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Pytko KG, Dannenberg RL, Eckert KA, Hedglin M. Replication of [AT/TA] 25 Microsatellite Sequences by Human DNA Polymerase δ Holoenzymes Is Dependent on dNTP and RPA Levels. Biochemistry 2024; 63:969-983. [PMID: 38623046 DOI: 10.1021/acs.biochem.4c00006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Fragile sites are unstable genomic regions that are prone to breakage during stressed DNA replication. Several common fragile sites (CFS) contain A+T-rich regions including perfect [AT/TA] microsatellite repeats that may collapse into hairpins when in single-stranded DNA (ssDNA) form and coincide with chromosomal hotspots for breakage and rearrangements. While many factors contribute to CFS instability, evidence exists for replication stalling within [AT/TA] microsatellite repeats. Currently, it is unknown how stress causes replication stalling within [AT/TA] microsatellite repeats. To investigate this, we utilized FRET to characterize the structures of [AT/TA]25 sequences and also reconstituted lagging strand replication to characterize the progression of pol δ holoenzymes through A+T-rich sequences. The results indicate that [AT/TA]25 sequences adopt hairpins that are unwound by the major ssDNA-binding complex, RPA, and the progression of pol δ holoenzymes through A+T-rich sequences saturated with RPA is dependent on the template sequence and dNTP concentration. Importantly, the effects of RPA on the replication of [AT/TA]25 sequences are dependent on dNTP concentration, whereas the effects of RPA on the replication of A+T-rich, nonstructure-forming sequences are independent of dNTP concentration. Collectively, these results reveal complexities in lagging strand replication and provide novel insights into how [AT/TA] microsatellite repeats contribute to genome instability.
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Affiliation(s)
- Kara G Pytko
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
| | - Rachel L Dannenberg
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
| | - Kristin A Eckert
- Department of Pathology and Laboratory Medicine, The Jake Gittlen Laboratories for Cancer Research, Hershey, PA 17033, United States
| | - Mark Hedglin
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
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2
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Pangeni S, Biswas G, Kaushik V, Kuppa S, Yang O, Lin CT, Mishra G, Levy Y, Antony E, Ha T. Rapid Long-distance Migration of RPA on Single Stranded DNA Occurs Through Intersegmental Transfer Utilizing Multivalent Interactions. J Mol Biol 2024; 436:168491. [PMID: 38360091 PMCID: PMC10949852 DOI: 10.1016/j.jmb.2024.168491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/04/2024] [Accepted: 02/08/2024] [Indexed: 02/17/2024]
Abstract
Replication Protein A (RPA) is asingle strandedDNA(ssDNA)binding protein that coordinates diverse DNA metabolic processes including DNA replication, repair, and recombination. RPA is a heterotrimeric protein with six functional oligosaccharide/oligonucleotide (OB) domains and flexible linkers. Flexibility enables RPA to adopt multiple configurations andis thought to modulate its function. Here, usingsingle moleculeconfocal fluorescencemicroscopy combinedwith optical tweezers and coarse-grained molecular dynamics simulations, we investigated the diffusional migration of single RPA molecules on ssDNA undertension.The diffusioncoefficientDis the highest (20,000nucleotides2/s) at 3pNtension and in 100 mMKCl and markedly decreases whentensionor salt concentrationincreases. We attribute the tension effect to intersegmental transfer which is hindered by DNA stretching and the salt effect to an increase in binding site size and interaction energy of RPA-ssDNA. Our integrative study allowed us to estimate the size and frequency of intersegmental transfer events that occur through transient bridging of distant sites on DNA by multiple binding sites on RPA. Interestingly, deletion of RPA trimeric core still allowed significant ssDNA binding although the reduced contact area made RPA 15-fold more mobile. Finally, we characterized the effect of RPA crowding on RPA migration. These findings reveal how the high affinity RPA-ssDNA interactions are remodeled to yield access, a key step in several DNA metabolic processes.
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Affiliation(s)
- Sushil Pangeni
- TC Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Gargi Biswas
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Vikas Kaushik
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, USA
| | - Sahiti Kuppa
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, USA
| | - Olivia Yang
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Chang-Ting Lin
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Garima Mishra
- Department of Physics, Ashoka University, Sonepet, Haryana, India
| | - Yaakov Levy
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO, USA.
| | - Taekjip Ha
- TC Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA; Department of Pediatrics, Harvard Medical School, Boston, MA, USA; Howard Hughes Medical Institute, Boston, MA, USA.
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3
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Ahmad F, Patterson A, Deveryshetty J, Mattice JR, Pokhrel N, Bothner B, Antony E. Hydrogen-deuterium exchange reveals a dynamic DNA-binding map of replication protein A. Nucleic Acids Res 2021; 49:1455-1469. [PMID: 33444457 PMCID: PMC7897470 DOI: 10.1093/nar/gkaa1288] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 12/21/2020] [Accepted: 12/28/2020] [Indexed: 12/29/2022] Open
Abstract
Replication protein A (RPA) binds to single-stranded DNA (ssDNA) and interacts with over three dozen enzymes and serves as a recruitment hub to coordinate most DNA metabolic processes. RPA binds ssDNA utilizing multiple oligosaccharide/oligonucleotide binding domains and based on their individual DNA binding affinities are classified as high versus low-affinity DNA-binding domains (DBDs). However, recent evidence suggests that the DNA-binding dynamics of DBDs better define their roles. Utilizing hydrogen-deuterium exchange mass spectrometry (HDX-MS), we assessed the ssDNA-driven dynamics of the individual domains of human RPA. As expected, ssDNA binding shows HDX changes in DBDs A, B, C, D and E. However, DBD-A and DBD-B are dynamic and do not show robust DNA-dependent protection. DBD-C displays the most extensive changes in HDX, suggesting a major role in stabilizing RPA on ssDNA. Slower allosteric changes transpire in the protein-protein interaction domains and linker regions, and thus do not directly interact with ssDNA. Within a dynamics-based model for RPA, we propose that DBD-A and -B act as the dynamic half and DBD-C, -D and -E function as the less-dynamic half. Thus, segments of ssDNA buried under the dynamic half are likely more readily accessible to RPA-interacting proteins.
