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Biochemical and functional characterization of an endonuclease III from Thermococcus barophilus Ch5. World J Microbiol Biotechnol 2022; 38:145. [PMID: 35750964 DOI: 10.1007/s11274-022-03328-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 06/01/2022] [Indexed: 10/17/2022]
Abstract
Endonuclease III (EndoIII) is a bifunctional DNA glycosylase that is essential to excise thymine glycol (Tg) from DNA. Although EndoIII is widespread in bacteria, eukarya and Archaea, our understanding on archaeal EndoIII function remains relatively incomplete due to the limited reports. Herein, we characterized an EndoIII from the hyperthermophilic euryarchaeon Thermococcus barophilus Ch5 (Tba-EndoIII) biochemically, demonstrating that the enzyme can excise Tg from dsDNA and display maximum activity at 50 ~ 70 °C and at pH 6.0 ~ 9.0 without the requirement of a divalent metal ion. Importantly, Tba-EndoIII differs from other reported archaeal EndoIII homologues in thermostability and salt requirement. As observed in other EndoIII homologues, the conserved residues D155 and H157 in Helix-hairpin-Helix motif of Tba-EndoIII are essential for Tg excision. Intriguingly, we first dissected that the conserved residues C215 and C221 in the Fe-S cluster loop in Tba-EndoIII are involved in intermediate formation and Tg excision. Additionally, we first revealed that the conserved residue L48 is flexible for intermediate formation and AP cleavage, but plays no detectable role in Tg excision. Overall, our work has revealed additional archaeal EndoIII function and catalytic mechanism.
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Torgasheva NA, Menzorova NI, Sibirtsev YT, Rasskazov VA, Zharkov DO, Nevinsky GA. Base excision DNA repair in the embryonic development of the sea urchin, Strongylocentrotus intermedius. MOLECULAR BIOSYSTEMS 2016; 12:2247-56. [PMID: 27158700 DOI: 10.1039/c5mb00906e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In actively proliferating cells, such as the cells of the developing embryo, DNA repair is crucial for preventing the accumulation of mutations and synchronizing cell division. Sea urchin embryo growth was analyzed and extracts were prepared. The relative activity of DNA polymerase, apurinic/apyrimidinic (AP) endonuclease, uracil-DNA glycosylase, 8-oxoguanine-DNA glycosylase, and other glycosylases was analyzed using specific oligonucleotide substrates of these enzymes; the reaction products were resolved by denaturing 20% polyacrylamide gel electrophoresis. We have characterized the profile of several key base excision repair activities in the developing embryos (2 blastomers to mid-pluteus) of the grey sea urchin, Strongylocentrotus intermedius. The uracil-DNA glycosylase specific activity sharply increased after blastula hatching, whereas the specific activity of 8-oxoguanine-DNA glycosylase steadily decreased over the course of the development. The AP-endonuclease activity gradually increased but dropped at the last sampled stage (mid-pluteus 2). The DNA polymerase activity was high at the first cleavage division and then quickly decreased, showing a transient peak at blastula hatching. It seems that the developing sea urchin embryo encounters different DNA-damaging factors early in development within the protective envelope and later as a free-floating larva, with hatching necessitating adaptation to the shift in genotoxic stress conditions. No correlation was observed between the dynamics of the enzyme activities and published gene expression data from developing congeneric species, S. purpuratus. The results suggest that base excision repair enzymes may be regulated in the sea urchin embryos at the level of covalent modification or protein stability.
