1
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Appleby R, Bollschweiler D, Chirgadze DY, Joudeh L, Pellegrini L. A metal ion-dependent mechanism of RAD51 nucleoprotein filament disassembly. iScience 2023; 26:106689. [PMID: 37216117 PMCID: PMC10192527 DOI: 10.1016/j.isci.2023.106689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 03/21/2023] [Accepted: 04/13/2023] [Indexed: 05/24/2023] Open
Abstract
The RAD51 ATPase polymerizes on single-stranded DNA to form nucleoprotein filaments (NPFs) that are critical intermediates in the reaction of homologous recombination. ATP binding maintains the NPF in a competent conformation for strand pairing and exchange. Once strand exchange is completed, ATP hydrolysis licenses the filament for disassembly. Here we show that the ATP-binding site of the RAD51 NPF contains a second metal ion. In the presence of ATP, the metal ion promotes the local folding of RAD51 into the conformation required for DNA binding. The metal ion is absent in the ADP-bound RAD51 filament, that rearranges in a conformation incompatible with DNA binding. The presence of the second metal ion explains how RAD51 couples the nucleotide state of the filament to DNA binding. We propose that loss of the second metal ion upon ATP hydrolysis drives RAD51 dissociation from the DNA and weakens filament stability, contributing to NPF disassembly.
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Affiliation(s)
- Robert Appleby
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | | | | | - Luay Joudeh
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Luca Pellegrini
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
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2
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Chang HY, Lee CY, Lu CH, Lee W, Yang HL, Yeh HY, Li HW, Chi P. Microcephaly family protein MCPH1 stabilizes RAD51 filaments. Nucleic Acids Res 2020; 48:9135-9146. [PMID: 32735676 PMCID: PMC7498314 DOI: 10.1093/nar/gkaa636] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 06/30/2020] [Accepted: 07/22/2020] [Indexed: 01/19/2023] Open
Abstract
Microcephalin 1 (MCPH1) was identified from genetic mutations in patients with primary autosomal recessive microcephaly. In response to DNA double-strand breaks (DSBs), MCPH1 forms damage-induced foci and recruits BRCA2-RAD51 complex, a key component of the DSB repair machinery for homologous recombination (HR), to damage sites. Accordingly, the efficiency of HR is significantly attenuated upon depletion of MCPH1. The biochemical characteristics of MCPH1 and its functional interaction with the HR machinery had remained unclear due to lack of highly purified MCPH1 recombinant protein for functional study. Here, we established a mammalian expression system to express and purify MCPH1 protein. We show that MCPH1 is a bona fide DNA-binding protein and provide direct biochemical analysis of this MCPH family protein. Furthermore, we reveal that MCPH1 directly interacts with RAD51 at multiple contact points, providing evidence for how MCPH1 physically engages with the HR machinery. Importantly, we demonstrate that MCPH1 enhances the stability of RAD51 on single-strand DNA, a prerequisite step for RAD51-mediated recombination. Single-molecule tethered particle motion analysis showed a ∼2-fold increase in the lifetime of RAD51-ssDNA filaments in the presence of MCPH1. Thus, our study demonstrates direct crosstalk between microcephaly protein MCPH1 and the recombination component RAD51 for DSB repair.
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Affiliation(s)
- Hao-Yen Chang
- Institute of Biochemical Sciences, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Chia-Yi Lee
- Institute of Biochemical Sciences, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Chih-Hao Lu
- Department of Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Wei Lee
- Department of Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Han-Lin Yang
- Department of Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Hsin-Yi Yeh
- Institute of Biochemical Sciences, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Hung-Wen Li
- Department of Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Peter Chi
- Institute of Biochemical Sciences, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.,Institute of Biological Chemistry, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
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3
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Kretov DA, Clément MJ, Lambert G, Durand D, Lyabin DN, Bollot G, Bauvais C, Samsonova A, Budkina K, Maroun RC, Hamon L, Bouhss A, Lescop E, Toma F, Curmi PA, Maucuer A, Ovchinnikov LP, Pastré D. YB-1, an abundant core mRNA-binding protein, has the capacity to form an RNA nucleoprotein filament: a structural analysis. Nucleic Acids Res 2019; 47:3127-3141. [PMID: 30605522 PMCID: PMC6451097 DOI: 10.1093/nar/gky1303] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 12/20/2022] Open
Abstract
The structural rearrangements accompanying mRNA during translation in mammalian cells remain poorly understood. Here, we discovered that YB-1 (YBX1), a major partner of mRNAs in the cytoplasm, forms a linear nucleoprotein filament with mRNA, when part of the YB-1 unstructured C-terminus has been truncated. YB-1 possesses a cold-shock domain (CSD), a remnant of bacterial cold shock proteins that have the ability to stimulate translation under the low temperatures through an RNA chaperone activity. The structure of the nucleoprotein filament indicates that the CSD of YB-1 preserved its chaperone activity also in eukaryotes and shows that mRNA is channeled between consecutive CSDs. The energy benefit needed for the formation of stable nucleoprotein filament relies on an electrostatic zipper mediated by positively charged amino acid residues in the YB-1 C-terminus. Thus, YB-1 displays a structural plasticity to unfold structured mRNAs into extended linear filaments. We anticipate that our findings will shed the light on the scanning of mRNAs by ribosomes during the initiation and elongation steps of mRNA translation.
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Affiliation(s)
- Dmitry A Kretov
- Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Russian Federation.,SABNP, University of Evry, INSERM U1204, Université Paris-Saclay, 91025 Evry, France
| | - Marie-Jeanne Clément
- SABNP, University of Evry, INSERM U1204, Université Paris-Saclay, 91025 Evry, France
| | - Guillaume Lambert
- SABNP, University of Evry, INSERM U1204, Université Paris-Saclay, 91025 Evry, France
| | - Dominique Durand
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Dmitry N Lyabin
- Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Russian Federation
| | | | - Cyril Bauvais
- Synsight, a/s IncubAlliance 86 rue de Paris Orsay 91400, France
| | - Anastasiia Samsonova
- SABNP, University of Evry, INSERM U1204, Université Paris-Saclay, 91025 Evry, France
| | - Karina Budkina
- Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Russian Federation.,SABNP, University of Evry, INSERM U1204, Université Paris-Saclay, 91025 Evry, France
| | - Rachid C Maroun
- SABNP, University of Evry, INSERM U1204, Université Paris-Saclay, 91025 Evry, France
| | - Loic Hamon
- SABNP, University of Evry, INSERM U1204, Université Paris-Saclay, 91025 Evry, France
| | - Ahmed Bouhss
- SABNP, University of Evry, INSERM U1204, Université Paris-Saclay, 91025 Evry, France
| | - Ewen Lescop
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Université Paris-Saclay, 91198 Gif sur Yvette cedex, France
| | - Flavio Toma
- SABNP, University of Evry, INSERM U1204, Université Paris-Saclay, 91025 Evry, France
| | - Patrick A Curmi
- SABNP, University of Evry, INSERM U1204, Université Paris-Saclay, 91025 Evry, France
| | - Alexandre Maucuer
- SABNP, University of Evry, INSERM U1204, Université Paris-Saclay, 91025 Evry, France
| | - Lev P Ovchinnikov
- Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Russian Federation
| | - David Pastré
- SABNP, University of Evry, INSERM U1204, Université Paris-Saclay, 91025 Evry, France
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4
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Shalaeva DN, Cherepanov DA, Galperin MY, Golovin AV, Mulkidjanian AY. Evolution of cation binding in the active sites of P-loop nucleoside triphosphatases in relation to the basic catalytic mechanism. eLife 2018; 7:e37373. [PMID: 30526846 PMCID: PMC6310460 DOI: 10.7554/elife.37373] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 11/26/2018] [Indexed: 01/01/2023] Open
Abstract
The ubiquitous P-loop fold nucleoside triphosphatases (NTPases) are typically activated by an arginine or lysine 'finger'. Some of the apparently ancestral NTPases are, instead, activated by potassium ions. To clarify the activation mechanism, we combined comparative structure analysis with molecular dynamics (MD) simulations of Mg-ATP and Mg-GTP complexes in water and in the presence of potassium, sodium, or ammonium ions. In all analyzed structures of diverse P-loop NTPases, the conserved P-loop motif keeps the triphosphate chain of bound NTPs (or their analogs) in an extended, catalytically prone conformation, similar to that imposed on NTPs in water by potassium or ammonium ions. MD simulations of potassium-dependent GTPase MnmE showed that linking of alpha- and gamma phosphates by the activating potassium ion led to the rotation of the gamma-phosphate group yielding an almost eclipsed, catalytically productive conformation of the triphosphate chain, which could represent the basic mechanism of hydrolysis by P-loop NTPases.
