1
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Elias M, Guan X, Hudson D, Bose R, Kwak J, Petrounia I, Touah K, Mansour S, Yue P, Errasti G, Delacroix T, Ghosh A, Chakrabarti R. Evolution of Organic Solvent-Resistant DNA Polymerases. ACS Synth Biol 2023; 12:3170-3188. [PMID: 37611245 DOI: 10.1021/acssynbio.2c00515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
The introduction of thermostable polymerases revolutionized the polymerase chain reaction (PCR) and biotechnology. However, many GC-rich genes cannot be PCR-amplified with high efficiency in water, irrespective of temperature. Although polar organic cosolvents can enhance nucleic acid polymerization and amplification by destabilizing duplex DNA and secondary structures, nature has not selected for the evolution of solvent-tolerant polymerase enzymes. Here, we used ultrahigh-throughput droplet-based selection and deep sequencing along with computational free-energy and binding affinity calculations to evolve Taq polymerase to generate enzymes that are both stable and highly active in the presence of organic cosolvents, resulting in up to 10% solvent resistance and over 100-fold increase in stability at 97.5 °C in the presence of 1,4-butanediol, as well as tolerance to up to 10 times higher concentrations of the potent cosolvents sulfolane and 2-pyrrolidone. Using these polymerases, we successfully amplified a broad spectrum of GC-rich templates containing regions with over 90% GC content, including templates recalcitrant to amplification with existing polymerases, even in the presence of cosolvents. We also demonstrated dramatically reduced GC bias in the amplification of genes with widely varying GC content in quantitative polymerase chain reaction (qPCR). By expanding the scope of solvent systems compatible with nucleic acid polymerization, these organic solvent-resistant polymerases enable a dramatic reduction of sequence bias not achievable through thermal resistance alone, with significant implications for a wide range of applications including sequencing and synthetic biology in mixed aqueous-organic media.
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Affiliation(s)
- Mohammed Elias
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
| | - Xiangying Guan
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
| | - Devin Hudson
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
| | - Rahul Bose
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
| | - Joon Kwak
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
| | - Ioanna Petrounia
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
| | - Kenza Touah
- Center for Protein Engineering & Drug Discovery, PMC Isochem SAS, 32 Rue Lavoisier, Vert-Le-Petit 91710, France
| | - Sourour Mansour
- Center for Protein Engineering & Drug Discovery, PMC Isochem SAS, 32 Rue Lavoisier, Vert-Le-Petit 91710, France
| | - Peng Yue
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
| | - Gauthier Errasti
- Center for Protein Engineering & Drug Discovery, PMC Isochem SAS, 32 Rue Lavoisier, Vert-Le-Petit 91710, France
| | - Thomas Delacroix
- Center for Protein Engineering & Drug Discovery, PMC Isochem SAS, 32 Rue Lavoisier, Vert-Le-Petit 91710, France
| | - Anisha Ghosh
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
- McGill University, 845 Rue Sherbrooke Ouest, Montreal, QC H3A 0G4, Canada
| | - Raj Chakrabarti
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
- Center for Protein Engineering & Drug Discovery, PMC Isochem SAS, 32 Rue Lavoisier, Vert-Le-Petit 91710, France
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2
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Vogt A, He Y. Structure and mechanism in non-homologous end joining. DNA Repair (Amst) 2023; 130:103547. [PMID: 37556875 PMCID: PMC10528545 DOI: 10.1016/j.dnarep.2023.103547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/11/2023]
Abstract
DNA double-stranded breaks (DSBs) are a particularly challenging form of DNA damage to repair because the damaged DNA must not only undergo the chemical reactions responsible for returning it to its original state, but, additionally, the two free ends can become physically separated in the nucleus and must be bridged prior to repair. In nonhomologous end joining (NHEJ), one of the major pathways of DSB repair, repair is carried out by a number of repair factors capable of binding to and directly joining DNA ends. It has been unclear how these processes are carried out at a molecular level, owing in part to the lack of structural evidence describing the coordination of the NHEJ factors with each other and a DNA substrate. Advances in cryo-Electron Microscopy (cryo-EM), allowing for the structural characterization of large protein complexes that would be intractable using other techniques, have led to the visualization several key steps of the NHEJ process, which support a model of sequential assembly of repair factors at the DSB, followed by end-bridging mediated by protein-protein complexes and transition to full synapsis. Here we examine the structural evidence for these models, devoting particular attention to recent work identifying a new NHEJ intermediate state and incorporating new NHEJ factors into the general mechanism. We also discuss the evolving understanding of end-bridging mechanisms in NHEJ and DNA-PKcs's role in mediating DSB repair.
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Affiliation(s)
- Alex Vogt
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA; Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, USA
| | - Yuan He
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA; Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, USA; Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA; Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Northwestern University, Chicago, USA.
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3
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Structural and Molecular Kinetic Features of Activities of DNA Polymerases. Int J Mol Sci 2022; 23:ijms23126373. [PMID: 35742812 PMCID: PMC9224347 DOI: 10.3390/ijms23126373] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/01/2022] [Accepted: 06/06/2022] [Indexed: 02/01/2023] Open
Abstract
DNA polymerases catalyze DNA synthesis during the replication, repair, and recombination of DNA. Based on phylogenetic analysis and primary protein sequences, DNA polymerases have been categorized into seven families: A, B, C, D, X, Y, and RT. This review presents generalized data on the catalytic mechanism of action of DNA polymerases. The structural features of different DNA polymerase families are described in detail. The discussion highlights the kinetics and conformational dynamics of DNA polymerases from all known polymerase families during DNA synthesis.
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4
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Rechkunova NI, Zhdanova PV, Lebedeva NA, Maltseva EA, Koval VV, Lavrik OI. Structural features of DNA polymerases β and λ in complex with benzo[a]pyrene-adducted DNA cause a difference in lesion tolerance. DNA Repair (Amst) 2022; 116:103353. [DOI: 10.1016/j.dnarep.2022.103353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 05/31/2022] [Indexed: 11/28/2022]
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5
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Ghosh D, Raghavan SC. 20 years of DNA Polymerase μ, the polymerase that still surprises. FEBS J 2021; 288:7230-7242. [DOI: 10.1111/febs.15852] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 03/02/2021] [Accepted: 03/01/2021] [Indexed: 12/22/2022]
Affiliation(s)
- Dipayan Ghosh
- Department of Biochemistry Indian Institute of Science Bangalore India
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6
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The molecular basis and disease relevance of non-homologous DNA end joining. Nat Rev Mol Cell Biol 2020; 21:765-781. [PMID: 33077885 DOI: 10.1038/s41580-020-00297-8] [Citation(s) in RCA: 198] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2020] [Indexed: 12/26/2022]
Abstract
Non-homologous DNA end joining (NHEJ) is the predominant repair mechanism of any type of DNA double-strand break (DSB) during most of the cell cycle and is essential for the development of antigen receptors. Defects in NHEJ result in sensitivity to ionizing radiation and loss of lymphocytes. The most critical step of NHEJ is synapsis, or the juxtaposition of the two DNA ends of a DSB, because all subsequent steps rely on it. Recent findings show that, like the end processing step, synapsis can be achieved through several mechanisms. In this Review, we first discuss repair pathway choice between NHEJ and other DSB repair pathways. We then integrate recent insights into the mechanisms of NHEJ synapsis with updates on other steps of NHEJ, such as DNA end processing and ligation. Finally, we discuss NHEJ-related human diseases, including inherited disorders and neoplasia, which arise from rare failures at different NHEJ steps.
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7
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Kaminski AM, Pryor JM, Ramsden DA, Kunkel TA, Pedersen LC, Bebenek K. Structural snapshots of human DNA polymerase μ engaged on a DNA double-strand break. Nat Commun 2020; 11:4784. [PMID: 32963245 PMCID: PMC7508851 DOI: 10.1038/s41467-020-18506-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/17/2020] [Indexed: 01/07/2023] Open
Abstract
Genomic integrity is threatened by cytotoxic DNA double-strand breaks (DSBs), which must be resolved efficiently to prevent sequence loss, chromosomal rearrangements/translocations, or cell death. Polymerase μ (Polμ) participates in DSB repair via the nonhomologous end-joining (NHEJ) pathway, by filling small sequence gaps in broken ends to create substrates ultimately ligatable by DNA Ligase IV. Here we present structures of human Polμ engaging a DSB substrate. Synapsis is mediated solely by Polμ, facilitated by single-nucleotide homology at the break site, wherein both ends of the discontinuous template strand are stabilized by a hydrogen bonding network. The active site in the quaternary Pol μ complex is poised for catalysis and nucleotide incoporation proceeds in crystallo. These structures demonstrate that Polμ may address complementary DSB substrates during NHEJ in a manner indistinguishable from single-strand breaks.