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Affiliation(s)
- Faiz Ahmad
- Department of Biochemistry, Saint Louis University, School of Medicine, St. Louis, MO 63104, USA
| | - Angela Patterson
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Jaigeeth Deveryshetty
- Department of Biochemistry, Saint Louis University, School of Medicine, St. Louis, MO 63104, USA
| | - Jenna R Mattice
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Nilisha Pokhrel
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53201, USA
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Edwin Antony
- Department of Biochemistry, Saint Louis University, School of Medicine, St. Louis, MO 63104, USA
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Nguyen DD, Kim EY, Sang PB, Chai W. Roles of OB-Fold Proteins in Replication Stress. Front Cell Dev Biol 2020; 8:574466. [PMID: 33043007 PMCID: PMC7517361 DOI: 10.3389/fcell.2020.574466] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 08/25/2020] [Indexed: 12/20/2022] Open
Abstract
Accurate DNA replication is essential for maintaining genome stability. However, this stability becomes vulnerable when replication fork progression is stalled or slowed - a condition known as replication stress. Prolonged fork stalling can cause DNA damage, leading to genome instabilities. Thus, cells have developed several pathways and a complex set of proteins to overcome the challenge at stalled replication forks. Oligonucleotide/oligosaccharide binding (OB)-fold containing proteins are a group of proteins that play a crucial role in fork protection and fork restart. These proteins bind to single-stranded DNA with high affinity and prevent premature annealing and unwanted nuclease digestion. Among these OB-fold containing proteins, the best studied in eukaryotic cells are replication protein A (RPA) and breast cancer susceptibility protein 2 (BRCA2). Recently, another RPA-like protein complex CTC1-STN1-TEN1 (CST) complex has been found to counter replication perturbation. In this review, we discuss the latest findings on how these OB-fold containing proteins (RPA, BRCA2, CST) cooperate to safeguard DNA replication and maintain genome stability.
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Affiliation(s)
| | | | | | - Weihang Chai
- Department of Cancer Biology, Cardinal Bernardin Cancer Center, Loyola University Chicago Stritch School of Medicine, Maywood, IL, United States
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5
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Onwubiko NO, Borst A, Diaz SA, Passkowski K, Scheffel F, Tessmer I, Nasheuer HP. SV40 T antigen interactions with ssDNA and replication protein A: a regulatory role of T antigen monomers in lagging strand DNA replication. Nucleic Acids Res 2020; 48:3657-3677. [PMID: 32128579 PMCID: PMC7144908 DOI: 10.1093/nar/gkaa138] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 02/14/2020] [Accepted: 02/26/2020] [Indexed: 01/08/2023] Open
Abstract
DNA replication is a central process in all living organisms. Polyomavirus DNA replication serves as a model system for eukaryotic DNA replication and has considerably contributed to our understanding of basic replication mechanisms. However, the details of the involved processes are still unclear, in particular regarding lagging strand synthesis. To delineate the complex mechanism of coordination of various cellular proteins binding simultaneously or consecutively to DNA to initiate replication, we investigated single-stranded DNA (ssDNA) interactions by the SV40 large T antigen (Tag). Using single molecule imaging by atomic force microscopy (AFM) combined with biochemical and spectroscopic analyses we reveal independent activity of monomeric and oligomeric Tag in high affinity binding to ssDNA. Depending on ssDNA length, we obtain dissociation constants for Tag-ssDNA interactions (KD values of 10–30 nM) that are in the same order of magnitude as ssDNA binding by human replication protein A (RPA). Furthermore, we observe the formation of RPA-Tag-ssDNA complexes containing hexameric as well as monomeric Tag forms. Importantly, our data clearly show stimulation of primase function in lagging strand Okazaki fragment synthesis by monomeric Tag whereas hexameric Tag inhibits the reaction, redefining DNA replication initiation on the lagging strand.
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Affiliation(s)
- Nichodemus O Onwubiko
- Biochemistry, School of Natural Sciences, Center for Chromosome Biology, Biomedical SciencesBuilding, NUI Galway, New Castle Road, Galway, Ireland
| | - Angela Borst
- Rudolf Virchow Center for Experimental Biomedicine, University ofWürzburg, Josef Schneider Strasse 2, 97080 Würzburg, Germany
| | - Suraya A Diaz
- Biochemistry, School of Natural Sciences, Center for Chromosome Biology, Biomedical SciencesBuilding, NUI Galway, New Castle Road, Galway, Ireland
| | - Katharina Passkowski
- Rudolf Virchow Center for Experimental Biomedicine, University ofWürzburg, Josef Schneider Strasse 2, 97080 Würzburg, Germany
| | - Felicia Scheffel
- Rudolf Virchow Center for Experimental Biomedicine, University ofWürzburg, Josef Schneider Strasse 2, 97080 Würzburg, Germany
| | - Ingrid Tessmer
- Rudolf Virchow Center for Experimental Biomedicine, University ofWürzburg, Josef Schneider Strasse 2, 97080 Würzburg, Germany
| | - Heinz P Nasheuer
- Biochemistry, School of Natural Sciences, Center for Chromosome Biology, Biomedical SciencesBuilding, NUI Galway, New Castle Road, Galway, Ireland
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6
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Rechkunova NI, Lavrik OI. Photoreactive DNA as a Tool to Study Replication Protein A Functioning in DNA Replication and Repair. Photochem Photobiol 2020; 96:440-449. [PMID: 32017119 DOI: 10.1111/php.13222] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 12/08/2019] [Indexed: 11/30/2022]
Abstract
Replication protein A (RPA), eukaryotic single-stranded DNA-binding protein, is a key player in multiple processes of DNA metabolism including DNA replication, recombination and DNA repair. Human RPA composed of subunits of 70-, 32- and 14-kDa binds ssDNA with high affinity and interacts specifically with multiple proteins. The RPA heterotrimer binds ssDNA in several modes, with occlusion lengths of 8-10, 13-22 and 30 nucleotides corresponding to global, transitional and elongated conformations of protein. Varying the structure of photoreactive DNA, the intermediates of different stages of DNA replication or DNA repair were designed and applied to identify positioning of the RPA subunits on the specific DNA structures. Using this approach, RPA interactions with various types of DNA structures attributed to replication and DNA repair intermediates were examined. This review is dedicated to blessed memory of Prof. Alain Favre who contributed to the development of photoreactive nucleotide derivatives and their application for the study of protein-nucleic acids interactions.
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Affiliation(s)
- Nadejda I Rechkunova
- Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia.,Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
| | - Olga I Lavrik
- Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia.,Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
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Khodaverdian VY, Hanscom T, Yu AM, Yu TL, Mak V, Brown AJ, Roberts SA, McVey M. Secondary structure forming sequences drive SD-MMEJ repair of DNA double-strand breaks. Nucleic Acids Res 2018; 45:12848-12861. [PMID: 29121353 PMCID: PMC5728401 DOI: 10.1093/nar/gkx1056] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 10/18/2017] [Indexed: 12/29/2022] Open
Abstract
Alternative end-joining (alt-EJ) repair of DNA double-strand breaks is associated with deletions, chromosome translocations, and genome instability. Alt-EJ frequently uses annealing of microhomologous sequences to tether broken ends. When accessible pre-existing microhomologies do not exist, we have postulated that new microhomologies can be created via limited DNA synthesis at secondary-structure forming sequences. This model, called synthesis-dependent microhomology-mediated end joining (SD-MMEJ), predicts that differences between DNA sequences near double-strand breaks should alter repair outcomes in predictable ways. To test this hypothesis, we injected plasmids with sequence variations flanking an I-SceI endonuclease recognition site into I-SceI expressing Drosophila embryos and used Illumina amplicon sequencing to compare repair junctions. As predicted by the model, we found that small changes in sequences near the I-SceI site had major impacts on the spectrum of repair junctions. Bioinformatic analyses suggest that these repair differences arise from transiently forming loops and hairpins within 30 nucleotides of the break. We also obtained evidence for ‘trans SD-MMEJ,’ involving at least two consecutive rounds of microhomology annealing and synthesis across the break site. These results highlight the importance of sequence context for alt-EJ repair and have important implications for genome editing and genome evolution.