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Affiliation(s)
- Daria N Shalaeva
- School of PhysicsUniversity of OsnabrückOsnabrückGermany
- A.N. Belozersky Institute of Physico-Chemical BiologyLomonosov Moscow State UniversityMoscowRussia
- School of Bioengineering and BioinformaticsLomonosov Moscow State UniversityMoscowRussia
| | - Dmitry A Cherepanov
- A.N. Belozersky Institute of Physico-Chemical BiologyLomonosov Moscow State UniversityMoscowRussia
- Semenov Institute of Chemical PhysicsRussian Academy of SciencesMoscowRussia
| | - Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesdaUnited States
| | - Andrey V Golovin
- School of Bioengineering and BioinformaticsLomonosov Moscow State UniversityMoscowRussia
| | - Armen Y Mulkidjanian
- School of PhysicsUniversity of OsnabrückOsnabrückGermany
- A.N. Belozersky Institute of Physico-Chemical BiologyLomonosov Moscow State UniversityMoscowRussia
- School of Bioengineering and BioinformaticsLomonosov Moscow State UniversityMoscowRussia
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5
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Swi5-Sfr1 stimulates Rad51 recombinase filament assembly by modulating Rad51 dissociation. Proc Natl Acad Sci U S A 2018; 115:E10059-E10068. [PMID: 30297419 DOI: 10.1073/pnas.1812753115] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Eukaryotic Rad51 protein is essential for homologous-recombination repair of DNA double-strand breaks. Rad51 recombinases first assemble onto single-stranded DNA to form a nucleoprotein filament, required for function in homology pairing and strand exchange. This filament assembly is the first regulation step in homologous recombination. Rad51 nucleation is kinetically slow, and several accessory factors have been identified to regulate this step. Swi5-Sfr1 (S5S1) stimulates Rad51-mediated homologous recombination by stabilizing Rad51 nucleoprotein filaments, but the mechanism of stabilization is unclear. We used single-molecule tethered particle motion experiments to show that mouse S5S1 (mS5S1) efficiently stimulates mouse RAD51 (mRAD51) nucleus formation and inhibits mRAD51 dissociation from filaments. We also used single-molecule fluorescence resonance energy transfer experiments to show that mS5S1 promotes stable nucleus formation by specifically preventing mRAD51 dissociation. This leads to a reduction of nucleation size from three mRAD51 to two mRAD51 molecules in the presence of mS5S1. Compared with mRAD51, fission yeast Rad51 (SpRad51) exhibits fast nucleation but quickly dissociates from the filament. SpS5S1 specifically reduces SpRad51 disassembly to maintain a stable filament. These results clearly demonstrate the conserved function of S5S1 by primarily stabilizing Rad51 on DNA, allowing both the formation of the stable nucleus and the maintenance of filament length.
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6
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Brouwer I, Moschetti T, Candelli A, Garcin EB, Modesti M, Pellegrini L, Wuite GJ, Peterman EJ. Two distinct conformational states define the interaction of human RAD51-ATP with single-stranded DNA. EMBO J 2018; 37:embj.201798162. [PMID: 29507080 PMCID: PMC5881629 DOI: 10.15252/embj.201798162] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 12/14/2022] Open
Abstract
An essential mechanism for repairing DNA double‐strand breaks is homologous recombination (HR). One of its core catalysts is human RAD51 (hRAD51), which assembles as a helical nucleoprotein filament on single‐stranded DNA, promoting DNA‐strand exchange. Here, we study the interaction of hRAD51 with single‐stranded DNA using a single‐molecule approach. We show that ATP‐bound hRAD51 filaments can exist in two different states with different contour lengths and with a free‐energy difference of ~4 kBT per hRAD51 monomer. Upon ATP hydrolysis, the filaments convert into a disassembly‐competent ADP‐bound configuration. In agreement with the single‐molecule analysis, we demonstrate the presence of two distinct protomer interfaces in the crystal structure of a hRAD51‐ATP filament, providing a structural basis for the two conformational states of the filament. Together, our findings provide evidence that hRAD51‐ATP filaments can exist in two interconvertible conformational states, which might be functionally relevant for DNA homology recognition and strand exchange.
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Affiliation(s)
- Ineke Brouwer
- Department of Physics and Astronomy and LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | | | - Andrea Candelli
- Department of Physics and Astronomy and LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Edwige B Garcin
- Cancer Research Center of Marseille, CNRS UMR7258, Inserm U1068, Institut Paoli-Calmettes, Aix-Marseille Université, Marseille, France
| | - Mauro Modesti
- Cancer Research Center of Marseille, CNRS UMR7258, Inserm U1068, Institut Paoli-Calmettes, Aix-Marseille Université, Marseille, France
| | - Luca Pellegrini
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Gijs Jl Wuite
- Department of Physics and Astronomy and LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Erwin Jg Peterman
- Department of Physics and Astronomy and LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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7
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Schay G, Borka B, Kernya L, Bulyáki É, Kardos J, Fekete M, Fidy J. Without Binding ATP, Human Rad51 Does Not Form Helical Filaments on ssDNA. J Phys Chem B 2016; 120:2165-78. [PMID: 26890079 DOI: 10.1021/acs.jpcb.5b12220] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Construction of the presynaptic filament (PSF) of proper helical structure by Rad51 recombinases is a prerequisite of the progress of homologous recombination repair. We studied the contribution of ATP-binding to this structure of wt human Rad51 (hRad51). We exploited the protein-dissociation effect of high hydrostatic pressure to determine the free energy of dissociation of the protomer interfaces in hRad51 oligomer states and used electron microscopy to obtain topological parameters. Without cofactors ATP and Ca(2+) and template DNA, hRad51 did not exist in monomer form, but it formed rodlike long filaments without helical order. ΔG(diss) indicated a strong inherent tendency of aggregation. Binding solely ssDNA left the filament unstructured with slightly increased ΔG(diss). Adding only ATP and Ca(2+) to the buffer disintegrated the self-associated rods into rings and short helices of further increased ΔG(diss). Rad51 binding to ssDNA only with ATP and Ca bound could lead to ordered helical filament formation of proper pitch size with interface contacts of K(d) ∼ 2 × 10(-11) M, indicating a structure of outstanding stability. ATP/Ca binding increased the ΔG(diss) of protomer contacts in the filament by 16 kJ/mol. The results emphasize that ATP-binding in the PSF of hRad51 has an essential, yet purely structural, role.
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Affiliation(s)
- Gusztáv Schay
- Department of Biophysics and Radiation Biology, Semmelweis University , Tűzoltó utca 37-47, Budapest H-1094, Hungary
| | - Bálint Borka
- Department of Biophysics and Radiation Biology, Semmelweis University , Tűzoltó utca 37-47, Budapest H-1094, Hungary
| | - Linda Kernya
- MTA-ELTE NAP B Neuroimmunology Research Group, Department of Biochemistry, Eötvös Loránd University , Pázmány P. sétány 1/C, Budapest H-1117, Hungary
| | - Éva Bulyáki
- MTA-ELTE NAP B Neuroimmunology Research Group, Department of Biochemistry, Eötvös Loránd University , Pázmány P. sétány 1/C, Budapest H-1117, Hungary
| | - József Kardos
- MTA-ELTE NAP B Neuroimmunology Research Group, Department of Biochemistry, Eötvös Loránd University , Pázmány P. sétány 1/C, Budapest H-1117, Hungary
| | - Melinda Fekete
- Department of Biophysics and Radiation Biology, Semmelweis University , Tűzoltó utca 37-47, Budapest H-1094, Hungary
| | - Judit Fidy
- Department of Biophysics and Radiation Biology, Semmelweis University , Tűzoltó utca 37-47, Budapest H-1094, Hungary
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8
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Mason JM, Dusad K, Wright WD, Grubb J, Budke B, Heyer WD, Connell PP, Weichselbaum RR, Bishop DK. RAD54 family translocases counter genotoxic effects of RAD51 in human tumor cells. Nucleic Acids Res 2015; 43:3180-96. [PMID: 25765654 PMCID: PMC4381078 DOI: 10.1093/nar/gkv175] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 02/20/2015] [Indexed: 12/14/2022] Open
Abstract
The RAD54 family DNA translocases have several biochemical activities. One activity, demonstrated previously for the budding yeast translocases, is ATPase-dependent disruption of RAD51-dsDNA binding. This activity is thought to promote dissociation of RAD51 from heteroduplex DNA following strand exchange during homologous recombination. In addition, previous experiments in budding yeast have shown that the same activity of Rad54 removes Rad51 from undamaged sites on chromosomes; mutants lacking Rad54 accumulate nonrepair-associated complexes that can block growth and lead to chromosome loss. Here, we show that human RAD54 also promotes the dissociation of RAD51 from dsDNA and not ssDNA. We also show that translocase depletion in tumor cell lines leads to the accumulation of RAD51 on chromosomes, forming complexes that are not associated with markers of DNA damage. We further show that combined depletion of RAD54L and RAD54B and/or artificial induction of RAD51 overexpression blocks replication and promotes chromosome segregation defects. These results support a model in which RAD54L and RAD54B counteract genome-destabilizing effects of direct binding of RAD51 to dsDNA in human tumor cells. Thus, in addition to having genome-stabilizing DNA repair activity, human RAD51 has genome-destabilizing activity when expressed at high levels, as is the case in many human tumors.