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Affiliation(s)
- Andrea M. Kaminski
- grid.94365.3d0000 0001 2297 5165Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 TW Alexander Dr., Bldg. 101/Rm F338, Research Triangle Park, NC 27709 USA
| | - John M. Pryor
- grid.10698.360000000122483208Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, 32-046 Lineberger Comprehensive Cancer Center, 450 West Dr., CB 7295, Chapel Hill, NC 27599 USA
| | - Dale A. Ramsden
- grid.10698.360000000122483208Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, 32-046 Lineberger Comprehensive Cancer Center, 450 West Dr., CB 7295, Chapel Hill, NC 27599 USA
| | - Thomas A. Kunkel
- grid.94365.3d0000 0001 2297 5165Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 TW Alexander Dr., Bldg. 101/Rm F338, Research Triangle Park, NC 27709 USA
| | - Lars C. Pedersen
- grid.94365.3d0000 0001 2297 5165Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 TW Alexander Dr., Bldg. 101/Rm F338, Research Triangle Park, NC 27709 USA
| | - Katarzyna Bebenek
- grid.94365.3d0000 0001 2297 5165Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 TW Alexander Dr., Bldg. 101/Rm F338, Research Triangle Park, NC 27709 USA
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8
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Zhao B, Watanabe G, Lieber MR. Polymerase μ in non-homologous DNA end joining: importance of the order of arrival at a double-strand break in a purified system. Nucleic Acids Res 2020; 48:3605-3618. [PMID: 32052035 PMCID: PMC7144918 DOI: 10.1093/nar/gkaa094] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/14/2020] [Accepted: 02/04/2020] [Indexed: 01/07/2023] Open
Abstract
During non-homologous DNA end joining (NHEJ), bringing two broken dsDNA ends into proximity is an essential prerequisite for ligation by XRCC4:Ligase IV (X4L4). This physical juxtaposition of DNA ends is called NHEJ synapsis. In addition to the key NHEJ synapsis proteins, Ku, X4L4, and XLF, it has been suggested that DNA polymerase mu (pol μ) may also align two dsDNA ends into close proximity for synthesis. Here, we directly observe the NHEJ synapsis by pol μ using a single molecule FRET (smFRET) assay where we can measure the duration of the synapsis. The results show that pol μ alone can mediate efficient NHEJ synapsis of 3′ overhangs that have at least 1 nt microhomology. The abundant Ku protein in cells limits the accessibility of pol μ to DNA ends with overhangs. But X4L4 can largely reverse the Ku inhibition, perhaps by pushing the Ku inward to expose the overhang for NHEJ synapsis. Based on these studies, the mechanistic flexibility known to exist at other steps of NHEJ is now also apparent for the NHEJ synapsis step.
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Affiliation(s)
- Bailin Zhao
- Department of Pathology, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology & Immunology, and Section of Computational & Molecular Biology, USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Ave, Rm. 5428, Los Angeles, CA 90089, USA
| | - Go Watanabe
- Department of Pathology, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology & Immunology, and Section of Computational & Molecular Biology, USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Ave, Rm. 5428, Los Angeles, CA 90089, USA
| | - Michael R Lieber
- Department of Pathology, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology & Immunology, and Section of Computational & Molecular Biology, USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Ave, Rm. 5428, Los Angeles, CA 90089, USA
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9
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Aline Dias da P, Nathalia Marins de A, Gabriel Guarany de A, Robson Francisco de S, Cristiane Rodrigues G. The World of Cyclic Dinucleotides in Bacterial Behavior. Molecules 2020; 25:molecules25102462. [PMID: 32466317 PMCID: PMC7288161 DOI: 10.3390/molecules25102462] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 03/05/2020] [Accepted: 03/17/2020] [Indexed: 02/07/2023] Open
Abstract
The regulation of multiple bacterial phenotypes was found to depend on different cyclic dinucleotides (CDNs) that constitute intracellular signaling second messenger systems. Most notably, c-di-GMP, along with proteins related to its synthesis, sensing, and degradation, was identified as playing a central role in the switching from biofilm to planktonic modes of growth. Recently, this research topic has been under expansion, with the discoveries of new CDNs, novel classes of CDN receptors, and the numerous functions regulated by these molecules. In this review, we comprehensively describe the three main bacterial enzymes involved in the synthesis of c-di-GMP, c-di-AMP, and cGAMP focusing on description of their three-dimensional structures and their structural similarities with other protein families, as well as the essential residues for catalysis. The diversity of CDN receptors is described in detail along with the residues important for the interaction with the ligand. Interestingly, genomic data strongly suggest that there is a tendency for bacterial cells to use both c-di-AMP and c-di-GMP signaling networks simultaneously, raising the question of whether there is crosstalk between different signaling systems. In summary, the large amount of sequence and structural data available allows a broad view of the complexity and the importance of these CDNs in the regulation of different bacterial behaviors. Nevertheless, how cells coordinate the different CDN signaling networks to ensure adaptation to changing environmental conditions is still open for much further exploration.
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10
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Acharya N, Khandagale P, Thakur S, Sahu JK, Utkalaja BG. Quaternary structural diversity in eukaryotic DNA polymerases: monomeric to multimeric form. Curr Genet 2020; 66:635-655. [PMID: 32236653 DOI: 10.1007/s00294-020-01071-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 03/13/2020] [Accepted: 03/24/2020] [Indexed: 12/14/2022]
Abstract
Sixteen eukaryotic DNA polymerases have been identified and studied so far. Based on the sequence similarity of the catalytic subunits of DNA polymerases, these have been classified into four A, B, X and Y families except PrimPol, which belongs to the AEP family. The quaternary structure of these polymerases also varies depending upon whether they are composed of one or more subunits. Therefore, in this review, we used a quaternary structure-based classification approach to group DNA polymerases as either monomeric or multimeric and highlighted functional significance of their accessory subunits. Additionally, we have briefly summarized various DNA polymerase discoveries from a historical perspective, emphasized unique catalytic mechanism of each DNA polymerase and highlighted recent advances in understanding their cellular functions.
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Affiliation(s)
- Narottam Acharya
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, 751023, India.
| | - Prashant Khandagale
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, 751023, India
| | - Shweta Thakur
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, 751023, India
| | - Jugal Kishor Sahu
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, 751023, India
| | - Bhabasha Gyanadeep Utkalaja
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, 751023, India
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11
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Beard WA, Horton JK, Prasad R, Wilson SH. Eukaryotic Base Excision Repair: New Approaches Shine Light on Mechanism. Annu Rev Biochem 2020; 88:137-162. [PMID: 31220977 DOI: 10.1146/annurev-biochem-013118-111315] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Genomic DNA is susceptible to endogenous and environmental stresses that modify DNA structure and its coding potential. Correspondingly, cells have evolved intricate DNA repair systems to deter changes to their genetic material. Base excision DNA repair involves a number of enzymes and protein cofactors that hasten repair of damaged DNA bases. Recent advances have identified macromolecular complexes that assemble at the DNA lesion and mediate repair. The repair of base lesions generally requires five enzymatic activities: glycosylase, endonuclease, lyase, polymerase, and ligase. The protein cofactors and mechanisms for coordinating the sequential enzymatic steps of repair are being revealed through a range of experimental approaches. We discuss the enzymes and protein cofactors involved in eukaryotic base excision repair, emphasizing the challenge of integrating findings from multiple methodologies. The results provide an opportunity to assimilate biochemical findings with cell-based assays to uncover new insights into this deceptively complex repair pathway.
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Affiliation(s)
- William A Beard
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Science, National Institutes of Health, Research Triangle Park, North Carolina 27709-2233, USA;
| | - Julie K Horton
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Science, National Institutes of Health, Research Triangle Park, North Carolina 27709-2233, USA;
| | - Rajendra Prasad
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Science, National Institutes of Health, Research Triangle Park, North Carolina 27709-2233, USA;
| | - Samuel H Wilson
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Science, National Institutes of Health, Research Triangle Park, North Carolina 27709-2233, USA;
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12
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Hoitsma NM, Whitaker AM, Schaich MA, Smith MR, Fairlamb MS, Freudenthal BD. Structure and function relationships in mammalian DNA polymerases. Cell Mol Life Sci 2020; 77:35-59. [PMID: 31722068 PMCID: PMC7050493 DOI: 10.1007/s00018-019-03368-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 10/11/2019] [Accepted: 10/31/2019] [Indexed: 12/19/2022]
Abstract
DNA polymerases are vital for the synthesis of new DNA strands. Since the discovery of DNA polymerase I in Escherichia coli, a diverse library of mammalian DNA polymerases involved in DNA replication, DNA repair, antibody generation, and cell checkpoint signaling has emerged. While the unique functions of these DNA polymerases are differentiated by their association with accessory factors and/or the presence of distinctive catalytic domains, atomic resolution structures of DNA polymerases in complex with their DNA substrates have revealed mechanistic subtleties that contribute to their specialization. In this review, the structure and function of all 15 mammalian DNA polymerases from families B, Y, X, and A will be reviewed and discussed with special emphasis on the insights gleaned from recently published atomic resolution structures.
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Affiliation(s)
- Nicole M Hoitsma
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Amy M Whitaker
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Matthew A Schaich
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Mallory R Smith
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Max S Fairlamb
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA.
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13
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Loc'h J, Gerodimos CA, Rosario S, Tekpinar M, Lieber MR, Delarue M. Structural evidence for an in trans base selection mechanism involving Loop1 in polymerase μ at an NHEJ double-strand break junction. J Biol Chem 2019; 294:10579-10595. [PMID: 31138645 DOI: 10.1074/jbc.ra119.008739] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/13/2019] [Indexed: 11/06/2022] Open
Abstract
Eukaryotic DNA polymerase (Pol) X family members such as Pol μ and terminal deoxynucleotidyl transferase (TdT) are important components for the nonhomologous DNA end-joining (NHEJ) pathway. TdT participates in a specialized version of NHEJ, V(D)J recombination. It has primarily nontemplated polymerase activity but can take instructions across strands from the downstream dsDNA, and both activities are highly dependent on a structural element called Loop1. However, it is unclear whether Pol μ follows the same mechanism, because the structure of its Loop1 is disordered in available structures. Here, we used a chimeric TdT harboring Loop1 of Pol μ that recapitulated the functional properties of Pol μ in ligation experiments. We solved three crystal structures of this TdT chimera bound to several DNA substrates at 1.96-2.55 Å resolutions, including a full DNA double-strand break (DSB) synapsis. We then modeled the full Pol μ sequence in the context of one these complexes. The atomic structure of an NHEJ junction with a Pol X construct that mimics Pol μ in a reconstituted system explained the distinctive properties of Pol μ compared with TdT. The structure suggested a mechanism of base selection relying on Loop1 and taking instructions via the in trans templating base independently of the primer strand. We conclude that our atomic-level structural observations represent a paradigm shift for the mechanism of base selection in the Pol X family of DNA polymerases.
