1
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Hanthi YW, Ramirez-Otero MA, Appleby R, De Antoni A, Joudeh L, Sannino V, Waked S, Ardizzoia A, Barra V, Fachinetti D, Pellegrini L, Costanzo V. RAD51 protects abasic sites to prevent replication fork breakage. Mol Cell 2024; 84:3026-3043.e11. [PMID: 39178838 DOI: 10.1016/j.molcel.2024.07.004] [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: 03/20/2024] [Revised: 06/03/2024] [Accepted: 07/08/2024] [Indexed: 08/26/2024]
Abstract
Abasic sites are DNA lesions repaired by base excision repair. Cleavage of unrepaired abasic sites in single-stranded DNA (ssDNA) can lead to chromosomal breakage during DNA replication. How rupture of abasic DNA is prevented remains poorly understood. Here, using cryoelectron microscopy (cryo-EM), Xenopus laevis egg extracts, and human cells, we show that RAD51 nucleofilaments specifically recognize and protect abasic sites, which increase RAD51 association rate to DNA. In the absence of BRCA2 or RAD51, abasic sites accumulate as a result of DNA base methylation, oxidation, and deamination, inducing abasic ssDNA gaps that make replicating DNA fibers sensitive to APE1. RAD51 assembled on abasic DNA prevents abasic site cleavage by the MRE11-RAD50 complex, suppressing replication fork breakage triggered by an excess of abasic sites or POLθ polymerase inhibition. Our study highlights the critical role of BRCA2 and RAD51 in safeguarding against unrepaired abasic sites in DNA templates stemming from base alterations, ensuring genomic stability.
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Affiliation(s)
| | | | - Robert Appleby
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Anna De Antoni
- IFOM, The AIRC Institute of Molecular Oncology, Milan, Italy
| | - Luay Joudeh
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | | | - Salli Waked
- IFOM, The AIRC Institute of Molecular Oncology, Milan, Italy
| | | | - Viviana Barra
- Institute Curie, PSL Research University, CNRS, UMR 144, 26 Rue d'Ulm, 75005 Paris, France
| | - Daniele Fachinetti
- Institute Curie, PSL Research University, CNRS, UMR 144, 26 Rue d'Ulm, 75005 Paris, France
| | - Luca Pellegrini
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK.
| | - Vincenzo Costanzo
- IFOM, The AIRC Institute of Molecular Oncology, Milan, Italy; Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy.
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2
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Hengel SR, Oppenheimer KG, Smith CM, Schaich MA, Rein HL, Martino J, Darrah KE, Witham M, Ezekwenna OC, Burton KR, Van Houten B, Spies M, Bernstein KA. The human Shu complex promotes RAD51 activity by modulating RPA dynamics on ssDNA. Nat Commun 2024; 15:7197. [PMID: 39169038 PMCID: PMC11339404 DOI: 10.1038/s41467-024-51595-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/09/2024] [Indexed: 08/23/2024] Open
Abstract
Templated DNA repair that occurs during homologous recombination and replication stress relies on RAD51. RAD51 activity is positively regulated by BRCA2 and the RAD51 paralogs. The Shu complex is a RAD51 paralog-containing complex consisting of SWSAP1, SWS1, and SPIDR. We demonstrate that SWSAP1-SWS1 binds RAD51, maintains RAD51 filament stability, and enables strand exchange. Using single-molecule confocal fluorescence microscopy combined with optical tweezers, we show that SWSAP1-SWS1 decorates RAD51 filaments proficient for homologous recombination. We also find SWSAP1-SWS1 enhances RPA diffusion on ssDNA. Importantly, we show human sgSWSAP1 and sgSWS1 knockout cells are sensitive to pharmacological inhibition of PARP and APE1. Lastly, we identify cancer variants in SWSAP1 that alter Shu complex formation. Together, we show that SWSAP1-SWS1 stimulates RAD51-dependent high-fidelity repair and may be an important new cancer therapeutic target.
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Affiliation(s)
- Sarah R Hengel
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA.
- Tufts University, Department of Biology, Medford, MA, USA.
| | - Katherine G Oppenheimer
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA
| | - Chelsea M Smith
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA
- University of North Carolina at Chapel Hill, Department of Pathology and Laboratory Medicine, Chapel Hill, NC, USA
| | - Matthew A Schaich
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA
| | - Hayley L Rein
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA
| | - Julieta Martino
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA
- GeneDx, Gaithersburg, MD, USA
| | - Kristie E Darrah
- University of Pennsylvania School of Medicine, Penn Center for Genome Integrity, Department of Biochemistry and Biophysics, 421 Curie Boulevard, Philadelphia, PA, USA
| | - Maggie Witham
- Tufts University, Department of Biology, Medford, MA, USA
| | | | - Kyle R Burton
- Tufts University, Department of Biology, Medford, MA, USA
| | - Bennett Van Houten
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA
| | - Maria Spies
- University of Iowa, Department of Biochemistry and Molecular Biology, Iowa City, IA, USA
| | - Kara A Bernstein
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA.
- University of Pennsylvania School of Medicine, Penn Center for Genome Integrity, Department of Biochemistry and Biophysics, 421 Curie Boulevard, Philadelphia, PA, USA.
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3
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Wang X, Zhao X, Yu Z, Fan T, Guo Y, Liang J, Wang Y, Zhan J, Chen G, Zhou C, Zhang X, Li X, Chen X. Rtt105 stimulates Rad51-ssDNA assembly and orchestrates Rad51 and RPA actions to promote homologous recombination repair. Proc Natl Acad Sci U S A 2024; 121:e2402262121. [PMID: 39145931 DOI: 10.1073/pnas.2402262121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 07/09/2024] [Indexed: 08/16/2024] Open
Abstract
Homologous recombination (HR) is essential for the maintenance of genome stability. During HR, Replication Protein A (RPA) rapidly coats the 3'-tailed single-strand DNA (ssDNA) generated by end resection. Then, the ssDNA-bound RPA must be timely replaced by Rad51 recombinase to form Rad51 nucleoprotein filaments that drive homology search and HR repair. How cells regulate Rad51 assembly dynamics and coordinate RPA and Rad51 actions to ensure proper HR remains poorly understood. Here, we identified that Rtt105, a Ty1 transposon regulator, acts to stimulate Rad51 assembly and orchestrate RPA and Rad51 actions during HR. We found that Rtt105 interacts with Rad51 in vitro and in vivo and restrains the adenosine 5' triphosphate (ATP) hydrolysis activity of Rad51. We showed that Rtt105 directly stimulates dynamic Rad51-ssDNA assembly, strand exchange, and D-loop formation in vitro. Notably, we found that Rtt105 physically regulates the binding of Rad51 and RPA to ssDNA via different motifs and that both regulations are necessary and epistatic in promoting Rad51 nucleation, strand exchange, and HR repair. Consequently, disrupting either of the interactions impaired HR and conferred DNA damage sensitivity, underscoring the importance of Rtt105 in orchestrating the actions of Rad51 and RPA. Our work reveals additional layers of mechanisms regulating Rad51 filament dynamics and the coordination of HR.
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Affiliation(s)
- Xuejie Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Department of Radiation Oncology, Renmin Hospital of Wuhan University, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430072, China
| | - Xiaocong Zhao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Department of Radiation Oncology, Renmin Hospital of Wuhan University, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430072, China
| | - Zhengshi Yu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Department of Radiation Oncology, Renmin Hospital of Wuhan University, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430072, China
| | - Tianai Fan
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Department of Radiation Oncology, Renmin Hospital of Wuhan University, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430072, China
| | - Yunjing Guo
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Department of Radiation Oncology, Renmin Hospital of Wuhan University, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430072, China
| | - Jianqiang Liang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Department of Radiation Oncology, Renmin Hospital of Wuhan University, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430072, China
| | - Yanyan Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Department of Radiation Oncology, Renmin Hospital of Wuhan University, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430072, China
| | - Jingfei Zhan
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Department of Radiation Oncology, Renmin Hospital of Wuhan University, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430072, China
| | - Guifang Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Department of Radiation Oncology, Renmin Hospital of Wuhan University, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430072, China
| | - Chun Zhou
- School of Public Health, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Xinghua Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Department of Radiation Oncology, Renmin Hospital of Wuhan University, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430072, China
| | - Xiangpan Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Department of Radiation Oncology, Renmin Hospital of Wuhan University, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430072, China
| | - Xuefeng Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Department of Radiation Oncology, Renmin Hospital of Wuhan University, Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan 430072, China
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4
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Gao Y, Wen P, Shao C, Ye C, Chen Y, You J, Su Z. CDC20 Holds Novel Regulation Mechanism in RPA1 during Different Stages of DNA Damage to Induce Radio-Chemoresistance. Int J Mol Sci 2024; 25:8383. [PMID: 39125953 PMCID: PMC11312485 DOI: 10.3390/ijms25158383] [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: 05/31/2024] [Revised: 07/25/2024] [Accepted: 07/28/2024] [Indexed: 08/12/2024] Open
Abstract
Targeting CDC20 can enhance the radiosensitivity of tumor cells, but the function and mechanism of CDC20 on DNA damage repair response remains vague. To examine that issue, tumor cell lines, including KYSE200, KYSE450, and HCT116, were utilized to detect the expression, function, and underlying mechanism of CDC20 in radio-chemoresistance. Western blot and immunofluorescence staining were employed to confirm CDC20 expression and location, and radiation could upregulate the expression of CDC20 in the cell nucleus. The homologous recombination (HR) and non-homologous end joining (NHEJ) reporter gene systems were utilized to explore the impact of CDC20 on DNA damage repair, indicating that CDC20 could promote HR repair and radio/chemo-resistance. In the early stages of DNA damage, CDC20 stabilizes the RPA1 protein through protein-protein interactions, activating the ATR-mediated signaling cascade, thereby aiding in genomic repair. In the later stages, CDC20 assists in the subsequent steps of damage repair by the ubiquitin-mediated degradation of RPA1. CCK-8 and colony formation assay were used to detect the function of CDC20 in cell vitality and proliferation, and targeting CDC20 can exacerbate the increase in DNA damage levels caused by cisplatin or etoposide. A tumor xenograft model was conducted in BALB/c-nu/nu mice to confirm the function of CDC20 in vivo, confirming the in vitro results. In conclusion, this study provides further validation of the potential clinical significance of CDC20 as a strategy to overcome radio-chemoresistance via uncovering a novel role of CDC20 in regulating RPA1 during DNA damage repair.
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Affiliation(s)
- Yang Gao
- Department of Histology and Embryology, Shantou University Medical College, Shantou 515041, China; (Y.G.); (C.S.); (C.Y.); (Y.C.); (J.Y.)
| | - Pengbo Wen
- School of Medical Information and Engineering, Xuzhou Medical University, Xuzhou 221002, China;
| | - Chenran Shao
- Department of Histology and Embryology, Shantou University Medical College, Shantou 515041, China; (Y.G.); (C.S.); (C.Y.); (Y.C.); (J.Y.)
| | - Cheng Ye
- Department of Histology and Embryology, Shantou University Medical College, Shantou 515041, China; (Y.G.); (C.S.); (C.Y.); (Y.C.); (J.Y.)
| | - Yuji Chen
- Department of Histology and Embryology, Shantou University Medical College, Shantou 515041, China; (Y.G.); (C.S.); (C.Y.); (Y.C.); (J.Y.)
| | - Junyu You
- Department of Histology and Embryology, Shantou University Medical College, Shantou 515041, China; (Y.G.); (C.S.); (C.Y.); (Y.C.); (J.Y.)
| | - Zhongjing Su
- Department of Histology and Embryology, Shantou University Medical College, Shantou 515041, China; (Y.G.); (C.S.); (C.Y.); (Y.C.); (J.Y.)
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5
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Chadda R, Kaushik V, Ahmad IM, Deveryshetty J, Holehouse AS, Sigurdsson ST, Biswas G, Levy Y, Bothner B, Cooley RB, Mehl RA, Dastvan R, Origanti S, Antony E. Partial wrapping of single-stranded DNA by replication protein A and modulation through phosphorylation. Nucleic Acids Res 2024:gkae584. [PMID: 38989614 DOI: 10.1093/nar/gkae584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 05/30/2024] [Accepted: 06/25/2024] [Indexed: 07/12/2024] Open
Abstract
Single-stranded DNA (ssDNA) intermediates which emerge during DNA metabolic processes are shielded by replication protein A (RPA). RPA binds to ssDNA and acts as a gatekeeper to direct the ssDNA towards downstream DNA metabolic pathways with exceptional specificity. Understanding the mechanistic basis for such RPA-dependent functional specificity requires knowledge of the structural conformation of ssDNA when RPA-bound. Previous studies suggested a stretching of ssDNA by RPA. However, structural investigations uncovered a partial wrapping of ssDNA around RPA. Therefore, to reconcile the models, in this study, we measured the end-to-end distances of free ssDNA and RPA-ssDNA complexes using single-molecule FRET and double electron-electron resonance (DEER) spectroscopy and found only a small systematic increase in the end-to-end distance of ssDNA upon RPA binding. This change does not align with a linear stretching model but rather supports partial wrapping of ssDNA around the contour of DNA binding domains of RPA. Furthermore, we reveal how phosphorylation at the key Ser-384 site in the RPA70 subunit provides access to the wrapped ssDNA by remodeling the DNA-binding domains. These findings establish a precise structural model for RPA-bound ssDNA, providing valuable insights into how RPA facilitates the remodeling of ssDNA for subsequent downstream processes.
