1
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Miron S, Legrand P, Dupaigne P, van Rossum-Fikkert SE, Ristic D, Majeed A, Kanaar R, Zinn-Justin S, Zelensky AN. DMC1 and RAD51 bind FxxA and FxPP motifs of BRCA2 via two separate interfaces. Nucleic Acids Res 2024:gkae452. [PMID: 38828772 DOI: 10.1093/nar/gkae452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 04/29/2024] [Accepted: 05/29/2024] [Indexed: 06/05/2024] Open
Abstract
In vertebrates, the BRCA2 protein is essential for meiotic and somatic homologous recombination due to its interaction with the RAD51 and DMC1 recombinases through FxxA and FxPP motifs (here named A- and P-motifs, respectively). The A-motifs present in the eight BRC repeats of BRCA2 compete with the A-motif of RAD51, which is responsible for its self-oligomerization. BRCs thus disrupt RAD51 nucleoprotein filaments in vitro. The role of the P-motifs is less studied. We recently found that deletion of Brca2 exons 12-14 encoding one of them (the prototypical 'PhePP' motif), disrupts DMC1 but not RAD51 function in mouse meiosis. Here we provide a mechanistic explanation for this phenotype by solving the crystal structure of the complex between a BRCA2 fragment containing the PhePP motif and DMC1. Our structure reveals that, despite sharing a conserved phenylalanine, the A- and P-motifs bind to distinct sites on the ATPase domain of the recombinases. The P-motif interacts with a site that is accessible in DMC1 octamers and nucleoprotein filaments. Moreover, we show that this interaction also involves the adjacent protomer and thus increases the stability of the DMC1 nucleoprotein filaments. We extend our analysis to other P-motifs from RAD51AP1 and FIGNL1.
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Affiliation(s)
- Simona Miron
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Pierre Legrand
- Synchrotron SOLEIL, HelioBio group, L'Orme des Merisiers, Gif sur-Yvette, France
| | - Pauline Dupaigne
- Genome Maintenance and Molecular Microscopy UMR 9019 CNRS, Université Paris-Saclay, Gustave Roussy, Villejuif, France
| | - Sari E van Rossum-Fikkert
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000CA, Rotterdam, The Netherlands
| | - Dejan Ristic
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000CA, Rotterdam, The Netherlands
| | - Atifa Majeed
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Roland Kanaar
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000CA, Rotterdam, The Netherlands
- Oncode Institute, Erasmus University Medical Center, 3000CA, Rotterdam, The Netherlands
| | - Sophie Zinn-Justin
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Alex N Zelensky
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000CA, Rotterdam, The Netherlands
- Oncode Institute, Erasmus University Medical Center, 3000CA, Rotterdam, The Netherlands
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2
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Valdez BC, Tsimberidou AM, Yuan B, Nieto Y, Baysal MA, Chakraborty A, Andersen CR, Andersson BS. Synergistic cytotoxicity of histone deacetylase and poly-ADP ribose polymerase inhibitors and decitabine in pancreatic cancer cells: Implications for novel therapy. Oncotarget 2024; 15:361-373. [PMID: 38829622 PMCID: PMC11146633 DOI: 10.18632/oncotarget.28588] [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: 03/09/2024] [Accepted: 05/17/2024] [Indexed: 06/05/2024] Open
Abstract
Histone deacetylase inhibitors (HDACi) can modulate the acetylation status of proteins, influencing the genomic instability exhibited by cancer cells. Poly (ADP ribose) polymerase (PARP) inhibitors (PARPi) have a direct effect on protein poly (ADP-ribosyl)ation, which is important for DNA repair. Decitabine is a nucleoside cytidine analogue, which when phosphorylated gets incorporated into the growing DNA strand, inhibiting methylation and inducing DNA damage by inactivating and trapping DNA methyltransferase on the DNA, thereby activating transcriptionally silenced DNA loci. We explored various combinations of HDACi and PARPi +/- decitabine (hypomethylating agent) in pancreatic cancer cell lines BxPC-3 and PL45 (wild-type BRCA1 and BRCA2) and Capan-1 (mutated BRCA2). The combination of HDACi (panobinostat or vorinostat) with PARPi (talazoparib or olaparib) resulted in synergistic cytotoxicity in all cell lines tested. The addition of decitabine further increased the synergistic cytotoxicity noted with HDACi and PARPi, triggering apoptosis (evidenced by increased cleavage of caspase 3 and PARP1). The 3-drug combination treatments (vorinostat, talazoparib, and decitabine; vorinostat, olaparib, and decitabine; panobinostat, talazoparib, and decitabine; panobinostat, olaparib, and decitabine) induced more DNA damage (increased phosphorylation of histone 2AX) than the individual drugs and impaired the DNA repair pathways (decreased levels of ATM, BRCA1, and ATRX proteins). The 3-drug combinations also altered the epigenetic regulation of gene expression (NuRD complex subunits, reduced levels). This is the first study to demonstrate synergistic interactions between the aforementioned agents in pancreatic cancer cell lines and provides preclinical data to design individualized therapeutic approaches with the potential to improve pancreatic cancer treatment outcomes.