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Affiliation(s)
- Jérôme Loc'h
- From the Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du CNRS, 25 Rue du Dr. Roux, 75015 Paris, France and
| | - Christina A Gerodimos
- the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology and the Department of Biological Sciences, Section of Molecular and Computational Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Sandrine Rosario
- From the Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du CNRS, 25 Rue du Dr. Roux, 75015 Paris, France and
| | - Mustafa Tekpinar
- From the Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du CNRS, 25 Rue du Dr. Roux, 75015 Paris, France and
| | - Michael R Lieber
- the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology and the Department of Biological Sciences, Section of Molecular and Computational Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Marc Delarue
- From the Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du CNRS, 25 Rue du Dr. Roux, 75015 Paris, France and
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14
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Chang YK, Huang YP, Liu XX, Ko TP, Bessho Y, Kawano Y, Maestre-Reyna M, Wu WJ, Tsai MD. Human DNA Polymerase μ Can Use a Noncanonical Mechanism for Multiple Mn 2+-Mediated Functions. J Am Chem Soc 2019; 141:8489-8502. [PMID: 31067051 DOI: 10.1021/jacs.9b01741] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Recent research on the structure and mechanism of DNA polymerases has continued to generate fundamentally important features, including a noncanonical pathway involving "prebinding" of metal-bound dNTP (MdNTP) in the absence of DNA. While this noncanonical mechanism was shown to be a possible subset for African swine fever DNA polymerase X (Pol X) and human Pol λ, it remains unknown whether it could be the primary pathway for a DNA polymerase. Pol μ is a unique member of the X-family with multiple functions and with unusual Mn2+ preference. Here we report that Pol μ not only prebinds MdNTP in a catalytically active conformation but also exerts a Mn2+ over Mg2+ preference at this early stage of catalysis, for various functions: incorporation of dNTP into a single nucleotide gapped DNA, incorporation of rNTP in the nonhomologous end joining (NHEJ) repair, incorporation of dNTP to an ssDNA, and incorporation of an 8-oxo-dGTP opposite template dA (mismatched) or dC (matched). The structural basis of this noncanonical mechanism and Mn2+ over Mg2+ preference in these functions was analyzed by solving 19 structures of prebinding binary complexes, precatalytic ternary complexes, and product complexes. The results suggest that the noncanonical pathway is functionally relevant for the multiple functions of Pol μ. Overall, this work provides the structural and mechanistic basis for the long-standing puzzle in the Mn2+ preference of Pol μ and expands the landscape of the possible mechanisms of DNA polymerases to include both mechanistic pathways.
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Affiliation(s)
- Yao-Kai Chang
- Institute of Biological Chemistry, Academia Sinica , 128 Academia Road Sec. 2 , Nankang, Taipei 115 , Taiwan.,Institute of Biochemical Sciences , National Taiwan University , Taipei 106 , Taiwan
| | - Ya-Ping Huang
- Institute of Biological Chemistry, Academia Sinica , 128 Academia Road Sec. 2 , Nankang, Taipei 115 , Taiwan
| | - Xiao-Xia Liu
- Institute of Biological Chemistry, Academia Sinica , 128 Academia Road Sec. 2 , Nankang, Taipei 115 , Taiwan
| | - Tzu-Ping Ko
- Institute of Biological Chemistry, Academia Sinica , 128 Academia Road Sec. 2 , Nankang, Taipei 115 , Taiwan
| | - Yoshitaka Bessho
- Institute of Biological Chemistry, Academia Sinica , 128 Academia Road Sec. 2 , Nankang, Taipei 115 , Taiwan.,RIKEN SPring-8 Center , 1-1-1 Kouto , Sayo , Hyogo 679-5148 , Japan
| | - Yoshiaki Kawano
- RIKEN SPring-8 Center , 1-1-1 Kouto , Sayo , Hyogo 679-5148 , Japan
| | - Manuel Maestre-Reyna
- Institute of Biological Chemistry, Academia Sinica , 128 Academia Road Sec. 2 , Nankang, Taipei 115 , Taiwan
| | - Wen-Jin Wu
- Institute of Biological Chemistry, Academia Sinica , 128 Academia Road Sec. 2 , Nankang, Taipei 115 , Taiwan
| | - Ming-Daw Tsai
- Institute of Biological Chemistry, Academia Sinica , 128 Academia Road Sec. 2 , Nankang, Taipei 115 , Taiwan.,Institute of Biochemical Sciences , National Taiwan University , Taipei 106 , Taiwan
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15
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Beard WA, Wilson SH. DNA polymerase beta and other gap-filling enzymes in mammalian base excision repair. Enzymes 2019; 45:1-26. [PMID: 31627875 DOI: 10.1016/bs.enz.2019.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
DNA polymerase β plays a central role in the base excision DNA repair pathway that cleanses the genome of apurinic/apyrimidinic (AP) sites. AP sites arise in DNA from spontaneous base loss and DNA damage-specific glycosylases that hydrolyze the N-glycosidic bond between the deoxyribose and damaged base. AP sites are deleterious lesions because they can be mutagenic and/or cytotoxic. DNA polymerase β contributes two enzymatic activities, DNA synthesis and lyase, during the repair of AP sites; these activities reside on carboxyl- and amino-terminal domains, respectively. Accordingly, its cellular, structural, and kinetic attributes have been extensively characterized and it serves as model enzyme for the nucleotidyl transferase reaction utilized by other replicative, repair, and trans-lesion DNA polymerases.
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Affiliation(s)
- William A Beard
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Science, National Institutes of Health, Durham, NC, United States
| | - Samuel H Wilson
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Science, National Institutes of Health, Durham, NC, United States.
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16
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Raper AT, Reed AJ, Suo Z. Kinetic Mechanism of DNA Polymerases: Contributions of Conformational Dynamics and a Third Divalent Metal Ion. Chem Rev 2018; 118:6000-6025. [DOI: 10.1021/acs.chemrev.7b00685] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Austin T. Raper
- Department of Chemistry and Biochemistry, Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, United States
| | - Andrew J. Reed
- Department of Chemistry and Biochemistry, Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, United States
| | - Zucai Suo
- Department of Chemistry and Biochemistry, Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, United States
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17
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Loc'h J, Delarue M. Terminal deoxynucleotidyltransferase: the story of an untemplated DNA polymerase capable of DNA bridging and templated synthesis across strands. Curr Opin Struct Biol 2018; 53:22-31. [PMID: 29656238 DOI: 10.1016/j.sbi.2018.03.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/27/2018] [Accepted: 03/30/2018] [Indexed: 01/08/2023]
Abstract
Terminal deoxynucleotidyltransferase (TdT) is a member of the polX family which is involved in DNA repair. It has been known for years as an untemplated DNA polymerase used during V(D)J recombination to generate diversity at the CDR3 region of immunoglobulins and T-cell receptors. Recently, however, TdT was crystallized in the presence of a complete DNA synapsis made of two double-stranded DNA (dsDNA), each with a 3' protruding end, and overlapping with only one micro-homology base-pair, thus giving structural insight for the first time into DNA synthesis across strands. It was subsequently shown that TdT indeed has an in trans template-dependent activity in the presence of an excess of the downstream DNA duplex. A possible biological role of this dual activity is discussed.
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Affiliation(s)
- Jérôme Loc'h
- Unit of Structural Dynamics of Biological Macromolecules and UMR 3528 du CNRS, Institut Pasteur, 75015 Paris, France
| | - Marc Delarue
- Unit of Structural Dynamics of Biological Macromolecules and UMR 3528 du CNRS, Institut Pasteur, 75015 Paris, France.
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18
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Pannunzio NR, Watanabe G, Lieber MR. Nonhomologous DNA end-joining for repair of DNA double-strand breaks. J Biol Chem 2017; 293:10512-10523. [PMID: 29247009 DOI: 10.1074/jbc.tm117.000374] [Citation(s) in RCA: 314] [Impact Index Per Article: 44.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Nonhomologous DNA end-joining (NHEJ) is the predominant double-strand break (DSB) repair pathway throughout the cell cycle and accounts for nearly all DSB repair outside of the S and G2 phases. NHEJ relies on Ku to thread onto DNA termini and thereby improve the affinity of the NHEJ enzymatic components consisting of polymerases (Pol μ and Pol λ), a nuclease (the Artemis·DNA-PKcs complex), and a ligase (XLF·XRCC4·Lig4 complex). Each of the enzymatic components is distinctive for its versatility in acting on diverse incompatible DNA end configurations coupled with a flexibility in loading order, resulting in many possible junctional outcomes from one DSB. DNA ends can either be directly ligated or, if the ends are incompatible, processed until a ligatable configuration is achieved that is often stabilized by up to 4 bp of terminal microhomology. Processing of DNA ends results in nucleotide loss or addition, explaining why DSBs repaired by NHEJ are rarely restored to their original DNA sequence. Thus, NHEJ is a single pathway with multiple enzymes at its disposal to repair DSBs, resulting in a diversity of repair outcomes.
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Affiliation(s)
- Nicholas R Pannunzio
- From the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology, Section of Molecular and Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Go Watanabe
- From the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology, Section of Molecular and Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Michael R Lieber
- From the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology, Section of Molecular and Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
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19
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Moon AF, Pryor JM, Ramsden DA, Kunkel TA, Bebenek K, Pedersen LC. Structural accommodation of ribonucleotide incorporation by the DNA repair enzyme polymerase Mu. Nucleic Acids Res 2017; 45:9138-9148. [PMID: 28911097 PMCID: PMC5587726 DOI: 10.1093/nar/gkx527] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 06/23/2017] [Indexed: 02/02/2023] Open
Abstract
While most DNA polymerases discriminate against ribonucleotide triphosphate (rNTP) incorporation very effectively, the Family X member DNA polymerase μ (Pol μ) incorporates rNTPs almost as efficiently as deoxyribonucleotides. To gain insight into how this occurs, here we have used X-ray crystallography to describe the structures of pre- and post-catalytic complexes of Pol μ with a ribonucleotide bound at the active site. These structures reveal that Pol μ binds and incorporates a rNTP with normal active site geometry and no distortion of the DNA substrate or nucleotide. Moreover, a comparison of rNTP incorporation kinetics by wildtype and mutant Pol μ indicates that rNTP accommodation involves synergistic interactions with multiple active site residues not found in polymerases with greater discrimination. Together, the results are consistent with the hypothesis that rNTP incorporation by Pol μ is advantageous in gap-filling synthesis during DNA double strand break repair by nonhomologous end joining, particularly in nonreplicating cells containing very low deoxyribonucleotide concentrations.