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Affiliation(s)
- Rahul Chadda
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Vikas Kaushik
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Iram Munir Ahmad
- Department of Chemistry, Science Institute, University of Iceland, 107 Reykjavik, Iceland
| | - Jaigeeth Deveryshetty
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Alex S Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University in Saint Louis School of Medicine, St. Louis, MO 63110, USA
| | - Snorri Th Sigurdsson
- Department of Chemistry, Science Institute, University of Iceland, 107 Reykjavik, Iceland
| | - Gargi Biswas
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Yaakov Levy
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Richard B Cooley
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | - Ryan A Mehl
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | - Reza Dastvan
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Sofia Origanti
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
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6
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Nickens DG, Feng Z, Shen J, Gray SJ, Simmons R, Niu H, Bochman M. Cdc13 exhibits dynamic DNA strand exchange in the presence of telomeric DNA. Nucleic Acids Res 2024; 52:6317-6332. [PMID: 38613387 PMCID: PMC11194072 DOI: 10.1093/nar/gkae265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 03/22/2024] [Accepted: 04/01/2024] [Indexed: 04/14/2024] Open
Abstract
Telomerase is the enzyme that lengthens telomeres and is tightly regulated by a variety of means to maintain genome integrity. Several DNA helicases function at telomeres, and we previously found that the Saccharomyces cerevisiae helicases Hrq1 and Pif1 directly regulate telomerase. To extend these findings, we are investigating the interplay between helicases, single-stranded DNA (ssDNA) binding proteins (ssBPs), and telomerase. The yeast ssBPs Cdc13 and RPA differentially affect Hrq1 and Pif1 helicase activity, and experiments to measure helicase disruption of Cdc13/ssDNA complexes instead revealed that Cdc13 can exchange between substrates. Although other ssBPs display dynamic binding, this was unexpected with Cdc13 due to the reported in vitro stability of the Cdc13/telomeric ssDNA complex. We found that the DNA exchange by Cdc13 occurs rapidly at physiological temperatures, requires telomeric repeat sequence DNA, and is affected by ssDNA length. Cdc13 truncations revealed that the low-affinity binding site (OB1), which is distal from the high-affinity binding site (OB3), is required for this intermolecular dynamic DNA exchange (DDE). We hypothesize that DDE by Cdc13 is the basis for how Cdc13 'moves' at telomeres to alternate between modes where it regulates telomerase activity and assists in telomere replication.
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Affiliation(s)
- David G Nickens
- Molecular & Cellular Biochemistry Department, Indiana University, Bloomington, IN 47405, USA
| | - Zhitong Feng
- Molecular & Cellular Biochemistry Department, Indiana University, Bloomington, IN 47405, USA
| | - Jiangchuan Shen
- Molecular & Cellular Biochemistry Department, Indiana University, Bloomington, IN 47405, USA
| | - Spencer J Gray
- Molecular & Cellular Biochemistry Department, Indiana University, Bloomington, IN 47405, USA
| | - Robert H Simmons
- Molecular & Cellular Biochemistry Department, Indiana University, Bloomington, IN 47405, USA
| | - Hengyao Niu
- Molecular & Cellular Biochemistry Department, Indiana University, Bloomington, IN 47405, USA
| | - Matthew L Bochman
- Molecular & Cellular Biochemistry Department, Indiana University, Bloomington, IN 47405, USA
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7
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Weeks-Pollenz SJ, Petrides MJ, Davis R, Harris KK, Bloom LB. Single-stranded DNA binding protein hitches a ride with the Escherichia coli YoaA-χ helicase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.21.600097. [PMID: 38948847 PMCID: PMC11213134 DOI: 10.1101/2024.06.21.600097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
The Escherichia coli XPD/Rad3-like helicase, YoaA, and DNA polymerase III subunit, χ, are involved in E. coli DNA damage tolerance and repair. YoaA and χ promote tolerance to the DNA chain-terminator, 3 -azidothymidine (AZT), and together form the functional helicase complex, YoaA-χ. How YoaA-χ contributes to DNA damage tolerance is not well understood. E. coli single-stranded DNA binding protein (SSB) accumulates at stalled replication forks, and the SSB-χ interaction is required to promote AZT tolerance via an unknown mechanism. YoaA-χ and SSB interactions were investigated in vitro to better understand this DNA damage tolerance mechanism, and we discovered YoaA-χ and SSB have a functional interaction. SSB confers a substrate-specific effect on the helicase activity of YoaA-χ, barely affecting YoaA-χ on an overhang DNA substrate but inhibiting YoaA-χ on forked DNA. A paralog helicase, DinG, unwinds SSB-bound DNA in a similar manner to YoaA-χ on the substrates tested. Through use of ensemble experiments, we believe SSB binds behind YoaA-χ relative to the DNA ds/ss junction and show via single-molecule assays that SSB translocates along ssDNA with YoaA-χ. This is, to our knowledge, the first demonstration of a mechanoenzyme pulling SSB along ssDNA.
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Affiliation(s)
| | | | | | | | - Linda B. Bloom
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, 32610-0245, USA
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8
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Jurkovic CM, Raisch J, Tran S, Nguyen HD, Lévesque D, Scott MS, Campos EI, Boisvert FM. Replisome Proximal Protein Associations and Dynamic Proteomic Changes at Stalled Replication Forks. Mol Cell Proteomics 2024; 23:100767. [PMID: 38615877 PMCID: PMC11101681 DOI: 10.1016/j.mcpro.2024.100767] [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: 08/16/2023] [Revised: 03/19/2024] [Accepted: 04/11/2024] [Indexed: 04/16/2024] Open
Abstract
DNA replication is a fundamental cellular process that ensures the transfer of genetic information during cell division. Genome duplication takes place in S phase and requires a dynamic and highly coordinated recruitment of multiple proteins at replication forks. Various genotoxic stressors lead to fork instability and collapse, hence the need for DNA repair pathways. By identifying the multitude of protein interactions implicated in those events, we can better grasp the complex and dynamic molecular mechanisms that facilitate DNA replication and repair. Proximity-dependent biotin identification was used to identify associations with 17 proteins within four core replication components, namely the CDC45/MCM2-7/GINS helicase that unwinds DNA, the DNA polymerases, replication protein A subunits, and histone chaperones needed to disassemble and reassemble chromatin. We further investigated the impact of genotoxic stress on these interactions. This analysis revealed a vast proximity association network with 108 nuclear proteins further modulated in the presence of hydroxyurea; 45 being enriched and 63 depleted. Interestingly, hydroxyurea treatment also caused a redistribution of associations with 11 interactors, meaning that the replisome is dynamically reorganized when stressed. The analysis identified several poorly characterized proteins, thereby uncovering new putative players in the cellular response to DNA replication arrest. It also provides a new comprehensive proteomic framework to understand how cells respond to obstacles during DNA replication.
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Affiliation(s)
- Carla-Marie Jurkovic
- Faculty of Medicine and Health Sciences, Department of Immunology and Cell Biology, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Jennifer Raisch
- Faculty of Medicine and Health Sciences, Department of Immunology and Cell Biology, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Stephanie Tran
- Genetics & Genome Biology Program, Department of Molecular Biology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Hoang Dong Nguyen
- Faculty of Medicine and Health Sciences, Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Dominique Lévesque
- Faculty of Medicine and Health Sciences, Department of Immunology and Cell Biology, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Michelle S Scott
- Faculty of Medicine and Health Sciences, Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Eric I Campos
- Genetics & Genome Biology Program, Department of Molecular Biology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
| | - François-Michel Boisvert
- Faculty of Medicine and Health Sciences, Department of Immunology and Cell Biology, Université de Sherbrooke, Sherbrooke, Québec, Canada.
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9
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Sampathkumar A, Zhong C, Tang Y, Fujita Y, Ito M, Shinohara A. Replication protein-A, RPA, plays a pivotal role in the maintenance of recombination checkpoint in yeast meiosis. Sci Rep 2024; 14:9550. [PMID: 38664461 PMCID: PMC11045724 DOI: 10.1038/s41598-024-60082-x] [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: 09/27/2023] [Accepted: 04/18/2024] [Indexed: 04/28/2024] Open
Abstract
DNA double-strand breaks (DSBs) activate DNA damage responses (DDRs) in both mitotic and meiotic cells. A single-stranded DNA (ssDNA) binding protein, Replication protein-A (RPA) binds to the ssDNA formed at DSBs to activate ATR/Mec1 kinase for the response. Meiotic DSBs induce homologous recombination monitored by a meiotic DDR called the recombination checkpoint that blocks the pachytene exit in meiotic prophase I. In this study, we further characterized the essential role of RPA in the maintenance of the recombination checkpoint during Saccharomyces cerevisiae meiosis. The depletion of an RPA subunit, Rfa1, in a recombination-defective dmc1 mutant, fully alleviates the pachytene arrest with the persistent unrepaired DSBs. RPA depletion decreases the activity of a meiosis-specific CHK2 homolog, Mek1 kinase, which in turn activates the Ndt80 transcriptional regulator for pachytene exit. These support the idea that RPA is a sensor of ssDNAs for the activation of meiotic DDR. Rfa1 depletion also accelerates the prophase I delay in the zip1 mutant defective in both chromosome synapsis and the recombination, consistent with the notion that the accumulation of ssDNAs rather than defective synapsis triggers prophase I delay in the zip1 mutant.
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Affiliation(s)
- Arivarasan Sampathkumar
- Institute for Protein Research, University of Osaka, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Chen Zhong
- Institute for Protein Research, University of Osaka, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yuting Tang
- Institute for Protein Research, University of Osaka, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yurika Fujita
- Institute for Protein Research, University of Osaka, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Masaru Ito
- Institute for Protein Research, University of Osaka, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Akira Shinohara
- Institute for Protein Research, University of Osaka, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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10
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Granger SL, Sharma R, Kaushik V, Razzaghi M, Honda M, Gaur P, Bhat DS, Labenz SM, Heinen JE, Williams BA, Tabei SMA, Wlodarski MW, Antony E, Spies M. Human hnRNPA1 reorganizes telomere-bound Replication Protein A. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.09.540056. [PMID: 37214874 PMCID: PMC10197631 DOI: 10.1101/2023.05.09.540056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Human replication protein A (RPA) is a heterotrimeric ssDNA binding protein responsible for many aspects of cellular DNA metabolism. Dynamic interactions of the four RPA DNA binding domains (DBDs) with DNA control replacement of RPA by downstream proteins in various cellular metabolic pathways. RPA plays several important functions at telomeres where it binds to and melts telomeric G-quadruplexes, non-canonical DNA structures formed at the G-rich telomeric ssDNA overhangs. Here, we combine single-molecule total internal reflection fluorescence microscopy (smTIRFM) and mass photometry (MP) with biophysical and biochemical analyses to demonstrate that heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) specifically remodels RPA bound to telomeric ssDNA by dampening the RPA configurational dynamics and forming a ternary complex. Uniquely, among hnRNPA1 target RNAs, telomeric repeat-containing RNA (TERRA) is selectively capable of releasing hnRNPA1 from the RPA-telomeric DNA complex. We speculate that this telomere specific RPA-DNA-hnRNPA1 complex is an important structure in telomere protection. One Sentence Summary At the single-stranded ends of human telomeres, the heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) binds to and modulates conformational dynamics of the ssDNA binding protein RPA forming a ternary complex which is controlled by telomeric repeat-containing RNA (TERRA).
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11
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Chadda R, Kaushik V, Ahmad IM, Deveryshetty J, Holehouse A, Sigurdsson ST, Bothner B, Dastvan R, Origanti S, Antony E. Wrapping of single-stranded DNA by Replication Protein A and modulation through phosphorylation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.28.587234. [PMID: 38585962 PMCID: PMC10996701 DOI: 10.1101/2024.03.28.587234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Single-stranded DNA (ssDNA) intermediates, which emerge during DNA metabolic processes are shielded by Replication Protein A (RPA). RPA binds to ssDNA and acts as a gatekeeper, directing the ssDNA towards downstream DNA metabolic pathways with exceptional specificity. Understanding the mechanistic basis for such RPA-dependent specificity requires a comprehensive understanding of the structural conformation of ssDNA when bound to RPA. Previous studies suggested a stretching of ssDNA by RPA. However, structural investigations uncovered a partial wrapping of ssDNA around RPA. Therefore, to reconcile the models, in this study, we measured the end-to-end distances of free ssDNA and RPA-ssDNA complexes using single-molecule FRET and Double Electron-Electron Resonance (DEER) spectroscopy and found only a small systematic increase in the end-to-end distance of ssDNA upon RPA binding. This change does not align with a linear stretching model but rather supports partial wrapping of ssDNA around the contour of DNA binding domains of RPA. Furthermore, we reveal how phosphorylation at the key Ser-384 site in the RPA70 subunit provides access to the wrapped ssDNA by remodeling the DNA-binding domains. These findings establish a precise structural model for RPA-bound ssDNA, providing valuable insights into how RPA facilitates the remodeling of ssDNA for subsequent downstream processes.