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Affiliation(s)
- Benigno C. Valdez
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Apostolia M. Tsimberidou
- Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Bin Yuan
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Yago Nieto
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Mehmet A. Baysal
- Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Abhijit Chakraborty
- Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Clark R. Andersen
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Borje S. Andersson
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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3
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MacDonald N, Raven N, Diep W, Evans S, Pannipitiya S, Bramwell G, Vanbeek C, Thomas F, Russell T, Dujon AM, Telonis-Scott M, Ujvari B. The molecular evolution of cancer associated genes in mammals. Sci Rep 2024; 14:11650. [PMID: 38773187 PMCID: PMC11109183 DOI: 10.1038/s41598-024-62425-0] [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: 11/16/2023] [Accepted: 05/16/2024] [Indexed: 05/23/2024] Open
Abstract
Cancer is a disease that many multicellular organisms have faced for millions of years, and species have evolved various tumour suppression mechanisms to control oncogenesis. Although cancer occurs across the tree of life, cancer related mortality risks vary across mammalian orders, with Carnivorans particularly affected. Evolutionary theory predicts different selection pressures on genes associated with cancer progression and suppression, including oncogenes, tumour suppressor genes and immune genes. Therefore, we investigated the evolutionary history of cancer associated gene sequences across 384 mammalian taxa, to detect signatures of selection across categories of oncogenes (GRB2, FGL2 and CDC42), tumour suppressors (LITAF, Casp8 and BRCA2) and immune genes (IL2, CD274 and B2M). This approach allowed us to conduct a fine scale analysis of gene wide and site-specific signatures of selection across mammalian lineages under the lens of cancer susceptibility. Phylogenetic analyses revealed that for most species the evolution of cancer associated genes follows the species' evolution. The gene wide selection analyses revealed oncogenes being the most conserved, tumour suppressor and immune genes having similar amounts of episodic diversifying selection. Despite BRCA2's status as a key caretaker gene, episodic diversifying selection was detected across mammals. The site-specific selection analyses revealed that the two apoptosis associated domains of the Casp8 gene of bats (Chiroptera) are under opposing forces of selection (positive and negative respectively), highlighting the importance of site-specific selection analyses to understand the evolution of highly complex gene families. Our results highlighted the need to critically assess different types of selection pressure on cancer associated genes when investigating evolutionary adaptations to cancer across the tree of life. This study provides an extensive assessment of cancer associated genes in mammals with highly representative, and substantially large sample size for a comparative genomic analysis in the field and identifies various avenues for future research into the mechanisms of cancer resistance and susceptibility in mammals.
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Affiliation(s)
- Nick MacDonald
- School of Life and Environmental Sciences, Deakin University, Geelong, Waurn Ponds, Geelong, VIC, 3216, Australia
| | - Nynke Raven
- School of Life and Environmental Sciences, Deakin University, Geelong, Waurn Ponds, Geelong, VIC, 3216, Australia
| | - Wendy Diep
- School of Life and Environmental Sciences, Deakin University, Geelong, Waurn Ponds, Geelong, VIC, 3216, Australia
| | - Samantha Evans
- School of Life and Environmental Sciences, Deakin University, Geelong, Waurn Ponds, Geelong, VIC, 3216, Australia
| | - Senuri Pannipitiya
- School of Life and Environmental Sciences, Deakin University, Geelong, Waurn Ponds, Geelong, VIC, 3216, Australia
| | - Georgina Bramwell
- School of Life and Environmental Sciences, Deakin University, Geelong, Waurn Ponds, Geelong, VIC, 3216, Australia
| | - Caitlin Vanbeek
- School of Life and Environmental Sciences, Deakin University, Geelong, Waurn Ponds, Geelong, VIC, 3216, Australia
| | - Frédéric Thomas
- CREEC, UMR IRD 224-CNRS 5290, Université de Montpellier, Montpellier, France
- MIVEGEC, IRD, CNRS, Université Montpellier, Montpellier, France
| | - Tracey Russell
- Faculty of Science, School of Life and Environmental Sciences, Sydney, NSW, Australia
| | - Antoine M Dujon
- School of Life and Environmental Sciences, Deakin University, Geelong, Waurn Ponds, Geelong, VIC, 3216, Australia
| | - Marina Telonis-Scott
- School of Life and Environmental Sciences, Deakin University, Burwood, Burwood, VIC, 3125, Australia
| | - Beata Ujvari
- School of Life and Environmental Sciences, Deakin University, Geelong, Waurn Ponds, Geelong, VIC, 3216, Australia.