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Affiliation(s)
- Andrea F Moon
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - John M Pryor
- Department of Biochemistry and Biophysics, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Dale A Ramsden
- Department of Biochemistry and Biophysics, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Thomas A Kunkel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Katarzyna Bebenek
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Lars C Pedersen
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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20
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Sastre-Moreno G, Pryor JM, Díaz-Talavera A, Ruiz JF, Ramsden DA, Blanco L. Polμ tumor variants decrease the efficiency and accuracy of NHEJ. Nucleic Acids Res 2017; 45:10018-10031. [PMID: 28973441 PMCID: PMC5622330 DOI: 10.1093/nar/gkx625] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 07/03/2017] [Accepted: 07/12/2017] [Indexed: 11/14/2022] Open
Abstract
The non homologous end-joining (NHEJ) pathway of double-strand break (DSB) repair often requires DNA synthesis to fill the gaps generated upon alignment of the broken ends, a complex task performed in human cells by two specialized DNA polymerases, Polλ and Polμ. It is now well established that Polμ is the one adapted to repair DSBs with non-complementary ends, the most challenging scenario, although the structural basis and physiological implications of this adaptation are not fully understood. Here, we demonstrate that two human Polμ point mutations, G174S and R175H, previously identified in two different tumor samples and affecting two adjacent residues, limit the efficiency of accurate NHEJ by Polμ in vitro and in vivo. Moreover, we show that this limitation is the consequence of a decreased template dependency during NHEJ, which renders the error-rate of the mutants higher due to the ability of Polμ to randomly incorporate nucleotides at DSBs. These results highlight the relevance of the 8 kDa domain of Polμ for accurate and efficient NHEJ, but also its contribution to the error-prone behavior of Polμ at 2-nt gaps. This work provides the first demonstration that mutations affecting Polμ identified in tumors can alter the efficiency and fidelity of NHEJ.
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Affiliation(s)
- Guillermo Sastre-Moreno
- Centro de Biología Molecular ‘Severo Ochoa’, Universidad Autónoma de Madrid/CSIC, Madrid, Spain
| | - John M. Pryor
- Department of Biochemistry and Biophysics and Curriculum in Genetics and Molecular Biology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Alberto Díaz-Talavera
- Centro de Biología Molecular ‘Severo Ochoa’, Universidad Autónoma de Madrid/CSIC, Madrid, Spain
| | - José F. Ruiz
- Departamento Bioquímica Vegetal y Biología Molecular, Universidad de Sevilla, Sevilla, Spain
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla/CSIC, Sevilla, Spain
| | - Dale A. Ramsden
- Department of Biochemistry and Biophysics and Curriculum in Genetics and Molecular Biology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Luis Blanco
- Centro de Biología Molecular ‘Severo Ochoa’, Universidad Autónoma de Madrid/CSIC, Madrid, Spain
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21
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Howard MJ, Wilson SH. Processive searching ability varies among members of the gap-filling DNA polymerase X family. J Biol Chem 2017; 292:17473-17481. [PMID: 28893909 DOI: 10.1074/jbc.m117.801860] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 08/29/2017] [Indexed: 11/06/2022] Open
Abstract
DNA repair proteins must locate rare damaged sites within the genome. DNA polymerase β (Pol β), a member of the DNA polymerase X family that is involved in base excision repair, uses a processive hopping search mechanism to locate substrates. This effectively enhances its search footprint on DNA, increasing the probability of locating damaged sites. Processive searching has been reported or proposed for many DNA-binding proteins, raising the question of how widespread or specific to certain enzymes the ability to perform this function is. To provide insight into this question, we compared the ability of three homologous DNA Pol X family members to perform a processive search for 1-nucleotide gaps in DNA using a previously developed biochemical assay. We found that at near-predicted physiological ionic strengths, the intramolecular searching ability of Pol β is at least 4-fold higher than that of Pol μ and ∼2-fold higher than that of Pol λ. Pol β also was able to perform intersegmental transfer with the intersegmental searching ability of Pol β being at least 6- and ∼2-fold higher than that of Pols μ and λ, respectively. Mutational analysis suggested that differences in the N-terminal domains of these polymerases are responsible for the varying degrees of searching competence. Of note, the differences in processive searching ability observed among the DNA Pol X family members correlated with their proposed biological functions in base excision repair and nonhomologous end joining.
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Affiliation(s)
- Michael J Howard
- From the Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Samuel H Wilson
- From the Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
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22
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Wu WJ, Yang W, Tsai MD. How DNA polymerases catalyse replication and repair with contrasting fidelity. Nat Rev Chem 2017. [DOI: 10.1038/s41570-017-0068] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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23
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Jamsen JA, Beard WA, Pedersen LC, Shock DD, Moon AF, Krahn JM, Bebenek K, Kunkel TA, Wilson SH. Time-lapse crystallography snapshots of a double-strand break repair polymerase in action. Nat Commun 2017; 8:253. [PMID: 28811466 PMCID: PMC5557891 DOI: 10.1038/s41467-017-00271-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 06/15/2017] [Indexed: 11/08/2022] Open
Abstract
DNA polymerase (pol) μ is a DNA-dependent polymerase that incorporates nucleotides during gap-filling synthesis in the non-homologous end-joining pathway of double-strand break repair. Here we report time-lapse X-ray crystallography snapshots of catalytic events during gap-filling DNA synthesis by pol μ. Unique catalytic intermediates and active site conformational changes that underlie catalysis are uncovered, and a transient third (product) metal ion is observed in the product state. The product manganese coordinates phosphate oxygens of the inserted nucleotide and PPi. The product metal is not observed during DNA synthesis in the presence of magnesium. Kinetic analyses indicate that manganese increases the rate constant for deoxynucleoside 5'-triphosphate insertion compared to magnesium. The likely product stabilization role of the manganese product metal in pol μ is discussed. These observations provide insight on structural attributes of this X-family double-strand break repair polymerase that impact its biological function in genome maintenance.DNA polymerase (pol) μ functions in DNA double-strand break repair. Here the authors use time-lapse X-ray crystallography to capture the states of pol µ during the conversion from pre-catalytic to product complex and observe a third transiently bound metal ion in the product state.
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Affiliation(s)
- Joonas A Jamsen
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - William A Beard
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Lars C Pedersen
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - David D Shock
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Andrea F Moon
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Katarzyna Bebenek
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Thomas A Kunkel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Samuel H Wilson
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA.
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24
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Non-homologous DNA end joining and alternative pathways to double-strand break repair. Nat Rev Mol Cell Biol 2017; 18:495-506. [PMID: 28512351 DOI: 10.1038/nrm.2017.48] [Citation(s) in RCA: 973] [Impact Index Per Article: 139.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
DNA double-strand breaks (DSBs) are the most dangerous type of DNA damage because they can result in the loss of large chromosomal regions. In all mammalian cells, DSBs that occur throughout the cell cycle are repaired predominantly by the non-homologous DNA end joining (NHEJ) pathway. Defects in NHEJ result in sensitivity to ionizing radiation and the ablation of lymphocytes. The NHEJ pathway utilizes proteins that recognize, resect, polymerize and ligate the DNA ends in a flexible manner. This flexibility permits NHEJ to function on a wide range of DNA-end configurations, with the resulting repaired DNA junctions often containing mutations. In this Review, we discuss the most recent findings regarding the relative involvement of the different NHEJ proteins in the repair of various DNA-end configurations. We also discuss the shunting of DNA-end repair to the auxiliary pathways of alternative end joining (a-EJ) or single-strand annealing (SSA) and the relevance of these different pathways to human disease.
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25
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Raper AT, Reed AJ, Gadkari VV, Suo Z. Advances in Structural and Single-Molecule Methods for Investigating DNA Lesion Bypass and Repair Polymerases. Chem Res Toxicol 2016; 30:260-269. [PMID: 28092942 DOI: 10.1021/acs.chemrestox.6b00342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Innovative advances in X-ray crystallography and single-molecule biophysics have yielded unprecedented insight into the mechanisms of DNA lesion bypass and damage repair. Time-dependent X-ray crystallography has been successfully applied to view the bypass of 8-oxo-7,8-dihydro-2'-deoxyguanine (8-oxoG), a major oxidative DNA lesion, and the incorporation of the triphosphate form, 8-oxo-dGTP, catalyzed by human DNA polymerase β. Significant findings of these studies are highlighted here, and their contributions to the current mechanistic understanding of mutagenic translesion DNA synthesis (TLS) and base excision repair are discussed. In addition, single-molecule Förster resonance energy transfer (smFRET) techniques have recently been adapted to investigate nucleotide binding and incorporation opposite undamaged dG and 8-oxoG by Sulfolobus solfataricus DNA polymerase IV (Dpo4), a model Y-family DNA polymerase. The mechanistic response of Dpo4 to a DNA lesion and the complex smFRET technique are described here. In this perspective, we also describe how time-dependent X-ray crystallography and smFRET can be used to achieve the spatial and temporal resolutions necessary to answer some of the mechanistic questions that remain in the fields of TLS and DNA damage repair.