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Affiliation(s)
- Rahul Chadda
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Vikas Kaushik
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Iram Munir Ahmad
- Department of Chemistry, Science Institute, University of Iceland, 107 Reykjavik, Iceland
| | - Jaigeeth Deveryshetty
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Alex Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University in Saint Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Snorri Th.d Sigurdsson
- Department of Chemistry, Science Institute, University of Iceland, 107 Reykjavik, Iceland
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717
| | - Reza Dastvan
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Sofia Origanti
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
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12
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Zhao Y, Liu W, Li Y, Ma J, Liu T, Cui H, Deng Y, Liao X, Wang Z. Human Bocavirus 1 NP1 acts as an ssDNA-binding protein to help AAV2 DNA replication and cooperates with RPA to regulate AAV2 capsid expression. J Virol 2024; 98:e0151523. [PMID: 38323812 PMCID: PMC10949510 DOI: 10.1128/jvi.01515-23] [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: 09/28/2023] [Accepted: 01/14/2024] [Indexed: 02/08/2024] Open
Abstract
Adeno-associated virus (AAV) requires co-infection with helper virus for efficient replication. We previously reported that Human Bocavirus 1 (HBoV1) genes, including NP1, NS2, and BocaSR, were critical for AAV2 replication. Here, we first demonstrate the essential roles of the NP1 protein in AAV2 DNA replication and protein expression. We show that NP1 binds to single-strand DNA (ssDNA) at least 30 nucleotides (nt) in length in a sequence-independent manner. Furthermore, NP1 colocalized with the BrdU-labeled AAV2 DNA replication center, and the loss of the ssDNA-binding ability of NP1 by site-directed mutation completely abolished AAV2 DNA replication. We used affinity-tagged NP1 protein to identify host cellular proteins associated with NP1 in cells cotransfected with the HBoV1 helper genes and AAV2 duplex genome. Of the identified proteins, we demonstrate that NP1 directly binds to the DBD-F domain of the RPA70 subunit with a high affinity through the residues 101-121. By reconstituting the heterotrimer protein RPA in vitro using gel filtration, we demonstrate that NP1 physically associates with RPA to form a heterologous complex characterized by typical fast-on/fast-off kinetics. Following a dominant-negative strategy, we found that NP1-RPA complex mainly plays a role in expressing AAV2 capsid protein by enhancing the transcriptional activity of the p40 promoter. Our study revealed a novel mechanism by which HBoV1 NP1 protein supports AAV2 DNA replication and capsid protein expression through its ssDNA-binding ability and direct interaction with RPA, respectively.IMPORTANCERecombinant adeno-associated virus (rAAV) vectors have been extensively used in clinical gene therapy strategies. However, a limitation of these gene therapy strategies is the efficient production of the required vectors, as AAV alone is replication-deficient in the host cells. HBoV1 provides the simplest AAV2 helper genes consisting of NP1, NS2, and BocaSR. An important question regarding the helper function of HBoV1 is whether it provides any direct function that supports AAV2 DNA replication and protein expression. Also of interest is how HBoV1 interplays with potential host factors to constitute a permissive environment for AAV2 replication. Our studies revealed that the multifunctional protein NP1 plays important roles in AAV2 DNA replication via its sequence-independent ssDNA-binding ability and in regulating AAV2 capsid protein expression by physically interacting with host protein RPA. Our findings present theoretical guidance for the future application of the HBoV1 helper genes in the rAAV vector production.
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Affiliation(s)
- Yanqun Zhao
- Joint National Laboratory for Antibody Drug Engineering, The First Affiliated Hospital, Henan University, Kaifeng, Henan, China
| | - Wei Liu
- Joint National Laboratory for Antibody Drug Engineering, The First Affiliated Hospital, Henan University, Kaifeng, Henan, China
| | - Yanjie Li
- Joint National Laboratory for Antibody Drug Engineering, The First Affiliated Hospital, Henan University, Kaifeng, Henan, China
| | - Jing Ma
- Joint National Laboratory for Antibody Drug Engineering, The First Affiliated Hospital, Henan University, Kaifeng, Henan, China
| | - Ting Liu
- Joint National Laboratory for Antibody Drug Engineering, The First Affiliated Hospital, Henan University, Kaifeng, Henan, China
| | - Huichan Cui
- Joint National Laboratory for Antibody Drug Engineering, The First Affiliated Hospital, Henan University, Kaifeng, Henan, China
| | - Yongheng Deng
- Joint National Laboratory for Antibody Drug Engineering, The First Affiliated Hospital, Henan University, Kaifeng, Henan, China
| | - Xiaochen Liao
- Joint National Laboratory for Antibody Drug Engineering, The First Affiliated Hospital, Henan University, Kaifeng, Henan, China
| | - Zekun Wang
- Joint National Laboratory for Antibody Drug Engineering, The First Affiliated Hospital, Henan University, Kaifeng, Henan, China
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13
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Pangeni S, Biswas G, Kaushik V, Kuppa S, Yang O, Lin CT, Mishra G, Levy Y, Antony E, Ha T. Rapid Long-distance Migration of RPA on Single Stranded DNA Occurs Through Intersegmental Transfer Utilizing Multivalent Interactions. J Mol Biol 2024; 436:168491. [PMID: 38360091 PMCID: PMC10949852 DOI: 10.1016/j.jmb.2024.168491] [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: 12/28/2023] [Revised: 02/04/2024] [Accepted: 02/08/2024] [Indexed: 02/17/2024]
Abstract
Replication Protein A (RPA) is asingle strandedDNA(ssDNA)binding protein that coordinates diverse DNA metabolic processes including DNA replication, repair, and recombination. RPA is a heterotrimeric protein with six functional oligosaccharide/oligonucleotide (OB) domains and flexible linkers. Flexibility enables RPA to adopt multiple configurations andis thought to modulate its function. Here, usingsingle moleculeconfocal fluorescencemicroscopy combinedwith optical tweezers and coarse-grained molecular dynamics simulations, we investigated the diffusional migration of single RPA molecules on ssDNA undertension.The diffusioncoefficientDis the highest (20,000nucleotides2/s) at 3pNtension and in 100 mMKCl and markedly decreases whentensionor salt concentrationincreases. We attribute the tension effect to intersegmental transfer which is hindered by DNA stretching and the salt effect to an increase in binding site size and interaction energy of RPA-ssDNA. Our integrative study allowed us to estimate the size and frequency of intersegmental transfer events that occur through transient bridging of distant sites on DNA by multiple binding sites on RPA. Interestingly, deletion of RPA trimeric core still allowed significant ssDNA binding although the reduced contact area made RPA 15-fold more mobile. Finally, we characterized the effect of RPA crowding on RPA migration. These findings reveal how the high affinity RPA-ssDNA interactions are remodeled to yield access, a key step in several DNA metabolic processes.
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Affiliation(s)
- Sushil Pangeni
- TC Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Gargi Biswas
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Vikas Kaushik
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, USA
| | - Sahiti Kuppa
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, USA
| | - Olivia Yang
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Chang-Ting Lin
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Garima Mishra
- Department of Physics, Ashoka University, Sonepet, Haryana, India
| | - Yaakov Levy
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, USA.
| | - Taekjip Ha
- TC Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA; Department of Pediatrics, Harvard Medical School, Boston, MA, USA; Howard Hughes Medical Institute, Boston, MA, USA.
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14
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Kaushik V, Chadda R, Kuppa S, Pokhrel N, Vayyeti A, Grady S, Arnatt C, Antony E. Fluorescent human RPA to track assembly dynamics on DNA. Methods 2024; 223:95-105. [PMID: 38301751 PMCID: PMC10923064 DOI: 10.1016/j.ymeth.2024.01.019] [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: 11/01/2023] [Revised: 01/25/2024] [Accepted: 01/29/2024] [Indexed: 02/03/2024] Open
Abstract
DNA metabolic processes including replication, repair, recombination, and telomere maintenance occur on single-stranded DNA (ssDNA). In each of these complex processes, dozens of proteins function together on the ssDNA template. However, when double-stranded DNA is unwound, the transiently open ssDNA is protected and coated by the high affinity heterotrimeric ssDNA binding Replication Protein A (RPA). Almost all downstream DNA processes must first remodel/remove RPA or function alongside to access the ssDNA occluded under RPA. Formation of RPA-ssDNA complexes trigger the DNA damage checkpoint response and is a key step in activating most DNA repair and recombination pathways. Thus, in addition to protecting the exposed ssDNA, RPA functions as a gatekeeper to define functional specificity in DNA maintenance and genomic integrity. RPA achieves functional dexterity through a multi-domain architecture utilizing several DNA binding and protein-interaction domains connected by flexible linkers. This flexible and modular architecture enables RPA to adopt a myriad of configurations tailored for specific DNA metabolic roles. To experimentally capture the dynamics of the domains of RPA upon binding to ssDNA and interacting proteins we here describe the generation of active site-specific fluorescent versions of human RPA (RPA) using 4-azido-L-phenylalanine (4AZP) incorporation and click chemistry. This approach can also be applied to site-specific modifications of other multi-domain proteins. Fluorescence-enhancement through non-canonical amino acids (FEncAA) and Förster Resonance Energy Transfer (FRET) assays for measuring dynamics of RPA on DNA are also described. The fluorescent human RPA described here will enable high-resolution structure-function analysis of RPA-ssDNA interactions.
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Affiliation(s)
- Vikas Kaushik
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Rahul Chadda
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Sahiti Kuppa
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Nilisha Pokhrel
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233, USA
| | - Abhinav Vayyeti
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Scott Grady
- Department of Chemistry, St. Louis University, St. Louis, MO 63103, USA
| | - Chris Arnatt
- Department of Chemistry, St. Louis University, St. Louis, MO 63103, USA
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104, USA.
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15
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Olson CL, Wuttke DS. Guardians of the Genome: How the Single-Stranded DNA-Binding Proteins RPA and CST Facilitate Telomere Replication. Biomolecules 2024; 14:263. [PMID: 38540683 PMCID: PMC10968030 DOI: 10.3390/biom14030263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/02/2024] [Accepted: 02/20/2024] [Indexed: 04/26/2024] Open
Abstract
Telomeres act as the protective caps of eukaryotic linear chromosomes; thus, proper telomere maintenance is crucial for genome stability. Successful telomere replication is a cornerstone of telomere length regulation, but this process can be fraught due to the many intrinsic challenges telomeres pose to the replication machinery. In addition to the famous "end replication" problem due to the discontinuous nature of lagging strand synthesis, telomeres require various telomere-specific steps for maintaining the proper 3' overhang length. Bulk telomere replication also encounters its own difficulties as telomeres are prone to various forms of replication roadblocks. These roadblocks can result in an increase in replication stress that can cause replication forks to slow, stall, or become reversed. Ultimately, this leads to excess single-stranded DNA (ssDNA) that needs to be managed and protected for replication to continue and to prevent DNA damage and genome instability. RPA and CST are single-stranded DNA-binding protein complexes that play key roles in performing this task and help stabilize stalled forks for continued replication. The interplay between RPA and CST, their functions at telomeres during replication, and their specialized features for helping overcome replication stress at telomeres are the focus of this review.
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Affiliation(s)
- Conner L. Olson
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Deborah S. Wuttke
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO 80309, USA
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16
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Hengel SR, Oppenheimer K, Smith C, Schaich MA, Rein HL, Martino J, Darrah K, Ezekwenna O, Burton K, Van Houten B, Spies M, Bernstein KA. The human Shu complex promotes RAD51 activity by modulating RPA dynamics on ssDNA. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580393. [PMID: 38405734 PMCID: PMC10888808 DOI: 10.1101/2024.02.14.580393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Templated DNA repair that occurs during homologous recombination and replication stress relies on RAD51. RAD51 activity is positively regulated by BRCA2 and the RAD51 paralogs. The Shu complex is a RAD51 paralog-containing complex consisting of SWSAP1 and SWS1. We demonstrate that SWSAP1-SWS1 binds RAD51, maintains RAD51 filament stability, and enables strand exchange. Using single molecule confocal fluorescence microscopy combined with optical tweezers, we show that SWSAP1-SWS1 decorates RAD51 filaments proficient for homologous recombination. We also find SWSAP1-SWS1 enhances RPA diffusion on ssDNA. Importantly, we show human sgSWSAP1 and sgSWS1 knockout cells are sensitive to pharmacological inhibition of PARP and APE1. Lastly, we identify cancer variants in SWSAP1 that alter SWS1 complex formation. Together, we show that SWSAP1-SWS1 stimulates RAD51-dependent high-fidelity repair and may be an important new cancer therapeutic target.
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17
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Kumar N, Taneja A, Ghosh M, Rothweiler U, Sundaresan N, Singh M. Harmonin homology domain-mediated interaction of RTEL1 helicase with RPA and DNA provides insights into its recruitment to DNA repair sites. Nucleic Acids Res 2024; 52:1450-1470. [PMID: 38153196 PMCID: PMC10853778 DOI: 10.1093/nar/gkad1208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 12/04/2023] [Accepted: 12/06/2023] [Indexed: 12/29/2023] Open
Abstract
The regulator of telomere elongation helicase 1 (RTEL1) plays roles in telomere DNA maintenance, DNA repair, and genome stability by dismantling D-loops and unwinding G-quadruplex structures. RTEL1 comprises a helicase domain, two tandem harmonin homology domains 1&2 (HHD1 and HHD2), and a Zn2+-binding RING domain. In vitro D-loop disassembly by RTEL1 is enhanced in the presence of replication protein A (RPA). However, the mechanism of RTEL1 recruitment at non-telomeric D-loops remains unknown. In this study, we have unravelled a direct physical interaction between RTEL1 and RPA. Under DNA damage conditions, we showed that RTEL1 and RPA colocalise in the cell. Coimmunoprecipitation showed that RTEL1 and RPA interact, and the deletion of HHDs of RTEL1 significantly reduced this interaction. NMR chemical shift perturbations (CSPs) showed that RPA uses its 32C domain to interact with the HHD2 of RTEL1. Interestingly, HHD2 also interacted with DNA in the in vitro experiments. HHD2 structure was determined using X-ray crystallography, and NMR CSPs mapping revealed that both RPA 32C and DNA competitively bind to HHD2 on an overlapping surface. These results establish novel roles of accessory HHDs in RTEL1's functions and provide mechanistic insights into the RPA-mediated recruitment of RTEL1 to DNA repair sites.
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Affiliation(s)
- Niranjan Kumar
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru 560012, India
| | - Arushi Taneja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Meenakshi Ghosh
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru 560012, India
| | - Ulli Rothweiler
- The Norwegian Structural Biology Centre, Department of Chemistry, The Arctic University of Norway, N-9037, Tromsø, Norway
| | | | - Mahavir Singh
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru 560012, India
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18
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Fousek-Schuller VJ, Borgstahl GEO. The Intriguing Mystery of RPA Phosphorylation in DNA Double-Strand Break Repair. Genes (Basel) 2024; 15:167. [PMID: 38397158 PMCID: PMC10888239 DOI: 10.3390/genes15020167] [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: 12/20/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/25/2024] Open
Abstract
Human Replication Protein A (RPA) was historically discovered as one of the six components needed to reconstitute simian virus 40 DNA replication from purified components. RPA is now known to be involved in all DNA metabolism pathways that involve single-stranded DNA (ssDNA). Heterotrimeric RPA comprises several domains connected by flexible linkers and is heavily regulated by post-translational modifications (PTMs). The structure of RPA has been challenging to obtain. Various structural methods have been applied, but a complete understanding of RPA's flexible structure, its function, and how it is regulated by PTMs has yet to be obtained. This review will summarize recent literature concerning how RPA is phosphorylated in the cell cycle, the structural analysis of RPA, DNA and protein interactions involving RPA, and how PTMs regulate RPA activity and complex formation in double-strand break repair. There are many holes in our understanding of this research area. We will conclude with perspectives for future research on how RPA PTMs control double-strand break repair in the cell cycle.