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4
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Uhrig ME, Sharma N, Maxwell P, Selemenakis P, Mazin AV, Wiese C. Disparate requirements for RAD54L in replication fork reversal. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.07.26.550704. [PMID: 37546955 PMCID: PMC10402051 DOI: 10.1101/2023.07.26.550704] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
RAD54L is a DNA motor protein with multiple roles in homologous recombination DNA repair (HR). In vitro , RAD54L was shown to also catalyze the reversal and restoration of model replication forks. In cells, however, little is known about how RAD54L may regulate the dynamics of DNA replication. Here, we show that RAD54L restrains the progression of replication forks and functions as a fork remodeler in human cells. Analogous to HLTF, SMARCAL1, and FBH1, and consistent with a role in fork reversal, RAD54L decelerates fork progression in response to replication stress and suppresses the formation of replication-associated ssDNA gaps. Interestingly, loss of RAD54L prevents nascent strand DNA degradation in both BRCA1/2- and 53BP1-deficient cells, suggesting that RAD54L functions in both pathways of RAD51-mediated replication fork reversal. In the HLTF/SMARCAL1 pathway, RAD54L is critical, but its ability to catalyze branch migration is dispensable, indicative of its function downstream of HLTF/SMARCAL1. Conversely, in the FBH1 pathway, branch migration activity of RAD54L is essential, and FBH1 engagement is dependent on its concerted action with RAD54L. Collectively, our results reveal disparate requirements for RAD54L in two distinct RAD51-mediated fork reversal pathways, positing its potential as a future therapeutic target.
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5
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Tong J, Song J, Zhang W, Zhai J, Guan Q, Wang H, Liu G, Zheng C. When DNA-damage responses meet innate and adaptive immunity. Cell Mol Life Sci 2024; 81:185. [PMID: 38630271 PMCID: PMC11023972 DOI: 10.1007/s00018-024-05214-2] [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: 11/04/2023] [Revised: 03/17/2024] [Accepted: 03/18/2024] [Indexed: 04/19/2024]
Abstract
When cells proliferate, stress on DNA replication or exposure to endogenous or external insults frequently results in DNA damage. DNA-Damage Response (DDR) networks are complex signaling pathways used by multicellular organisms to prevent DNA damage. Depending on the type of broken DNA, the various pathways, Base-Excision Repair (BER), Nucleotide Excision Repair (NER), Mismatch Repair (MMR), Homologous Recombination (HR), Non-Homologous End-Joining (NHEJ), Interstrand Crosslink (ICL) repair, and other direct repair pathways, can be activated separately or in combination to repair DNA damage. To preserve homeostasis, innate and adaptive immune responses are effective defenses against endogenous mutation or invasion by external pathogens. It is interesting to note that new research keeps showing how closely DDR components and the immune system are related. DDR and immunological response are linked by immune effectors such as the cyclic GMP-AMP synthase (cGAS)-Stimulator of Interferon Genes (STING) pathway. These effectors act as sensors of DNA damage-caused immune response. Furthermore, DDR components themselves function in immune responses to trigger the generation of inflammatory cytokines in a cascade or even trigger programmed cell death. Defective DDR components are known to disrupt genomic stability and compromise immunological responses, aggravating immune imbalance and leading to serious diseases such as cancer and autoimmune disorders. This study examines the most recent developments in the interaction between DDR elements and immunological responses. The DDR network's immune modulators' dual roles may offer new perspectives on treating infectious disorders linked to DNA damage, including cancer, and on the development of target immunotherapy.
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Affiliation(s)
- Jie Tong
- College of Life Science, Hebei University, Baoding, 071002, China
- Institute of Life Science and Green Development, Hebei University, Baoding, 071002, China
| | - Jiangwei Song
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100089, China
| | - Wuchao Zhang
- College of Veterinary Medicine, Hebei Agricultural University, Baoding, 071000, China
| | - Jingbo Zhai
- Key Laboratory of Zoonose Prevention and Control at Universities of Inner Mongolia Autonomous Region, Medical College, Inner Mongolia Minzu University, Tongliao, 028000, China
| | - Qingli Guan
- The Affiliated Hospital of Chinese PLA 80th Group Army, Weifang, 261000, China
| | - Huiqing Wang
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.
| | - Gentao Liu
- Department of Oncology, Tenth People's Hospital Affiliated to Tongji University & Cancer Center, Tongji University School of Medicine, Shanghai, 20000, China.
| | - Chunfu Zheng
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada.
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6
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Sun M, Xie H, Zhang W, Li X, Jiang Z, Liang Y, Zhao G, Huang N, Mao J, Liu G, Zhang Z. Bioinspired Lipoproteins of Furoxans-Gemcitabine Preferentially Targets Glioblastoma and Overcomes Radiotherapy Resistance. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2306190. [PMID: 38049204 PMCID: PMC10853724 DOI: 10.1002/advs.202306190] [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: 09/29/2023] [Revised: 10/31/2023] [Indexed: 12/06/2023]
Abstract
Radiotherapy (RT) resistance is an enormous challenge in glioblastoma multiforme (GBM) treatment, which is largely associated with DNA repair, poor distribution of reactive radicals in tumors, and limited delivery of radiosensitizers to the tumor sites. Inspired by the aberrant upregulation of RAD51 (a critical protein of DNA repair), scavenger receptor B type 1 (SR-B1), and C-C motif chemokine ligand 5 (CCL5) in GBM patients, a reduction-sensitive nitric oxide (NO) donor conjugate of gemcitabine (RAD51 inhibitor) (NG) is synthesized as radio-sensitizer and a CCL5 peptide-modified bioinspired lipoprotein system of NG (C-LNG) is rationally designed, aiming to preferentially target the tumor sites and overcome the RT resistance. C-LNG can preferentially accumulate at the orthotopic GBM tumor sites with considerable intratumor permeation, responsively release the gemcitabine and NO, and then generate abundant peroxynitrite (ONOO- ) upon X-ray radiation, thereby producing a 99.64% inhibition of tumor growth and a 71.44% survival rate at 120 days in GL261-induced orthotopic GBM tumor model. Therefore, the rationally designed bioinspired lipoprotein of NG provides an essential strategy to target GBM and overcome RT resistance.