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Affiliation(s)
- Natalya A Torgasheva
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 8 Lavrentieva Ave., Novosibirsk 630090, Russia. and Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia
| | - Natalya I Menzorova
- G. B. Elyakov Pacific Institute of Bioorganic Chemistry FEB RAS, 159 100 let Vladivostoku Ave., Vladivostok 690022, Russia
| | - Yurii T Sibirtsev
- G. B. Elyakov Pacific Institute of Bioorganic Chemistry FEB RAS, 159 100 let Vladivostoku Ave., Vladivostok 690022, Russia
| | - Valery A Rasskazov
- G. B. Elyakov Pacific Institute of Bioorganic Chemistry FEB RAS, 159 100 let Vladivostoku Ave., Vladivostok 690022, Russia
| | - Dmitry O Zharkov
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 8 Lavrentieva Ave., Novosibirsk 630090, Russia. and Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia
| | - Georgy A Nevinsky
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 8 Lavrentieva Ave., Novosibirsk 630090, Russia. and Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia
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3
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Weeks LD, Zentner GE, Scacheri PC, Gerson SL. Uracil DNA glycosylase (UNG) loss enhances DNA double strand break formation in human cancer cells exposed to pemetrexed. Cell Death Dis 2014; 5:e1045. [PMID: 24503537 PMCID: PMC3944228 DOI: 10.1038/cddis.2013.477] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 10/10/2013] [Indexed: 11/26/2022]
Abstract
Misincorporation of genomic uracil and formation of DNA double strand breaks (DSBs) are known consequences of exposure to TS inhibitors such as pemetrexed. Uracil DNA glycosylase (UNG) catalyzes the excision of uracil from DNA and initiates DNA base excision repair (BER). To better define the relationship between UNG activity and pemetrexed anticancer activity, we have investigated DNA damage, DSB formation, DSB repair capacity, and replication fork stability in UNG+/+ and UNG−/− cells. We report that despite identical growth rates and DSB repair capacities, UNG−/− cells accumulated significantly greater uracil and DSBs compared with UNG+/+ cells when exposed to pemetrexed. ChIP-seq analysis of γ-H2AX enrichment confirmed fewer DSBs in UNG+/+ cells. Furthermore, DSBs in UNG+/+ and UNG−/− cells occur at distinct genomic loci, supporting differential mechanisms of DSB formation in UNG-competent and UNG-deficient cells. UNG−/− cells also showed increased evidence of replication fork instability (PCNA dispersal) when exposed to pemetrexed. Thymidine co-treatment rescues S-phase arrest in both UNG+/+ and UNG−/− cells treated with IC50-level pemetrexed. However, following pemetrexed exposure, UNG−/− but not UNG+/+ cells are refractory to thymidine rescue, suggesting that deficient uracil excision rather than dTTP depletion is the barrier to cell cycle progression in UNG−/− cells. Based on these findings we propose that pemetrexed-induced uracil misincorporation is genotoxic, contributing to replication fork instability, DSB formation and ultimately cell death.
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Affiliation(s)
- L D Weeks
- Department of Pathology, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - G E Zentner
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - P C Scacheri
- 1] Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA [2] Case Comprehensive Cancer Center, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | - S L Gerson
- 1] Department of Pathology, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA [2] Case Comprehensive Cancer Center, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA [3] Department of Medicine, Division of Hematology/Oncology, Case Western Reserve University School of Medicine, 2103 Cornell Road, Cleveland, OH 44106, USA
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Trimming of damaged 3' overhangs of DNA double-strand breaks by the Metnase and Artemis endonucleases. DNA Repair (Amst) 2013; 12:422-32. [PMID: 23602515 DOI: 10.1016/j.dnarep.2013.03.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/01/2013] [Accepted: 03/21/2013] [Indexed: 11/22/2022]
Abstract
Both Metnase and Artemis possess endonuclease activities that trim 3' overhangs of duplex DNA. To assess the potential of these enzymes for facilitating resolution of damaged ends during double-strand break rejoining, substrates bearing a variety of normal and structurally modified 3' overhangs were constructed, and treated either with Metnase or with Artemis plus DNA-dependent protein kinase (DNA-PK). Unlike Artemis, which trims long overhangs to 4-5 bases, cleavage by Metnase was more evenly distributed over the length of the overhang, but with significant sequence dependence. In many substrates, Metnase also induced marked cleavage in the double-stranded region within a few bases of the overhang. Like Artemis, Metnase efficiently trimmed overhangs terminated in 3'-phosphoglycolates (PGs), and in some cases the presence of 3'-PG stimulated cleavage and altered its specificity. The nonplanar base thymine glycol in a 3' overhang severely inhibited cleavage by Metnase in the vicinity of the modified base, while Artemis was less affected. Nevertheless, thymine glycol moieties could be removed by Metnase- or Artemis-mediated cleavage at sites farther from the terminus than the lesion itself. In in vitro end-joining systems based on human cell extracts, addition of Artemis, but not Metnase, effected robust trimming of an unligatable 3'-PG overhang, resulting in a dramatic stimulation of ligase IV- and XLF-dependent end joining. Thus, while both Metnase and Artemis are biochemically capable of resolving a variety of damaged DNA ends for the repair of complex double-strand breaks, Artemis appears to act more efficiently in the context of other nonhomologous end joining proteins.