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Affiliation(s)
| | - Gloria E. O. Borgstahl
- Eppley Institute for Research in Cancer & Allied Diseases, UNMC, Omaha, NE 68198-6805, USA
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19
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Kaushik V, Chadda R, Kuppa S, Pokhrel N, Vayyeti A, Grady S, Arnatt C, Antony E. Fluorescent human RPA to track assembly dynamics on DNA. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.23.568455. [PMID: 38045304 PMCID: PMC10690285 DOI: 10.1101/2023.11.23.568455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
DNA metabolic processes including replication, repair, recombination, and telomere maintenance occur on single-stranded DNA (ssDNA). In each of these complex processes, dozens of proteins function together on the ssDNA template. However, when double-stranded DNA is unwound, the transiently open ssDNA is protected and coated by the high affinity heterotrimeric ssDNA binding Replication Protein A (RPA). Almost all downstream DNA processes must first remodel/remove RPA or function alongside to access the ssDNA occluded under RPA. Formation of RPA-ssDNA complexes trigger the DNA damage checkpoint response and is a key step in activating most DNA repair and recombination pathways. Thus, in addition to protecting the exposed ssDNA, RPA functions as a gatekeeper to define functional specificity in DNA maintenance and genomic integrity. RPA achieves functional dexterity through a multi-domain architecture utilizing several DNA binding and protein-interaction domains connected by flexible linkers. This flexible and modular architecture enables RPA to adopt a myriad of configurations tailored for specific DNA metabolic roles. To experimentally capture the dynamics of the domains of RPA upon binding to ssDNA and interacting proteins we here describe the generation of active site-specific fluorescent versions of human RPA (RPA) using 4-azido-L-phenylalanine (4AZP) incorporation and click chemistry. This approach can also be applied to site-specific modifications of other multi-domain proteins. Fluorescence-enhancement through non-canonical amino acids (FEncAA) and Förster Resonance Energy Transfer (FRET) assays for measuring dynamics of RPA on DNA are also described.
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Affiliation(s)
- Vikas Kaushik
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104
| | - Rahul Chadda
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104
| | - Sahiti Kuppa
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104
| | - Nilisha Pokhrel
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233
| | - Abhinav Vayyeti
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104
| | - Scott Grady
- Department of Chemistry, St. Louis University, St. Louis, MO 63103
| | - Chris Arnatt
- Department of Chemistry, St. Louis University, St. Louis, MO 63103
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104
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20
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Pike AM, Friend CM, Bell SP. Distinct RPA functions promote eukaryotic DNA replication initiation and elongation. Nucleic Acids Res 2023; 51:10506-10518. [PMID: 37739410 PMCID: PMC10602884 DOI: 10.1093/nar/gkad765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 08/14/2023] [Accepted: 09/10/2023] [Indexed: 09/24/2023] Open
Abstract
Replication protein A (RPA) binds single-stranded DNA (ssDNA) and serves critical functions in eukaryotic DNA replication, the DNA damage response, and DNA repair. During DNA replication, RPA is required for extended origin DNA unwinding and DNA synthesis. To determine the requirements for RPA during these processes, we tested ssDNA-binding proteins (SSBs) from different domains of life in reconstituted Saccharomyces cerevisiae origin unwinding and DNA replication reactions. Interestingly, Escherichia coli SSB, but not T4 bacteriophage Gp32, fully substitutes for RPA in promoting origin DNA unwinding. Using RPA mutants, we demonstrated that specific ssDNA-binding properties of RPA are required for origin unwinding but that its protein-interaction domains are dispensable. In contrast, we found that each of these auxiliary RPA domains have distinct functions at the eukaryotic replication fork. The Rfa1 OB-F domain negatively regulates lagging-strand synthesis, while the Rfa2 winged-helix domain stimulates nascent strand initiation. Together, our findings reveal a requirement for specific modes of ssDNA binding in the transition to extensive origin DNA unwinding and identify RPA domains that differentially impact replication fork function.
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Affiliation(s)
- Alexandra M Pike
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Department of Biology, Cambridge, MA 02139, USA
| | - Caitlin M Friend
- Massachusetts Institute of Technology, Department of Biology, Cambridge, MA 02139, USA
| | - Stephen P Bell
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Department of Biology, Cambridge, MA 02139, USA
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21
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Gall-Duncan T, Luo J, Jurkovic CM, Fischer LA, Fujita K, Deshmukh AL, Harding RJ, Tran S, Mehkary M, Li V, Leib DE, Chen R, Tanaka H, Mason AG, Lévesque D, Khan M, Razzaghi M, Prasolava T, Lanni S, Sato N, Caron MC, Panigrahi GB, Wang P, Lau R, Castel AL, Masson JY, Tippett L, Turner C, Spies M, La Spada AR, Campos EI, Curtis MA, Boisvert FM, Faull RLM, Davidson BL, Nakamori M, Okazawa H, Wold MS, Pearson CE. Antagonistic roles of canonical and Alternative-RPA in disease-associated tandem CAG repeat instability. Cell 2023; 186:4898-4919.e25. [PMID: 37827155 PMCID: PMC11209935 DOI: 10.1016/j.cell.2023.09.008] [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: 06/30/2022] [Revised: 06/30/2023] [Accepted: 09/09/2023] [Indexed: 10/14/2023]
Abstract
Expansions of repeat DNA tracts cause >70 diseases, and ongoing expansions in brains exacerbate disease. During expansion mutations, single-stranded DNAs (ssDNAs) form slipped-DNAs. We find the ssDNA-binding complexes canonical replication protein A (RPA1, RPA2, and RPA3) and Alternative-RPA (RPA1, RPA3, and primate-specific RPA4) are upregulated in Huntington disease and spinocerebellar ataxia type 1 (SCA1) patient brains. Protein interactomes of RPA and Alt-RPA reveal unique and shared partners, including modifiers of CAG instability and disease presentation. RPA enhances in vitro melting, FAN1 excision, and repair of slipped-CAGs and protects against CAG expansions in human cells. RPA overexpression in SCA1 mouse brains ablates expansions, coincident with decreased ATXN1 aggregation, reduced brain DNA damage, improved neuron morphology, and rescued motor phenotypes. In contrast, Alt-RPA inhibits melting, FAN1 excision, and repair of slipped-CAGs and promotes CAG expansions. These findings suggest a functional interplay between the two RPAs where Alt-RPA may antagonistically offset RPA's suppression of disease-associated repeat expansions, which may extend to other DNA processes.
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Affiliation(s)
- Terence Gall-Duncan
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Jennifer Luo
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | | | - Laura A Fischer
- Developmental Biology and Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Kyota Fujita
- Neuropathology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Amit L Deshmukh
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Rachel J Harding
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada; Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Stephanie Tran
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Mustafa Mehkary
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Vanessa Li
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - David E Leib
- Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19146, USA
| | - Ran Chen
- Pediatrics, Division of Hematology and Oncology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hikari Tanaka
- Neuropathology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Amanda G Mason
- Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Dominique Lévesque
- Immunology and Cell Biology, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Mahreen Khan
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Mortezaali Razzaghi
- Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Tanya Prasolava
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Stella Lanni
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Nozomu Sato
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Marie-Christine Caron
- CHU de Québec-Université Laval, Oncology Division, Molecular Biology, Medical Biochemistry, and Pathology, Laval University Cancer Research Center, Québec, QC, Canada
| | - Gagan B Panigrahi
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Peixiang Wang
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Rachel Lau
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | | | - Jean-Yves Masson
- CHU de Québec-Université Laval, Oncology Division, Molecular Biology, Medical Biochemistry, and Pathology, Laval University Cancer Research Center, Québec, QC, Canada
| | - Lynette Tippett
- School of Psychology, University of Auckland, Auckland, New Zealand; University Research Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Clinton Turner
- Anatomical Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand
| | - Maria Spies
- Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Albert R La Spada
- Pathology & Laboratory Medicine, Neurology, and Biological Chemistry, University of California, Irvine School of Medicine, Irvine, CA, USA; Neurobiology & Behavior, University of California, Irvine, Irvine, CA, USA; Center for Neurotherapeutics, University of California, Irvine, Irvine, CA 92697, USA
| | - Eric I Campos
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Maurice A Curtis
- University Research Centre for Brain Research, University of Auckland, Auckland, New Zealand; Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | | | - Richard L M Faull
- University Research Centre for Brain Research, University of Auckland, Auckland, New Zealand; Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Beverly L Davidson
- Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19146, USA
| | - Masayuki Nakamori
- Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hitoshi Okazawa
- Neuropathology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Marc S Wold
- Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Christopher E Pearson
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada; Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada.
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22
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Sharma R, Oak N, Chen W, Gogal R, Kirschner M, Beier F, Schnieders MJ, Spies M, Nichols KE, Wlodarski M. Germline landscape of RPA1, RPA2 and RPA3 variants in pediatric malignancies: identification of RPA1 as a novel cancer predisposition candidate gene. Front Oncol 2023; 13:1229507. [PMID: 37869077 PMCID: PMC10588448 DOI: 10.3389/fonc.2023.1229507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 09/18/2023] [Indexed: 10/24/2023] Open
Abstract
Replication Protein A (RPA) is single-strand DNA binding protein that plays a key role in the replication and repair of DNA. RPA is a heterotrimer made of 3 subunits - RPA1, RPA2, and RPA3. Germline pathogenic variants affecting RPA1 were recently described in patients with Telomere Biology Disorders (TBD), also known as dyskeratosis congenita or short telomere syndrome. Premature telomere shortening is a hallmark of TBD and results in bone marrow failure and predisposition to hematologic malignancies. Building on the finding that somatic mutations in RPA subunit genes occur in ~1% of cancers, we hypothesized that germline RPA alterations might be enriched in human cancers. Because germline RPA1 mutations are linked to early onset TBD with predisposition to myelodysplastic syndromes, we interrogated pediatric cancer cohorts to define the prevalence and spectrum of rare/novel and putative damaging germline RPA1, RPA2, and RPA3 variants. In this study of 5,993 children with cancer, 75 (1.25%) harbored heterozygous rare (non-cancer population allele frequency (AF) < 0.1%) variants in the RPA heterotrimer genes, of which 51 cases (0.85%) had ultra-rare (AF < 0.005%) or novel variants. Compared with Genome Aggregation Database (gnomAD) non-cancer controls, there was significant enrichment of ultra-rare and novel RPA1, but not RPA2 or RPA3, germline variants in our cohort (adjusted p-value < 0.05). Taken together, these findings suggest that germline putative damaging variants affecting RPA1 are found in excess in children with cancer, warranting further investigation into the functional role of these variants in oncogenesis.
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Affiliation(s)
- Richa Sharma
- Department of Hematology, St. Jude Children´s Research Hospital, Memphis, TN, United States
| | - Ninad Oak
- Department of Oncology, St. Jude Children’s Research Hospital, Memphis, TN, United States
| | - Wenan Chen
- Center for Applied Bioinformatics, St. Jude Children’s Research Hospital, Memphis, TN, United States
| | - Rose Gogal
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Martin Kirschner
- Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation, Medical Faculty, RWTH Aachen University, Aachen, Germany
- Center for Integrated Oncology Aachen Bonn Cologne Düsseldorf (CIO ABCD), Bonn, Germany
| | - Fabian Beier
- Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation, Medical Faculty, RWTH Aachen University, Aachen, Germany
- Center for Integrated Oncology Aachen Bonn Cologne Düsseldorf (CIO ABCD), Bonn, Germany
| | - Michael J. Schnieders
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Maria Spies
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Kim E. Nichols
- Department of Oncology, St. Jude Children’s Research Hospital, Memphis, TN, United States
| | - Marcin Wlodarski
- Department of Hematology, St. Jude Children´s Research Hospital, Memphis, TN, United States
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23
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Wu Y, Fu W, Zang N, Zhou C. Structural characterization of human RPA70N association with DNA damage response proteins. eLife 2023; 12:e81639. [PMID: 37668474 PMCID: PMC10479964 DOI: 10.7554/elife.81639] [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: 07/05/2022] [Accepted: 08/09/2023] [Indexed: 09/06/2023] Open
Abstract
The heterotrimeric Replication protein A (RPA) is the ubiquitous eukaryotic single-stranded DNA (ssDNA) binding protein and participates in nearly all aspects of DNA metabolism, especially DNA damage response. The N-terminal OB domain of the RPA70 subunit (RPA70N) is a major protein-protein interaction element for RPA and binds to more than 20 partner proteins. Previous crystallography studies of RPA70N with p53, DNA2 and PrimPol fragments revealed that RPA70N binds to amphipathic peptides that mimic ssDNA. NMR chemical-shift studies also provided valuable information on the interaction of RPA70N residues with target sequences. However, it is still unclear how RPA70N recognizes and distinguishes such a diverse group of target proteins. Here, we present high-resolution crystal structures of RPA70N in complex with peptides from eight DNA damage response proteins. The structures show that, in addition to the ssDNA mimicry mode of interaction, RPA70N employs multiple ways to bind its partners. Our results advance the mechanistic understanding of RPA70N-mediated recruitment of DNA damage response proteins.