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Affiliation(s)
- Austin T Raper
- Department of Chemistry and Biochemistry and The Ohio State Biochemistry Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Andrew J Reed
- Department of Chemistry and Biochemistry and The Ohio State Biochemistry Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Varun V Gadkari
- Department of Chemistry and Biochemistry and The Ohio State Biochemistry Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Zucai Suo
- Department of Chemistry and Biochemistry and The Ohio State Biochemistry Program, The Ohio State University , Columbus, Ohio 43210, United States
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26
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Chang HHY, Watanabe G, Gerodimos CA, Ochi T, Blundell TL, Jackson SP, Lieber MR. Different DNA End Configurations Dictate Which NHEJ Components Are Most Important for Joining Efficiency. J Biol Chem 2016; 291:24377-24389. [PMID: 27703001 PMCID: PMC5114395 DOI: 10.1074/jbc.m116.752329] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 09/26/2016] [Indexed: 02/02/2023] Open
Abstract
The nonhomologous DNA end-joining (NHEJ) pathway is a key mechanism for repairing dsDNA breaks that occur often in eukaryotic cells. In the simplest model, these breaks are first recognized by Ku, which then interacts with other NHEJ proteins to improve their affinity at DNA ends. These include DNA-PKcs and Artemis for trimming the DNA ends; DNA polymerase μ and λ to add nucleotides; and the DNA ligase IV complex to ligate the ends with the additional factors, XRCC4 (X-ray repair cross-complementing protein 4), XLF (XRCC4-like factor/Cernunos), and PAXX (paralog of XRCC4 and XLF). In vivo studies have demonstrated the degrees of importance of these NHEJ proteins in the mechanism of repair of dsDNA breaks, but interpretations can be confounded by other cellular processes. In vitro studies with NHEJ proteins have been performed to evaluate the nucleolytic resection, polymerization, and ligation steps, but a complete system has been elusive. Here we have developed a NHEJ reconstitution system that includes the nuclease, polymerase, and ligase components to evaluate relative NHEJ efficiency and analyze ligated junctional sequences for various types of DNA ends, including blunt, 5' overhangs, and 3' overhangs. We find that different dsDNA end structures have differential dependence on these enzymatic components. The dependence of some end joining on only Ku and XRCC4·DNA ligase IV allows us to formulate a physical model that incorporates nuclease and polymerase components as needed.
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Affiliation(s)
- Howard H Y Chang
- From the Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology and the Section of Molecular & Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, 90033 and
| | - Go Watanabe
- From the Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology and the Section of Molecular & Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, 90033 and
| | - Christina A Gerodimos
- From the Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology and the Section of Molecular & Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, 90033 and
| | - Takashi Ochi
- the Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge CB2 1QN, United Kingdom
| | - Tom L Blundell
- the Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge CB2 1QN, United Kingdom
| | - Stephen P Jackson
- the Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge CB2 1QN, United Kingdom
| | - Michael R Lieber
- From the Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology and the Section of Molecular & Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, 90033 and.
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27
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Loc'h J, Rosario S, Delarue M. Structural Basis for a New Templated Activity by Terminal Deoxynucleotidyl Transferase: Implications for V(D)J Recombination. Structure 2016; 24:1452-63. [PMID: 27499438 DOI: 10.1016/j.str.2016.06.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 06/13/2016] [Accepted: 06/13/2016] [Indexed: 12/20/2022]
Abstract
Eukaryotic DNA polymerase of the polX family, such as pol μ and terminal deoxynucleotidyl transferase (TdT), are key components of the non-homologous end-joining or V(D)J recombination machinery, respectively. The established role of TdT is to add random nucleotides during V(D)J recombination. Here we show that TdT also has a templated-polymerase activity, similar to pol μ, in the presence of higher concentrations of a downstream DNA duplex, and performs a micro-homology single base-pair search to align the DNA synapsis. To understand the molecular basis of this alignment, we solve crystal structures of TdT with four DNA strands and study the influence of the 3' protruding end. Two mutations in TdT inspired by sequence alignments with pol μ further improve the templated activity. We propose that both templated and untemplated activities of TdT are needed to explain the distributions of lengths of N regions observed experimentally in T cell receptors and antibodies.
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Affiliation(s)
- Jérôme Loc'h
- Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du C.N.R.S., 25 rue du Dr Roux, 75015 Paris, France
| | - Sandrine Rosario
- Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du C.N.R.S., 25 rue du Dr Roux, 75015 Paris, France
| | - Marc Delarue
- Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du C.N.R.S., 25 rue du Dr Roux, 75015 Paris, France.
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28
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Essential role for polymerase specialization in cellular nonhomologous end joining. Proc Natl Acad Sci U S A 2015; 112:E4537-45. [PMID: 26240371 DOI: 10.1073/pnas.1505805112] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nonhomologous end joining (NHEJ) repairs chromosome breaks and must remain effective in the face of extensive diversity in broken end structures. We show here that this flexibility is often reliant on the ability to direct DNA synthesis across strand breaks, and that polymerase (Pol) μ and Pol λ are the only mammalian DNA polymerases that have this activity. By systematically varying substrate in cells, we show each polymerase is uniquely proficient in different contexts. The templating nucleotide is also selected differently, with Pol μ using the unpaired base adjacent to the downstream 5' phosphate even when there are available template sites further upstream of this position; this makes Pol μ more flexible but also less accurate than Pol λ. Loss of either polymerase alone consequently has clear and distinguishable effects on the fidelity of repair, but end remodeling by cellular nucleases and the remaining polymerase helps mitigate the effects on overall repair efficiency. Accordingly, when cells are deficient in both polymerases there is synergistic impact on NHEJ efficiency, both in terms of repair of defined substrates and cellular resistance to ionizing radiation. Pol μ and Pol λ thus provide distinct solutions to a problem for DNA synthesis that is unique to this pathway and play a key role in conferring on NHEJ the flexibility required for accurate and efficient repair.
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29
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Creative template-dependent synthesis by human polymerase mu. Proc Natl Acad Sci U S A 2015; 112:E4530-6. [PMID: 26240373 DOI: 10.1073/pnas.1505798112] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Among the many proteins used to repair DNA double-strand breaks by nonhomologous end joining (NHEJ) are two related family X DNA polymerases, Pol λ and Pol µ. Which of these two polymerases is preferentially used for filling DNA gaps during NHEJ partly depends on sequence complementarity at the break, with Pol λ and Pol µ repairing complementary and noncomplementary ends, respectively. To better understand these substrate preferences, we present crystal structures of Pol µ on a 2-nt gapped DNA substrate, representing three steps of the catalytic cycle. In striking contrast to Pol λ, Pol µ "skips" the first available template nucleotide, instead using the template base at the 5' end of the gap to direct nucleotide binding and incorporation. This remarkable divergence from canonical 3'-end gap filling is consistent with data on end-joining substrate specificity in cells, and provides insights into polymerase substrate choices during NHEJ.
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30
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Gouge J, Rosario S, Romain F, Poitevin F, Béguin P, Delarue M. Structural basis for a novel mechanism of DNA bridging and alignment in eukaryotic DSB DNA repair. EMBO J 2015; 34:1126-42. [PMID: 25762590 PMCID: PMC4406656 DOI: 10.15252/embj.201489643] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 01/08/2015] [Accepted: 01/09/2015] [Indexed: 01/18/2023] Open
Abstract
Eukaryotic DNA polymerase mu of the PolX family can promote the association of the two 3'-protruding ends of a DNA double-strand break (DSB) being repaired (DNA synapsis) even in the absence of the core non-homologous end-joining (NHEJ) machinery. Here, we show that terminal deoxynucleotidyltransferase (TdT), a closely related PolX involved in V(D)J recombination, has the same property. We solved its crystal structure with an annealed DNA synapsis containing one micro-homology (MH) base pair and one nascent base pair. This structure reveals how the N-terminal domain and Loop 1 of Tdt cooperate for bridging the two DNA ends, providing a templating base in trans and limiting the MH search region to only two base pairs. A network of ordered water molecules is proposed to assist the incorporation of any nucleotide independently of the in trans templating base. These data are consistent with a recent model that explains the statistics of sequences synthesized in vivo by Tdt based solely on this dinucleotide step. Site-directed mutagenesis and functional tests suggest that this structural model is also valid for Pol mu during NHEJ.
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Affiliation(s)
- Jérôme Gouge
- Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du C.N.R.S., Paris, France
| | - Sandrine Rosario
- Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du C.N.R.S., Paris, France
| | - Félix Romain
- Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du C.N.R.S., Paris, France
| | - Frédéric Poitevin
- Institut de Physique Théorique, CEA-Saclay, CNRS URA 2306, Gif-sur-Yvette, France
| | - Pierre Béguin
- Unité de Biologie Moléculaire du Gène chez les Extrêmophiles, Institut Pasteur, Paris, France
| | - Marc Delarue
- Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du C.N.R.S., Paris, France
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31
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Bienstock RJ, Beard WA, Wilson SH. Phylogenetic analysis and evolutionary origins of DNA polymerase X-family members. DNA Repair (Amst) 2014; 22:77-88. [PMID: 25112931 DOI: 10.1016/j.dnarep.2014.07.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/25/2014] [Accepted: 07/09/2014] [Indexed: 01/19/2023]
Abstract
Mammalian DNA polymerase (pol) β is the founding member of a large group of DNA polymerases now termed the X-family. DNA polymerase β has been kinetically, structurally, and biologically well characterized and can serve as a phylogenetic reference. Accordingly, we have performed a phylogenetic analysis to understand the relationship between pol β and other members of the X-family of DNA polymerases. The bacterial X-family DNA polymerases, Saccharomyces cerevisiae pol IV, and four mammalian X-family polymerases appear to be directly related. These enzymes originated from an ancient common ancestor characterized in two Bacillus species. Understanding distinct functions for each of the X-family polymerases, evolving from a common bacterial ancestor is of significant interest in light of the specialized roles of these enzymes in DNA metabolism.