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Affiliation(s)
- Jennifer M Mason
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, Box 13, 920 East 58th St., Chicago, IL 60637, USA
| | - Kritika Dusad
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, Box 13, 920 East 58th St., Chicago, IL 60637, USA
| | - William Douglass Wright
- Department of Molecular and Cellular Biology, University of California, Davis, Davis CA 95616, USA
| | - Jennifer Grubb
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, Box 13, 920 East 58th St., Chicago, IL 60637, USA
| | - Brian Budke
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, Box 13, 920 East 58th St., Chicago, IL 60637, USA
| | - Wolf-Dietrich Heyer
- Department of Molecular and Cellular Biology, University of California, Davis, Davis CA 95616, USA Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Philip P Connell
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, Box 13, 920 East 58th St., Chicago, IL 60637, USA
| | - Ralph R Weichselbaum
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, Box 13, 920 East 58th St., Chicago, IL 60637, USA
| | - Douglas K Bishop
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, Box 13, 920 East 58th St., Chicago, IL 60637, USA Department of Microbiology and Molecular Genetics, University of California, Davis, Davis CA 95616, USA
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9
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Liu H, Yan P, Fanning E. Human DNA helicase B functions in cellular homologous recombination and stimulates Rad51-mediated 5'-3' heteroduplex extension in vitro. PLoS One 2015; 10:e0116852. [PMID: 25617833 PMCID: PMC4305318 DOI: 10.1371/journal.pone.0116852] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 12/15/2014] [Indexed: 11/18/2022] Open
Abstract
Homologous recombination is involved in the repair of DNA damage and collapsed replication fork, and is critical for the maintenance of genomic stability. Its process involves a network of proteins with different enzymatic activities. Human DNA helicase B (HDHB) is a robust 5′-3′ DNA helicase which accumulates on chromatin in cells exposed to DNA damage. HDHB facilitates cellular recovery from replication stress, but its role in DNA damage response remains unclear. Here we report that HDHB silencing results in reduced sister chromatid exchange, impaired homologous recombination repair, and delayed RPA late-stage foci formation induced by ionizing radiation. Ectopically expressed HDHB colocalizes with Rad51, Rad52, RPA, and ssDNA. In vitro, HDHB stimulates Rad51-mediated heteroduplex extension in 5′-3′ direction. A helicase-defective mutant HDHB failed to promote this reaction. Our studies implicate HDHB promotes homologous recombination in vivo and stimulates 5′-3′ heteroduplex extension during Rad51-mediated strand exchange in vitro.
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Affiliation(s)
- Hanjian Liu
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Peijun Yan
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Ellen Fanning
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
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10
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Visualization and quantification of nascent RAD51 filament formation at single-monomer resolution. Proc Natl Acad Sci U S A 2014; 111:15090-5. [PMID: 25288749 DOI: 10.1073/pnas.1307824111] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
During recombinational repair of double-stranded DNA breaks, RAD51 recombinase assembles as a nucleoprotein filament around single-stranded DNA to form a catalytically proficient structure able to promote homology recognition and strand exchange. Mediators and accessory factors guide the action and control the dynamics of RAD51 filaments. Elucidation of these control mechanisms necessitates development of approaches to quantitatively probe transient aspects of RAD51 filament dynamics. Here, we combine fluorescence microscopy, optical tweezers, and microfluidics to visualize the assembly of RAD51 filaments on bare single-stranded DNA and quantify the process with single-monomer sensitivity. We show that filaments are seeded from RAD51 nuclei that are heterogeneous in size. This heterogeneity appears to arise from the energetic balance between RAD51 self-assembly in solution and the size-dependent interaction time of the nuclei with DNA. We show that nucleation intrinsically is substrate selective, strongly favoring filament formation on bare single-stranded DNA. Furthermore, we devised a single-molecule fluorescence recovery after photobleaching assay to independently observe filament nucleation and growth, permitting direct measurement of their contributions to filament formation. Our findings yield a comprehensive, quantitative understanding of RAD51 filament formation on bare single-stranded DNA that will serve as a basis to elucidate how mediators help RAD51 filament assembly and accessory factors control filament dynamics.
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11
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Bugreev DV, Huang F, Mazina OM, Pezza RJ, Voloshin ON, Camerini-Otero RD, Mazin AV. HOP2-MND1 modulates RAD51 binding to nucleotides and DNA. Nat Commun 2014; 5:4198. [PMID: 24943459 PMCID: PMC4279451 DOI: 10.1038/ncomms5198] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 05/22/2014] [Indexed: 12/21/2022] Open
Abstract
The HOP2-MND1 heterodimer is required for progression of homologous recombination in eukaryotes. In vitro, HOP2-MND1 stimulates the DNA strand exchange activities of RAD51 and DMC1. We demonstrate that HOP2-MND1 induces changes in the conformation of RAD51 that profoundly alter the basic properties of RAD51. HOP2-MND1 enhances the interaction of RAD51 with nucleotide cofactors and modifies its DNA binding specificity in a manner that stimulates DNA strand exchange. It enables RAD51 DNA strand exchange in the absence of divalent metal ions required for ATP binding and offsets the effect of the K133A mutation that disrupts ATP binding. During nucleoprotein formation HOP2-MND1 helps to load RAD51 on ssDNA restricting its dsDNA-binding and during the homology search it promotes dsDNA binding removing the inhibitory effect of ssDNA. The magnitude of the changes induced in RAD51 defines HOP2-MND1 as a “molecular trigger” of RAD51 DNA strand exchange.
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Affiliation(s)
- Dmitry V Bugreev
- 1] Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102-1192, USA [2]
| | - Fei Huang
- 1] Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102-1192, USA [2]
| | - Olga M Mazina
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102-1192, USA
| | - Roberto J Pezza
- Oklahoma Medical Research Foundation, Department of Cell Biology, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma 73104, USA
| | - Oleg N Voloshin
- Genetics and Biochemistry Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - R Daniel Camerini-Otero
- Genetics and Biochemistry Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Alexander V Mazin
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102-1192, USA
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12
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Rao DECS, Luo Y. pH-dependent activities and structural stability of loop-2-anchoring helix of RadA recombinase from Methanococcus voltae. Protein Pept Lett 2014; 21:679-87. [PMID: 24654848 PMCID: PMC4150490 DOI: 10.2174/0929866521666140320103512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/25/2014] [Accepted: 02/27/2014] [Indexed: 11/22/2022]
Abstract
RadA is an archaeal orthologue of human recombinase Rad51. This superfamily of recombinases, which also includes eukaryal meiosis-specific DMC1 and remotely related bacterial RecA, form filaments on single-stranded DNA in the presence of ATP and promote a strand exchange reaction between the single-stranded DNA and a homologous double-stranded DNA. Due to its feasibility of getting crystals and similarity (> 40% sequence identity) to eukaryal homologues, we have studied RadA from Methanococcus voltae (MvRadA) as a structural model for understanding the molecular mechanism of homologous strand exchange. Here we show this protein’s ATPase and strand exchange activities are minimal at pH 6.0. Interestingly, MvRadA’s pH dependence is similar to the properties of human Rad51 but dissimilar to that of the well-studied E. coli RecA. A structure subsequently determined at pH 6.0 reveals features indicative of an ATPase-inactive form with a disordered L2 loop. Comparison with a previously determined ATPase-active form at pH 7.5 implies that the stability of the ATPase-active conformation is reduced at the acidic pH. We interpret these results as further suggesting an ordered disposition of the DNA-binding L2 region, similar to what has been observed in the previously observed ATPase-active conformation, is required for promoting hydrolysis of ATP and strand exchange between single- and double-stranded DNA. His-276 in the mobile L2 region was observed to be partially responsible for the pH-dependent activities of MvRadA.
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Affiliation(s)
| | - Yu Luo
- Department of Biochemistry, University of Saskatchewan, 2D01 Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan, Canada S7N 5E5.
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The HsRAD51B-HsRAD51C stabilizes the HsRAD51 nucleoprotein filament. DNA Repair (Amst) 2013; 12:723-32. [PMID: 23810717 DOI: 10.1016/j.dnarep.2013.05.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 04/28/2013] [Accepted: 05/14/2013] [Indexed: 12/17/2022]
Abstract
There are six human RAD51 related proteins (HsRAD51 paralogs), HsRAD51B, HsRAD51C, HsRAD51D, HsXRCC2, HsXRCC3 and HsDMC1, that appear to enhance HsRAD51 mediated homologous recombinational (HR) repair of DNA double strand breaks (DSBs). Here we model the structures of HsRAD51, HsRAD51B and HsRAD51C and show similar domain orientations within a hypothetical nucleoprotein filament (NPF). We then demonstrate that HsRAD51B-HsRAD51C heterodimer forms stable complex on ssDNA and partially stabilizes the HsRAD51 NPF against the anti-recombinogenic activity of BLM. Moreover, HsRAD51B-HsRAD51C stimulates HsRAD51 mediated D-loop formation in the presence of RPA. However, HsRAD51B-HsRAD51C does not facilitate HsRAD51 nucleation on a RPA coated ssDNA. These results suggest that the HsRAD51B-HsRAD51C complex plays a role in stabilizing the HsRAD51 NPF during the presynaptic phase of HR, which appears downstream of BRCA2-mediated HsRAD51 NPF formation.
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14
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North JA, Amunugama R, Klajner M, Bruns AN, Poirier MG, Fishel R. ATP-dependent nucleosome unwrapping catalyzed by human RAD51. Nucleic Acids Res 2013; 41:7302-12. [PMID: 23757189 PMCID: PMC3753615 DOI: 10.1093/nar/gkt411] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Double-strand breaks (DSB) occur in chromatin following replication fork collapse and chemical or physical damage [Symington and Gautier (Double-strand break end resection and repair pathway choice. Annu. Rev. Genet. 2011;45:247–271.)] and may be repaired by homologous recombination (HR) and non-homologous end-joining. Nucleosomes are the fundamental units of chromatin and must be remodeled during DSB repair by HR [Andrews and Luger (Nucleosome structure(s) and stability: variations on a theme. Annu. Rev. Biophys. 2011;40:99–117.)]. Physical initiation of HR requires RAD51, which forms a nucleoprotein filament (NPF) that catalyzes homologous pairing and strand exchange (recombinase) between DNAs that ultimately bridges the DSB gap [San Filippo, Sung and Klein. (Mechanism of eukaryotic HR. Annu. Rev. Biochem. 2008;77:229–257.)]. RAD51 forms an NPF on single-stranded DNA and double-stranded DNA (dsDNA). Although the single-stranded DNA NPF is essential for recombinase initiation, the role of the dsDNA NPF is less clear. Here, we demonstrate that the human RAD51 (HsRAD51) dsDNA NPF disassembles nucleosomes by unwrapping the DNA from the core histones. HsRAD51 that has been constitutively or biochemically activated for recombinase functions displays significantly reduced nucleosome disassembly activity. These results suggest that HsRAD51 can perform ATP hydrolysis-dependent nucleosome disassembly in addition to its recombinase functions.