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Affiliation(s)
- Yeyao Wu
- School of Public Health & Sir Run Run Shaw Hospital, Zhejiang University School of MedicineZhejiangChina
| | - Wangmi Fu
- School of Public Health & Sir Run Run Shaw Hospital, Zhejiang University School of MedicineZhejiangChina
| | - Ning Zang
- School of Public Health & Sir Run Run Shaw Hospital, Zhejiang University School of MedicineZhejiangChina
| | - Chun Zhou
- School of Public Health & Sir Run Run Shaw Hospital, Zhejiang University School of MedicineZhejiangChina
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24
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Yates LA, Zhang X. Phosphoregulation of the checkpoint kinase Mec1 ATR. DNA Repair (Amst) 2023; 129:103543. [PMID: 37480741 DOI: 10.1016/j.dnarep.2023.103543] [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: 07/05/2023] [Revised: 07/14/2023] [Accepted: 07/15/2023] [Indexed: 07/24/2023]
Abstract
Yeast Mec1, and its mammalian ortholog, Ataxia-Telangiectasia and Rad3-related, are giant protein kinases central to replication stress and double strand DNA break repair. Mec1ATR, in complex with Ddc2ATRIP, is a 'sensor' of single stranded DNA, and phosphorylates numerous cell cycle and DNA repair factors to enforce cell cycle arrest and facilitate repair. Over the last several years, new techniques - particularly in structural biology - have provided molecular mechanisms for Mec1ATR function. It is becoming increasingly clear how post-translational modification of Mec1ATR and its interaction partners modulates the DNA damage checkpoint. In this review, we summarise the most recent work unravelling Mec1ATR function in the DNA damage checkpoint and provide a molecular context for its regulation by phosphorylation.
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Affiliation(s)
- Luke A Yates
- Section of Structural, Department of Infectious Disease, Sir Alexander Fleming Building, Imperial College London, SW7 2AZ, UK; DNA processing machines laboratory, Francis Crick Institute, London NW1 1AT, UK.
| | - Xiaodong Zhang
- Section of Structural, Department of Infectious Disease, Sir Alexander Fleming Building, Imperial College London, SW7 2AZ, UK; DNA processing machines laboratory, Francis Crick Institute, London NW1 1AT, UK.
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25
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Wang X, Zhang S, Zhang Z, Mazloum NA, Lee EYC, Lee MYW. The DHX9 helicase interacts with human DNA polymerase δ4 and stimulates its activity in D-loop extension synthesis. DNA Repair (Amst) 2023; 128:103513. [PMID: 37285751 PMCID: PMC10330758 DOI: 10.1016/j.dnarep.2023.103513] [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: 03/08/2023] [Revised: 04/28/2023] [Accepted: 05/11/2023] [Indexed: 06/09/2023]
Abstract
The extension of the invading strand within a displacement loop (D-loop) is a key step in homology directed repair (HDR) of doubled stranded DNA breaks. The primary goal of these studies was to test the hypotheses that 1) D-loop extension by human DNA polymerase δ4 (Pol δ4) is facilitated by DHX9, a 3' to 5' motor helicase, which acts to unwind the leading edge of the D-loop, and 2) the recruitment of DHX9 is mediated by direct protein-protein interactions between DHX9 and Pol δ4 and/or PCNA. DNA synthesis by Pol δ4 was analyzed in a reconstitution assay by the extension of a 93mer oligonucleotide inserted into a plasmid to form a D-loop. Product formation by Pol δ4 was monitored by incorporation of [α-32P]dNTPs into the 93mer primer followed by denaturing gel electrophoresis. The results showed that DHX9 strongly stimulated Pol δ4 mediated D-loop extension. Direct interactions of DHX9 with PCNA, the p125 and the p12 subunits of Pol δ4 were demonstrated by pull-down assays with purified proteins. These data support the hypothesis that DHX9 helicase is recruited by Pol δ4/PCNA to facilitate D-loop synthesis in HDR, and is a participant in cellular HDR. The involvement of DHX9 in HDR represents an important addition to its multiple cellular roles. Such helicase-polymerase interactions may represent an important aspect of the mechanisms involved in D-loop primer extension synthesis in HDR.
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Affiliation(s)
- Xiaoxiao Wang
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY 10595, USA
| | - Sufang Zhang
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY 10595, USA
| | - Zhongtao Zhang
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY 10595, USA
| | - Nayef A Mazloum
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY 10595, USA
| | - Ernest Y C Lee
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY 10595, USA
| | - Marietta Y W Lee
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY 10595, USA.
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26
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Bocanegra R, Ortíz-Rodríguez M, Zumeta L, Plaza-G A I, Faro E, Ibarra B. DNA replication machineries: Structural insights from crystallography and electron microscopy. Enzymes 2023; 54:249-271. [PMID: 37945174 DOI: 10.1016/bs.enz.2023.07.004] [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] [Indexed: 11/12/2023]
Abstract
Since the discovery of DNA as the genetic material, scientists have been investigating how the information contained in this biological polymer is transmitted from generation to generation. X-ray crystallography, and more recently, cryo-electron microscopy techniques have been instrumental in providing essential information about the structure, functions and interactions of the DNA and the protein machinery (replisome) responsible for its replication. In this chapter, we highlight several works that describe the structure and structure-function relationships of the core components of the prokaryotic and eukaryotic replisomes. We also discuss the most recent studies on the structural organization of full replisomes.
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Affiliation(s)
| | | | - Lyra Zumeta
- IMDEA Nanociencia, Campus Cantoblanco, Madrid, Spain
| | | | - Elías Faro
- IMDEA Nanociencia, Campus Cantoblanco, Madrid, Spain
| | - Borja Ibarra
- IMDEA Nanociencia, Campus Cantoblanco, Madrid, Spain.
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27
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Mukherjee A, Hossain Z, Erben E, Ma S, Choi JY, Kim HS. Identification of a small-molecule inhibitor that selectively blocks DNA-binding by Trypanosoma brucei replication protein A1. Nat Commun 2023; 14:4390. [PMID: 37474515 PMCID: PMC10359466 DOI: 10.1038/s41467-023-39839-x] [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: 10/12/2022] [Accepted: 06/30/2023] [Indexed: 07/22/2023] Open
Abstract
Replication Protein A (RPA) is a broadly conserved complex comprised of the RPA1, 2 and 3 subunits. RPA protects the exposed single-stranded DNA (ssDNA) during DNA replication and repair. Using structural modeling, we discover an inhibitor, JC-229, that targets RPA1 in Trypanosoma brucei, the causative parasite of African trypanosomiasis. The inhibitor is highly toxic to T. brucei cells, while mildly toxic to human cells. JC-229 treatment mimics the effects of TbRPA1 depletion, including DNA replication inhibition and DNA damage accumulation. In-vitro ssDNA-binding assays demonstrate that JC-229 inhibits the activity of TbRPA1, but not the human ortholog. Indeed, despite the high sequence identity with T. cruzi and Leishmania RPA1, JC-229 only impacts the ssDNA-binding activity of TbRPA1. Site-directed mutagenesis confirms that the DNA-Binding Domain A (DBD-A) in TbRPA1 contains a JC-229 binding pocket. Residue Serine 105 determines specific binding and inhibition of TbRPA1 but not T. cruzi and Leishmania RPA1. Our data suggest a path toward developing and testing highly specific inhibitors for the treatment of African trypanosomiasis.
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Affiliation(s)
- Aditi Mukherjee
- Public Health Research Institute, Rutgers Biomedical Health Sciences, Newark, NJ, 07103, USA
| | - Zakir Hossain
- Department of Chemistry and Biochemistry, Queens College, New York, NY, 11367, USA
| | - Esteban Erben
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Martín, Provincia de Buenos Aires, Argentina
- Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Provincia de Buenos Aires, Argentina
| | - Shuai Ma
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA
| | - Jun Yong Choi
- Department of Chemistry and Biochemistry, Queens College, New York, NY, 11367, USA.
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA.
- Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA.
| | - Hee-Sook Kim
- Public Health Research Institute, Rutgers Biomedical Health Sciences, Newark, NJ, 07103, USA.
- Department of Microbiology, Biochemistry, and Molecular Genetics, New Jersey Medical School, Rutgers Biomedical Health Sciences, Newark, NJ, 07103, USA.
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28
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Holland CL, Weis MF, England CJ, Berry AM, Hall PD, Lewis LK. Deficiency in homologous recombination is associated with changes in cell cycling and morphology in Saccharomyces cerevisiae. Exp Cell Res 2023:113701. [PMID: 37393982 DOI: 10.1016/j.yexcr.2023.113701] [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: 05/04/2023] [Revised: 06/23/2023] [Accepted: 06/25/2023] [Indexed: 07/04/2023]
Abstract
Exposure of eukaryotic cells to ionizing radiation or clastogenic chemicals leads to formation of DNA double-strand breaks (DSBs). These lesions are also generated internally by chemicals and enzymes, in the absence of exogenous agents, though the sources and consequences of such endogenously generated DSBs remain poorly understood. In the current study, we have investigated the impact of reduced recombinational repair of endogenous DSBs on stress responses, cell morphology and other physical properties of S. cerevisiae (budding yeast) cells. Use of phase contrast and DAPI-based fluorescence microscopy combined with FACS analysis confirmed that recombination-deficient rad52 cell cultures exhibit chronically high levels of G2 phase cells. Cell cycle phase transit times during G1, S and M were similar in WT and rad52 cells, but the length of G2 phase was increased by three-fold in the mutants. rad52 cells were larger than WT in all phases of the cycle and displayed other quantifiable changes in physical characteristics. The high G2 cell phenotype was abolished when DNA damage checkpoint genes, but not spindle assembly checkpoint genes, were co-inactivated with RAD52. Several other RAD52 group mutants (rad51, rad54, rad55, rad57 and rad59) also exhibited the high G2 cell phenotype. The results indicate that recombination deficiency leads to accumulation of unrepaired DSBs during normal mitotic growth that activate a major stress response and produce distinct changes in cellular physiology and morphology.
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Affiliation(s)
- Cory L Holland
- Chemistry and Biochemistry, Texas State University, 601 University Drive, San Marcos, TX, 78666, USA
| | - Monica F Weis
- Chemistry and Biochemistry, Texas State University, 601 University Drive, San Marcos, TX, 78666, USA
| | - Corbin J England
- Chemistry and Biochemistry, Texas State University, 601 University Drive, San Marcos, TX, 78666, USA
| | - Armand M Berry
- Chemistry and Biochemistry, Texas State University, 601 University Drive, San Marcos, TX, 78666, USA
| | - Paige D Hall
- Chemistry and Biochemistry, Texas State University, 601 University Drive, San Marcos, TX, 78666, USA
| | - L Kevin Lewis
- Chemistry and Biochemistry, Texas State University, 601 University Drive, San Marcos, TX, 78666, USA.
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29
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Ding J, Li X, Shen J, Zhao Y, Zhong S, Lai L, Niu H, Qi Z. ssDNA accessibility of Rad51 is regulated by orchestrating multiple RPA dynamics. Nat Commun 2023; 14:3864. [PMID: 37391417 PMCID: PMC10313831 DOI: 10.1038/s41467-023-39579-y] [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: 11/23/2022] [Accepted: 06/20/2023] [Indexed: 07/02/2023] Open
Abstract
The eukaryotic single-stranded DNA (ssDNA)-binding protein Replication Protein A (RPA) plays a crucial role in various DNA metabolic pathways, including DNA replication and repair, by dynamically associating with ssDNA. While the binding of a single RPA molecule to ssDNA has been thoroughly studied, the accessibility of ssDNA is largely governed by the bimolecular behavior of RPA, the biophysical nature of which remains unclear. In this study, we develop a three-step low-complexity ssDNA Curtains method, which, when combined with biochemical assays and a Markov chain model in non-equilibrium physics, allow us to decipher the dynamics of multiple RPA binding to long ssDNA. Interestingly, our results suggest that Rad52, the mediator protein, can modulate the ssDNA accessibility of Rad51, which is nucleated on RPA coated ssDNA through dynamic ssDNA exposure between neighboring RPA molecules. We find that this process is controlled by the shifting between the protection mode and action mode of RPA ssDNA binding, where tighter RPA spacing and lower ssDNA accessibility are favored under RPA protection mode, which can be facilitated by the Rfa2 WH domain and inhibited by Rad52 RPA interaction.
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Affiliation(s)
- Jiawei Ding
- Center for Quantitative Biology, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Xiangting Li
- Department of Computational Medicine, University of California, Los Angeles, CA, USA
| | - Jiangchuan Shen
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA
| | - Yiling Zhao
- Center for Quantitative Biology, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Shuchen Zhong
- BNLMS, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Luhua Lai
- Center for Quantitative Biology, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- BNLMS, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Hengyao Niu
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA.
| | - Zhi Qi
- Center for Quantitative Biology, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
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30
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Hernandez-Martinez JM, Rosell R, Arrieta O. Somatic and germline ATM variants in non-small-cell lung cancer: Therapeutic implications. Crit Rev Oncol Hematol 2023:104058. [PMID: 37343657 DOI: 10.1016/j.critrevonc.2023.104058] [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: 05/15/2023] [Accepted: 06/16/2023] [Indexed: 06/23/2023] Open
Abstract
ATM is an apical kinase of the DNA damage response involved in the repair of DNA double-strand breaks. Germline ATM variants (gATM) have been associated with an increased risk of developing lung adenocarcinoma (LUAD), and approximately 9% of LUAD tumors harbor somatic ATM mutations (sATM). Biallelic carriers of pathogenic gATM exhibit a plethora of immunological abnormalities, but few studies have evaluated the contribution of immune dysfunction to lung cancer susceptibility. Indeed, little is known about the clinicopathological characteristics of lung cancer patients with sATM or gATM alterations. The introduction of targeted therapies and immunotherapies, and the increasing number of clinical trials evaluating treatment combinations, warrants a careful reexamination of the benefits and harms that different therapeutic approaches have had in lung cancer patients with sATM or gATM. This review will discuss the role of ATM in the pathogenesis of lung cancer, highlighting potential therapeutic approaches to manage ATM-deficient lung cancers.