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Affiliation(s)
- Rachelle J Bienstock
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, United States
| | - William A Beard
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, United States
| | - Samuel H Wilson
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, United States.
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32
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Martin MJ, Blanco L. Decision-making during NHEJ: a network of interactions in human Polμ implicated in substrate recognition and end-bridging. Nucleic Acids Res 2014; 42:7923-34. [PMID: 24878922 PMCID: PMC4081086 DOI: 10.1093/nar/gku475] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Human Polμ is a DNA polymerase belonging to the X family that has been implicated in the non-homologous end-joining (NHEJ) pathway during repair of double-strand breaks in DNA. Loop1 is a flexible piece of Polμ which has a critical role during terminal transferase and end-joining activities: it acts as a pseudo-template when the template strand is discontinuous or unavailable, whilst diffusing away if present to avoid steric clashes. Mutational analysis and inspection of the 3D structures available allowed us to identify a network of residues in charge of sensing the presence or absence of discontinuities in the template strand, which will in turn determine the final position adopted by Loop1. This network is formed by the previously uncharacterized thumb mini-loop (NSH motif) and the positively charged helix N, which contribute to the correct positioning of Loop1 and to juxtapose the discontinuous template strand during NHEJ of incompatible ends. Accordingly, single mutation of specific conserved residues in these motifs, whilst irrelevant in most of the cases for gap filling, largely affected terminal transferase and end-joining activities. Other point mutations in the ‘hinges’ of Loop1, such as residues Phe385 or Phe389, corroborated the flexibility requirements of this motif.
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Affiliation(s)
- Maria Jose Martin
- Centro de Biologia Molecular Severo Ochoa (CSIC-UAM), 28049 Madrid, Spain
| | - Luis Blanco
- Centro de Biologia Molecular Severo Ochoa (CSIC-UAM), 28049 Madrid, Spain
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33
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Bebenek K, Pedersen LC, Kunkel TA. Structure-function studies of DNA polymerase λ. Biochemistry 2014; 53:2781-92. [PMID: 24716527 PMCID: PMC4018081 DOI: 10.1021/bi4017236] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
![]()
DNA polymerase λ
(pol λ) functions in DNA repair with
its main roles considered to be filling short gaps during repair of
double-strand breaks by nonhomologous end joining and during base
excision repair. As indicated by structural and biochemical studies
over the past 10 years, pol λ shares many common properties
with other family X siblings (pol β, pol μ, and terminal
deoxynucleotidyl transferase) but also has unique structural features
that determine its specific functions. In this review, we consider
how structural studies over the past decade furthered our understanding
of the behavior and biological roles of pol λ.
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Affiliation(s)
- Katarzyna Bebenek
- Laboratory of Structural Biology and ‡Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, National Institutes of Health , Research Triangle Park, North Carolina 27709, United States
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34
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Structures of the Leishmania infantum polymerase beta. DNA Repair (Amst) 2014; 18:1-9. [PMID: 24666693 DOI: 10.1016/j.dnarep.2014.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 02/28/2014] [Accepted: 03/01/2014] [Indexed: 11/21/2022]
Abstract
Protozoans of the genus Leishmania, the pathogenic agent causing leishmaniasis, encode the family X DNA polymerase Li Pol β. Here, we report the first crystal structures of Li Pol β. Our pre- and post-catalytic structures show that the polymerase adopts the common family X DNA polymerase fold. However, in contrast to other family X DNA polymerases, the dNTP-induced conformational changes in Li Pol β are much more subtle. Moreover, pre- and post-catalytic structures reveal that Li Pol β interacts with the template strand through a nonconserved, variable region known as loop3. Li Pol β Δloop3 mutants display a higher catalytic rate, catalytic efficiency and overall error rates with respect to WT Li Pol β. These results further demonstrate the subtle structural variability that exists within this family of enzymes and provides insight into how this variability underlies the substantial functional differences among their members.
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35
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Moon AF, Pryor JM, Ramsden DA, Kunkel TA, Bebenek K, Pedersen LC. Sustained active site rigidity during synthesis by human DNA polymerase μ. Nat Struct Mol Biol 2014; 21:253-60. [PMID: 24487959 PMCID: PMC4164209 DOI: 10.1038/nsmb.2766] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 12/26/2013] [Indexed: 01/09/2023]
Abstract
DNA polymerase μ (Pol μ) is the only template-dependent human DNA polymerase capable of repairing double-strand DNA breaks (DSBs) with unpaired 3' ends in nonhomologous end joining (NHEJ). To probe this function, we structurally characterized Pol μ's catalytic cycle for single-nucleotide incorporation. These structures indicate that, unlike other template-dependent DNA polymerases, Pol μ shows no large-scale conformational changes in protein subdomains, amino acid side chains or DNA upon dNTP binding or catalysis. Instead, the only major conformational change is seen earlier in the catalytic cycle, when the flexible loop 1 region repositions upon DNA binding. Pol μ variants with changes in loop 1 have altered catalytic properties and are partially defective in NHEJ. The results indicate that specific loop 1 residues contribute to Pol μ's unique ability to catalyze template-dependent NHEJ of DSBs with unpaired 3' ends.
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Affiliation(s)
- Andrea F Moon
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - John M Pryor
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Dale A Ramsden
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Thomas A Kunkel
- 1] Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA. [2] Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Katarzyna Bebenek
- 1] Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA. [2] Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Lars C Pedersen
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
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36
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Wu S, Beard WA, Pedersen LG, Wilson SH. Structural comparison of DNA polymerase architecture suggests a nucleotide gateway to the polymerase active site. Chem Rev 2013; 114:2759-74. [PMID: 24359247 DOI: 10.1021/cr3005179] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Sangwook Wu
- Department of Chemistry, University of North Carolina , Chapel Hill, North Carolina 27599-3290, United States
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37
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The BRCT domain and the specific loop 1 of human Polμ are targets of Cdk2/cyclin A phosphorylation. DNA Repair (Amst) 2013; 12:824-34. [DOI: 10.1016/j.dnarep.2013.07.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 07/01/2013] [Accepted: 07/18/2013] [Indexed: 12/18/2022]
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38
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Garrido P, Mejia E, Garcia-Diaz M, Blanco L, Picher AJ. The active site of TthPolX is adapted to prevent 8-oxo-dGTP misincorporation. Nucleic Acids Res 2013; 42:534-43. [PMID: 24084083 PMCID: PMC3874185 DOI: 10.1093/nar/gkt870] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Full genome sequencing of bacterial genomes has revealed the presence of numerous genes encoding family X DNA polymerases. These enzymes play a variety of biological roles and, accordingly, display often striking functional differences. Here we report that the PolX from the heat-stable organism Thermus thermophilus (TthPolX) inserts the four dNTPs with strong asymmetry. We demonstrate that this behaviour is related to the presence of a single divergent residue in the active site of TthPolX. Mutation of this residue (Ser266) to asparagine, the residue present in most PolXs, had a strong effect on TthPolX polymerase activity, increasing and equilibrating the insertion efficiencies of the 4 dNTPs. Moreover, we show that this behaviour correlates with the ability of TthPolX to insert 8-oxo-dGMP. Although the wild-type enzyme inefficiently incorporates 8-oxo-dGMP, the substitution of Ser266 to asparagine resulted in a dramatic increase in 8-oxo-dGMP incorporation opposite dA. These results suggest that the presence of a serine at position 266 in TthPolX allows the enzyme to minimize the formation of dA:8-oxo-dGMP at the expense of decreasing the insertion rate of pyrimidines. We discuss the structural basis for these effects and the implications of this behaviour for the GO system (BER of 8-oxo-dG lesions).
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Affiliation(s)
- Patricia Garrido
- X-Pol Biotech S.L.U. Parque Científico de Madrid. Cantoblanco, Madrid 28049, Spain, Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA and Centro de Biología Molecular Severo Ochoa (CSIC-UAM). Cantoblanco, Madrid 28049, Spain
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39
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Costi R, Crucitti GC, Pescatori L, Messore A, Scipione L, Tortorella S, Amoroso A, Crespan E, Campiglia P, Maresca B, Porta A, Granata I, Novellino E, Gouge J, Delarue M, Maga G, Di Santo R. New nucleotide-competitive non-nucleoside inhibitors of terminal deoxynucleotidyl transferase: discovery, characterization, and crystal structure in complex with the target. J Med Chem 2013; 56:7431-41. [PMID: 23968551 DOI: 10.1021/jm4010187] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Terminal deoxynucletidyl transferase (TdT) is overexpressed in some cancer types, where it might compete with pol μ during the mutagenic repair of double strand breaks (DSBs) through the nonhomologous end joining (NHEJ) pathway. Here we report the discovery and characterization of pyrrolyl and indolyl diketo acids that specifically target TdT and behave as nucleotide-competitive inhibitors. These compounds show a selective toxicity toward MOLT-4 compared to HeLa cells that correlate well with in vitro selectivity for TdT. The binding site of two of these inhibitors was determined by cocrystallization with TdT, explaining why these compounds are competitive inhibitors of the deoxynucleotide triphosphate (dNTP). In addition, because of the observed dual localization of the phenyl substituent, these studies open the possibility of rationally designing more potent compounds.