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Affiliation(s)
- Maoyuan Sun
- Department of NeurosurgeryThe Second Affiliated Hospital of Chongqing Medical UniversityChongqing400016China
| | - Honglei Xie
- Institute of PharmacologySchool of Pharmaceutical SciencesShandong First Medical University & Shandong Academy of Medical Sciences619 Changcheng RoadTaian271016China
| | - Wenli Zhang
- Department of RadiologyThe Second Affiliated Hospital of Chongqing Medical UniversityChongqing400016China
| | - Xianlu Li
- School of Pharmacy & Key Laboratory of Smart Drug Delivery (Ministry of Education)Fudan UniversityShanghai201203China
| | - Zhan Jiang
- Department of OncologyThe Chongqing General HospitalChongqing400016China
| | - Yiyu Liang
- School of Pharmacy & Key Laboratory of Smart Drug Delivery (Ministry of Education)Fudan UniversityShanghai201203China
| | - Guanjian Zhao
- Department of NeurosurgeryThe Second Affiliated Hospital of Chongqing Medical UniversityChongqing400016China
| | - Ning Huang
- Department of NeurosurgeryThe Second Affiliated Hospital of Chongqing Medical UniversityChongqing400016China
| | - Jinning Mao
- Health Management CenterThe Second Affiliated HospitalChongqing Medical UniversityChongqing400016China
| | - Guodong Liu
- Department of NeurosurgeryThe Second Affiliated Hospital of Chongqing Medical UniversityChongqing400016China
| | - Zhiwen Zhang
- School of Pharmacy & Key Laboratory of Smart Drug Delivery (Ministry of Education)Fudan UniversityShanghai201203China
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7
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Lim PX, Zaman M, Feng W, Jasin M. BRCA2 promotes genomic integrity and therapy resistance primarily through its role in homology-directed repair. Mol Cell 2024; 84:447-462.e10. [PMID: 38244544 PMCID: PMC11188060 DOI: 10.1016/j.molcel.2023.12.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 10/10/2023] [Accepted: 12/15/2023] [Indexed: 01/22/2024]
Abstract
Tumor suppressor BRCA2 functions in homology-directed repair (HDR), the protection of stalled replication forks, and the suppression of replicative gaps, but their relative contributions to genome integrity and chemotherapy response are under scrutiny. Here, we report that mouse and human cells require a RAD51 filament stabilization motif in BRCA2 for fork protection and gap suppression but not HDR. In mice, the loss of fork protection/gap suppression does not compromise genome stability or shorten tumor latency. By contrast, HDR deficiency increases spontaneous and replication stress-induced chromosome aberrations and tumor predisposition. Unlike with HDR, fork protection/gap suppression defects are also observed in Brca2 heterozygous cells, likely due to reduced RAD51 stabilization at stalled forks/gaps. Gaps arise from PRIMPOL activity, which is associated with 5-hydroxymethyl-2'-deoxyuridine sensitivity due to the formation of SMUG1-generated abasic sites and is exacerbated by poly(ADP-ribose) polymerase (PARP) inhibition. However, HDR proficiency has the major role in mitigating sensitivity to chemotherapeutics, including PARP inhibitors.
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Affiliation(s)
- Pei Xin Lim
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Mahdia Zaman
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Weiran Feng
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA.
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8
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Ito M, Fujita Y, Shinohara A. Positive and negative regulators of RAD51/DMC1 in homologous recombination and DNA replication. DNA Repair (Amst) 2024; 134:103613. [PMID: 38142595 DOI: 10.1016/j.dnarep.2023.103613] [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: 08/02/2023] [Revised: 12/10/2023] [Accepted: 12/10/2023] [Indexed: 12/26/2023]
Abstract
RAD51 recombinase plays a central role in homologous recombination (HR) by forming a nucleoprotein filament on single-stranded DNA (ssDNA) to catalyze homology search and strand exchange between the ssDNA and a homologous double-stranded DNA (dsDNA). The catalytic activity of RAD51 assembled on ssDNA is critical for the DNA-homology-mediated repair of DNA double-strand breaks in somatic and meiotic cells and restarting stalled replication forks during DNA replication. The RAD51-ssDNA complex also plays a structural role in protecting the regressed/reversed replication fork. Two types of regulators control RAD51 filament formation, stability, and dynamics, namely positive regulators, including mediators, and negative regulators, so-called remodelers. The appropriate balance of action by the two regulators assures genome stability. This review describes the roles of positive and negative RAD51 regulators in HR and DNA replication and its meiosis-specific homolog DMC1 in meiotic recombination. We also provide future study directions for a comprehensive understanding of RAD51/DMC1-mediated regulation in maintaining and inheriting genome integrity.