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Affiliation(s)
- Juan-Manuel Hernandez-Martinez
- Thoracic Oncology Unit and Experimental Oncology Laboratory, Instituto Nacional de Cancerología de México (INCan); CONACYT-Instituto Nacional de Cancerología, Mexico City, Mexico
| | - Rafael Rosell
- Institut d'Investigació en Ciències Germans Trias i Pujol, Badalona, Spain; (4)Institut Català d'Oncologia, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Oscar Arrieta
- Thoracic Oncology Unit and Experimental Oncology Laboratory, Instituto Nacional de Cancerología de México (INCan).
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31
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Driscoll G, Yan S. Maintaining chromosome and genome stability by the RPA-RNF20-SNF2H cascade. Proc Natl Acad Sci U S A 2023; 120:e2306455120. [PMID: 37276422 PMCID: PMC10268305 DOI: 10.1073/pnas.2306455120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023] Open
Affiliation(s)
- Garrett Driscoll
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC28223
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC28223
- School of Data Science, University of North Carolina at Charlotte, Charlotte, NC28223
- Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, Charlotte, NC28223
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32
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Bhat D, Malacaria E, Biagi L, Razzaghi M, Honda M, Hobbs K, Hengel S, Pichierri P, Spies M, Spies M. Therapeutic disruption of RAD52-ssDNA complexation via novel drug-like inhibitors. NAR Cancer 2023; 5:zcad018. [PMID: 37139244 PMCID: PMC10150327 DOI: 10.1093/narcan/zcad018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/09/2023] [Accepted: 04/14/2023] [Indexed: 05/05/2023] Open
Abstract
RAD52 protein is a coveted target for anticancer drug discovery. Similar to poly-ADP-ribose polymerase (PARP) inhibitors, pharmacological inhibition of RAD52 is synthetically lethal with defects in genome caretakers BRCA1 and BRCA2 (∼25% of breast and ovarian cancers). Emerging structure activity relationships for RAD52 are complex, making it challenging to transform previously identified disruptors of the RAD52-ssDNA interaction into drug-like leads using traditional medicinal chemistry approaches. Using pharmacophoric informatics on the RAD52 complexation by epigallocatechin (EGC), and the Enamine in silico REAL database, we identified six distinct chemical scaffolds that occupy the same physical space on RAD52 as EGC. All six were RAD52 inhibitors (IC50 ∼23-1200 μM) with two of the compounds (Z56 and Z99) selectively killing BRCA-mutant cells and inhibiting cellular activities of RAD52 at micromolar inhibitor concentrations. While Z56 had no effect on the ssDNA-binding protein RPA and was toxic to BRCA-mutant cells only, Z99 inhibited both proteins and displayed toxicity towards BRCA-complemented cells. Optimization of the Z99 scaffold resulted in a set of more powerful and selective inhibitors (IC50 ∼1.3-8 μM), which were only toxic to BRCA-mutant cells. RAD52 complexation by Z56, Z99 and its more specific derivatives provide a roadmap for next generation of cancer therapeutics.
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Affiliation(s)
- Divya S Bhat
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA
| | - Eva Malacaria
- Mechanisms, Biomarkers and Models Section, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Ludovica Di Biagi
- Mechanisms, Biomarkers and Models Section, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Mortezaali Razzaghi
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA
| | - Masayoshi Honda
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA
| | - Kathryn F Hobbs
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA
- Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, The University of Iowa, Iowa City, IA 52242, USA
| | - Sarah R Hengel
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA
| | - Pietro Pichierri
- Mechanisms, Biomarkers and Models Section, Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - M Ashley Spies
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA
- Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, The University of Iowa, Iowa City, IA 52242, USA
- Naturis Informatika LLC, 401 Mullin Ave., Iowa City, IA 52246, USA
| | - Maria Spies
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA
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33
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Roshan P, Kuppa S, Mattice JR, Kaushik V, Chadda R, Pokhrel N, Tumala BR, Biswas A, Bothner B, Antony E, Origanti S. An Aurora B-RPA signaling axis secures chromosome segregation fidelity. Nat Commun 2023; 14:3008. [PMID: 37230964 PMCID: PMC10212944 DOI: 10.1038/s41467-023-38711-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 05/09/2023] [Indexed: 05/27/2023] Open
Abstract
Errors in chromosome segregation underlie genomic instability associated with cancers. Resolution of replication and recombination intermediates and protection of vulnerable single-stranded DNA (ssDNA) intermediates during mitotic progression requires the ssDNA binding protein Replication Protein A (RPA). However, the mechanisms that regulate RPA specifically during unperturbed mitotic progression are poorly resolved. RPA is a heterotrimer composed of RPA70, RPA32 and RPA14 subunits and is predominantly regulated through hyperphosphorylation of RPA32 in response to DNA damage. Here, we have uncovered a mitosis-specific regulation of RPA by Aurora B kinase. Aurora B phosphorylates Ser-384 in the DNA binding domain B of the large RPA70 subunit and highlights a mode of regulation distinct from RPA32. Disruption of Ser-384 phosphorylation in RPA70 leads to defects in chromosome segregation with loss of viability and a feedback modulation of Aurora B activity. Phosphorylation at Ser-384 remodels the protein interaction domains of RPA. Furthermore, phosphorylation impairs RPA binding to DSS1 that likely suppresses homologous recombination during mitosis by preventing recruitment of DSS1-BRCA2 to exposed ssDNA. We showcase a critical Aurora B-RPA signaling axis in mitosis that is essential for maintaining genomic integrity.
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Affiliation(s)
- Poonam Roshan
- Department of Biology, St. Louis University, St. Louis, MO, 63103, USA
| | - Sahiti Kuppa
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Jenna R Mattice
- Department of Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Vikas Kaushik
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Rahul Chadda
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Nilisha Pokhrel
- Department of Biological Sciences, Marquette University, Milwaukee, WI, 53217, USA
| | - Brunda R Tumala
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Aparna Biswas
- Department of Biology, St. Louis University, St. Louis, MO, 63103, USA
| | - Brian Bothner
- Department of Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, 63104, USA.
| | - Sofia Origanti
- Department of Biology, St. Louis University, St. Louis, MO, 63103, USA.
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34
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Greenwood SN, Kulkarni RS, Mikhail M, Weiser BP. Replication Protein A Enhances Kinetics of Uracil DNA Glycosylase on ssDNA and Across DNA Junctions: Explored with a DNA Repair Complex Produced with SpyCatcher/SpyTag Ligation. Chembiochem 2023; 24:e202200765. [PMID: 36883884 PMCID: PMC10267839 DOI: 10.1002/cbic.202200765] [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: 12/22/2022] [Revised: 03/06/2023] [Accepted: 03/08/2023] [Indexed: 03/09/2023]
Abstract
DNA repair proteins participate in extensive protein-protein interactions that promote the formation of DNA repair complexes. To understand how complex formation affects protein function during base excision repair, we used SpyCatcher/SpyTag ligation to produce a covalent complex between human uracil DNA glycosylase (UNG2) and replication protein A (RPA). Our covalent "RPA-Spy-UNG2" complex could identify and excise uracil bases in duplex areas next to ssDNA-dsDNA junctions slightly faster than the wild-type proteins, but this was highly dependent on DNA structure, as the turnover of the RPA-Spy-UNG2 complex slowed at DNA junctions where RPA tightly engaged long ssDNA sections. Conversely, the enzymes preferred uracil sites in ssDNA where RPA strongly enhanced uracil excision by UNG2 regardless of ssDNA length. Finally, RPA was found to promote UNG2 excision of two uracil sites positioned across a ssDNA-dsDNA junction, and dissociation of UNG2 from RPA enhanced this process. Our approach of ligating together RPA and UNG2 to reveal how complex formation affects enzyme function could be applied to examine other assemblies of DNA repair proteins.
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Affiliation(s)
- Sharon N Greenwood
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA
| | - Rashmi S Kulkarni
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA
| | - Michel Mikhail
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA
- Department of Internal Medicine, Newark Beth Israel Medical Center, Newark, NJ 07112, USA
| | - Brian P Weiser
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA
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35
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Phase separation properties of RPA combine high-affinity ssDNA binding with dynamic condensate functions at telomeres. Nat Struct Mol Biol 2023; 30:451-462. [PMID: 36894693 PMCID: PMC10113159 DOI: 10.1038/s41594-023-00932-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 01/27/2023] [Indexed: 03/11/2023]
Abstract
RPA has been shown to protect single-stranded DNA (ssDNA) intermediates from instability and breakage. RPA binds ssDNA with sub-nanomolar affinity, yet dynamic turnover is required for downstream ssDNA transactions. How ultrahigh-affinity binding and dynamic turnover are achieved simultaneously is not well understood. Here we reveal that RPA has a strong propensity to assemble into dynamic condensates. In solution, purified RPA phase separates into liquid droplets with fusion and surface wetting behavior. Phase separation is stimulated by sub-stoichiometric amounts of ssDNA, but not RNA or double-stranded DNA, and ssDNA gets selectively enriched in RPA condensates. We find the RPA2 subunit required for condensation and multi-site phosphorylation of the RPA2 N-terminal intrinsically disordered region to regulate RPA self-interaction. Functionally, quantitative proximity proteomics links RPA condensation to telomere clustering and integrity in cancer cells. Collectively, our results suggest that RPA-coated ssDNA is contained in dynamic RPA condensates whose properties are important for genome organization and stability.
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36
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Weidle UH, Nopora A. Up-regulated Circular RNAs in Colorectal Cancer: New Entities for Therapy and Tools for Identification of Therapeutic Targets. Cancer Genomics Proteomics 2023; 20:132-153. [PMID: 36870691 PMCID: PMC9989668 DOI: 10.21873/cgp.20369] [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: 11/22/2022] [Revised: 12/20/2022] [Accepted: 12/28/2022] [Indexed: 03/06/2023] Open
Abstract
Patients with disseminated colorectal cancer have a dismal prognosis with a 5-year survival rate of only 13%. In order to identify new treatment modalities and new targets, we searched the literature for up-regulated circular RNAs in colorectal cancer which induce tumor growth in corresponding preclinical in vivo models. We identified nine circular RNAs that mediate resistance against chemotherapeutic agents, seven that up-regulate transmembrane receptors, five that induce secreted factors, nine that activate signaling components, five which up-regulate enzymes, six which activate actin-related proteins, six which induce transcription factors and two which up-regulate the MUSASHI family of RNA binding proteins. All of the circular RNAs discussed in this paper induce the corresponding targets by sponging microRNAs (miRs) and can be inhibited by RNAi or shRNA in vitro and in xenograft models. We have focused on circular RNAs with demonstrated activity in preclinical in vivo models because the latter is an important milestone in drug development. All circular RNAs with in vitro activity only data are not referenced in this review. The translational impact of inhibition of these circular RNAs and of the identified targets for treatment of colorectal cancer (CRC) are discussed.
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Affiliation(s)
- Ulrich H Weidle
- Roche Pharma Research and Early Development, Roche Innovation Center Munich, Penzberg, Germany
| | - Adam Nopora
- Roche Pharma Research and Early Development, Roche Innovation Center Munich, Penzberg, Germany
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37
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Ling JA, Gildenberg MS, Honda M, Kondratick CM, Spies M, Washington MT. Fork-Remodeling Helicase Rad5 Preferentially Reverses Replication Forks with Gaps in the Leading Strand. J Mol Biol 2023; 435:167946. [PMID: 36623584 PMCID: PMC9915103 DOI: 10.1016/j.jmb.2023.167946] [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: 10/13/2022] [Revised: 12/15/2022] [Accepted: 01/02/2023] [Indexed: 01/09/2023]
Abstract
DNA damage bypass pathways promote the replication of damaged DNA when replication forks stall at sites of DNA damage. Template switching is a DNA damage bypass pathway in which fork-reversal helicases convert stalled replication forks into four-way DNA junctions called chicken foot intermediates, which are subsequently extended by replicative DNA polymerases. In yeast, fork-reversal is carried out by the Rad5 helicase using an unknown mechanism. To better understand the mechanism of Rad5 and its specificity for different fork DNA substrates, we used a FRET-based assay to observe fork reversal in real time. We examined the ability of Rad5 to bind and catalyze the reversal of various fork DNA substrates in the presence of short gaps in the leading or lagging strand as well as in the presence or absence of RPA and RNA primers in the lagging strand. We found that Rad5 preferentially reverses fork DNA substrates with short gaps (10 to 30 nt.) in the leading strand. Thus, Rad5 preferentially reverses fork DNA substrates that form chicken foot intermediates with 5' overhangs that can be extended by replicative DNA polymerases during the subsequent steps of template switching.
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Affiliation(s)
- Justin A Ling
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City, IA 52242-1109, United States. https://twitter.com/Biochem_Ling
| | - Melissa S Gildenberg
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City, IA 52242-1109, United States. https://twitter.com/MGild01
| | - Masayoshi Honda
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City, IA 52242-1109, United States
| | - Christine M Kondratick
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City, IA 52242-1109, United States
| | - Maria Spies
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City, IA 52242-1109, United States. https://twitter.com/maria_spies
| | - M Todd Washington
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City, IA 52242-1109, United States.