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Affiliation(s)
- Roberta Costi
- Dipartimento di Chimica e Tecnologie del Farmaco, Istituto Pasteur-Fondazione Cenci Bolognetti, "Sapienza" Università di Roma , P.le Aldo Moro 5, I-00185 Roma, Italy
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40
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Martin MJ, Garcia-Ortiz MV, Gomez-Bedoya A, Esteban V, Guerra S, Blanco L. A specific N-terminal extension of the 8 kDa domain is required for DNA end-bridging by human Polμ and Polλ. Nucleic Acids Res 2013; 41:9105-16. [PMID: 23935073 PMCID: PMC3799444 DOI: 10.1093/nar/gkt681] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Human DNA polymerases mu (Polµ) and lambda (Polλ) are X family members involved in the repair of double-strand breaks in DNA during non-homologous end joining. Crucial abilities of these enzymes include bridging of the two 3′ single-stranded overhangs and trans-polymerization using one 3′ end as primer and the other as template, to minimize sequence loss. In this context, we have studied the importance of a previously uncharacterised sequence (‘brooch’), located at the N-terminal boundary of the Polß-like polymerase core, and formed by Tyr141, Ala142, Cys143, Gln144 and Arg145 in Polµ, and by Trp239, Val240, Cys241, Ala242 and Gln243 in Polλ. The brooch is potentially implicated in the maintenance of a closed conformation throughout the catalytic cycle, and our studies indicate that it could be a target of Cdk phosphorylation in Polµ. The brooch is irrelevant for 1 nt gap filling, but of specific importance during end joining: single mutations in the conserved residues reduced the formation of two ended synapses and strongly diminished the ability of Polµ and polymerase lambda to perform non-homologous end joining reactions in vitro.
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Affiliation(s)
- Maria Jose Martin
- Centro de Biologia Molecular Severo Ochoa (CSIC-UAM), 28049 Madrid, Spain
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41
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Gouge J, Rosario S, Romain F, Beguin P, Delarue M. Structures of intermediates along the catalytic cycle of terminal deoxynucleotidyltransferase: dynamical aspects of the two-metal ion mechanism. J Mol Biol 2013; 425:4334-52. [PMID: 23856622 DOI: 10.1016/j.jmb.2013.07.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/28/2013] [Accepted: 07/03/2013] [Indexed: 11/19/2022]
Abstract
Terminal deoxynucleotidyltransferase (Tdt) is a non-templated eukaryotic DNA polymerase of the polX family that is responsible for the random addition of nucleotides at the V(D)J junctions of immunoglobulins and T-cell receptors. Here we describe a series of high-resolution X-ray structures that mimic the pre-catalytic state, the post-catalytic state and a competent state that can be transformed into the two other ones in crystallo via the addition of dAMPcPP and Zn(2+), respectively. We examined the effect of Mn(2+), Co(2+) and Zn(2+) because they all have a marked influence on the kinetics of the reaction. We demonstrate a dynamic role of divalent transition metal ions bound to site A: (i) Zn(2+) (or Co(2+)) in Metal A site changes coordination from octahedral to tetrahedral after the chemical step, which explains the known higher affinity of Tdt for the primer strand when these ions are present, and (ii) metal A has to leave to allow the translocation of the primer strand and to clear the active site, a typical feature for a ratchet-like mechanism. Except for Zn(2+), the sugar puckering of the primer strand 3' terminus changes from C2'-endo to C3'-endo during catalysis. In addition, our data are compatible with a scheme where metal A is the last component that binds to the active site to complete its productive assembly, as already inferred in human pol beta. The new structures have potential implications for modeling pol mu, a closely related polX implicated in the repair of DNA double-strand breaks, in a complex with a DNA synapsis.
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Affiliation(s)
- Jérôme Gouge
- Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du CNRS, 25 rue du Dr Roux, 75015 Paris, France
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"Gate-keeper" residues and active-site rearrangements in DNA polymerase μ help discriminate non-cognate nucleotides. PLoS Comput Biol 2013; 9:e1003074. [PMID: 23717197 PMCID: PMC3662701 DOI: 10.1371/journal.pcbi.1003074] [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] [Received: 12/05/2012] [Accepted: 04/11/2013] [Indexed: 11/19/2022] Open
Abstract
Incorporating the cognate instead of non-cognate substrates is crucial for DNA polymerase function. Here we analyze molecular dynamics simulations of DNA polymerase μ (pol μ) bound to different non-cognate incoming nucleotides including A:dCTP, A:dGTP, A(syn):dGTP, A:dATP, A(syn):dATP, T:dCTP, and T:dGTP to study the structure-function relationships involved with aberrant base pairs in the conformational pathway; while a pol μ complex with the A:dTTP base pair is available, no solved non-cognate structures are available. We observe distinct differences of the non-cognate systems compared to the cognate system. Specifically, the motions of active-site residue His329 and Asp330 distort the active site, and Trp436, Gln440, Glu443 and Arg444 tend to tighten the nucleotide-binding pocket when non-cognate nucleotides are bound; the latter effect may further lead to an altered electrostatic potential within the active site. That most of these “gate-keeper” residues are located farther apart from the upstream primer in pol μ, compared to other X family members, also suggests an interesting relation to pol μ's ability to incorporate nucleotides when the upstream primer is not paired. By examining the correlated motions within pol μ complexes, we also observe different patterns of correlations between non-cognate systems and the cognate system, especially decreased interactions between the incoming nucleotides and the nucleotide-binding pocket. Altered correlated motions in non-cognate systems agree with our recently proposed hybrid conformational selection/induced-fit models. Taken together, our studies propose the following order for difficulty of non-cognate system insertions by pol μ: T:dGTP<A(syn):dATP<T:dCTP<A:dGTP<A(syn):dGTP<A:dCTP<A:dATP. This sequence agrees with available kinetic data for non-cognate nucleotide insertions, with the exception of A:dGTP, which may be more sensitive to the template sequence. The structures and conformational aspects predicted here are experimentally testable. DNA polymerase μ (pol μ) is an enzyme that participates in DNA repair and thus has a central role in maintaining the integrity of genetic information. To efficiently repair the DNA, discriminating the cognate instead of non-cognate nucleotides (“fidelity-checking”) is required. Here we analyze molecular dynamics simulations of pol μ bound to different non-cognate nucleotides to study the structure-function relationships involved in the fidelity-checking mechanism of pol μ on the atomic level. Our results suggest that His329, Asp330, Trp436, Gln440, Glu443, and Arg444 are of great importance for pol μ's fidelity-checking mechanism. We also observe altered patterns of correlated motions within pol μ complex when non-cognate instead of cognate nucleotides are bound, which agrees with our recently proposed hybrid conformational selection/induced-fit models. Taken together, our studies help interpret the available kinetic data of various non-cognate nucleotide insertions by pol μ. We also suggest experimentally testable predictions; for example, a point mutation like E443M may reduce the ability of pol μ to insert the cognate more than of non-cognate nucleotides. Our studies suggest an interesting relation to pol μ's unique ability to incorporate nucleotides when the upstream primer is not paired.
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43
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Chiruvella KK, Liang Z, Wilson TE. Repair of double-strand breaks by end joining. Cold Spring Harb Perspect Biol 2013; 5:a012757. [PMID: 23637284 DOI: 10.1101/cshperspect.a012757] [Citation(s) in RCA: 279] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nonhomologous end joining (NHEJ) refers to a set of genome maintenance pathways in which two DNA double-strand break (DSB) ends are (re)joined by apposition, processing, and ligation without the use of extended homology to guide repair. Canonical NHEJ (c-NHEJ) is a well-defined pathway with clear roles in protecting the integrity of chromosomes when DSBs arise. Recent advances have revealed much about the identity, structure, and function of c-NHEJ proteins, but many questions exist regarding their concerted action in the context of chromatin. Alternative NHEJ (alt-NHEJ) refers to more recently described mechanism(s) that repair DSBs in less-efficient backup reactions. There is great interest in defining alt-NHEJ more precisely, including its regulation relative to c-NHEJ, in light of evidence that alt-NHEJ can execute chromosome rearrangements. Progress toward these goals is reviewed.
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44
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Lucas D, Delgado-García JM, Escudero B, Albo C, Aza A, Acín-Pérez R, Torres Y, Moreno P, Enríquez JA, Samper E, Blanco L, Fairén A, Bernad A, Gruart A. Increased learning and brain long-term potentiation in aged mice lacking DNA polymerase μ. PLoS One 2013; 8:e53243. [PMID: 23301049 PMCID: PMC3536760 DOI: 10.1371/journal.pone.0053243] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 11/27/2012] [Indexed: 01/14/2023] Open
Abstract
A definitive consequence of the aging process is the progressive deterioration of higher cognitive functions. Defects in DNA repair mechanisms mostly result in accelerated aging and reduced brain function. DNA polymerase µ is a novel accessory partner for the non-homologous end-joining DNA repair pathway for double-strand breaks, and its deficiency causes reduced DNA repair. Using associative learning and long-term potentiation experiments, we demonstrate that Polµ−/− mice, however, maintain the ability to learn at ages when wild-type mice do not. Expression and biochemical analyses suggest that brain aging is delayed in Polµ−/− mice, being associated with a reduced error-prone DNA oxidative repair activity and a more efficient mitochondrial function. This is the first example in which the genetic ablation of a DNA-repair function results in a substantially better maintenance of learning abilities, together with fewer signs of brain aging, in old mice.