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Affiliation(s)
- Masaru Ito
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
| | - Yurika Fujita
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
| | - Akira Shinohara
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
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9
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Nasheuer HP, Meaney AM, Hulshoff T, Thiele I, Onwubiko NO. Replication Protein A, the Main Eukaryotic Single-Stranded DNA Binding Protein, a Focal Point in Cellular DNA Metabolism. Int J Mol Sci 2024; 25:588. [PMID: 38203759 PMCID: PMC10779431 DOI: 10.3390/ijms25010588] [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: 11/30/2023] [Revised: 12/28/2023] [Accepted: 12/29/2023] [Indexed: 01/12/2024] Open
Abstract
Replication protein A (RPA) is a heterotrimeric protein complex and the main single-stranded DNA (ssDNA)-binding protein in eukaryotes. RPA has key functions in most of the DNA-associated metabolic pathways and DNA damage signalling. Its high affinity for ssDNA helps to stabilise ssDNA structures and protect the DNA sequence from nuclease attacks. RPA consists of multiple DNA-binding domains which are oligonucleotide/oligosaccharide-binding (OB)-folds that are responsible for DNA binding and interactions with proteins. These RPA-ssDNA and RPA-protein interactions are crucial for DNA replication, DNA repair, DNA damage signalling, and the conservation of the genetic information of cells. Proteins such as ATR use RPA to locate to regions of DNA damage for DNA damage signalling. The recruitment of nucleases and DNA exchange factors to sites of double-strand breaks are also an important RPA function to ensure effective DNA recombination to correct these DNA lesions. Due to its high affinity to ssDNA, RPA's removal from ssDNA is of central importance to allow these metabolic pathways to proceed, and processes to exchange RPA against downstream factors are established in all eukaryotes. These faceted and multi-layered functions of RPA as well as its role in a variety of human diseases will be discussed.
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Affiliation(s)
- Heinz Peter Nasheuer
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, Biochemistry, University of Galway, H91 TK33 Galway, Ireland
| | - Anna Marie Meaney
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, Biochemistry, University of Galway, H91 TK33 Galway, Ireland
| | - Timothy Hulshoff
- Molecular Systems Physiology Group, School of Biological and Chemical Sciences, University of Galway, H91 TK33 Galway, Ireland
| | - Ines Thiele
- Molecular Systems Physiology Group, School of Biological and Chemical Sciences, University of Galway, H91 TK33 Galway, Ireland
| | - Nichodemus O. Onwubiko
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, Biochemistry, University of Galway, H91 TK33 Galway, Ireland
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10
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Alvaro-Aranda L, Petitalot A, Djeghmoum Y, Panigada D, Singh JK, Ehlén Å, Vugic D, Martin C, Miron S, Contreras-Perez A, Nhiri N, Boucherit V, Lafitte P, Dumoulin I, Rouleau E, Jacquet E, Feliubadaló L, Del Valle J, Stoppa-Lyonnet D, Zinn-Justin S, Lázaro C, Caputo SM, Carreira A. The BRCA2 R2645G variant increases DNA binding and induces hyper-recombination. Nucleic Acids Res 2023:gkad1222. [PMID: 38142462 DOI: 10.1093/nar/gkad1222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 11/30/2023] [Accepted: 12/12/2023] [Indexed: 12/26/2023] Open
Abstract
BRCA2 tumor suppressor protein ensures genome integrity by mediating DNA repair via homologous recombination (HR). This function is executed in part by its canonical DNA binding domain located at the C-terminus (BRCA2CTD), the only folded domain of the protein. Most germline pathogenic missense variants are located in this highly conserved region which binds to single-stranded DNA (ssDNA) and to the acidic protein DSS1. These interactions are essential for the HR function of BRCA2. Here, we report that the variant R2645G, identified in breast cancer and located at the DSS1 interface, unexpectedly increases the ssDNA binding activity of BRCA2CTDin vitro. Human cells expressing this variant display a hyper-recombination phenotype, chromosomal instability in the form of chromatid gaps when exposed to DNA damage, and increased PARP inhibitor sensitivity. In mouse embryonic stem cells (mES), this variant alters viability and confers sensitivity to cisplatin and Mitomycin C. These results suggest that BRCA2 interaction with ssDNA needs to be tightly regulated to limit HR and prevent chromosomal instability and we propose that this control mechanism involves DSS1. Given that several missense variants located within this region have been identified in breast cancer patients, these findings might have clinical implications for carriers.