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Affiliation(s)
- Varandt Y Khodaverdian
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Terrence Hanscom
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Amy Marie Yu
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Taylor L Yu
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Victoria Mak
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
| | - Alexander J Brown
- School of Molecular Biosciences, Washington State University, P100 Dairy Road, Pullman, WA 99164, USA
| | - Steven A Roberts
- School of Molecular Biosciences, Washington State University, P100 Dairy Road, Pullman, WA 99164, USA
| | - Mitch McVey
- Department of Biology, Tufts University, 200 Boston Avenue, Suite 4700, Medford, MA 02155, USA
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8
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Safa L, Gueddouda NM, Thiébaut F, Delagoutte E, Petruseva I, Lavrik O, Mendoza O, Bourdoncle A, Alberti P, Riou JF, Saintomé C. 5' to 3' Unfolding Directionality of DNA Secondary Structures by Replication Protein A: G-QUADRUPLEXES AND DUPLEXES. J Biol Chem 2016; 291:21246-21256. [PMID: 27440048 DOI: 10.1074/jbc.m115.709667] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Indexed: 11/06/2022] Open
Abstract
The replication protein A (RPA) is a single-stranded DNA-binding protein that plays an essential role in DNA metabolism. RPA is able to unfold G-quadruplex (G4) structures formed by telomeric DNA sequences, a function important for telomere maintenance. To elucidate the mechanism through which RPA unfolds telomeric G4s, we studied its interaction with oligonucleotides that adopt a G4 structure extended with a single-stranded tail on either side of the G4. Binding and unfolding was characterized using several biochemical and biophysical approaches and in the presence of specific G4 ligands, such as telomestatin and 360A. Our data show that RPA can bind on each side of the G4 but it unwinds the G4 only from 5' toward 3'. We explain the 5' to 3' unfolding directionality in terms of the 5' to 3' oriented laying out of hRPA subunits along single-stranded DNA. Furthermore, we demonstrate by kinetics experiments that RPA proceeds with the same directionality for duplex unfolding.
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Affiliation(s)
- Layal Safa
- From the Structure et Instabilité des Génomes, Sorbonne Universités, Muséum National d'Histoire Naturelle, INSERM U1154, CNRS UMR 7196, CP26, 57 rue Cuvier, 75005, Paris, France, the Sorbonne Universités, UPMC University Paris 06, F-75005, Paris, France
| | - Nassima Meriem Gueddouda
- the Laboratoire ARNA-INSERM U1212, UMR 5320, Institut européen de chimie et biologie, 2 rue Robert Escarpit, 33607 Pessac, France
| | - Frédéric Thiébaut
- From the Structure et Instabilité des Génomes, Sorbonne Universités, Muséum National d'Histoire Naturelle, INSERM U1154, CNRS UMR 7196, CP26, 57 rue Cuvier, 75005, Paris, France, the Sorbonne Universités, UPMC University Paris 06, F-75005, Paris, France, the Ecole Normale Supérieure, PSL Research University, Département de Chimie, 24 rue Lhomond, CNRS, UMR 7203 LBM, 75005 Paris, France, and
| | - Emmanuelle Delagoutte
- From the Structure et Instabilité des Génomes, Sorbonne Universités, Muséum National d'Histoire Naturelle, INSERM U1154, CNRS UMR 7196, CP26, 57 rue Cuvier, 75005, Paris, France
| | - Irina Petruseva
- the Novosibirsk Institute of Chemical Biology and Fundamental Medecine, Siberian Division of Russian Academy of Science, 630090 Novosibirsk, Russia
| | - Olga Lavrik
- the Novosibirsk Institute of Chemical Biology and Fundamental Medecine, Siberian Division of Russian Academy of Science, 630090 Novosibirsk, Russia
| | - Oscar Mendoza
- the Laboratoire ARNA-INSERM U1212, UMR 5320, Institut européen de chimie et biologie, 2 rue Robert Escarpit, 33607 Pessac, France
| | - Anne Bourdoncle
- the Laboratoire ARNA-INSERM U1212, UMR 5320, Institut européen de chimie et biologie, 2 rue Robert Escarpit, 33607 Pessac, France
| | - Patrizia Alberti
- From the Structure et Instabilité des Génomes, Sorbonne Universités, Muséum National d'Histoire Naturelle, INSERM U1154, CNRS UMR 7196, CP26, 57 rue Cuvier, 75005, Paris, France,
| | - Jean-François Riou
- From the Structure et Instabilité des Génomes, Sorbonne Universités, Muséum National d'Histoire Naturelle, INSERM U1154, CNRS UMR 7196, CP26, 57 rue Cuvier, 75005, Paris, France
| | - Carole Saintomé
- From the Structure et Instabilité des Génomes, Sorbonne Universités, Muséum National d'Histoire Naturelle, INSERM U1154, CNRS UMR 7196, CP26, 57 rue Cuvier, 75005, Paris, France, the Sorbonne Universités, UPMC University Paris 06, F-75005, Paris, France,
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9
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Chen R, Subramanyam S, Elcock AH, Spies M, Wold MS. Dynamic binding of replication protein a is required for DNA repair. Nucleic Acids Res 2016; 44:5758-72. [PMID: 27131385 PMCID: PMC4937323 DOI: 10.1093/nar/gkw339] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 04/15/2016] [Indexed: 12/14/2022] Open
Abstract
Replication protein A (RPA), the major eukaryotic single-stranded DNA (ssDNA) binding protein, is essential for replication, repair and recombination. High-affinity ssDNA-binding by RPA depends on two DNA binding domains in the large subunit of RPA. Mutation of the evolutionarily conserved aromatic residues in these two domains results in a separation-of-function phenotype: aromatic residue mutants support DNA replication but are defective in DNA repair. We used biochemical and single-molecule analyses, and Brownian Dynamics simulations to determine the molecular basis of this phenotype. Our studies demonstrated that RPA binds to ssDNA in at least two modes characterized by different dissociation kinetics. We also showed that the aromatic residues contribute to the formation of the longer-lived state, are required for stable binding to short ssDNA regions and are needed for RPA melting of partially duplex DNA structures. We conclude that stable binding and/or the melting of secondary DNA structures by RPA is required for DNA repair, including RAD51 mediated DNA strand exchange, but is dispensable for DNA replication. It is likely that the binding modes are in equilibrium and reflect dynamics in the RPA-DNA complex. This suggests that dynamic binding of RPA to DNA is necessary for different cellular functions.