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Affiliation(s)
- Justin A North
- Department of Physics, The Ohio State University, Columbus OH 43210, USA, Molecular Virology, Immunology and Medical Genetics, The Ohio State University Medical Center, Columbus, OH 43210, USA, Chemistry and Biochemistry Department, The Ohio State University, Columbus OH 43210, USA and Human Cancer Genetics, The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
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15
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Amunugama R, He Y, Willcox S, Forties RA, Shim KS, Bundschuh R, Luo Y, Griffith J, Fishel R. RAD51 protein ATP cap regulates nucleoprotein filament stability. J Biol Chem 2012; 287:8724-36. [PMID: 22275364 DOI: 10.1074/jbc.m111.239426] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
RAD51 mediates homologous recombination by forming an active DNA nucleoprotein filament (NPF). A conserved aspartate that forms a salt bridge with the ATP γ-phosphate is found at the nucleotide-binding interface between RAD51 subunits of the NPF known as the ATP cap. The salt bridge accounts for the nonphysiological cation(s) required to fully activate the RAD51 NPF. In contrast, RecA homologs and most RAD51 paralogs contain a conserved lysine at the analogous structural position. We demonstrate that substitution of human RAD51(Asp-316) with lysine (HsRAD51(D316K)) decreases NPF turnover and facilitates considerably improved recombinase functions. Structural analysis shows that archaebacterial Methanococcus voltae RadA(D302K) (MvRAD51(D302K)) and HsRAD51(D316K) form extended active NPFs without salt. These studies suggest that the HsRAD51(Asp-316) salt bridge may function as a conformational sensor that enhances turnover at the expense of recombinase activity.
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Affiliation(s)
- Ravindra Amunugama
- Biophysics Graduate Program, Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University, Columbus, Ohio 43210, USA
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16
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Amunugama R, Fishel R. Homologous Recombination in Eukaryotes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 110:155-206. [DOI: 10.1016/b978-0-12-387665-2.00007-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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17
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Ziemienowicz A, Rahavi SMR, Kovalchuk I. The stimulatory effect of CaCl(2), NaCl and NH(4)NO(3) salts on the ssDNA-binding activity of RecA depends on nucleotide cofactor and buffer pH. BMB Rep 2011; 44:341-6. [PMID: 21615990 DOI: 10.5483/bmbrep.2011.44.5.341] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The single-stranded DNA binding activity of the Escherichia coli RecA protein is crucial for homologous recombination to occur. This and other biochemical activities of ssDNA binding proteins may be affected by various factors. In this study, we analyzed the effect of CaCl(2), NaCl and NH(4)NO(3) salts in combination with the pH and nucleotide cofactor effect on the ssDNA-binding activity of RecA. The studies revealed that, in addition to the inhibitory effect, these salts exert also a stimulatory effect on RecA. These effects occur only under very strict conditions, and the presence or absence and the type of nucleotide cofactor play here a major role. It was observed that in contrast to ATP, ATPγS prevented the inhibitory effect of NaCl and NH(4)NO(3), even at very high salt concentration. These results indicate that ATPγS most likely stabilizes the structure of RecA required for DNA binding, making it resistant to high salt concentrations.
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18
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Amunugama R, Fishel R. Subunit interface residues F129 and H294 of human RAD51 are essential for recombinase function. PLoS One 2011; 6:e23071. [PMID: 21857994 PMCID: PMC3155514 DOI: 10.1371/journal.pone.0023071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 07/05/2011] [Indexed: 11/30/2022] Open
Abstract
RAD51 mediated homologous recombinational repair (HRR) of DNA double-strand breaks (DSBs) is essential to maintain genomic integrity. RAD51 forms a nucleoprotein filament (NPF) that catalyzes the fundamental homologous pairing and strand exchange reaction (recombinase) required for HRR. Based on structural and functional homology with archaeal and yeast RAD51, we have identified the human RAD51 (HsRAD51) subunit interface residues HsRad51(F129) in the Walker A box and HsRad51(H294) in the L2 ssDNA binding region as potentially important participants in salt-induced conformational transitions essential for recombinase activity. We demonstrate that the HsRad51(F129V) and HsRad51(H294V) substitution mutations reduce DNA dependent ATPase activity and are largely defective in the formation of a functional NPF, which ultimately eliminates recombinase catalytic functions. Our data are consistent with the conclusion that the HsRAD51(F129) and HsRAD51(H294) residues are important participants in the cation-induced allosteric activation of HsRAD51.
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Affiliation(s)
- Ravindra Amunugama
- Biophysics Graduate Program, The Ohio State University Medical Center and Comprehensive Cancer Center, Columbus, Ohio, United States of America
- Department of Molecular Virology, Immunology, and Medical Genetics, Human Cancer Genetics, The Ohio State University Medical Center and Comprehensive Cancer Center, Columbus, Ohio, United States of America
| | - Richard Fishel
- Department of Molecular Virology, Immunology, and Medical Genetics, Human Cancer Genetics, The Ohio State University Medical Center and Comprehensive Cancer Center, Columbus, Ohio, United States of America
- Physics Department, The Ohio State University Columbus, Columbus, Ohio, United States of America
- * E-mail:
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The RecA/RAD51 protein drives migration of Holliday junctions via polymerization on DNA. Proc Natl Acad Sci U S A 2011; 108:6432-7. [PMID: 21464277 DOI: 10.1073/pnas.1016072108] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The Holliday junction (HJ), a cross-shaped structure that physically links the two DNA helices, is a key intermediate in homologous recombination, DNA repair, and replication. Several helicase-like proteins are known to bind HJs and promote their branch migration (BM) by translocating along DNA at the expense of ATP hydrolysis. Surprisingly, the bacterial recombinase protein RecA and its eukaryotic homologue Rad51 also promote BM of HJs despite the fact they do not bind HJs preferentially and do not translocate along DNA. RecA/Rad51 plays a key role in DNA double-stranded break repair and homologous recombination. RecA/Rad51 binds to ssDNA and forms contiguous filaments that promote the search for homologous DNA sequences and DNA strand exchange. The mechanism of BM promoted by RecA/RAD51 is unknown. Here, we demonstrate that cycles of RecA/Rad51 polymerization and dissociation coupled with ATP hydrolysis drives the BM of HJs.
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Boyko A, Matsuoka A, Kovalchuk I. Potassium chloride and rare earth elements improve plant growth and increase the frequency of the Agrobacterium tumefaciens-mediated plant transformation. PLANT CELL REPORTS 2011; 30:505-18. [PMID: 21132499 DOI: 10.1007/s00299-010-0960-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 10/08/2010] [Accepted: 11/23/2010] [Indexed: 05/17/2023]
Abstract
Plant transformation efficiency depends on the ability of the transgene to successfully interact with plant host factors. Our previous work and the work of others showed that manipulation of the activity of host factors allows for increased frequency of transformation. Recently we reported that exposure of tobacco plants to increased concentrations of ammonium nitrate increases the frequency of both homologous recombination and plant transgenesis. Here we tested the influence of KCl and salts of rare earth elements, Ce and La on the efficiency of Agrobacterium-mediated plant transformation. We found that exposure to KCl, CeCl(3) and LaCl(3) leads to an increase in recombination frequency in Arabidopsis and tobacco. Plants grown in the presence of CeCl(3) and LaCl(3) had higher biomass, longer roots and greater root number. Analysis of transformation efficiency showed that exposure of tobacco plants to 50 mM KCl resulted in ~6.0-fold increase in the number of regenerated calli and transgenic plants as compared to control plants. Exposure to various concentrations of CeCl(3) showed a maximum increase of ~3.0-fold in both the number of calli and transgenic plants. Segregation analysis showed that exposure to KCl and cerium (III) chloride leads to more frequent integrations of the transgene at a single locus. Analysis of transgene intactness showed better preservation of right T-DNA border during transgene integration. Our data suggest that KCl and CeCl(3) can be effectively used to improve quantity and quality of transgene integrations.
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Affiliation(s)
- Alex Boyko
- Department of Biological Sciences, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada.
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21
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Serrano L, Liang L, Chang Y, Deng L, Maulion C, Nguyen S, Tischfield JA. Homologous recombination conserves DNA sequence integrity throughout the cell cycle in embryonic stem cells. Stem Cells Dev 2010; 20:363-74. [PMID: 20491544 DOI: 10.1089/scd.2010.0159] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The maintenance of genomic integrity is crucial to embryonic stem cells (ESC) considering the potential for propagating undesirable mutations to the resulting somatic and germ cell lineages. Indeed, mouse ESC (mESC) exhibit a significantly lower mutation frequency compared to differentiated cells. This could be due to more effective elimination of genetically damaged cells via apoptosis, or especially robust, sequence-conserving DNA damage repair mechanisms such as homologous recombination (HR). We used fluorescence microscopy and 3-dimensional image analysis to compare mESC and differentiated cells, with regard to HR-mediated repair of spontaneous and X-ray-induced double-strand breaks (DSBs). Microscopic analysis of repair foci, flow cytometry, and functional assays of the major DSB repair pathways indicate that HR is greater in mESC compared to fibroblasts. Strikingly, HR appears to be the predominant pathway choice to repair induced or spontaneous DNA damage throughout the ESC cycle in contrast to fibroblasts, where it is restricted to replicated chromatin. This suggests that alternative templates, such as homologous chromosomes, are more frequently used to repair DSB in ESC. Relatively frequent HR utilizing homolog chromosome sequences preserves genome integrity in ESC and has distinctive and important genetic consequences to subsequent somatic and germ cell lineages.