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Affiliation(s)
- Lucia Alvaro-Aranda
- Genome Instability and Cancer Predisposition Laboratory, Centro de Biologia Molecular Severo Ochoa (CBMSO), CSIC-UAM, Madrid 28049, Spain
| | - Ambre Petitalot
- Department of Genetics, Institut Curie, Paris 75005, France
- PSL Research University, Paris 75005, France
| | - Yasmina Djeghmoum
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405 Orsay, France
- Paris-Saclay University CNRS, UMR3348, F-91405 Orsay, France
| | - Davide Panigada
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405 Orsay, France
- Paris-Saclay University CNRS, UMR3348, F-91405 Orsay, France
| | - Jenny Kaur Singh
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405 Orsay, France
- Paris-Saclay University CNRS, UMR3348, F-91405 Orsay, France
| | - Åsa Ehlén
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405 Orsay, France
- Paris-Saclay University CNRS, UMR3348, F-91405 Orsay, France
| | - Domagoj Vugic
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405 Orsay, France
- Paris-Saclay University CNRS, UMR3348, F-91405 Orsay, France
| | - Charlotte Martin
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405 Orsay, France
- Paris-Saclay University CNRS, UMR3348, F-91405 Orsay, France
| | - Simona Miron
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Paris-Saclay University, 91190 Gif-sur-Yvette, France
| | - Aida Contreras-Perez
- Genome Instability and Cancer Predisposition Laboratory, Centro de Biologia Molecular Severo Ochoa (CBMSO), CSIC-UAM, Madrid 28049, Spain
| | - Naima Nhiri
- Institut de Chimie des Substances Naturelles, Paris-Saclay University, CNRS, 91190 Gif-sur-Yvette, France
| | - Virginie Boucherit
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405 Orsay, France
- Paris-Saclay University CNRS, UMR3348, F-91405 Orsay, France
| | - Philippe Lafitte
- Department of Genetics, Institut Curie, Paris 75005, France
- PSL Research University, Paris 75005, France
| | - Isaac Dumoulin
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405 Orsay, France
- Paris-Saclay University CNRS, UMR3348, F-91405 Orsay, France
| | - Etienne Rouleau
- Department of Genetics, Institut Curie, Paris 75005, France
- PSL Research University, Paris 75005, France
| | - Eric Jacquet
- Institut de Chimie des Substances Naturelles, Paris-Saclay University, CNRS, 91190 Gif-sur-Yvette, France
| | - Lidia Feliubadaló
- Hereditary Cancer Program, Catalan Institute of Oncology (ICO), Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
- Ciber Oncología (CIBERONC), Instituto Salud Carlos III, Madrid, Spain
| | - Jesús Del Valle
- Hereditary Cancer Program, Catalan Institute of Oncology (ICO), Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
- Ciber Oncología (CIBERONC), Instituto Salud Carlos III, Madrid, Spain
| | - Dominique Stoppa-Lyonnet
- Department of Genetics, Institut Curie, Paris 75005, France
- Paris-Cité University, Paris, France
- INSERM U830, Institut Curie, Paris 75005, France
| | - Sophie Zinn-Justin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Paris-Saclay University, 91190 Gif-sur-Yvette, France
| | - Conxi Lázaro
- Hereditary Cancer Program, Catalan Institute of Oncology (ICO), Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
- Ciber Oncología (CIBERONC), Instituto Salud Carlos III, Madrid, Spain
| | - Sandrine M Caputo
- Department of Genetics, Institut Curie, Paris 75005, France
- PSL Research University, Paris 75005, France
| | - Aura Carreira
- Genome Instability and Cancer Predisposition Laboratory, Centro de Biologia Molecular Severo Ochoa (CBMSO), CSIC-UAM, Madrid 28049, Spain
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405 Orsay, France
- Paris-Saclay University CNRS, UMR3348, F-91405 Orsay, France
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11
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Liu J, Zhang J, Zheng Y, Zhao G, Jiang H, Yuan B. miR-302d Targeting of CDKN1A Regulates DNA Damage and Steroid Hormone Secretion in Bovine Cumulus Cells. Genes (Basel) 2023; 14:2195. [PMID: 38137018 PMCID: PMC10743266 DOI: 10.3390/genes14122195] [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: 11/08/2023] [Revised: 12/05/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
(1) Background: DNA damage in cumulus cells hinders oocyte maturation and affects steroid hormone secretion. It is crucial to identify the key factors that regulate cellular DNA damage and steroid hormone secretion. (2) Methods: Treatment of bovine cumulus cells with bleomycin to induce DNA damage. The effects of DNA damage on cell biology were determined by detecting changes in DNA damage degree, cell cycle, viability, apoptosis, and steroid hormones. It was verified that mir-302d targeted regulation of CDKN1A expression, and then affected DNA damage and steroid hormone secretion in cumulus cells. (3) Results: Bleomycin induced increased DNA damage, decreased G1-phase cells, increased S-phase cells, inhibited proliferation, promoted apoptosis, affected E2 and P4 secretion, increased CDKN1A expression, and decreased miR-302d expression. Knockdown of CDKN1A reduced DNA damage, increased G1-phase cells, decreased G2-phase cells, promoted proliferation, inhibited apoptosis, increased E2 and P4 secretion, and increased the expression of BRCA1, MRE11, ATM, CDK1, CDK2, CCNE2, STAR, CYP11A1, and HSD3B1. The expression of RAD51, CCND1, p53, and FAS was decreased. Overexpression of CDKN1A resulted in the opposite results. miR-302d targets CDKN1A expression to regulate DNA damage and then affects the cell cycle, proliferation, apoptosis, steroid hormone secretion, and the expression of related genes. (4) Conclusions: miR-302d and CDKN1A were candidate molecular markers for the diagnosis of DNA damage in bovine cumulus cells.
