 human fallopian tube cell lines providing a model to study the acute loss of BRCA2 protein in the setting of initiation and progression towards tumorigenesis. In these otherwise normal human somatic cells, we have found that acute loss of BRCA2 impinges upon viability as well as other cellular abnormalities that may drive the accumulation and tolerance for further somatic mutations. We have discovered copy number variations modulated by crosslinking compounds in our inducible BRCA2 human fallopian tube cells. We are analyzing both the genetic and biochemical functions of BRCA2 in these processes. Our long-term goal is to elucidate the underlying molecular mechanisms that drive and sustain tumor initiation in the absence of normal BRCA2 function.
Citation Format: Jimenez-Sainz J., and Jensen R.B.. CONDITIONAL BRCA2 SWITCH IN HUMAN CELLS TO STUDY TUMOR PROGRESSION [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr GMM-033.
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Wang C, Jimenez-Sainz J, Jensen RB, Mazin AA. Abstract 1748: RAD51 has an anti-recombinase activity that is countered by BRCA2 - In vitro. Cancer Res 2019. [DOI: 10.1158/1538-7445.am2019-1748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Homologous Recombination (HR) is a high-fidelity process with a range of biologic functions from generation of genetic diversity to repair of DNA double-strand breaks (DSBs). In mammalian cells, BRCA2 facilitates the polymerization of RAD51 onto ssDNA to form a presynaptic nucleoprotein filament. This filament can then strand invade a homologous dsDNA to form the displacement loop (D-loop) structure leading to the eventual DSB repair. This pro-recombinatory feature of RAD51-BRCA2 is well documented. Here, we present biochemical evidence that RAD51 can cause D-loop disassembly. Furthermore, we show that this RAD51 anti-recombinatory activity is countered by BRCA2. These results demonstrate that BRCA2 may have a previously unexpected role: regulation of HR at a post-synaptic stage by modulating RAD51-mediated D-loop dissociation. Our results provide a biochemical mechanistic understanding of homeostasis between RAD51 and BRCA2, which has been suggested to be an important factor of HR based on previously published cellular data.
Citation Format: Charles Wang, Judit Jimenez-Sainz, Ryan B. Jensen, Alexander A. Mazin. RAD51 has an anti-recombinase activity that is countered by BRCA2 - In vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1748.
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Daley JM, Jimenez-Sainz J, Wang W, Miller AS, Xue X, Nguyen KA, Jensen RB, Sung P. Enhancement of BLM-DNA2-Mediated Long-Range DNA End Resection by CtIP. Cell Rep 2018; 21:324-332. [PMID: 29020620 DOI: 10.1016/j.celrep.2017.09.048] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 07/18/2017] [Accepted: 09/14/2017] [Indexed: 01/24/2023] Open
Abstract
DNA double-strand break repair by homologous recombination entails the resection of DNA ends to reveal ssDNA tails, which are used to invade a homologous DNA template. CtIP and its yeast ortholog Sae2 regulate the nuclease activity of MRE11 in the initial stage of resection. Deletion of CtIP in the mouse or SAE2 in yeast engenders a more severe phenotype than MRE11 nuclease inactivation, indicative of a broader role of CtIP/Sae2. Here, we provide biochemical evidence that CtIP promotes long-range resection via the BLM-DNA2 pathway. Specifically, CtIP interacts with BLM and enhances its helicase activity, and it enhances DNA cleavage by DNA2. Thus, CtIP influences multiple aspects of end resection beyond MRE11 regulation.
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Affiliation(s)
- James M Daley
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Judit Jimenez-Sainz
- Department of Therapeutic Radiobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Weibin Wang
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Adam S Miller
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Xiaoyu Xue
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Kevin A Nguyen
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Ryan B Jensen
- Department of Therapeutic Radiobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.
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Jimenez-Sainz J. Applying Pharmacogenomics in Therapeutics. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2017. [PMCID: PMC5369037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Chatterjee G, Jimenez-Sainz J, Presti T, Nguyen T, Jensen RB. Distinct binding of BRCA2 BRC repeats to RAD51 generates differential DNA damage sensitivity. Nucleic Acids Res 2016; 44:5256-70. [PMID: 27084934 PMCID: PMC4914107 DOI: 10.1093/nar/gkw242] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 03/29/2016] [Indexed: 01/01/2023] Open
Abstract
BRCA2 is a multi-faceted protein critical for the proper regulation of homology-directed repair of DNA double-strand breaks. Elucidating the mechanistic features of BRCA2 is crucial for understanding homologous recombination and how patient-derived mutations impact future cancer risk. Eight centrally located BRC repeats in BRCA2 mediate binding and regulation of RAD51 on resected DNA substrates. Herein, we dissect the biochemical and cellular features of the BRC repeats tethered to the DNA binding domain of BRCA2. To understand how the BRC repeats and isolated domains of BRCA2 contribute to RAD51 binding, we analyzed both the biochemical and cellular properties of these proteins. In contrast to the individual BRC repeat units, we find that the BRC5-8 region potentiates RAD51-mediated DNA strand pairing and provides complementation functions exceeding those of BRC repeats 1-4. Furthermore, BRC5-8 can efficiently repair nuclease-induced DNA double-strand breaks and accelerate the assembly of RAD51 repair complexes upon DNA damage. These findings highlight the importance of the BRC5-8 domain in stabilizing the RAD51 filament and promoting homology-directed repair under conditions of cellular DNA damage.
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Affiliation(s)
- Gouri Chatterjee
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Judit Jimenez-Sainz
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Thomas Presti
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Tiffany Nguyen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Ryan B Jensen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
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Zhao W, Vaithiyalingam S, San Filippo J, Maranon DG, Jimenez-Sainz J, Fontenay GV, Kwon Y, Leung SG, Lu L, Jensen RB, Chazin WJ, Wiese C, Sung P. Promotion of BRCA2-Dependent Homologous Recombination by DSS1 via RPA Targeting and DNA Mimicry. Mol Cell 2015; 59:176-87. [PMID: 26145171 DOI: 10.1016/j.molcel.2015.05.032] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 04/21/2015] [Accepted: 05/22/2015] [Indexed: 10/23/2022]
Abstract
The tumor suppressor BRCA2 is thought to facilitate the handoff of ssDNA from replication protein A (RPA) to the RAD51 recombinase during DNA break and replication fork repair by homologous recombination. However, we find that RPA-RAD51 exchange requires the BRCA2 partner DSS1. Biochemical, structural, and in vivo analyses reveal that DSS1 allows the BRCA2-DSS1 complex to physically and functionally interact with RPA. Mechanistically, DSS1 acts as a DNA mimic to attenuate the affinity of RPA for ssDNA. A mutation in the solvent-exposed acidic domain of DSS1 compromises the efficacy of RPA-RAD51 exchange. Thus, by targeting RPA and mimicking DNA, DSS1 functions with BRCA2 in a two-component homologous recombination mediator complex in genome maintenance and tumor suppression. Our findings may provide a paradigm for understanding the roles of DSS1 in other biological processes.
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Affiliation(s)
- Weixing Zhao
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Sivaraja Vaithiyalingam
- Departments of Biochemistry and Chemistry, and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Joseph San Filippo
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
| | - David G Maranon
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Judit Jimenez-Sainz
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Gerald V Fontenay
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Youngho Kwon
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Stanley G Leung
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Lucy Lu
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Ryan B Jensen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Walter J Chazin
- Departments of Biochemistry and Chemistry, and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA.
| | - Claudia Wiese
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA; Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.
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