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Affiliation(s)
- Ran Chen
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Shyamal Subramanyam
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Adrian H Elcock
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Maria Spies
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Marc S Wold
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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10
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Touma C, Kariawasam R, Gimenez AX, Bernardo RE, Ashton NW, Adams MN, Paquet N, Croll TI, O'Byrne KJ, Richard DJ, Cubeddu L, Gamsjaeger R. A structural analysis of DNA binding by hSSB1 (NABP2/OBFC2B) in solution. Nucleic Acids Res 2016; 44:7963-73. [PMID: 27387285 PMCID: PMC5027503 DOI: 10.1093/nar/gkw617] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 06/28/2016] [Indexed: 02/07/2023] Open
Abstract
Single-stranded DNA binding proteins (SSBs) play an important role in DNA processing events such as replication, recombination and repair. Human single-stranded DNA binding protein 1 (hSSB1/NABP2/OBFC2B) contains a single oligosaccharide/oligonucleotide binding (OB) domain followed by a charged C-terminus and is structurally homologous to the SSB from the hyperthermophilic crenarchaeote Sulfolobus solfataricus. Recent work has revealed that hSSB1 is critical to homologous recombination and numerous other important biological processes such as the regulation of telomeres, the maintenance of DNA replication forks and oxidative damage repair. Since the ability of hSSB1 to directly interact with single-stranded DNA (ssDNA) is paramount for all of these processes, understanding the molecular details of ssDNA recognition is essential. In this study, we have used solution-state nuclear magnetic resonance in combination with biophysical and functional experiments to structurally analyse ssDNA binding by hSSB1. We reveal that ssDNA recognition in solution is modulated by base-stacking of four key aromatic residues within the OB domain. This DNA binding mode differs significantly from the recently determined crystal structure of the SOSS1 complex containing hSSB1 and ssDNA. Our findings elucidate the detailed molecular mechanism in solution of ssDNA binding by hSSB1, a major player in the maintenance of genomic stability.
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Affiliation(s)
- Christine Touma
- School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia
| | - Ruvini Kariawasam
- School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia
| | - Adrian X Gimenez
- School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia
| | - Ray E Bernardo
- School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia
| | - Nicholas W Ashton
- School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia
| | - Mark N Adams
- School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia
| | - Nicolas Paquet
- School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia
| | - Tristan I Croll
- School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia
| | - Kenneth J O'Byrne
- School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia
| | - Derek J Richard
- School of Biomedical Research, Institute of Health and Biomedical Innovation at the Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD 4102, Australia
| | - Liza Cubeddu
- School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia School of Molecular Biosciences, University of Sydney, NSW 2006, Australia
| | - Roland Gamsjaeger
- School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia School of Molecular Biosciences, University of Sydney, NSW 2006, Australia
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11
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Aklilu BB, Culligan KM. Molecular Evolution and Functional Diversification of Replication Protein A1 in Plants. FRONTIERS IN PLANT SCIENCE 2016; 7:33. [PMID: 26858742 PMCID: PMC4731521 DOI: 10.3389/fpls.2016.00033] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 01/10/2016] [Indexed: 05/23/2023]
Abstract
Replication protein A (RPA) is a heterotrimeric, single-stranded DNA binding complex required for eukaryotic DNA replication, repair, and recombination. RPA is composed of three subunits, RPA1, RPA2, and RPA3. In contrast to single RPA subunit genes generally found in animals and yeast, plants encode multiple paralogs of RPA subunits, suggesting subfunctionalization. Genetic analysis demonstrates that five Arabidopsis thaliana RPA1 paralogs (RPA1A to RPA1E) have unique and overlapping functions in DNA replication, repair, and meiosis. We hypothesize here that RPA1 subfunctionalities will be reflected in major structural and sequence differences among the paralogs. To address this, we analyzed amino acid and nucleotide sequences of RPA1 paralogs from 25 complete genomes representing a wide spectrum of plants and unicellular green algae. We find here that the plant RPA1 gene family is divided into three general groups termed RPA1A, RPA1B, and RPA1C, which likely arose from two progenitor groups in unicellular green algae. In the family Brassicaceae the RPA1B and RPA1C groups have further expanded to include two unique sub-functional paralogs RPA1D and RPA1E, respectively. In addition, RPA1 groups have unique domains, motifs, cis-elements, gene expression profiles, and pattern of conservation that are consistent with proposed functions in monocot and dicot species, including a novel C-terminal zinc-finger domain found only in plant RPA1C-like sequences. These results allow for improved prediction of RPA1 subunit functions in newly sequenced plant genomes, and potentially provide a unique molecular tool to improve classification of Brassicaceae species.
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Affiliation(s)
- Behailu B. Aklilu
- Department of Molecular, Cellular and Biomedical Sciences, University of New HampshireDurham, NH, USA
- Program in Genetics, University of New HampshireDurham, NH, USA
| | - Kevin M. Culligan
- Department of Molecular, Cellular and Biomedical Sciences, University of New HampshireDurham, NH, USA
- Program in Genetics, University of New HampshireDurham, NH, USA
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12
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Mechanochemical regulations of RPA's binding to ssDNA. Sci Rep 2015; 5:9296. [PMID: 25787788 PMCID: PMC4365408 DOI: 10.1038/srep09296] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 02/24/2015] [Indexed: 11/10/2022] Open
Abstract
Replication protein A (RPA) is a ubiquitous eukaryotic single-stranded DNA (ssDNA) binding protein that serves to protect ssDNA from degradation and annealing, and as a template for recruitment of many downstream factors in virtually all DNA transactions in cell. During many of these transactions, DNA is tethered and is likely subject to force. Previous studies of RPA's binding behavior on ssDNA were conducted in the absence of force; therefore the RPA-ssDNA conformations regulated by force remain unclear. Here, using a combination of atomic force microscopy imaging and mechanical manipulation of single ssDNA tethers, we show that force mediates a switch of the RPA bound ssDNA from amorphous aggregation to a much more regular extended conformation. Further, we found an interesting non-monotonic dependence of the binding affinity on monovalent salt concentration in the presence of force. In addition, we discovered that zinc in micromolar concentrations drives ssDNA to a unique, highly stiff and more compact state. These results provide new mechanochemical insights into the influences and the mechanisms of action of RPA on large single ssDNA.