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Affiliation(s)
- Lourdes Serrano
- Department of Genetics, Human Genetics Institute, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854-8082, USA
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22
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Nomme J, Renodon-Cornière A, Asanomi Y, Sakaguchi K, Stasiak AZ, Stasiak A, Norden B, Tran V, Takahashi M. Design of potent inhibitors of human RAD51 recombinase based on BRC motifs of BRCA2 protein: modeling and experimental validation of a chimera peptide. J Med Chem 2010; 53:5782-91. [PMID: 20684611 PMCID: PMC2917172 DOI: 10.1021/jm1002974] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have previously shown that a 28-amino acid peptide derived from the BRC4 motif of BRCA2 tumor suppressor inhibits selectively human RAD51 recombinase (HsRad51). With the aim of designing better inhibitors for cancer treatment, we combined an in silico docking approach with in vitro biochemical testing to construct a highly efficient chimera peptide from eight existing human BRC motifs. We built a molecular model of all BRC motifs complexed with HsRad51 based on the crystal structure of the BRC4 motif-HsRad51 complex, computed the interaction energy of each residue in each BRC motif, and selected the best amino acid residue at each binding position. This analysis enabled us to propose four amino acid substitutions in the BRC4 motif. Three of these increased the inhibitory effect in vitro, and this effect was found to be additive. We thus obtained a peptide that is about 10 times more efficient in inhibiting HsRad51-ssDNA complex formation than the original peptide.
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Affiliation(s)
- Julian Nomme
- UMR 6204 U-3B, Centre National de la Recherche Scientifique & Universite de Nantes, France
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Ristic D, Kanaar R, Wyman C. Visualizing RAD51-mediated joint molecules: implications for recombination mechanism and the effect of sequence heterology. Nucleic Acids Res 2010; 39:155-67. [PMID: 20817928 PMCID: PMC3017611 DOI: 10.1093/nar/gkq766] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The defining event in homologous recombination is the exchange of base-paired partners between a single-stranded (ss) DNA and a homologous duplex driven by recombinase proteins, such as human RAD51. To understand the mechanism of this essential genome maintenance event, we analyzed the structure of RAD51–DNA complexes representing strand exchange intermediates at nanometer resolution by scanning force microscopy. Joint molecules were formed between substrates with a defined ssDNA segment and homologous region on a double-stranded (ds) partner. We discovered and quantified several notable architectural features of RAD51 joint molecules. Each end of the RAD51-bound joints had a distinct structure. Using linear substrates, a 10-nt region of mispaired bases blocked extension of joint molecules in all examples observed, whereas 4 nt of heterology only partially blocked joint molecule extension. Joint molecules, including 10 nt of heterology, had paired DNA on either side of the heterologous substitution, indicating that pairing could initiate from the free 3′end of ssDNA or from a region adjacent to the ss–ds junction. RAD51 filaments covering joint ss–dsDNA regions were more stable to disassembly than filaments covering dsDNA. We discuss how distinct structural features of RAD51-bound DNA joints can play important roles as recognition sites for proteins that facilitate and control strand exchange.
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Affiliation(s)
- D Ristic
- Department of Cell Biology and Genetics, Cancer Genomics Center, Erasmus MC, CA Rotterdam, The Netherlands
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24
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Kagawa W, Kurumizaka H. From meiosis to postmeiotic events: uncovering the molecular roles of the meiosis-specific recombinase Dmc1. FEBS J 2009; 277:590-8. [PMID: 20015079 DOI: 10.1111/j.1742-4658.2009.07503.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In meiosis, the accurate segregation of maternal and paternal chromosomes is accomplished by homologous recombination. A central player in meiotic recombination is the Dmc1 recombinase, a member of the RecA/Rad51 recombinase superfamily, which is widely conserved from viruses to humans. Dmc1 is a meiosis-specific protein that functions with the ubiquitously expressed homolog, the Rad51 recombinase, which is essential for both mitotic and meiotic recombination. Since its discovery, it has been speculated that Dmc1 is important for unique aspects of meiotic recombination. Understanding the distinctive properties of Dmc1, namely, the features that distinguish it from Rad51, will further clarify the mechanisms of meiotic recombination. Recent structural, biochemical, and genetic findings are now revealing the molecular mechanisms of Dmc1-mediated homologous recombination and its regulation by various recombination mediators.
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Affiliation(s)
- Wataru Kagawa
- Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo, Japan.
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25
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The BRC repeats of human BRCA2 differentially regulate RAD51 binding on single- versus double-stranded DNA to stimulate strand exchange. Proc Natl Acad Sci U S A 2009; 106:13254-9. [PMID: 19628690 DOI: 10.1073/pnas.0906208106] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The breast and ovarian cancer suppressor BRCA2 controls the enzyme RAD51 during homologous DNA recombination (HDR) to preserve genome stability. BRCA2 binds to RAD51 through 8 conserved BRC repeat motifs dispersed in an 1127-residue region (BRCA2([BRC1-8])). Here, we show that BRCA2([BRC1-8]) exerts opposing effects on the binding of RAD51 to single-stranded (ss) versus double-stranded (ds) DNA substrates, enhancing strand exchange. BRCA2([BRC1-8]) alters the electrophoretic mobility of RAD51 bound to an ssDNA substrate, accompanied by an increase in ssDNA-bound protein assemblies, revealed by electron microscopy. Single-molecule fluorescence spectroscopy shows that BRCA2([BRC1-8]) promotes RAD51 loading onto ssDNA. In contrast, BRCA2([BRC1-8]) has a different effect on RAD51 assembly on dsDNA; it suppresses and slows this process. When homologous ssDNA and dsDNA are both present, BRCA2([BRC1-8]) stimulates strand exchange, with delayed RAD51 loading onto dsDNA accompanying the appearance of joint molecules representing recombination products. Collectively, our findings suggest that BRCA2([BRC1-8]) targets RAD51 to ssDNA while inhibiting dsDNA binding and that these contrasting activities together bolster one another to stimulate HDR. Our work provides fresh insight into the mechanism of HDR in humans, and its regulation by the BRCA2 tumor suppressor.
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Barros P, Boán F, Blanco MG, Gómez-Márquez J. Effect of monovalent cations and G-quadruplex structures on the outcome of intramolecular homologous recombination. FEBS J 2009; 276:2983-93. [DOI: 10.1111/j.1742-4658.2009.07013.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Li Y, He Y, Luo Y. Conservation of a conformational switch in RadA recombinase from Methanococcus maripaludis. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2009; 65:602-10. [PMID: 19465774 PMCID: PMC2685736 DOI: 10.1107/s0907444909011871] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Accepted: 03/30/2009] [Indexed: 12/26/2022]
Abstract
Archaeal RadAs are close homologues of eukaryal Rad51s ( approximately 40% sequence identity). These recombinases promote ATP hydrolysis and a hallmark strand-exchange reaction between homologous single-stranded and double-stranded DNA substrates. Pairing of the 3'-overhangs located at the damaged DNA with a homologous double-stranded DNA enables the re-synthesis of the damaged region using the homologous DNA as the template. In recent studies, conformational changes in the DNA-interacting regions of Methanococcus voltae RadA have been correlated with the presence of activity-stimulating potassium or calcium ions in the ATPase centre. The series of crystal structures of M. maripaludis RadA presented here further suggest the conservation of an allosteric switch in the ATPase centre which controls the conformational status of DNA-interacting loops. Structural comparison with the distant Escherichia coli RecA homologue supports the notion that the conserved Lys248 and Lys250 residues in RecA play a role similar to that of cations in RadA. The conservation of a cationic bridge between the DNA-interacting L2 region and the terminal phosphate of ATP, together with the apparent stability of the nucleoprotein filament, suggests a gap-displacement model which may explain the advantage of ATP hydrolysis for DNA-strand exchange.
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Affiliation(s)
- Yang Li
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
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28
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Boyko A, Matsuoka A, Kovalchuk I. High frequency Agrobacterium tumefaciens-mediated plant transformation induced by ammonium nitrate. PLANT CELL REPORTS 2009; 28:737-57. [PMID: 19221758 DOI: 10.1007/s00299-009-0676-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Revised: 01/13/2009] [Accepted: 01/25/2009] [Indexed: 05/07/2023]
Abstract
Success in plant genetic transformation depends on the efficiency of explant regeneration and transgene integration. Whereas the former one depends on explant totipotency, the latter depends on the activity of host DNA repair and chromatin organisation factors. We analyzed whether factors that result in an increase in recombination frequency can also increase transformation efficiency. Here, we report that a threefold increase in the concentration of NH(4)NO(3) in the growth medium results in more than a threefold increase in the Agrobacterium tumefaciens-mediated transformation frequency of Nicotiana tabacum plants. Regeneration of calli without selection showed that the increase in transformation frequency was primarily due to the increase in transgene integration efficiency rather than in tissue regeneration efficiency. PCR analysis of insertion sites showed a decrease in the frequency of truncations of the T-DNA right border and an increase on the left border. We hypothesize that exposure to ammonium nitrate modifies the activity of host factors leading to higher frequency of transgene integrations and possibly to the shift in the mechanism of transgene integrations.