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38
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Trivedi S, Blazícková J, Silva N. PARG and BRCA1-BARD1 cooperative function regulates DNA repair pathway choice during gametogenesis. Nucleic Acids Res 2022; 50:12291-12308. [PMID: 36478097 PMCID: PMC9757042 DOI: 10.1093/nar/gkac1153] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 11/09/2022] [Accepted: 11/18/2022] [Indexed: 12/14/2022] Open
Abstract
Meiotic chromosome segregation relies on programmed DNA double-strand break induction. These are in turn repaired by homologous recombination, generating physical attachments between the parental chromosomes called crossovers. A subset of breaks yields recombinant outcomes, while crossover-independent mechanisms repair the majority of lesions. The balance between different repair pathways is crucial to ensure genome integrity. We show that Caenorhabditis elegans BRC-1/BRCA1-BRD-1/BARD1 and PARG-1/PARG form a complex in vivo, essential for accurate DNA repair in the germline. Simultaneous depletion of BRC-1 and PARG-1 causes synthetic lethality due to reduced crossover formation and impaired break repair, evidenced by hindered RPA-1 removal and presence of aberrant chromatin bodies in diakinesis nuclei, whose formation depends on spo-11 function. These factors undergo a similar yet independent loading in developing oocytes, consistent with operating in different pathways. Abrogation of KU- or Theta-mediated end joining elicits opposite effects in brc-1; parg-1 doubles, suggesting a profound impact in influencing DNA repair pathway choice by BRC-1-PARG-1. Importantly, lack of PARG-1 catalytic activity suppresses untimely accumulation of RAD-51 foci in brc-1 mutants but is only partially required for fertility. Our data show that BRC-1/BRD-1-PARG-1 joint function is essential for genome integrity in meiotic cells by regulating multiple DNA repair pathways.
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Affiliation(s)
- Shalini Trivedi
- Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - Jitka Blazícková
- Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - Nicola Silva
- To whom correspondence should be addressed. Tel: +420 549 49 8033;
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39
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Bhat DS, Spies MA, Spies M. A moving target for drug discovery: Structure activity relationship and many genome (de)stabilizing functions of the RAD52 protein. DNA Repair (Amst) 2022; 120:103421. [PMID: 36327799 PMCID: PMC9888176 DOI: 10.1016/j.dnarep.2022.103421] [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: 07/29/2022] [Revised: 10/18/2022] [Accepted: 10/24/2022] [Indexed: 02/02/2023]
Abstract
BRCA-ness phenotype, a signature of many breast and ovarian cancers, manifests as deficiency in homologous recombination, and as defects in protection and repair of damaged DNA replication forks. A dependence of such cancers on DNA repair factors less important for survival of BRCA-proficient cells, offers opportunities for development of novel chemotherapeutic interventions. The first drugs targeting BRCA-deficient cancers, poly-ADP-ribose polymerase (PARP) inhibitors have been approved for the treatment of advanced, chemotherapy resistant cancers in patients with BRCA1/2 germline mutations. Nine additional proteins that can be targeted to selectively kill BRCA-deficient cancer cells have been identified. Among them, a DNA repair protein RAD52 is an especially attractive target due to general tolerance of the RAD52 loss of function, and protective role of an inactivating mutation. Yet, the effective pharmacological inhibitors of RAD52 have not been forthcoming. In this review, we discuss advances in the state of our knowledge of the RAD52 structure, activities and cellular functions, with a specific focus on the features that make RAD52 an attractive, but difficult drug target.
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Affiliation(s)
- Divya S Bhat
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA
| | - M Ashley Spies
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA; Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, The University of Iowa, Iowa City, Iowa 52242, USA
| | - Maria Spies
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA.
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40
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Wieser TA, Wuttke DS. Replication Protein A Utilizes Differential Engagement of Its DNA-Binding Domains to Bind Biologically Relevant ssDNAs in Diverse Binding Modes. Biochemistry 2022; 61:2592-2606. [PMID: 36278947 PMCID: PMC9798700 DOI: 10.1021/acs.biochem.2c00504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Replication protein A (RPA) is a ubiquitous ssDNA-binding protein that functions in many DNA processing pathways to maintain genome integrity. Recent studies suggest that RPA forms a highly dynamic complex with ssDNA that can engage with DNA in many modes that are orchestrated by the differential engagement of the four DNA-binding domains (DBDs) in RPA. To understand how these modes influence RPA interaction with biologically relevant ligands, we performed a comprehensive and systematic evaluation of RPA's binding to a diverse set of ssDNA ligands that varied in sequence, length, and structure. These equilibrium binding data show that WT RPA binds structured ssDNA ligands differently from its engagement with minimal ssDNAs. Next, we investigated each DBD's contributions to RPA's binding modes through mutation of conserved, functionally important aromatic residues. Mutations in DBD-A and -B have a much larger effect on binding when ssDNA is embedded into DNA secondary structures compared to their association with unstructured minimal ssDNA. As our data support a complex interplay of binding modes, it is critical to define the trimer core DBDs' role in binding these biologically relevant ligands. We found that DBD-C is important for engaging DNA with diverse binding modes, including, unexpectedly, at short ssDNAs. Thus, RPA uses its constituent DBDs to bind biologically diverse ligands in unanticipated ways. These findings lead to a better understanding of how RPA carries out its functions at diverse locations of the genome and suggest a mechanism through which dynamic recognition can impact differential downstream outcomes.
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Affiliation(s)
- Thomas A Wieser
- Department of Biochemistry, University of Colorado Boulder, Jennie Smoly Caruthers Biotechnology Building, UCB 596, Boulder, Colorado80309, United States
| | - Deborah S Wuttke
- Department of Biochemistry, University of Colorado Boulder, Jennie Smoly Caruthers Biotechnology Building, UCB 596, Boulder, Colorado80309, United States
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41
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Zhang Y, Yang L, Fang K, Li Q, Xu H, Ren Y, Zi J, Chen CD, Liu S. Dynamic Responses of Chromosome-Binding Protein Complexes to Meiotic Prophase I of Mouse Spermatocyte. J Proteome Res 2022; 21:2715-2726. [PMID: 36223561 DOI: 10.1021/acs.jproteome.2c00414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Meiotic prophase I (MPI) is the most important event in mammalian meiosis. The status of the chromosome-binding proteins (CBPs) and the corresponding complexes and their functions in MPI have not yet been well scrutinized. Quantitative proteomics focused on MPI-related CBPs was accomplished, in which mouse primary spermatocytes in four different subphases of MPI were collected, and chromosome-enriched proteins were extracted and quantitatively identified. According to a stringent criterion, 1136 CBPs in the MPI subphases were quantified. Looking at the dynamic patterns of CBP abundance in response to MPI progression, the patterns were broadly divided into two groups: high abundance in leptotene and zygotene or that in pachytene and diplotene. Furthermore, 152 such CBPs were regarded as 26 CBP complexes with strict filtration, in which some of these complexes were perceived to be MPI-dependent for the first time. These complexes basically belonged to four functional categories, while their dynamic abundance changes following MPI appeared; the functions of DNA replication decreased; and transcription and synapsis were activated in zygotene, pachytene, and diplotene; in contrast to the traditional prediction, condensin activity weakened in pachytene and diplotene. Profiling of protein complexes thus offered convincing evidence of the importance of CBP complexes in MPI.
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Affiliation(s)
- Yuxing Zhang
- BGI-Shenzhen, Shenzhen 518083, China.,College of Life Sciences & Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049 China
| | | | - Kailun Fang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031 China
| | - Qidan Li
- BGI-Shenzhen, Shenzhen 518083, China
| | - Hongkai Xu
- BGI-Shenzhen, Shenzhen 518083, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Ren
- BGI-Shenzhen, Shenzhen 518083, China.,Experiment Center for Science and Technology, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Jin Zi
- BGI-Shenzhen, Shenzhen 518083, China
| | - Charlie Degui Chen
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Shanghai 200031, China
| | - Siqi Liu
- BGI-Shenzhen, Shenzhen 518083, China
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42
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Kuppa S, Deveryshetty J, Chadda R, Mattice JR, Pokhrel N, Kaushik V, Patterson A, Dhingra N, Pangeni S, Sadauskas MK, Shiekh S, Balci H, Ha T, Zhao X, Bothner B, Antony E. Rtt105 regulates RPA function by configurationally stapling the flexible domains. Nat Commun 2022; 13:5152. [PMID: 36056028 PMCID: PMC9440123 DOI: 10.1038/s41467-022-32860-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 08/18/2022] [Indexed: 11/23/2022] Open
Abstract
Replication Protein A (RPA) is a heterotrimeric complex that binds to single-stranded DNA (ssDNA) and recruits over three dozen RPA-interacting proteins to coordinate multiple aspects of DNA metabolism including DNA replication, repair, and recombination. Rtt105 is a molecular chaperone that regulates nuclear localization of RPA. Here, we show that Rtt105 binds to multiple DNA binding and protein-interaction domains of RPA and configurationally staples the complex. In the absence of ssDNA, Rtt105 inhibits RPA binding to Rad52, thus preventing spurious binding to RPA-interacting proteins. When ssDNA is available, Rtt105 promotes formation of high-density RPA nucleoprotein filaments and dissociates during this process. Free Rtt105 further stabilizes the RPA-ssDNA filaments by inhibiting the facilitated exchange activity of RPA. Collectively, our data suggest that Rtt105 sequesters free RPA in the nucleus to prevent untimely binding to RPA-interacting proteins, while stabilizing RPA-ssDNA filaments at DNA lesion sites. The single stranded DNA binding protein RPA coordinates DNA metabolism using multiple protein and DNA interaction domains. Here, the authors show that the chaperone-like protein Rtt105 staples RPA domains to prevent untimely protein interactions.
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Affiliation(s)
- Sahiti Kuppa
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Jaigeeth Deveryshetty
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Rahul Chadda
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Jenna R Mattice
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Nilisha Pokhrel
- Department of Biological Sciences, Marquette University, Milwaukee, WI, 53201, USA.,Laronde Bio, Cambridge, MA, USA
| | - Vikas Kaushik
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Angela Patterson
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Nalini Dhingra
- Molecular Biology Department, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Sushil Pangeni
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Marisa K Sadauskas
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Sajad Shiekh
- Department of Physics, Kent State University, Kent, OH, 44242, USA
| | - Hamza Balci
- Department of Physics, Kent State University, Kent, OH, 44242, USA
| | - Taekjip Ha
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, 21218, USA.,Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD, 21205, USA.,Howard Hughes Medical Institute, Baltimore, MD, 21205, USA
| | - Xiaolan Zhao
- Molecular Biology Department, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA. .,Department of Biological Sciences, Marquette University, Milwaukee, WI, 53201, USA.
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43
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Mellor C, Perez C, Sale JE. Creation and resolution of non-B-DNA structural impediments during replication. Crit Rev Biochem Mol Biol 2022; 57:412-442. [PMID: 36170051 PMCID: PMC7613824 DOI: 10.1080/10409238.2022.2121803] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 08/02/2022] [Accepted: 08/25/2022] [Indexed: 01/27/2023]
Abstract
During replication, folding of the DNA template into non-B-form secondary structures provides one of the most abundant impediments to the smooth progression of the replisome. The core replisome collaborates with multiple accessory factors to ensure timely and accurate duplication of the genome and epigenome. Here, we discuss the forces that drive non-B structure formation and the evidence that secondary structures are a significant and frequent source of replication stress that must be actively countered. Taking advantage of recent advances in the molecular and structural biology of the yeast and human replisomes, we examine how structures form and how they may be sensed and resolved during replication.
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Affiliation(s)
- Christopher Mellor
- Division of Protein & Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Consuelo Perez
- Division of Protein & Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Julian E Sale
- Division of Protein & Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Cambridge, UK
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44
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Sanz-Rodríguez CE, Hoffman B, Guyett PJ, Purmal A, Singh B, Pollastri MP, Mensa-Wilmot K. Physiologic Targets and Modes of Action for CBL0137, a Lead for Human African Trypanosomiasis Drug Development. Mol Pharmacol 2022; 102:1-16. [PMID: 35605992 PMCID: PMC9341264 DOI: 10.1124/molpharm.121.000430] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 04/20/2022] [Indexed: 08/15/2023] Open
Abstract
CBL0137 is a lead drug for human African trypanosomiasis, caused by Trypanosoma brucei Herein, we use a four-step strategy to 1) identify physiologic targets and 2) determine modes of molecular action of CBL0137 in the trypanosome. First, we identified fourteen CBL0137-binding proteins using affinity chromatography. Second, we developed hypotheses of molecular modes of action, using predicted functions of CBL0137-binding proteins as guides. Third, we documented effects of CBL0137 on molecular pathways in the trypanosome. Fourth, we identified physiologic targets of the drug by knocking down genes encoding CBL0137-binding proteins and comparing their molecular effects to those obtained when trypanosomes were treated with CBL0137. CBL0137-binding proteins included glycolysis enzymes (aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphofructokinase, phosphoglycerate kinase) and DNA-binding proteins [universal minicircle sequence binding protein 2, replication protein A1 (RPA1), replication protein A2 (RPA2)]. In chemical biology studies, CBL0137 did not reduce ATP level in the trypanosome, ruling out glycolysis enzymes as crucial targets for the drug. Thus, many CBL0137-binding proteins are not physiologic targets of the drug. CBL0137 inhibited 1) nucleus mitosis, 2) nuclear DNA replication, and 3) polypeptide synthesis as the first carbazole inhibitor of eukaryote translation. RNA interference (RNAi) against RPA1 inhibited both DNA synthesis and mitosis, whereas RPA2 knockdown inhibited mitosis, consistent with both proteins being physiologic targets of CBL0137. Principles used here to distinguish drug-binding proteins from physiologic targets of CBL0137 can be deployed with different drugs in other biologic systems. SIGNIFICANCE STATEMENT: To distinguish drug-binding proteins from physiologic targets in the African trypanosome, we devised and executed a multidisciplinary approach involving biochemical, genetic, cell, and chemical biology experiments. The strategy we employed can be used for drugs in other biological systems.