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13
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Dorsett Y, Zhou Y, Tubbs AT, Chen BR, Purman C, Lee BS, George R, Bredemeyer AL, Zhao JY, Sodergen E, Weinstock GM, Han ND, Reyes A, Oltz EM, Dorsett D, Misulovin Z, Payton JE, Sleckman BP. HCoDES reveals chromosomal DNA end structures with single-nucleotide resolution. Mol Cell 2014; 56:808-18. [PMID: 25435138 DOI: 10.1016/j.molcel.2014.10.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 10/21/2014] [Accepted: 10/23/2014] [Indexed: 01/27/2023]
Abstract
The structure of broken DNA ends is a critical determinant of the pathway used for DNA double-strand break (DSB) repair. Here, we develop an approach involving the hairpin capture of DNA end structures (HCoDES), which elucidates chromosomal DNA end structures at single-nucleotide resolution. HCoDES defines structures of physiologic DSBs generated by the RAG endonuclease, as well as those generated by nucleases widely used for genome editing. Analysis of G1 phase cells deficient in H2AX or 53BP1 reveals DNA ends that are frequently resected to form long single-stranded overhangs that can be repaired by mutagenic pathways. In addition to 3' overhangs, many of these DNA ends unexpectedly form long 5' single-stranded overhangs. The divergence in DNA end structures resolved by HCoDES suggests that H2AX and 53BP1 may have distinct activities in end protection. Thus, the high-resolution end structures obtained by HCoDES identify features of DNA end processing during DSB repair.
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Affiliation(s)
- Yair Dorsett
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Yanjiao Zhou
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA; Genome Institute, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Anthony T Tubbs
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Bo-Ruei Chen
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Caitlin Purman
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Baeck-Seung Lee
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Rosmy George
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Andrea L Bredemeyer
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jiang-Yang Zhao
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Erica Sodergen
- Genome Institute, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - George M Weinstock
- Genome Institute, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Nathan D Han
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Alejandro Reyes
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Eugene M Oltz
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Dale Dorsett
- Biochemistry Department, St. Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Ziva Misulovin
- Biochemistry Department, St. Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Jacqueline E Payton
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Barry P Sleckman
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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14
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Safa L, Delagoutte E, Petruseva I, Alberti P, Lavrik O, Riou JF, Saintomé C. Binding polarity of RPA to telomeric sequences and influence of G-quadruplex stability. Biochimie 2014; 103:80-8. [PMID: 24747047 DOI: 10.1016/j.biochi.2014.04.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 04/09/2014] [Indexed: 01/01/2023]
Abstract
Replication protein A (RPA) is a single-stranded DNA binding protein that plays an essential role in telomere maintenance. RPA binds to and unfolds G-quadruplex (G4) structures formed in telomeric DNA, thus facilitating lagging strand DNA replication and telomerase activity. To investigate the effect of G4 stability on the interactions with human RPA (hRPA), we used a combination of biochemical and biophysical approaches. Our data revealed an inverse relationship between G4 stability and ability of hRPA to bind to telomeric DNA; notably small G4 ligands that enhance G4 stability strongly impaired G4 unfolding by hRPA. To gain more insight into the mechanism of binding and unfolding of telomeric G4 structures by RPA, we carried out photo-crosslinking experiments to elucidate the spatial arrangement of the RPA subunits along the DNA strands. Our results showed that RPA1 and RPA2 are arranged from 5' to 3' along the unfolded telomeric G4, as already described for unstructured single-stranded DNA, while no contact is possible with RPA3 on this short oligonucleotide. In addition, these data are compatible with a 5' to 3' directionality in G4 unfolding by hRPA.
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Affiliation(s)
- Layal Safa
- Structure des Acides Nucléiques, Télomères et Evolution, Inserm U1154, CNRS UMR 7196, Muséum National d'Histoire Naturelle, 43 rue Cuvier, 75231 Paris cedex 05, France; Université Pierre et Marie Curie, 4 place Jussieu, 75005 Paris, France
| | - Emmanuelle Delagoutte
- Structure des Acides Nucléiques, Télomères et Evolution, Inserm U1154, CNRS UMR 7196, Muséum National d'Histoire Naturelle, 43 rue Cuvier, 75231 Paris cedex 05, France
| | - Irina Petruseva
- Novosibirsk Institute of Bioorganic Chemistry, Siberian Division of Russian Academy of Science, 630090 Novosibirsk, Russia
| | - Patrizia Alberti
- Structure des Acides Nucléiques, Télomères et Evolution, Inserm U1154, CNRS UMR 7196, Muséum National d'Histoire Naturelle, 43 rue Cuvier, 75231 Paris cedex 05, France
| | - Olga Lavrik
- Novosibirsk Institute of Bioorganic Chemistry, Siberian Division of Russian Academy of Science, 630090 Novosibirsk, Russia
| | - Jean-François Riou
- Structure des Acides Nucléiques, Télomères et Evolution, Inserm U1154, CNRS UMR 7196, Muséum National d'Histoire Naturelle, 43 rue Cuvier, 75231 Paris cedex 05, France.
| | - Carole Saintomé
- Structure des Acides Nucléiques, Télomères et Evolution, Inserm U1154, CNRS UMR 7196, Muséum National d'Histoire Naturelle, 43 rue Cuvier, 75231 Paris cedex 05, France; Université Pierre et Marie Curie, 4 place Jussieu, 75005 Paris, France.
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15
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G-quadruplex formation in telomeres enhances POT1/TPP1 protection against RPA binding. Proc Natl Acad Sci U S A 2014; 111:2990-5. [PMID: 24516170 DOI: 10.1073/pnas.1321436111] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human telomeres terminate with a single-stranded 3' G overhang, which can be recognized as a DNA damage site by replication protein A (RPA). The protection of telomeres (POT1)/POT1-interacting protein 1 (TPP1) heterodimer binds specifically to single-stranded telomeric DNA (ssTEL) and protects G overhangs against RPA binding. The G overhang spontaneously folds into various G-quadruplex (GQ) conformations. It remains unclear whether GQ formation affects the ability of POT1/TPP1 to compete against RPA to access ssTEL. Using single-molecule Förster resonance energy transfer, we showed that POT1 stably loads to a minimal DNA sequence adjacent to a folded GQ. At 150 mM K(+), POT1 loading unfolds the antiparallel GQ, as the parallel conformation remains folded. POT1/TPP1 loading blocks RPA's access to both folded and unfolded telomeres by two orders of magnitude. This protection is not observed at 150 mM Na(+), in which ssTEL forms only a less-stable antiparallel GQ. These results suggest that GQ formation of telomeric overhangs may contribute to suppression of DNA damage signals.