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Povirk LF. Processing of damaged DNA ends for double-strand break repair in mammalian cells. ISRN MOLECULAR BIOLOGY 2012; 2012. [PMID: 24236237 PMCID: PMC3825254 DOI: 10.5402/2012/345805] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Most DNA double-strand breaks (DSBs)formed in a natural environment have chemical modifications at or near the ends that preclude direct religation and require removal or other processing so that rejoining can proceed. Free radical-mediated DSBs typically bear unligatable 3'-phosphate or 3'-phosphoglycolate termini and often have oxidized bases and/or abasic sites near the break. Topoisomerase-mediated DSBs are blocked by covalently bound peptide fragments of the topoisomerase. Enzymes capable of resolving damaged ends include polynucleotide kinase/phosphatase, which restores missing 5'-phosphates and removes 3'-phosphates; tyrosyl-DNA phosphodiesterases I and II (TDP1 and TDP2), which remove peptide fragments of topoisomerases I and II, respectively, and the Artemis and Metnase endonucleases, which can trim damaged overhangs of diverse structure. TDP1 as well as APE1 can remove 3'-phosphoglycolates and other 3' blocks, while CtIP appears to provide an alternative pathway for topoisomerase II fragment removal. Ku, a core DSB joining protein, can cleave abasic sites near DNA ends. The downstream processes of patching and ligation are tolerant of residual damage, and can sometimes proceed without complete damage removal. Despite these redundant pathways for resolution, damaged ends appear to be a significant barrier to rejoining, and their resolution may be a rate-limiting step in repair of some DSBs..
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Affiliation(s)
- Lawrence F Povirk
- Department of Pharmacology and Toxicology, and Massey Cancer Center, Virginia Commonwealth University, 401 College St. Richmond, VA 23298, USA, 804-828-9640
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Grin IR, Zharkov DO. Eukaryotic endonuclease VIII-Like proteins: New components of the base excision DNA repair system. BIOCHEMISTRY (MOSCOW) 2011; 76:80-93. [DOI: 10.1134/s000629791101010x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Darwanto A, Farrel A, Rogstad DK, Sowers LC. Characterization of DNA glycosylase activity by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Anal Biochem 2009; 394:13-23. [PMID: 19607800 PMCID: PMC3990469 DOI: 10.1016/j.ab.2009.07.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 07/07/2009] [Accepted: 07/09/2009] [Indexed: 11/25/2022]
Abstract
The DNA of all organisms is persistently damaged by endogenous reactive molecules. Most of the single-base endogenous damage is repaired through the base excision repair (BER) pathway that is initiated by members of the DNA glycosylase family. Although the BER pathway is often considered to proceed through a common abasic site intermediate, emerging evidence indicates that there are likely distinct branches reflected by the multitude of chemically different 3' and 5' ends generated at the repair site. In this study, we have applied matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) to the analysis of model DNA substrates acted on by recombinant glycosylases. We examine the chemical identity of several possible abasic site and nicked intermediates generated by monofunctional and bifunctional glycosylases. Our results suggest that the intermediate from endoIII/Nth might not be a simple beta-elimination product as described previously. On the basis of (18)O incorporation experiments, we propose a new mechanism for the endoIII/Nth family of glycosylases that may resolve several of the previous controversies. We further demonstrate that the use of an array of lesion-containing oligonucleotides can be used to rapidly examine the substrate preferences of a given glycosylase. Some of the lesions examined here can be acted on by more than one glycosylase, resulting in a spectrum of damaged intermediates for each lesion, suggesting that the sequence and coordination of repair activities that act on these lesions may influence the biological outcome of damage repair.