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Affiliation(s)
- Jianbo Liu
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China; (J.L.); (J.Z.); (G.Z.); (H.J.)
- Experimental Testing Center, Jilin Agricultural Science and Technology University, Jilin 132101, China
| | - Jiabao Zhang
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China; (J.L.); (J.Z.); (G.Z.); (H.J.)
| | - Yi Zheng
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China; (J.L.); (J.Z.); (G.Z.); (H.J.)
| | - Guokun Zhao
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China; (J.L.); (J.Z.); (G.Z.); (H.J.)
| | - Hao Jiang
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China; (J.L.); (J.Z.); (G.Z.); (H.J.)
| | - Bao Yuan
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China; (J.L.); (J.Z.); (G.Z.); (H.J.)
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12
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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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13
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Farokhi Boroujeni S, Rodriguez G, Galpin K, Yakubovich E, Murshed H, Ibrahim D, Asif S, Vanderhyden BC. BRCA1 and BRCA2 deficient tumour models generate distinct ovarian tumour microenvironments and differential responses to therapy. J Ovarian Res 2023; 16:231. [PMID: 38017453 PMCID: PMC10683289 DOI: 10.1186/s13048-023-01313-z] [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: 08/18/2023] [Accepted: 11/09/2023] [Indexed: 11/30/2023] Open
Abstract
Clinical trials are currently exploring combinations of PARP inhibitors and immunotherapies for the treatment of ovarian cancer, but their effects on the ovarian tumour microenvironment (TME) remain unclear. Here, we investigate how olaparib, PD-L1 monoclonal antibodies, and their combination can influence TME composition and survival of tumour-bearing mice. We further explored how BRCA deficiencies can influence the response to therapy. Olaparib and combination therapies similarly improved the median survival of Brca1- and Brca2-deficient tumour-bearing mice. Anti-PD-L1 monotherapy improved the survival of mice with Brca1-null tumours, but not Brca2-null tumours. A detailed analysis of the TME revealed that olaparib monotherapy resulted in a large number of immunosuppressive and immunomodulatory effects in the more inflamed Brca1-deficient TME but not Brca2-deficient tumours. Anti-PD-L1 treatment was mostly immunosuppressive, resulting in a systemic reduction of cytokines and a compensatory increase in PD-L1 expression. The results of the combination therapy generally resembled the effects of one or both of the monotherapies, along with unique changes observed in certain immune populations. In-silico analysis of RNA-seq data also revealed numerous differences between Brca-deficient tumour models, such as the expression of genes involved in inflammation, angiogenesis and PD-L1 expression. In summary, these findings shed light on the influence of novel therapeutics and BRCA mutations on the ovarian TME.
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Affiliation(s)
- Salar Farokhi Boroujeni
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Galaxia Rodriguez
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Kristianne Galpin
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Edward Yakubovich
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Humaira Murshed
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Dalia Ibrahim
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Sara Asif
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Barbara C Vanderhyden
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada.
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.
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14
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Appleby R, Joudeh L, Cobbett K, Pellegrini L. Structural basis for stabilisation of the RAD51 nucleoprotein filament by BRCA2. Nat Commun 2023; 14:7003. [PMID: 37919288 PMCID: PMC10622577 DOI: 10.1038/s41467-023-42830-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 10/23/2023] [Indexed: 11/04/2023] Open
Abstract
The BRCA2 tumour suppressor protein preserves genomic integrity via interactions with the DNA-strand exchange RAD51 protein in homology-directed repair. The RAD51-binding TR2 motif at the BRCA2 C-terminus is essential for protection and restart of stalled replication forks. Biochemical evidence shows that TR2 recognises filamentous RAD51, but existing models of TR2 binding to RAD51 lack a structural basis. Here we used cryo-electron microscopy and structure-guided mutagenesis to elucidate the mechanism of TR2 binding to nucleoprotein filaments of human RAD51. We find that TR2 binds across the protomer interface in the filament, acting as a brace for adjacent RAD51 molecules. TR2 targets an acidic-patch motif on human RAD51 that serves as a recruitment hub in fission yeast Rad51 for recombination mediators Rad52 and Rad55-Rad57. Our findings provide a structural rationale for RAD51 filament stabilisation by BRCA2 and reveal a common recruitment mechanism of recombination mediators to the RAD51 filament.