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16
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Ray S, Qureshi M, Malcolm D, Budhathoki J, Çelik U, Balci H. RPA-mediated unfolding of systematically varying G-quadruplex structures. Biophys J 2013; 104:2235-45. [PMID: 23708363 PMCID: PMC3660638 DOI: 10.1016/j.bpj.2013.04.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 03/05/2013] [Accepted: 04/02/2013] [Indexed: 10/26/2022] Open
Abstract
G-quadruplex (GQ) is a noncanonical nucleic acid structure that is formed by guanine rich sequences. Unless it is destabilized by proteins such as replication protein A (RPA), GQ could interfere with DNA metabolic functions, such as replication or repair. We studied RPA-mediated GQ unfolding using single-molecule FRET on two groups of GQ structures that have different loop lengths and different numbers of G-tetrad layers. We observed a linear increase in the steady-state stability of the GQ against RPA-mediated unfolding with increasing number of layers or decreasing loop length. The stability demonstrated by different GQ structures varied by at least three orders of magnitude. Those with shorter loops (less than three nucleotides long) or a greater number of layers (more than three layers) maintained a significant folded population even at physiological RPA concentration (≈1 μM), raising the possibility of physiological viability of such GQ structures. Finally, we measured the transition time between the start and end of the RPA-mediated GQ unfolding process to be 0.35 ± 0.10 s for all GQ constructs we studied, despite significant differences in their steady-state stabilities. We propose a two-step RPA-mediated GQ unfolding mechanism that is consistent with our observations.
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Affiliation(s)
- Sujay Ray
- Physics Department, Kent State University, Kent, Ohio
| | | | | | | | - Uğur Çelik
- Department of Genetics and Bioengineering, Fatih University, Istanbul, Turkey
| | - Hamza Balci
- Physics Department, Kent State University, Kent, Ohio
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17
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Brosey CA, Yan C, Tsutakawa SE, Heller WT, Rambo RP, Tainer JA, Ivanov I, Chazin WJ. A new structural framework for integrating replication protein A into DNA processing machinery. Nucleic Acids Res 2013; 41:2313-27. [PMID: 23303776 PMCID: PMC3575853 DOI: 10.1093/nar/gks1332] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
By coupling the protection and organization of single-stranded DNA (ssDNA) with recruitment and alignment of DNA processing factors, replication protein A (RPA) lies at the heart of dynamic multi-protein DNA processing machinery. Nevertheless, how RPA coordinates biochemical functions of its eight domains remains unknown. We examined the structural biochemistry of RPA’s DNA-binding activity, combining small-angle X-ray and neutron scattering with all-atom molecular dynamics simulations to investigate the architecture of RPA’s DNA-binding core. The scattering data reveal compaction promoted by DNA binding; DNA-free RPA exists in an ensemble of states with inter-domain mobility and becomes progressively more condensed and less dynamic on binding ssDNA. Our results contrast with previous models proposing RPA initially binds ssDNA in a condensed state and becomes more extended as it fully engages the substrate. Moreover, the consensus view that RPA engages ssDNA in initial, intermediate and final stages conflicts with our data revealing that RPA undergoes two (not three) transitions as it binds ssDNA with no evidence for a discrete intermediate state. These results form a framework for understanding how RPA integrates the ssDNA substrate into DNA processing machinery, provides substrate access to its binding partners and promotes the progression and selection of DNA processing pathways.
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Affiliation(s)
- Chris A Brosey
- Department of Biochemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
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18
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Fan J, Pavletich NP. Structure and conformational change of a replication protein A heterotrimer bound to ssDNA. Genes Dev 2012; 26:2337-47. [PMID: 23070815 DOI: 10.1101/gad.194787.112] [Citation(s) in RCA: 174] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Replication protein A (RPA) is the main eukaryotic ssDNA-binding protein with essential roles in DNA replication, recombination, and repair. RPA maintains the DNA as single-stranded and also interacts with other DNA-processing proteins, coordinating their assembly and disassembly on DNA. RPA binds to ssDNA in two conformational states with opposing affinities for DNA and proteins. The RPA-protein interactions are compatible with a low DNA affinity state that involves DNA-binding domain A (DBD-A) and DBD-B but not with the high DNA affinity state that additionally engages DBD-C and DBD-D. The structure of the high-affinity RPA-ssDNA complex reported here shows a compact quaternary structure held together by a four-way interface between DBD-B, DBD-C, the intervening linker (BC linker), and ssDNA. The BC linker binds into the DNA-binding groove of DBD-B, mimicking DNA. The associated conformational change and partial occlusion of the DBD-A-DBA-B protein-protein interaction site establish a mechanism for the allosteric coupling of RPA-DNA and RPA-protein interactions.
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Affiliation(s)
- Jie Fan
- Sloan-Kettering Division, Joan and Sanford I. Weill Graduate School of Medical Sciences, Cornell University, New York, New York 10065, USA
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19
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Qureshi MH, Ray S, Sewell AL, Basu S, Balci H. Replication protein A unfolds G-quadruplex structures with varying degrees of efficiency. J Phys Chem B 2012; 116:5588-94. [PMID: 22500657 DOI: 10.1021/jp300546u] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Replication protein A (RPA) is known to interact with guanine- (G-) rich sequences that adopt G-quadruplex (GQ) structures. Most studies reported in the literature were performed on GQ formed by homogeneous sequences, such as the human telomeric repeat, and RPA's ability to unfold GQ structures of differing stability is not known. We compared the thermal stability of three potential GQ-forming DNA sequences (PQSs) to their stability against RPA-mediated unfolding using single-molecule fluorescence resonance energy transfer (FRET) and bulk biophysical and biochemical experiments. One of these sequences is the human telomeric repeat and the other two, located in the promoter region of tyrosine hydroxylase gene, are highly heterogeneous sequences that better represent PQSs in the genome. The three GQ constructs have thermal stabilities that differ significantly. Our measurements showed that the most thermally stable structure (Tm = 86 °C) was also the most stable against RPA-mediated unfolding, although the least thermally stable structure (Tm = 69 °C) had at least an order-of-magnitude higher stability against RPA-mediated unfolding than the structure with intermediate thermal stability (Tm = 78 °C). The significance of this observation becomes more evident when considered within the context of the cellular environment where protein-DNA interactions can be an important determinant of GQ viability. Considering these results, we conclude that thermal stability is not necessarily an adequate criterion for predicting the physiological viability of GQ structures. Finally, we measured the time it takes for an RPA molecule to unfold a GQ from a fully folded to a fully unfolded conformation using a single-molecule stopped-flow method. All three GQ structures were unfolded within Δt ≈ 0.30 ± 0.10 s, a surprising result considering that the unfolding time does not correlate with thermal stability or stability against RPA-mediated unfolding. These results suggest that the limiting step in G-quadruplex unfolding by RPA is simply the accessibility of the structure to the RPA protein.