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Affiliation(s)
- Daniel Lucas
- Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Madrid, Spain
| | | | - Beatriz Escudero
- Department of Regenerative Cardiology, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
- Development and Cardiac Repair Department, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Carmen Albo
- Department of Regenerative Cardiology, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
- Development and Cardiac Repair Department, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Ana Aza
- Centro de Biología Molecular Severo Ochoa, Campus de Cantoblanco, Madrid, Spain
| | - Rebeca Acín-Pérez
- Department of Regenerative Cardiology, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
- Development and Cardiac Repair Department, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Yaima Torres
- Department of Regenerative Cardiology, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
- Development and Cardiac Repair Department, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Paz Moreno
- Department of Regenerative Cardiology, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - José Antonio Enríquez
- Department of Regenerative Cardiology, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
- Development and Cardiac Repair Department, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Enrique Samper
- Department of Regenerative Cardiology, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
- Development and Cardiac Repair Department, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Luis Blanco
- Centro de Biología Molecular Severo Ochoa, Campus de Cantoblanco, Madrid, Spain
| | - Alfonso Fairén
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas - Universidad Miguel Hernández, San Juan de Alicante, Spain
| | - Antonio Bernad
- Department of Regenerative Cardiology, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
- Development and Cardiac Repair Department, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
- Translational Research Platform, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
- * E-mail: (AB); (AG)
| | - Agnès Gruart
- División de Neurociencias, Universidad Pablo de Olavide, Sevilla, Spain
- * E-mail: (AB); (AG)
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45
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Ramsden DA, Asagoshi K. DNA polymerases in nonhomologous end joining: are there any benefits to standing out from the crowd? ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2012; 53:741-751. [PMID: 22987211 DOI: 10.1002/em.21725] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 07/17/2012] [Accepted: 07/17/2012] [Indexed: 06/01/2023]
Abstract
Chromosome breaks, often with damaged or missing DNA flanking the break site, are an important threat to genome stability. They are repaired in vertebrates primarily by nonhomologous end joining (NHEJ). NHEJ is unique among the major DNA repair pathways in that a continuous template cannot be used by DNA polymerases to instruct replacement of damaged or lost DNA. Nevertheless, at least 3 out of the 17 mammalian DNA polymerases are specifically employed by NHEJ. Biochemical and structural studies are further revealing how each of the polymerases employed by NHEJ possesses distinct and sophisticated means to overcome the barriers this pathway presents to polymerase activity. Still unclear, though, is how the resulting network of overlapping and nonoverlapping polymerase activities contributes to repair in cells.
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Affiliation(s)
- Dale A Ramsden
- Lineberger Comprehensive Cancer Center, Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, USA.
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46
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Aza A, Martin MJ, Juarez R, Blanco L, Terrados G. DNA expansions generated by human Polμ on iterative sequences. Nucleic Acids Res 2012; 41:253-63. [PMID: 23143108 PMCID: PMC3592450 DOI: 10.1093/nar/gks1054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Polµ is the only DNA polymerase equipped with template-directed and terminal transferase activities. Polµ is also able to accept distortions in both primer and template strands, resulting in misinsertions and extension of realigned mismatched primer terminus. In this study, we propose a model for human Polµ-mediated dinucleotide expansion as a function of the sequence context. In this model, Polµ requires an initial dislocation, that must be subsequently stabilized, to generate large sequence expansions at different 5′-P-containing DNA substrates, including those that mimic non-homologous end-joining (NHEJ) intermediates. Our mechanistic studies point at human Polµ residues His329 and Arg387 as responsible for regulating nucleotide expansions occurring during DNA repair transactions, either promoting or blocking, respectively, iterative polymerization. This is reminiscent of the role of both residues in the mechanism of terminal transferase activity. The iterative synthesis performed by Polµ at various contexts may lead to frameshift mutations producing DNA damage and instability, which may end in different human disorders, including cancer or congenital abnormalities.
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Affiliation(s)
- Ana Aza
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, 28049 Madrid, Spain
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47
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Martin MJ, Juarez R, Blanco L. DNA-binding determinants promoting NHEJ by human Polμ. Nucleic Acids Res 2012; 40:11389-403. [PMID: 23034807 PMCID: PMC3526283 DOI: 10.1093/nar/gks896] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Non-homologous end-joining (NHEJ), the preferred pathway to repair double-strand breaks (DSBs) in higher eukaryotes, relies on a collection of molecular tools to process the broken ends, including specific DNA polymerases. Among them, Polµ is unique as it can catalyze DNA synthesis upon connection of two non-complementary ends. Here, we demonstrate that this capacity is intrinsic to Polµ, not conferred by other NHEJ factors. To understand the molecular determinants of its specific function in NHEJ, the interaction of human Polµ with DNA has been directly visualized by electromobility shift assay and footprinting assays. Stable interaction with a DNA gap requires the presence of a recessive 5′-P, thus orienting the catalytic domain for primer and nucleotide binding. Accordingly, recognition of the 5′-P is crucial to align the two DNA substrates of the NHEJ reaction. Site-directed mutagenesis demonstrates the relevance of three specific residues (Lys249, Arg253 and Arg416) in stabilizing the primer strand during end synapsis, allowing a range of microhomology-induced distortions beneficial for NHEJ. Moreover, our results suggest that the Polµ BRCT domain, thought to be exclusively involved in interaction with NHEJ core factors, has a direct role in binding the DNA region neighbor to the 5′-P, thus boosting Polµ-mediated NHEJ reactions.
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Affiliation(s)
- Maria Jose Martin
- Department of Genome Dynamics and Function, Centro de Biologia Molecular Severo Ochoa (CSIC-UAM), 28049 Madrid, Spain
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48
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Matsumoto T, Go K, Hyodo M, Koiwai K, Maezawa S, Hayano T, Suzuki M, Koiwai O. BRCT domain of DNA polymerase μ has DNA-binding activity and promotes the DNA polymerization activity. Genes Cells 2012; 17:790-806. [DOI: 10.1111/j.1365-2443.2012.01628.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 06/14/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Takuro Matsumoto
- Department of Applied Biological Science; Faculty of Science and Technology; Tokyo University of Science; Noda; Chiba; 278-8510; Japan
| | - Kaori Go
- Department of Applied Biological Science; Faculty of Science and Technology; Tokyo University of Science; Noda; Chiba; 278-8510; Japan
| | - Mariko Hyodo
- Department of Applied Biological Science; Faculty of Science and Technology; Tokyo University of Science; Noda; Chiba; 278-8510; Japan
| | - Kotaro Koiwai
- Department of Applied Biological Science; Faculty of Science and Technology; Tokyo University of Science; Noda; Chiba; 278-8510; Japan
| | - So Maezawa
- Department of Applied Biological Science; Faculty of Science and Technology; Tokyo University of Science; Noda; Chiba; 278-8510; Japan
| | - Takahide Hayano
- Department of Applied Biological Science; Faculty of Science and Technology; Tokyo University of Science; Noda; Chiba; 278-8510; Japan
| | - Masahiro Suzuki
- Department of Applied Biological Science; Faculty of Science and Technology; Tokyo University of Science; Noda; Chiba; 278-8510; Japan
| | - Osamu Koiwai
- Department of Applied Biological Science; Faculty of Science and Technology; Tokyo University of Science; Noda; Chiba; 278-8510; Japan
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49
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Baños B, Villar L, Salas M, de Vega M. DNA stabilization at the Bacillus subtilis PolX core--a binding model to coordinate polymerase, AP-endonuclease and 3'-5' exonuclease activities. Nucleic Acids Res 2012; 40:9750-62. [PMID: 22844091 PMCID: PMC3479172 DOI: 10.1093/nar/gks702] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Family X DNA polymerases (PolXs) are involved in DNA repair. Their binding to gapped DNAs relies on two conserved helix-hairpin-helix motifs, one located at the 8-kDa domain and the other at the fingers subdomain. Bacterial/archaeal PolXs have a specifically conserved third helix-hairpin-helix motif (GFGxK) at the fingers subdomain whose putative role in DNA binding had not been established. Here, mutagenesis at the corresponding residues of Bacillus subtilis PolX (PolXBs), Gly130, Gly132 and Lys134 produced enzymes with altered DNA binding properties affecting the three enzymatic activities of the protein: polymerization, located at the PolX core, 3'-5' exonucleolysis and apurinic/apyrimidinic (AP)-endonucleolysis, placed at the so-called polymerase and histidinol phosphatase domain. Furthermore, we have changed Lys192 of PolXBs, a residue moderately conserved in the palm subdomain of bacterial PolXs and immediately preceding two catalytic aspartates of the polymerization reaction. The results point to a function of residue Lys192 in guaranteeing the right orientation of the DNA substrates at the polymerization and histidinol phosphatase active sites. The results presented here and the recently solved structures of other bacterial PolX ternary complexes lead us to propose a structural model to account for the appropriate coordination of the different catalytic activities of bacterial PolXs.
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Affiliation(s)
- Benito Baños
- Instituto de Biología Molecular Eladio Viñuela (CSIC), Centro de Biología Molecular Severo Ochoa (CSIC-UAM), C/Nicolás Cabrera 1, Universidad Autónoma, Cantoblanco, 28049 Madrid, Spain
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50
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Gosavi RA, Moon AF, Kunkel TA, Pedersen LC, Bebenek K. The catalytic cycle for ribonucleotide incorporation by human DNA Pol λ. Nucleic Acids Res 2012; 40:7518-27. [PMID: 22584622 PMCID: PMC3424563 DOI: 10.1093/nar/gks413] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Although most DNA polymerases discriminate against ribonucleotide triphosphaets (rNTPs) during DNA synthesis, recent studies have shown that large numbers of ribonucleotides are incorporated into the eukaryotic nuclear genome. Here, we investigate how a DNA polymerase can stably incorporate an rNTP. The X-ray crystal structure of a variant of human DNA polymerase λ reveals that the rNTP occupies the nucleotide binding pocket without distortion of the active site, despite an unfavorable interaction between the 2′-O and Tyr505 backbone carbonyl. This indicates an energetically unstable binding state for the rNTP, stabilized by additional protein–nucleotide interactions. Supporting this idea is the 200-fold lower catalytic efficiency for rNTP relative to deoxyribonucleotide triphosphate (dNTP) incorporation, reflecting a higher apparent Km value for the rNTP. Furthermore, distortion observed in the structure of the post-catalytic product complex suggests that once the bond between the α- and β-phosphates of the rNTP is broken, the unfavorable binding state of the ribonucleotide cannot be maintained. Finally, structural and biochemical evaluation of dNTP insertion onto an ribonucleotide monophosphate (rNMP)-terminated primer indicates that a primer-terminal rNMP does not impede extension. The results are relevant to how ribonucleotides are incorporated into DNA in vivo, during replication and during repair, perhaps especially in non-proliferating cells when rNTP:dNTP ratios are high.
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Affiliation(s)
- Rajendrakumar A Gosavi
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, 27709, USA
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