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Affiliation(s)
- Agus Darwanto
- Department of Basic Science, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
| | - Alvin Farrel
- Department of Basic Science, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
| | - Daniel K. Rogstad
- Department of Basic Science, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
| | - Lawrence C. Sowers
- Department of Basic Science, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
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Shikazono N, Noguchi M, Fujii K, Urushibara A, Yokoya A. The yield, processing, and biological consequences of clustered DNA damage induced by ionizing radiation. JOURNAL OF RADIATION RESEARCH 2009; 50:27-36. [PMID: 19218779 DOI: 10.1269/jrr.08086] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
After living cells are exposed to ionizing radiation, a variety of chemical modifications of DNA are induced either directly by ionization of DNA or indirectly through interactions with water-derived radicals. The DNA lesions include single strand breaks (SSB), base lesions, sugar damage, and apurinic/apyrimidinic sites (AP sites). Clustered DNA damage, which is defined as two or more of such lesions within one to two helical turns of DNA induced by a single radiation track, is considered to be a unique feature of ionizing radiation. A double strand break (DSB) is a type of clustered DNA damage, in which single strand breaks are formed on opposite strands in close proximity. Formation and repair of DSBs have been studied in great detail over the years as they have been linked to important biological endpoints, such as cell death, loss of genetic material, chromosome aberration. Although non-DSB clustered DNA damage has received less attention, there is growing evidence of its biological significance. This review focuses on the current understanding of (1) the yield of non-DSB clustered damage induced by ionizing radiation (2) the processing, and (3) biological consequences of non-DSB clustered DNA damage.
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Affiliation(s)
- Naoya Shikazono
- Japan Atomic Energy Agency, Advanced Research Science Center, 2-4 Shirakata-Shirane, Tokai-mura, Ibaraki 319-1195, Japan.
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Imoto S, Bransfield LA, Croteau DL, Van Houten B, Greenberg MM. DNA tandem lesion repair by strand displacement synthesis and nucleotide excision repair. Biochemistry 2008; 47:4306-16. [PMID: 18341293 DOI: 10.1021/bi7021427] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
DNA tandem lesions are comprised of two contiguously damaged nucleotides. This subset of clustered lesions is produced by a variety of oxidizing agents, including ionizing radiation. Clustered lesions can inhibit base excision repair (BER). We report the effects of tandem lesions composed of a thymine glycol and a 5'-adjacent 2-deoxyribonolactone (LTg) or tetrahydrofuran abasic site (FTg). Some BER enzymes that act on the respective isolated lesions do not accept the tandem lesion as a substrate. For instance, endonuclease III (Nth) does not excise thymine glycol (Tg) when it is part of either tandem lesion. Similarly, endonuclease IV (Nfo) does not incise L or F when they are in tandem with Tg. Long-patch BER overcomes inhibition by the tandem lesion. DNA polymerase beta (Pol beta) carries out strand displacement synthesis, following APE1 incision of the abasic site. Pol beta activity is enhanced by flap endonuclease (FEN1), which cleaves the resulting flap. The tandem lesion is also incised by the bacterial nucleotide excision repair system UvrABC with almost the same efficiency as an isolated Tg. These data reveal two solutions that DNA repair systems can use to counteract the formation of tandem lesions.