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Affiliation(s)
- Mohammad H Qureshi
- Department of Physics, †Department of Biological Sciences, and ∥Department of Chemistry and Biochemistry, Kent State University , Kent, Ohio 44242, United States
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Abstract
Replication protein A (RPA), the major eukaryotic single-strand DNA (ssDNA)-binding protein, is essential for replication, repair, recombination, and checkpoint activation. Defects in RPA-associated cellular activities lead to genomic instability, a major factor in the pathogenesis of cancer and other diseases. ssDNA binding activity is primarily mediated by two domains in the 70-kDa subunit of the RPA complex. These ssDNA interactions are mediated by a combination of polar residues and four conserved aromatic residues. Mutation of the aromatic residues causes a modest decrease in binding to long (30-nucleotide) ssDNA fragments but results in checkpoint activation and cell cycle arrest in cells. We have used a combination of biochemical analysis and knockdown replacement studies in cells to determine the contribution of these aromatic residues to RPA function. Cells containing the aromatic residue mutants were able to progress normally through S-phase but were defective in DNA repair. Biochemical characterization revealed that mutation of the aromatic residues severely decreased binding to short ssDNA fragments less than 20 nucleotides long. These data indicate that altered binding of RPA to short ssDNA intermediates causes a defect in DNA repair but not in DNA replication. These studies show that cells require different RPA functions in DNA replication and DNA repair.
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Affiliation(s)
- Cathy S Hass
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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21
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Carra C, Saha J, Cucinotta FA. Theoretical prediction of the binding free energy for mutants of replication protein A. J Mol Model 2011; 18:3035-49. [PMID: 22160652 DOI: 10.1007/s00894-011-1313-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 11/16/2011] [Indexed: 01/29/2023]
Abstract
The replication protein A (RPA) is a heterotrimeric (70, 32, and 14 kDa subunits), single stranded DNA (ssDNA) binding protein required for pivotal functions in the cell metabolism, such as chromosomal replication, prevention of hairpin formation, DNA repair and recombination, and signaling after DNA damage. Studies based on deletions and mutations have identified the high affinity ssDNA binding domains in the 70 kDa subunit of RPA, regions A and B. Individually, the domain A and B have a low affinity for ssDNA, while tandems composed of AA, AB, BB, and BA sequences bind the ssDNA with moderate to high affinity. Single and double point mutations on polar residues in the binding domains leads to a reduction in affinity of RPA for ssDNA, in particular when two hydrophilic residues are involved. In view of these results, we performed a study based on molecular dynamics simulation aimed to reproduce the experimental change in binding free energy, ΔΔG, of RPA70 mutants to further elucidate the nature of the protein-ssDNA interaction. The MM-PB(GB)SA methods implemented in Amber10 and the code FoldX were used to estimate the binding free energy. The theoretical and experimental ΔΔG values correlate better when the results are obtained by MM-PBSA calculated on individual trajectories for each mutant. In these conditions, the correlation coefficient between experimental and theoretical ΔΔG reaches a value of 0.95 despite the overestimation of the energy change by one order of magnitude. The decomposition of the MM-GBSA energy per residue allows us to correlate the change of the affinity with the residue polarity and energy contribution to the binding. The method revealed reliable predictions of the change in the affinity in function of mutations, and can be used to identify new mutants with distinct binding properties.
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Affiliation(s)
- Claudio Carra
- Universities Space Research Association, Columbia, MD, USA.
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22
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Carra C, Cucinotta FA. Accurate prediction of the binding free energy and analysis of the mechanism of the interaction of replication protein A (RPA) with ssDNA. J Mol Model 2011; 18:2761-83. [PMID: 22116609 DOI: 10.1007/s00894-011-1288-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 10/19/2011] [Indexed: 10/15/2022]
Abstract
The eukaryotic replication protein A (RPA) has several pivotal functions in the cell metabolism, such as chromosomal replication, prevention of hairpin formation, DNA repair and recombination, and signaling after DNA damage. Moreover, RPA seems to have a crucial role in organizing the sequential assembly of DNA processing proteins along single stranded DNA (ssDNA). The strong RPA affinity for ssDNA, K(A) between 10(-9)-10(-10) M, is characterized by a low cooperativity with minor variation for changes on the nucleotide sequence. Recently, new data on RPA interactions was reported, including the binding free energy of the complex RPA70AB with dC(8) and dC(5), which has been estimated to be -10 ± 0.4 kcal mol(-1) and -7 ± 1 kcal mol(-1), respectively. In view of these results we performed a study based on molecular dynamics aimed to reproduce the absolute binding free energy of RPA70AB with the dC(5) and dC(8) oligonucleotides. We used several tools to analyze the binding free energy, rigidity, and time evolution of the complex. The results obtained by MM-PBSA method, with the use of ligand free geometry as a reference for the receptor in the separate trajectory approach, are in excellent agreement with the experimental data, with ±4 kcal mol(-1) error. This result shows that the MM-PB(GB)SA methods can provide accurate quantitative estimates of the binding free energy for interacting complexes when appropriate geometries are used for the receptor, ligand and complex. The decomposition of the MM-GBSA energy for each residue in the receptor allowed us to correlate the change of the affinity of the mutated protein with the ΔG(gas+sol) contribution of the residue considered in the mutation. The agreement with experiment is optimal and a strong change in the binding free energy can be considered as the dominant factor in the loss for the binding affinity resulting from mutation.
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Affiliation(s)
- Claudio Carra
- Universities Space Research Association, Houston, TX 77058, USA.
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23
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Pathania S, Nguyen J, Hill SJ, Scully R, Adelmant GO, Marto JA, Feunteun J, Livingston DM. BRCA1 is required for postreplication repair after UV-induced DNA damage. Mol Cell 2011; 44:235-51. [PMID: 21963239 DOI: 10.1016/j.molcel.2011.09.002] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 05/06/2011] [Accepted: 07/25/2011] [Indexed: 12/21/2022]
Abstract
BRCA1 contributes to the response to UV irradiation. Utilizing its BRCT motifs, it is recruited during S/G2 to UV-damaged sites in a DNA replication-dependent but nucleotide excision repair (NER)-independent manner. More specifically, at UV-stalled replication forks, it promotes photoproduct excision, suppression of translesion synthesis, and the localization and activation of replication factor C complex (RFC) subunits. The last function, in turn, triggers post-UV checkpoint activation and postreplicative repair. These BRCA1 functions differ from those required for DSBR.
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Affiliation(s)
- Shailja Pathania
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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24
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Single Molecule Detection of One, Two and Multiplex Proteins Involved in DNA/RNA Transaction. Cell Mol Bioeng 2011. [DOI: 10.1007/s12195-011-0159-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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25
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The Hus1 homologue of Leishmania major encodes a nuclear protein that participates in DNA damage response. Mol Biochem Parasitol 2011; 177:65-9. [DOI: 10.1016/j.molbiopara.2011.01.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 01/11/2011] [Accepted: 01/20/2011] [Indexed: 12/29/2022]
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26
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Oakley GG, Patrick SM. Replication protein A: directing traffic at the intersection of replication and repair. FRONT BIOSCI-LANDMRK 2010; 15:883-900. [PMID: 20515732 DOI: 10.2741/3652] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Since the initial discovery of replication protein A (RPA) as a DNA replication factor, much progress has been made on elucidating critical roles for RPA in other DNA metabolic pathways. RPA has been shown to be required for DNA replication, DNA repair, DNA recombination, and the DNA damage response pathway with roles in checkpoint activation. This review summarizes the current understanding of RPA structure, phosphorylation and protein-protein interactions in mediating these DNA metabolic processes.