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Affiliation(s)
- Carlos E Sanz-Rodríguez
- Department of Cellular Biology, University of Georgia, Athens, Georgia (C.E.S.-R., B.H., P.J.G., K.M.-W.); Buffalo Biolabs Inc, Buffalo, New York (A.P.); Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts (B.S., M.P.); and Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, Georgia (K.M.-W.)
| | - Benjamin Hoffman
- Department of Cellular Biology, University of Georgia, Athens, Georgia (C.E.S.-R., B.H., P.J.G., K.M.-W.); Buffalo Biolabs Inc, Buffalo, New York (A.P.); Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts (B.S., M.P.); and Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, Georgia (K.M.-W.)
| | - Paul J Guyett
- Department of Cellular Biology, University of Georgia, Athens, Georgia (C.E.S.-R., B.H., P.J.G., K.M.-W.); Buffalo Biolabs Inc, Buffalo, New York (A.P.); Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts (B.S., M.P.); and Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, Georgia (K.M.-W.)
| | - Andrei Purmal
- Department of Cellular Biology, University of Georgia, Athens, Georgia (C.E.S.-R., B.H., P.J.G., K.M.-W.); Buffalo Biolabs Inc, Buffalo, New York (A.P.); Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts (B.S., M.P.); and Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, Georgia (K.M.-W.)
| | - Baljinder Singh
- Department of Cellular Biology, University of Georgia, Athens, Georgia (C.E.S.-R., B.H., P.J.G., K.M.-W.); Buffalo Biolabs Inc, Buffalo, New York (A.P.); Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts (B.S., M.P.); and Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, Georgia (K.M.-W.)
| | - Michael P Pollastri
- Department of Cellular Biology, University of Georgia, Athens, Georgia (C.E.S.-R., B.H., P.J.G., K.M.-W.); Buffalo Biolabs Inc, Buffalo, New York (A.P.); Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts (B.S., M.P.); and Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, Georgia (K.M.-W.)
| | - Kojo Mensa-Wilmot
- Department of Cellular Biology, University of Georgia, Athens, Georgia (C.E.S.-R., B.H., P.J.G., K.M.-W.); Buffalo Biolabs Inc, Buffalo, New York (A.P.); Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts (B.S., M.P.); and Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, Georgia (K.M.-W.)
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45
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Current understanding of genomic stability maintenancein pluripotent stem cells. Acta Biochim Biophys Sin (Shanghai) 2022; 54:858-863. [PMID: 35713312 PMCID: PMC9828662 DOI: 10.3724/abbs.2022064] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Pluripotent stem cells (PSCs) are able to generate all cell types in the body and have wide applications in basic research and cell-based regenerative medicine. Maintaining stable genome in culture is the first priority for stem cell application in clinics. In addition, genomic instability in PSCs can cause developmental failure or abnormalities. Understanding how PSCs maintain genome stability is of critical importance. Due to their fundamental role in organism development, PSCs must maintain superior stable genome than differentiated cells. However, the underlying mechanisms are far from clear. Very limited studies suggest that PSCs utilize specific strategies and regulators to robustly improve genome stability. In this review, we summarize the current understandings of the unique properties of genome stability maintenance in PSCs.
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46
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The small nonstructural protein NP1 of human bocavirus 1 directly interacts with Ku70 and RPA70 and facilitates viral DNA replication. PLoS Pathog 2022; 18:e1010578. [PMID: 35653410 PMCID: PMC9197078 DOI: 10.1371/journal.ppat.1010578] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/14/2022] [Accepted: 05/10/2022] [Indexed: 11/19/2022] Open
Abstract
Human bocavirus 1 (HBoV1), a member of the genus Bocaparvovirus of the family Parvoviridae, causes acute respiratory tract infections in young children. Well-differentiated pseudostratified human airway epithelium cultured at an air-liquid interface (HAE-ALI) is an ideal in vitro culture model to study HBoV1 infection. Unique to other parvoviruses, bocaparvoviruses express a small nonstructured protein NP1 of ~25 kDa from an open reading frame (ORF) in the center of the viral genome. NP1 plays an important role in viral DNA replication and pre-mRNA processing. In this study, we performed an affinity purification assay to identify HBoV1 NP1-inteacting proteins. We identified that Ku70 and RPA70 directly interact with the NP1 at a high binding affinity, characterized with an equilibrium dissociation constant (KD) of 95 nM and 122 nM, respectively. Furthermore, we mapped the key NP1-interacting domains of Ku70 at aa266-439 and of RPA70 at aa181-422. Following a dominant negative strategy, we revealed that the interactions of Ku70 and RPA70 with NP1 play a significant role in HBoV1 DNA replication not only in an in vitro viral DNA replication assay but also in HBoV1-infected HAE-ALI cultures. Collectively, our study revealed a novel mechanism by which HBoV1 NP1 enhances viral DNA replication through its direct interactions with Ku70 and RPA70.
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47
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Hormeno S, Wilkinson OJ, Aicart-Ramos C, Kuppa S, Antony E, Dillingham MS, Moreno-Herrero F. Human HELB is a processive motor protein that catalyzes RPA clearance from single-stranded DNA. Proc Natl Acad Sci U S A 2022; 119:e2112376119. [PMID: 35385349 PMCID: PMC9169624 DOI: 10.1073/pnas.2112376119] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 03/01/2022] [Indexed: 01/17/2023] Open
Abstract
Human DNA helicase B (HELB) is a poorly characterized helicase suggested to play both positive and negative regulatory roles in DNA replication and recombination. In this work, we used bulk and single-molecule approaches to characterize the biochemical activities of HELB protein with a particular focus on its interactions with Replication Protein A (RPA) and RPA–single-stranded DNA (ssDNA) filaments. HELB is a monomeric protein that binds tightly to ssDNA with a site size of ∼20 nucleotides. It couples ATP hydrolysis to translocation along ssDNA in the 5′ to 3′ direction accompanied by the formation of DNA loops. HELB also displays classical helicase activity, but this is very weak in the absence of an assisting force. HELB binds specifically to human RPA, which enhances its ATPase and ssDNA translocase activities but inhibits DNA unwinding. Direct observation of HELB on RPA nucleoprotein filaments shows that translocating HELB concomitantly clears RPA from ssDNA. This activity, which can allow other proteins access to ssDNA intermediates despite their shielding by RPA, may underpin the diverse roles of HELB in cellular DNA transactions.
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Affiliation(s)
- Silvia Hormeno
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - Oliver J. Wilkinson
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Clara Aicart-Ramos
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - Sahiti Kuppa
- Department of Biochemistry, Saint Louis University, St. Louis, MO 63104
| | - Edwin Antony
- Department of Biochemistry, Saint Louis University, St. Louis, MO 63104
| | - Mark S. Dillingham
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Fernando Moreno-Herrero
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
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48
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Tsutakawa SE, Bacolla A, Katsonis P, Bralić A, Hamdan SM, Lichtarge O, Tainer JA, Tsai CL. Decoding Cancer Variants of Unknown Significance for Helicase-Nuclease-RPA Complexes Orchestrating DNA Repair During Transcription and Replication. Front Mol Biosci 2021; 8:791792. [PMID: 34966786 PMCID: PMC8710748 DOI: 10.3389/fmolb.2021.791792] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 11/16/2021] [Indexed: 01/13/2023] Open
Abstract
All tumors have DNA mutations, and a predictive understanding of those mutations could inform clinical treatments. However, 40% of the mutations are variants of unknown significance (VUS), with the challenge being to objectively predict whether a VUS is pathogenic and supports the tumor or whether it is benign. To objectively decode VUS, we mapped cancer sequence data and evolutionary trace (ET) scores onto crystallography and cryo-electron microscopy structures with variant impacts quantitated by evolutionary action (EA) measures. As tumors depend on helicases and nucleases to deal with transcription/replication stress, we targeted helicase–nuclease–RPA complexes: (1) XPB-XPD (within TFIIH), XPF-ERCC1, XPG, and RPA for transcription and nucleotide excision repair pathways and (2) BLM, EXO5, and RPA plus DNA2 for stalled replication fork restart. As validation, EA scoring predicts severe effects for most disease mutations, but disease mutants with low ET scores not only are likely destabilizing but also disrupt sophisticated allosteric mechanisms. For sites of disease mutations and VUS predicted to be severe, we found strong co-localization to ordered regions. Rare discrepancies highlighted the different survival requirements between disease and tumor mutations, as well as the value of examining proteins within complexes. In a genome-wide analysis of 33 cancer types, we found correlation between the number of mutations in each tumor and which pathways or functional processes in which the mutations occur, revealing different mutagenic routes to tumorigenesis. We also found upregulation of ancient genes including BLM, which supports a non-random and concerted cancer process: reversion to a unicellular, proliferation-uncontrolled, status by breaking multicellular constraints on cell division. Together, these genes and global analyses challenge the binary “driver” and “passenger” mutation paradigm, support a gradient impact as revealed by EA scoring from moderate to severe at a single gene level, and indicate reduced regulation as well as activity. The objective quantitative assessment of VUS scoring and gene overexpression in the context of functional interactions and pathways provides insights for biology, oncology, and precision medicine.
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Affiliation(s)
- Susan E Tsutakawa
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Albino Bacolla
- Department of Molecular and Cellular Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX, United States
| | - Panagiotis Katsonis
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - Amer Bralić
- Laboratory of DNA Replication and Recombination, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Samir M Hamdan
- Laboratory of DNA Replication and Recombination, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Olivier Lichtarge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - John A Tainer
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.,Department of Molecular and Cellular Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX, United States.,Department of Cancer Biology, University of Texas M.D. Anderson Cancer Center, Houston, TX, United States
| | - Chi-Lin Tsai
- Department of Molecular and Cellular Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX, United States
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49
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Myler LR, Kinzig CG, Sasi NK, Zakusilo G, Cai SW, de Lange T. The evolution of metazoan shelterin. Genes Dev 2021; 35:1625-1641. [PMID: 34764137 PMCID: PMC8653790 DOI: 10.1101/gad.348835.121] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 10/05/2021] [Indexed: 12/11/2022]
Abstract
In this study, Myler et al. investigated the evolutionary origins of shelterin complex, which is comprised of TRF1, TRF2, Rap1, TIN2, TPP1, and POT1; blocks the DNA damage response at chromosome ends; and interacts with telomerase and the CST complex to regulate telomere length. They describe the evolution of metazoan shelterin, showing that TRF1 emerged in vertebrates upon duplication of a TRF2-like ancestor, and providing insights into the biology of shelterin and its evolution from ancestral telomeric DNA-binding proteins. The mammalian telomeric shelterin complex—comprised of TRF1, TRF2, Rap1, TIN2, TPP1, and POT1—blocks the DNA damage response at chromosome ends and interacts with telomerase and the CST complex to regulate telomere length. The evolutionary origins of shelterin are unclear, partly because unicellular organisms have distinct telomeric proteins. Here, we describe the evolution of metazoan shelterin, showing that TRF1 emerged in vertebrates upon duplication of a TRF2-like ancestor. TRF1 and TRF2 diverged rapidly during vertebrate evolution through the acquisition of new domains and interacting factors. Vertebrate shelterin is also distinguished by the presence of an HJRL domain in the split C-terminal OB fold of POT1, whereas invertebrate POT1s carry inserts of variable nature. Importantly, the data reveal that, apart from the primate and rodent POT1 orthologs, all metazoan POT1s are predicted to have a fourth OB fold at their N termini. Therefore, we propose that POT1 arose from a four-OB-fold ancestor, most likely an RPA70-like protein. This analysis provides insights into the biology of shelterin and its evolution from ancestral telomeric DNA-binding proteins.
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Affiliation(s)
- Logan R Myler
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10021, USA
| | - Charles G Kinzig
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10021, USA
| | - Nanda K Sasi
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10021, USA
| | - George Zakusilo
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10021, USA
| | - Sarah W Cai
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10021, USA
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10021, USA
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50
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Bednar RM, Jana S, Kuppa S, Franklin R, Beckman J, Antony E, Cooley RB, Mehl RA. Genetic Incorporation of Two Mutually Orthogonal Bioorthogonal Amino Acids That Enable Efficient Protein Dual-Labeling in Cells. ACS Chem Biol 2021; 16:2612-2622. [PMID: 34590824 DOI: 10.1021/acschembio.1c00649] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The ability to site-specifically modify proteins at multiple sites in vivo will enable the study of protein function in its native environment with unprecedented levels of detail. Here, we present a versatile two-step strategy to meet this goal involving site-specific encoding of two distinct noncanonical amino acids bearing bioorthogonal handles into proteins in vivo followed by mutually orthogonal labeling. This general approach, that we call dual encoding and labeling (DEAL), allowed us to efficiently encode tetrazine- and azide-bearing amino acids into a protein and demonstrate for the first time that the bioorthogonal labeling reactions with strained alkene and alkyne labels can function simultaneously and intracellularly with high yields when site-specifically encoded in a single protein. Using our DEAL system, we were able to perform topologically defined protein-protein cross-linking, intramolecular stapling, and site-specific installation of fluorophores all inside living Escherichia coli cells, as well as study the DNA-binding properties of yeast Replication Protein A in vitro. By enabling the efficient dual modification of proteins in vivo, this DEAL approach provides a tool for the characterization and engineering of proteins in vivo.
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Affiliation(s)
- Riley M. Bednar
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural & Life Sciences Building, Corvallis, Oregon 97331-7305, United States
| | - Subhashis Jana
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural & Life Sciences Building, Corvallis, Oregon 97331-7305, United States
| | - Sahiti Kuppa
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Edward A. Doisy Research Center, 1100 South Grand Blvd., St. Louis, Missouri 63104, United States
| | - Rachel Franklin
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural & Life Sciences Building, Corvallis, Oregon 97331-7305, United States
| | - Joseph Beckman
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural & Life Sciences Building, Corvallis, Oregon 97331-7305, United States
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Edward A. Doisy Research Center, 1100 South Grand Blvd., St. Louis, Missouri 63104, United States
| | - Richard B. Cooley
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural & Life Sciences Building, Corvallis, Oregon 97331-7305, United States
| | - Ryan A. Mehl
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural & Life Sciences Building, Corvallis, Oregon 97331-7305, United States
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