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Affiliation(s)
- Alex Boyko
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Canada
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Balakrishnan K, Krishnan NM, Kulkarni A, Rao BJ. Human Rad51 mediated DNA unwinding is facilitated by conditions that favour Rad51-dsDNA aggregation. BMC BIOCHEMISTRY 2009; 10:2. [PMID: 19133161 PMCID: PMC2630921 DOI: 10.1186/1471-2091-10-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Accepted: 01/09/2009] [Indexed: 01/16/2023]
Abstract
Background Human Rad51 (RAD51), analogous to its bacterial homolog, RecA, binds and unwinds double stranded DNA (dsDNA) in the presence of certain nucleotide cofactors. ATP hydrolysis is not required for this process, because even ATP non hydrolysable analogs like AMP-PNP and ATPγS, support DNA unwinding. Even ADP, the product of ATP hydrolysis, feebly supports DNA unwinding. Results We find that human Rad52 (RAD52) stimulates RAD51 mediated DNA unwinding in the presence of all Adenine nucleotide cofactors, (except in AMP and no nucleotide conditions that intrinsically fail to support unwinding reaction) while enhancing aggregation of RAD51-dsDNA complexes in parallel. Interestingly, salt at low concentration can substitute the role of RAD52, in facilitating aggregation of RAD51-dsDNA complexes, that concomitantly also leads to better unwinding. Conclusion RAD52 itself being a highly aggregated protein perhaps acts as scaffold to bring together RAD51 and DNA molecules into large co-aggregates of RAD52-RAD51-DNA complexes to promote RAD51 mediated DNA unwinding reaction, when appropriate nucleotide cofactors are available, presumably through macromolecular crowding effects. Our work highlights the functional link between aggregation of protein-DNA complexes and DNA unwinding in RAD51 system.
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Affiliation(s)
- Kamakshi Balakrishnan
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai-400 005, India.
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30
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Direct imaging of human Rad51 nucleoprotein dynamics on individual DNA molecules. Proc Natl Acad Sci U S A 2009; 106:361-8. [PMID: 19122145 DOI: 10.1073/pnas.0811965106] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Rad51 protein (Rad51) is central to recombinational repair of double-strand DNA breaks. It polymerizes onto DNA and promotes strand exchange between homologous chromosomes. We visualized the real-time assembly and disassembly of human Rad51 nucleoprotein filaments on double-stranded DNA by single-molecule fluorescence microscopy. Rad51 assembly extends the DNA by approximately 65%. Nucleoprotein filament formation occurs via rapid nucleation followed by growth from these nuclei. Growth does not continue indefinitely, however, and nucleoprotein filaments terminate when approximately 2 mum in length. The dependence of nascent filament formation on Rad51 concentration suggests that 2-3 Rad51 monomers are involved in nucleation. Rad51 nucleoprotein filaments are stable and remain extended when ATP hydrolysis is prevented; however, when permitted, filaments decrease in length as a result of conversion to ADP-bound nucleoprotein complexes and partial protein dissociation. Dissociation of Rad51 from dsDNA is slow and incomplete, thereby rationalizing the need for other proteins that facilitate disassembly.
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Grigorescu AA, Vissers JHA, Ristic D, Pigli YZ, Lynch TW, Wyman C, Rice PA. Inter-subunit interactions that coordinate Rad51's activities. Nucleic Acids Res 2008; 37:557-67. [PMID: 19066203 PMCID: PMC2632893 DOI: 10.1093/nar/gkn973] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Rad51 is the central catalyst of homologous recombination in eukaryotes and is thus critical for maintaining genomic integrity. Recent crystal structures of filaments formed by Rad51 and the closely related archeal RadA and eubacterial RecA proteins place the ATPase site at the protomeric interface. To test the relevance of this feature, we mutated conserved residues at this interface and examined their effects on key activities of Rad51: ssDNA-stimulated ATP hydrolysis, DNA binding, polymerization on DNA substrates and catalysis of strand-exchange reactions. Our results show that the interface seen in the crystal structures is very important for nucleoprotein filament formation. H352 and R357 of yeast Rad51 are essential for assembling the catalytically competent form of the enzyme on DNA substrates and coordinating its activities. However, contrary to some previous suggestions, neither of these residues is critical for ATP hydrolysis.
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Affiliation(s)
- Arabela A Grigorescu
- Department of Biochemistry, Molecular Biology and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
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A chemical compound that stimulates the human homologous recombination protein RAD51. Proc Natl Acad Sci U S A 2008; 105:15848-53. [PMID: 18840682 DOI: 10.1073/pnas.0808046105] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
RAD51 and other members of the RecA family of strand exchange proteins assemble on ssDNA to form presynaptic filaments, which carry out the central steps of homologous recombination. A microplate-based assay was developed for high-throughput measurement of hRAD51 filament formation on ssDNA. With this method, a 10,000 compound library was screened, leading to the identification of a small molecule (RS-1) that enhances hRAD51 binding in a wide range of biochemical conditions. Salt titration experiments showed that RS-1 can enhance filament stability. Ultrastructural analysis of filaments formed on ssDNA showed that RS-1 can increase both protein-DNA complex lengths and the pitch of helical filament turns. RS-1 stimulated hRAD51-mediated homologous strand assimilation (D-loop) activity by at least 5- to 11-fold, depending on the condition. This D-loop stimulation occurred even in the presence of Ca(2+) or adenylyl-imidodiphosphate, indicating that the mechanism of stimulation was distinct from that conferred by Ca(2+) and/or inhibition of ATPase. No D-loop activity was observed in the absence of a nucleotide triphosphate cofactor, indicating that the compound does not substitute for this requirement. These results indicate that RS-1 enhances the homologous recombination activity of hRAD51 by promoting the formation of active presynaptic filaments. Cell survival assays in normal neonatal human dermal fibroblasts demonstrated that RS-1 promotes a dose-dependent resistance to the cross-linking chemotherapeutic drug cisplatin. Given that RAD51-dependent recombination is a major determinant of cisplatin resistance, RS-1 seems to function in vivo to stimulate homologous recombination repair proficiency. RS-1 has many potential applications in both research and medical settings.
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Miné J, Disseau L, Takahashi M, Cappello G, Dutreix M, Viovy JL. Real-time measurements of the nucleation, growth and dissociation of single Rad51-DNA nucleoprotein filaments. Nucleic Acids Res 2007; 35:7171-87. [PMID: 17947332 PMCID: PMC2175369 DOI: 10.1093/nar/gkm752] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Human Rad51 (hRad51), the protein central to DNA pairing and strand exchange during homologous recombination, polymerizes on DNA to form nucleoprotein filaments. By making use of magnetic tweezers to manipulate individual DNA molecules, we measured the nucleation and growth of hRad51 nucleoprotein filaments, and their subsequent disassembly in real time. The dependence of the initial polymerization rate upon the concentration of hRad51 suggests that the rate-limiting step is the formation of a nucleus involving 5.5 +/- 1.5 hRad51 monomers, corresponding to one helical turn of the hRad51 nucleoprotein filament. Polymerization is highly cooperative (i.e. a nucleation-limited reaction) at low concentrations and less cooperative (a growth-limited reaction) at high concentrations of the protein. We show that the observed preference of hRad51 to form nucleoprotein filaments on double-stranded DNA rather than on single-stranded DNA is due to the fact that it depolymerizes much faster from ssDNA than from dsDNA: indeed, hRad51 polymerizes faster on ssDNA than on dsDNA. Hydrolysis of ATP by hRad51 does not correlate with its dissociation from dsDNA. This suggests that hRad51 does not depolymerize rapidly from dsDNA after strand exchange but stays bound to the heteroduplex, highlighting the importance of partner proteins to facilitate hRad51 depolymerization from dsDNA.
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Affiliation(s)
- Judith Miné
- Laboratoire Physico-Chimie Curie, UMR CNRS 168, Institut Curie, Paris, France
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van der Heijden T, Seidel R, Modesti M, Kanaar R, Wyman C, Dekker C. Real-time assembly and disassembly of human RAD51 filaments on individual DNA molecules. Nucleic Acids Res 2007; 35:5646-57. [PMID: 17709342 PMCID: PMC2034483 DOI: 10.1093/nar/gkm629] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The human DNA repair protein RAD51 is the crucial component of helical nucleoprotein filaments that drive homologous recombination. The molecular mechanistic details of how this structure facilitates the requisite DNA strand rearrangements are not known but must involve dynamic interactions between RAD51 and DNA. Here, we report the real-time kinetics of human RAD51 filament assembly and disassembly on individual molecules of both single- and double-stranded DNA, as measured using magnetic tweezers. The relative rates of nucleation and filament extension are such that the observed filament formation consists of multiple nucleation events that are in competition with each other. For varying concentration of RAD51, a Hill coefficient of 4.3 ± 0.5 is obtained for both nucleation and filament extension, indicating binding to dsDNA with a binding unit consisting of multiple (≥4) RAD51 monomers. We report Monte Carlo simulations that fit the (dis)assembly data very well. The results show that, surprisingly, human RAD51 does not form long continuous filaments on DNA. Instead each nucleoprotein filament consists of a string of many small filament patches that are only a few tens of monomers long. The high flexibility and dynamic nature of this arrangement is likely to facilitate strand exchange.