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Affiliation(s)
- Greg G Oakley
- College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska 68583, USA
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Theriot CA, Hegde ML, Hazra TK, Mitra S. RPA physically interacts with the human DNA glycosylase NEIL1 to regulate excision of oxidative DNA base damage in primer-template structures. DNA Repair (Amst) 2010; 9:643-52. [PMID: 20338831 DOI: 10.1016/j.dnarep.2010.02.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 02/19/2010] [Accepted: 02/23/2010] [Indexed: 12/11/2022]
Abstract
The human DNA glycosylase NEIL1, activated during the S-phase, has been shown to excise oxidized base lesions in single-strand DNA substrates. Furthermore, our previous work demonstrating functional interaction of NEIL1 with PCNA and flap endonuclease 1 (FEN1) suggested its involvement in replication-associated repair. Here we show interaction of NEIL1 with replication protein A (RPA), the heterotrimeric single-strand DNA binding protein that is essential for replication and other DNA transactions. The NEIL1 immunocomplex isolated from human cells contains RPA, and its abundance in the complex increases after exposure to oxidative stress. NEIL1 directly interacts with the large subunit of RPA (K(d) approximately 20 nM) via the common interacting interface (residues 312-349) in NEIL1's disordered C-terminal region. RPA inhibits the base excision activity of both wild-type NEIL1 (389 residues) and its C-terminal deletion CDelta78 mutant (lacking the interaction domain) for repairing 5-hydroxyuracil (5-OHU) in a primer-template structure mimicking the DNA replication fork. This inhibition is reduced when the damage is located near the primer-template junction. Contrarily, RPA moderately stimulates wild-type NEIL1 but not the CDelta78 mutant when 5-OHU is located within the duplex region. While NEIL1 is inhibited by both RPA and Escherichia coli single-strand DNA binding protein, only inhibition by RPA is relieved by PCNA. These results showing modulation of NEIL1's activity on single-stranded DNA substrate by RPA and PCNA support NEIL1's involvement in repairing the replicating genome.
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Affiliation(s)
- Corey A Theriot
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.
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De Vlaminck I, Vidic I, van Loenhout MTJ, Kanaar R, Lebbink JHG, Dekker C. Torsional regulation of hRPA-induced unwinding of double-stranded DNA. Nucleic Acids Res 2010; 38:4133-42. [PMID: 20197317 PMCID: PMC2896508 DOI: 10.1093/nar/gkq067] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
All cellular single-stranded (ss) DNA is rapidly bound and stabilized by single stranded DNA-binding proteins (SSBs). Replication protein A, the main eukaryotic SSB, is able to unwind double-stranded (ds) DNA by binding and stabilizing transiently forming bubbles of ssDNA. Here, we study the dynamics of human RPA (hRPA) activity on topologically constrained dsDNA with single-molecule magnetic tweezers. We find that the hRPA unwinding rate is exponentially dependent on torsion present in the DNA. The unwinding reaction is self-limiting, ultimately removing the driving torsional stress. The process can easily be reverted: release of tension or the application of a rewinding torque leads to protein dissociation and helix rewinding. Based on the force and salt dependence of the in vitro kinetics we anticipate that the unwinding reaction occurs frequently in vivo. We propose that the hRPA unwinding reaction serves to protect and stabilize the dsDNA when it is structurally destabilized by mechanical stresses.
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Affiliation(s)
- Iwijn De Vlaminck
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
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29
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Nuss JE, Sweeney DJ, Alter GM. Prediction of and experimental support for the three-dimensional structure of replication protein A. Biochemistry 2009; 48:7892-905. [PMID: 19621872 DOI: 10.1021/bi801896s] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Replication protein A (RPA) is a heterotrimeric, multidomain, single-stranded DNA binding protein that is essential for DNA replication, repair, and recombination. Crystallographic and NMR studies on RPA protein fragments have provided structures for all domains; however, intact heterotrimeric RPA has resisted crystallization, and a complete protein structure has not yet been described. In this study, computational methods and experimental reactivity information (MRAN) were used to model the complete structure of RPA. To accomplish this, models of RPA's globular domains and its domain-linking regions were docked in various orders. We also determined rates of proteolytic cleavage and amino acid side chain chemical modifications in native, solution state RPA. These experimental data were used to select alternate modeling intermediates and final structural models, leading to a single model most consistent with our results. Using molecular dynamics simulations and multiple rounds of simulated annealing, we then relaxed this structural model and examined its flexibility. The family of resultant models is consistent with other, previously published, critical lines of evidence and with experimental reactivity data presented herein.
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Affiliation(s)
- Jonathan Eric Nuss
- Department of Biochemistry and Molecular Biology and Biomedical Sciences Ph.D. Program, Wright State University, Dayton, Ohio 45435, USA
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30
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Salas TR, Petruseva I, Lavrik O, Saintomé C. Evidence for direct contact between the RPA3 subunit of the human replication protein A and single-stranded DNA. Nucleic Acids Res 2008; 37:38-46. [PMID: 19010961 PMCID: PMC2615627 DOI: 10.1093/nar/gkn895] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Replication Protein A is a single-stranded (ss) DNA-binding protein that is highly conserved in eukaryotes and plays essential roles in many aspects of nucleic acid metabolism, including replication, recombination, DNA repair and telomere maintenance. It is a heterotrimeric complex consisting of three subunits: RPA1, RPA2 and RPA3. It possesses four DNA-binding domains (DBD), DBD-A, DBD-B and DBD-C in RPA1 and DBD-D in RPA2, and it binds ssDNA via a multistep pathway. Unlike the RPA1 and RPA2 subunits, no ssDNA-RPA3 interaction has as yet been observed although RPA3 contains a structural motif found in the other DBDs. We show here using 4-thiothymine residues as photoaffinity probe that RPA3 interacts directly with ssDNA on the 3'-side on a 31 nt ssDNA.
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Affiliation(s)
- Tonatiuh Romero Salas
- Laboratoire de Biophysique Moléculaire, Cellulaire et Tissulaire, CNRS-ParisVI-Paris XIII-UMR 7033, Paris, France
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31
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Current world literature. Trauma and rehabilitation. Curr Opin Neurol 2008; 21:762-4. [PMID: 18989123 DOI: 10.1097/wco.0b013e32831cbb85] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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