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Affiliation(s)
- Robert Appleby
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
| | - Luay Joudeh
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
| | - Katie Cobbett
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
| | - Luca Pellegrini
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK.
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15
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Belan O, Greenhough L, Kuhlen L, Anand R, Kaczmarczyk A, Gruszka DT, Yardimci H, Zhang X, Rueda DS, West SC, Boulton SJ. Visualization of direct and diffusion-assisted RAD51 nucleation by full-length human BRCA2 protein. Mol Cell 2023; 83:2925-2940.e8. [PMID: 37499663 PMCID: PMC7615647 DOI: 10.1016/j.molcel.2023.06.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 06/09/2023] [Accepted: 06/26/2023] [Indexed: 07/29/2023]
Abstract
Homologous recombination (HR) is essential for error-free repair of DNA double-strand breaks, perturbed replication forks (RFs), and post-replicative single-stranded DNA (ssDNA) gaps. To initiate HR, the recombination mediator and tumor suppressor protein BRCA2 facilitates nucleation of RAD51 on ssDNA prior to stimulation of RAD51 filament growth by RAD51 paralogs. Although ssDNA binding by BRCA2 has been implicated in RAD51 nucleation, the function of double-stranded DNA (dsDNA) binding by BRCA2 remains unclear. Here, we exploit single-molecule (SM) imaging to visualize BRCA2-mediated RAD51 nucleation in real time using purified proteins. We report that BRCA2 nucleates and stabilizes RAD51 on ssDNA either directly or through an unappreciated diffusion-assisted delivery mechanism involving binding to and sliding along dsDNA, which requires the cooperative action of multiple dsDNA-binding modules in BRCA2. Collectively, our work reveals two distinct mechanisms of BRCA2-dependent RAD51 loading onto ssDNA, which we propose are critical for its diverse functions in maintaining genome stability and cancer suppression.
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Affiliation(s)
- Ondrej Belan
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Luke Greenhough
- DNA Recombination and Repair Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Lucas Kuhlen
- Section of Structural Biology, Faculty of Medicine, Imperial College London, Sir Alexander Fleming Building, South Kensington, London SW7 2AZ, UK
| | - Roopesh Anand
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Artur Kaczmarczyk
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London W12 0NN, UK; Single Molecule Imaging Group, MRC-London Institute of Medical Sciences, London W12 0NN, UK
| | - Dominika T Gruszka
- Single Molecule Imaging of Genome Duplication and Maintenance Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Hasan Yardimci
- Single Molecule Imaging of Genome Duplication and Maintenance Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Xiaodong Zhang
- Section of Structural Biology, Faculty of Medicine, Imperial College London, Sir Alexander Fleming Building, South Kensington, London SW7 2AZ, UK
| | - David S Rueda
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London W12 0NN, UK; Single Molecule Imaging Group, MRC-London Institute of Medical Sciences, London W12 0NN, UK
| | - Stephen C West
- DNA Recombination and Repair Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Simon J Boulton
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
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16
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Lim PX, Zaman M, Jasin M. BRCA2 promotes genomic integrity and therapy resistance primarily through its role in homology-directed repair. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.11.536470. [PMID: 37090587 PMCID: PMC10120702 DOI: 10.1101/2023.04.11.536470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Highlights Gap suppression requires BRCA2 C-terminal RAD51 binding in mouse and human cells Brca2 heterozygosity in mice results in fork protection and gap suppression defects Gap suppression mitigates sensitivity to hmdU, but only when HDR is unperturbedHDR deficiency is the primary driver of chemotherapeutic sensitivity. eTOC blurb Lim et al . report that gap suppression as well as fork protection require BRCA2 stabilization of RAD51 filaments in human and mouse cells but have minimal impact on genome integrity, oncogenesis, and drug resistance. BRCA2 suppression of PRIMPOL-mediated replication gaps confers resistance to the nucleotide hmdU, incorporation of which leads to cytotoxic abasic sites.This effect is diminished when HDR is abrogated. Summary Tumor suppressor BRCA2 functions in homology-directed repair (HDR), protection of stalled replication forks, and suppression of replicative gaps. The relative contributions of these pathways to genome integrity and chemotherapy response are under scrutiny. Here, we report that mouse and human cells require a RAD51 filament stabilization motif in BRCA2 for both fork protection and gap suppression, but not HDR. Loss of fork protection and gap suppression do not compromise genome instability or shorten tumor latency in mice or cause replication stress in human mammary cells. By contrast, HDR deficiency increases spontaneous and replication stress-induced chromosome aberrations and tumor predisposition. Unlike with HDR, fork protection and gap suppression defects are also observed in Brca2 heterozygous mouse cells, likely due to reduced RAD51 stabilization at stalled forks and gaps. Gaps arise from PRIMPOL activity, which is associated with sensitivity to 5-hydroxymethyl-2’-deoxyuridine due to the formation of abasic sites by SMUG1 glycosylase and is exacerbated by poly(ADP-ribose) polymerase inhibition. However, HDR deficiency ultimately modulates sensitivity to chemotherapeutics, including PARP inhibitors.
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