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Affiliation(s)
- Thijn van der Heijden
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, Department of Cell Biology and Genetics and Department of Radiation Oncology, Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands
| | - Ralf Seidel
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, Department of Cell Biology and Genetics and Department of Radiation Oncology, Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands
| | - Mauro Modesti
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, Department of Cell Biology and Genetics and Department of Radiation Oncology, Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands
| | - Roland Kanaar
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, Department of Cell Biology and Genetics and Department of Radiation Oncology, Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands
| | - Claire Wyman
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, Department of Cell Biology and Genetics and Department of Radiation Oncology, Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands
- *To whom correspondence should be addressed. +31 15 2786094, Fax: +31 15 2781202, ,
| | - Cees Dekker
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, Department of Cell Biology and Genetics and Department of Radiation Oncology, Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands
- *To whom correspondence should be addressed. +31 15 2786094, Fax: +31 15 2781202, ,
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Li X, Zhang XP, Solinger JA, Kiianitsa K, Yu X, Egelman EH, Heyer WD. Rad51 and Rad54 ATPase activities are both required to modulate Rad51-dsDNA filament dynamics. Nucleic Acids Res 2007; 35:4124-40. [PMID: 17567608 PMCID: PMC1919488 DOI: 10.1093/nar/gkm412] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Rad51 and Rad54 are key proteins that collaborate during homologous recombination. Rad51 forms a presynaptic filament with ATP and ssDNA active in homology search and DNA strand exchange, but the precise role of its ATPase activity is poorly understood. Rad54 is an ATP-dependent dsDNA motor protein that can dissociate Rad51 from dsDNA, the product complex of DNA strand exchange. Kinetic analysis of the budding yeast proteins revealed that the catalytic efficiency of the Rad54 ATPase was stimulated by partial filaments of wild-type and Rad51-K191R mutant protein on dsDNA, unambiguously demonstrating that the Rad54 ATPase activity is stimulated under these conditions. Experiments with Rad51-K191R as well as with wild-type Rad51-dsDNA filaments formed in the presence of ATP, ADP or ATP-γ-S showed that efficient Rad51 turnover from dsDNA requires both the Rad51 ATPase and the Rad54 ATPase activities. The results with Rad51-K191R mutant protein also revealed an unexpected defect in binding to DNA. Once formed, Rad51-K191R-DNA filaments appeared normal upon electron microscopic inspection, but displayed significantly increased stability. These biochemical defects in the Rad51-K191R protein could lead to deficiencies in presynapsis (filament formation) and postsynapsis (filament disassembly) in vivo.
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Affiliation(s)
- Xuan Li
- Section of Microbiology, University of California, Davis, CA 95616-8665, Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908 and Section of Molecular and Cellular Biology, University of California, Davis, CA 95616-8665, USA
| | - Xiao-Ping Zhang
- Section of Microbiology, University of California, Davis, CA 95616-8665, Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908 and Section of Molecular and Cellular Biology, University of California, Davis, CA 95616-8665, USA
| | - Jachen A. Solinger
- Section of Microbiology, University of California, Davis, CA 95616-8665, Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908 and Section of Molecular and Cellular Biology, University of California, Davis, CA 95616-8665, USA
| | - Konstantin Kiianitsa
- Section of Microbiology, University of California, Davis, CA 95616-8665, Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908 and Section of Molecular and Cellular Biology, University of California, Davis, CA 95616-8665, USA
| | - Xiong Yu
- Section of Microbiology, University of California, Davis, CA 95616-8665, Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908 and Section of Molecular and Cellular Biology, University of California, Davis, CA 95616-8665, USA
| | - Edward H. Egelman
- Section of Microbiology, University of California, Davis, CA 95616-8665, Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908 and Section of Molecular and Cellular Biology, University of California, Davis, CA 95616-8665, USA
| | - Wolf-Dietrich Heyer
- Section of Microbiology, University of California, Davis, CA 95616-8665, Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908 and Section of Molecular and Cellular Biology, University of California, Davis, CA 95616-8665, USA
- *To whom correspondence should be addressed. Tel.: 530 752 3001; Fax: 530 752 3011
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Abstract
Breaks in both DNA strands are a particularly dangerous threat to genome stability. At a DNA double-strand break (DSB), potentially lost sequence information cannot be recovered from the same DNA molecule. However, simple repair by joining two broken ends, though inherently error prone, is preferable to leaving ends broken and capable of causing genome rearrangements. To avoid DSB-induced genetic disinformation and disruption of vital processes, such as replication and transcription, cells possess robust mechanisms to repair DSBs. Because all breaks are not created equal, the particular repair mechanism used depends largely on what is possible and needed based on the structure of the broken DNA. We argue that although categorizing different DSB repair mechanisms along pathways and subpathways can be conceptually useful, in cells flexible and reversible interactions among DSB repair factors form a web from which a nonpredetermined path to repair for any number of different DNA breaks will emerge.
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Affiliation(s)
- Claire Wyman
- Department of Cell Biology & Genetics and Department of Radiation Oncology, Erasmus MC, 3000 DR Rotterdam, The Netherlands.
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37
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Qian X, He Y, Ma X, Fodje MN, Grochulski P, Luo Y. Calcium stiffens archaeal Rad51 recombinase from Methanococcus voltae for homologous recombination. J Biol Chem 2006; 281:39380-7. [PMID: 17050545 DOI: 10.1074/jbc.m607785200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Archaeal RadA or Rad51 recombinases are close homologues of eukaryal Rad51 and DMC1. These and bacterial RecA orthologues play a key role in DNA repair by forming helical nucleoprotein filaments in which a hallmark strand exchange reaction between homologous DNA substrates occurs. Recent studies have discovered the stimulatory role by calcium on human and yeast recombinases. Here we report that the strand exchange activity but not the ATPase activity of an archaeal RadA/Rad51 recombinase from Methanococcus voltae (MvRadA) is also subject to calcium stimulation. Crystallized MvRadA filaments in the presence of CaCl(2) resemble that of the recently reported ATPase active form in the presence of an activating dose of KCl. At the ATPase center, one Ca(2+) ion takes the place of two K(+) ions in the K(+)-bound form. The terminal phosphate of the nonhydrolyzable ATP analogue is in a staggered conformation in the Ca(2+)-bound form. In comparison, an eclipsed conformation was seen in the K(+)-bound form. Despite the changes in the ATPase center, both forms harbor largely ordered L2 regions in essentially identical conformations. These data suggest a unified stimulation mechanism by potassium and calcium because of the existence of a conserved ATPase center promiscuous in binding cations.
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Affiliation(s)
- Xinguo Qian
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
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38
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Shivji MKK, Davies OR, Savill JM, Bates DL, Pellegrini L, Venkitaraman AR. A region of human BRCA2 containing multiple BRC repeats promotes RAD51-mediated strand exchange. Nucleic Acids Res 2006; 34:4000-11. [PMID: 16914443 PMCID: PMC1557805 DOI: 10.1093/nar/gkl505] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human BRCA2, a breast and ovarian cancer suppressor, binds to the DNA recombinase RAD51 through eight conserved BRC repeats, motifs of ∼30 residues, dispersed across a large region of the protein. BRCA2 is essential for homologous recombination in vivo, but isolated BRC repeat peptides can prevent the assembly of RAD51 into active nucleoprotein filaments in vitro, suggesting a model in which BRCA2 sequesters RAD51 in undamaged cells, and promotes recombinase function after DNA damage. How BRCA2 might fulfill these dual functions is unclear. We have purified a fragment of human BRCA2 (BRCA2BRC1–8) with 1127 residues spanning all 8 BRC repeats but excluding the C-terminal DNA-binding domain (BRCA2CTD). BRCA2BRC1–8 binds RAD51 nucleoprotein filaments in a ternary complex, indicating it may organize RAD51 on DNA. Human RAD51 is relatively ineffective in vitro at strand exchange between homologous DNA molecules unless non-physiological ions like NH4+ are present. In an ionic milieu more typical of the mammalian nucleus, BRCA2BRCI–8 stimulates RAD51-mediated strand exchange, suggesting it may be an essential co-factor in vivo. Thus, the human BRC repeats, embedded within their surronding sequences as an eight-repeat unit, mediate homologous recombination independent of the BRCA2CTD through a previously unrecognized role in control of RAD51 activity.
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Affiliation(s)
| | - Owen R. Davies
- Department of Biochemistry, University of CambridgeTennis Court Road, Cambridge CB2 1GA, UK
| | | | | | - Luca Pellegrini
- Department of Biochemistry, University of CambridgeTennis Court Road, Cambridge CB2 1GA, UK
| | - Ashok R. Venkitaraman
- To whom correspondence should be addressed. Ashok R. Venkitaraman, Hutchison/MRC Research Centre, University of Cambridge, Hills Road, Cambridge CB2 2XZ, UK. Tel: +44 1223 336901; Fax: +44 1223 763374;
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39
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Qian X, He Y, Wu Y, Luo Y. Asp302 determines potassium dependence of a RadA recombinase from Methanococcus voltae. J Mol Biol 2006; 360:537-47. [PMID: 16782126 DOI: 10.1016/j.jmb.2006.05.058] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 04/12/2006] [Accepted: 05/23/2006] [Indexed: 12/20/2022]
Abstract
Archaeal RadA/Rad51 are close homologues of eukaryal Rad51/DMC1. Such recombinases, as well as their bacterial RecA orthologues, form helical nucleoprotein filaments in which a hallmark strand exchange reaction occurs between homologous DNA substrates. Our recent ATPase and structure studies on RadA recombinase from Methanococcus voltae have suggested that not only magnesium but also potassium ions are absorbed at the ATPase center. Potassium, but not sodium, stimulates the ATP hydrolysis reaction with an apparent dissociation constant of approximately 40 mM. The minimal inhibitory effect by 40 mM NaCl further suggests that the protein does not have adequate affinity for sodium. The wild-type protein's strand exchange activity is also stimulated by potassium with an apparent dissociation constant of approximately 35 mM. We made site-directed mutations at the potassium-contacting residues Glu151 and Asp302. The mutant proteins are expectedly defective in promoting ATP hydrolysis. Similar potassium preference in strand exchange is observed for the E151D and E151K proteins. The D302K protein, however, shows comparable strand exchange efficiencies in the presence of either potassium or sodium. Crystallized E151D filaments reveal a potassium-dependent conformational change similar to what has previously been observed with the wild-type protein. We interpret these data as suggesting that both ATP hydrolysis and DNA strand exchange requires accessibility to an "active" conformation similar to the crystallized ATPase-active form in the presence of ATP, Mg2+ and K+.
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Affiliation(s)
- Xinguo Qian
- Department of Biochemistry, University of Saskatchewan, A3 Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan, Canada S7N 5E5
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40
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Shim KS, Schmutte C, Yoder K, Fishel R. Defining the salt effect on human RAD51 activities. DNA Repair (Amst) 2006; 5:718-30. [PMID: 16644292 DOI: 10.1016/j.dnarep.2006.03.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Revised: 03/09/2006] [Accepted: 03/10/2006] [Indexed: 10/24/2022]
Abstract
Previous work by Sung and colleagues identified unusual salt requirements for hRAD51 strand exchange compared to RecA [S. Sigurdsson, K. Trujillo, B. Song, S. Stratton, P. Sung, Basis for avid homologous DNA strand exchange by human Rad51 and RPA, J. Biol. Chem. 276 (2001) 8798-8806]. Later studies showed that this salt [(NH4)2SO4] appeared to enhance the ability of hRAD51 to distinguish ssDNA from dsDNA [Y. Liu, A.Z. Stasiak, J.Y. Masson, M.J. McIlwraith, A. Stasiak, S.C. West, Conformational changes modulate the activity of human RAD51 protein, J. Mol. Biol. 337 (2004) 817-827]. The mechanism of this salt effect remains enigmatic. Here, we detail the properties of several neutral salts on hRAD51 activities. We found that the cation identity correlated with the stimulatory effect of these neutral salts on hRAD51 ATPase and strand exchange activities. The salt effect appears to be related to the size of the cation, which may be largely mimicked with the cesium ion. These results are consistent with the hypothesis that stimulating cations induce an important conformation and/or transition state in hRAD51. In the presence of an optimal ammonium-based salt (NaNH4HPO4), hRAD51 mediated strand exchange was successfully performed using a simplified protocol. We confirmed and extend the observation that efficient strand exchange correlated with preferential binding of ssDNA over dsDNA. In addition we observed an induced stability of the hRAD51-DNA complex in the presence of ATP that becomes unstable following ATP hydrolysis (the ADP form or nucleotide free form). These salt-induced characteristics of hRAD51 increasingly resemble RecA-mediated recombinase activities, which should help in dissecting the mechanism of these proteins in homologous recombination.
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Affiliation(s)
- Kang-Sup Shim
- Department of Molecular Virology, Immunology, and Medical Genetics, Human Cancer Genetics, The Ohio State University College of Medicine and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43102, USA.
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Ristic D, Modesti M, van der Heijden T, van Noort J, Dekker C, Kanaar R, Wyman C. Human Rad51 filaments on double- and single-stranded DNA: correlating regular and irregular forms with recombination function. Nucleic Acids Res 2005; 33:3292-302. [PMID: 15944450 PMCID: PMC1145190 DOI: 10.1093/nar/gki640] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Recombinase proteins assembled into helical filaments on DNA are believed to be the catalytic core of homologous recombination. The assembly, disassembly and dynamic rearrangements of this structure must drive the DNA strand exchange reactions of homologous recombination. The sensitivity of eukaryotic recombinase activity to reaction conditions in vitro suggests that the status of bound nucleotide cofactors is important for function and possibly for filament structure. We analyzed nucleoprotein filaments formed by the human recombinase Rad51 in a variety of conditions on double-stranded and single-stranded DNA by scanning force microscopy. Regular filaments with extended double-stranded DNA correlated with active in vitro recombination, possibly due to stabilizing the DNA products of these assays. Though filaments formed readily on single-stranded DNA, they were very rarely regular structures. The irregular structure of filaments on single-stranded DNA suggests that Rad51 monomers are dynamic in filaments and that regular filaments are transient. Indeed, single molecule force spectroscopy of Rad51 filament assembly and disassembly in magnetic tweezers revealed protein association and disassociation from many points along the DNA, with kinetics different from those of RecA. The dynamic rearrangements of proteins and DNA within Rad51 nucleoprotein filaments could be key events driving strand exchange in homologous recombination.
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Affiliation(s)
- Dejan Ristic
- Department of Cell Biology and Genetics, Erasmus Medical CenterPO Box 1738, 3000 DR Rotterdam, The Netherlands
| | - Mauro Modesti
- Department of Cell Biology and Genetics, Erasmus Medical CenterPO Box 1738, 3000 DR Rotterdam, The Netherlands
| | - Thijn van der Heijden
- Kavli Institute of Nanoscience, Delft University of TechnologyLorentzweg 1, 2628 CJ Delft, The Netherlands
| | - John van Noort
- Kavli Institute of Nanoscience, Delft University of TechnologyLorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Cees Dekker
- Kavli Institute of Nanoscience, Delft University of TechnologyLorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Roland Kanaar
- Department of Cell Biology and Genetics, Erasmus Medical CenterPO Box 1738, 3000 DR Rotterdam, The Netherlands
- Department of Radiation Oncology, Erasmus Medical Center-DanielRotterdam, The Netherlands
| | - Claire Wyman
- Department of Cell Biology and Genetics, Erasmus Medical CenterPO Box 1738, 3000 DR Rotterdam, The Netherlands
- Department of Radiation Oncology, Erasmus Medical Center-DanielRotterdam, The Netherlands
- To whom correspondence should be addressed. Tel: +31 10 408 8337; Fax: +31 10 408 9468;
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42
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Wu Y, Qian X, He Y, Moya IA, Luo Y. Crystal structure of an ATPase-active form of Rad51 homolog from Methanococcus voltae. Insights into potassium dependence. J Biol Chem 2004; 280:722-8. [PMID: 15537659 DOI: 10.1074/jbc.m411093200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Homologous gene recombination is crucial for the repair of DNA. A superfamily of recombinases facilitate a central strand exchange reaction in the repair process. This reaction is initiated by coating single-stranded DNA (ssDNA) with recombinases in the presence of ATP and Mg(2+) co-factors to form helical nucleoprotein filaments with elevated ATPase and strand invasion activities. At the amino acid sequence level, archaeal RadA and Rad51 and eukaryal Rad51 and meiosis-specific DMC1 form a closely related group of recombinases distinct from bacterial RecA. Unlike the extensively studied Escherichia coli RecA (EcRecA), increasing evidences on yeast and human recombinases imply that their optimal activities are dependent on the presence of a monovalent cation, particularly potassium. Here we present the finding that archaeal RadA from Methanococcus voltae (MvRadA) is a stringent potassium-dependent ATPase, and the crystal structure of this protein in complex with the non-hydrolyzable ATP analog adenosine 5'-(beta,gamma-iminotriphosphate), Mg(2+), and K(+) at 2.4 A resolution. Potassium triggered an in situ conformational change in the ssDNA-binding L2 region concerted with incorporation of two potassium ions at the ATPase site in the RadA crystals preformed in K(+)-free medium. Both potassium ions were observed in contact with the gamma-phosphate of the ATP analog, implying a direct role by the monovalent cations in stimulating the ATPase activity. Cross-talk between the ATPase site and the ssDNA-binding L2 region visualized in the MvRadA structure provides an explanation to the co-factor-induced allosteric effect on RecA-like recombinases.
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Affiliation(s)
- Yan Wu
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
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43
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Abstract
Exchange of strands between homologous DNA molecules is catalyzed by evolutionarily conserved recombinases. These proteins can occur in different quaternary arrangements: rings or helical filaments. Recent results reveal that recombinase function follows from the filamentous form.
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Affiliation(s)
- Claire Wyman
- Department of Cell Biology & Genetics, Erasmus MC, PO Box 1738, 3000 DR Rotterdam, The Netherlands.
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Bugreev DV, Mazin AV. Ca2+ activates human homologous recombination protein Rad51 by modulating its ATPase activity. Proc Natl Acad Sci U S A 2004; 101:9988-93. [PMID: 15226506 PMCID: PMC454202 DOI: 10.1073/pnas.0402105101] [Citation(s) in RCA: 197] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human Rad51 (hRad51) protein plays a key role in homologous recombination and DNA repair. hRad51 protein forms a helical filament on single-stranded DNA (ssDNA), which performs the basic steps of homologous recombination: a search for homologous double-stranded DNA (dsDNA) and DNA strand exchange. hRad51 protein possesses DNA-dependent ATPase activity; however, the role of this activity has not been understood. Our current results show that Ca(2+) greatly stimulates DNA strand exchange activity of hRad51 protein. We found that Ca(2+) exerts its stimulatory effect by modulating the ATPase activity of hRad51 protein. Our data demonstrate that, in the presence of Mg(2+), the hRad51-ATP-ssDNA filament is quickly converted to an inactive hRad51-ADP-ssDNA form, due to relatively rapid ATP hydrolysis and slow dissociation of ADP. Ca(2+) maintains the active hRad51-ATP-ssDNA filament by reducing the ATP hydrolysis rate. These findings demonstrate a crucial role of the ATPase activity in regulation of DNA strand exchange activity of hRad51 protein. This mechanism of Rad51 protein regulation by modulating its ATPase activity is evolutionarily recent; we found no such mechanism for yeast Rad51 (yRad51) protein.
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Affiliation(s)
- Dmitry V Bugreev
- Department of Biochemistry, Drexel University College of Medicine, Philadelphia, PA 19102-1192, USA
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