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Affiliation(s)
- Shuhei Imoto
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA
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Hazra TK, Das A, Das S, Choudhury S, Kow YW, Roy R. Oxidative DNA damage repair in mammalian cells: a new perspective. DNA Repair (Amst) 2006; 6:470-80. [PMID: 17116430 PMCID: PMC2702509 DOI: 10.1016/j.dnarep.2006.10.011] [Citation(s) in RCA: 208] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Oxidatively induced DNA lesions have been implicated in the etiology of many diseases (including cancer) and in aging. Repair of oxidatively damaged bases in all organisms occurs primarily via the DNA base excision repair (BER) pathway, initiated with their excision by DNA glycosylases. Only two mammalian DNA glycosylases, OGG1 and NTH1 of E. coli Nth family, were previously characterized, which excise majority of the oxidatively damaged base lesions. We recently discovered and characterized two human orthologs of E. coli Nei, the prototype of the second family of oxidized base-specific glycosylases and named them NEIL (Nei-like)-1 and 2. NEILs are distinct from NTH1 and OGG1 in structural features and reaction mechanism but act on many of the same substrates. Nth-type DNA glycosylases after base excision, cleave the DNA strand at the resulting AP-site to produce a 3'-alphabeta unsaturated aldehyde whereas Nei-type enzymes produce 3'-phosphate terminus. E. coli APEs efficiently remove both types of termini in addition to cleaving AP sites to generate 3'-OH, the primer terminus for subsequent DNA repair synthesis. In contrast, the mammalian APE, APE1, which has an essential role in NTH1/OGG1-initiated BER, has negligible 3'-phosphatase activity and is dispensable for NEIL-initiated BER. Polynucleotide kinase (PNK), present in mammalian cells but not in E. coli, removes the 3' phosphate, and is involved in NEIL-initiated BER. NEILs show a unique preference for excising lesions from a DNA bubble, while most DNA glycosylases, including OGG1 and NTH1, are active only with duplex DNA. The dichotomy in the preference of NEILs and NTH1/OGG1 for bubble versus duplex DNA substrates suggests that NEILs function preferentially in repair of base lesions during replication and/or transcription and hence play a unique role in maintaining the functional integrity of mammalian genomes.
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Affiliation(s)
- Tapas K Hazra
- Sealy Center for Molecular Science and Department of Biochemistry and Molecular Biology, 6.136 Medical Research Building, Route 1079, University of Texas Medical Branch, Galveston, TX 77555, USA.
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Berti PJ, McCann JAB. Toward a detailed understanding of base excision repair enzymes: transition state and mechanistic analyses of N-glycoside hydrolysis and N-glycoside transfer. Chem Rev 2006; 106:506-55. [PMID: 16464017 DOI: 10.1021/cr040461t] [Citation(s) in RCA: 211] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Paul J Berti
- Department of Chemistry, McMaster University, Hamilton, Ontario, Canada.
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Budworth H, Matthewman G, O'Neill P, Dianov GL. Repair of tandem base lesions in DNA by human cell extracts generates persisting single-strand breaks. J Mol Biol 2005; 351:1020-9. [PMID: 16054643 DOI: 10.1016/j.jmb.2005.06.069] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Revised: 06/27/2005] [Accepted: 06/29/2005] [Indexed: 11/18/2022]
Abstract
Clustered DNA damage, where two or more lesions are located proximal to each other on the same or opposite DNA strands, is frequently produced as a result of exposure to ionising radiation. It has been suggested that such complex damaged sites pose problems for repair pathways. In this study, we addressed the question of how two 8-oxoguanine lesions, located two nucleotides apart on the same DNA strand, are repaired. We find that in human cell extracts repair of either of the 8-oxoguanine lesions within a tandem damaged site is initiated randomly and that the majority of the initiated repair proceeds to completion. However, a fraction of the initiated repair is delayed at the stage of an incised AP site and the rate of further processing of this incised AP site is dependent on the position of the remaining 8-oxoguanine. If the remaining 8-oxoguanine residue is located near the 5' terminus of the incised abasic site, repair continues as efficiently as repair of a single 8-oxoguanine residue. However, repair is delayed after the incision step when the remaining 8-oxoguanine residue is located near the 3' terminus. Although the presence of the 8-oxoguanine residue near the 3' terminus did not affect either DNA polymerase beta activity or poly(ADP)ribose polymerase-1 affinity and turnover on an incised AP site, we find that 8-oxoguanine-DNA glycosylase has reduced ability to remove an 8-oxoguanine residue located near the 3' terminus of the incised AP site. We find that binding of the 8-oxoguanine-DNA glycosylase to this 8-oxoguanine residue inhibits DNA repair synthesis by DNA polymerase beta, thus delaying repair. We propose that interference between a DNA glycosylase and DNA polymerase during the repair of tandem lesions may lead to accumulation of the intermediate products that contain persisting DNA strand breaks.
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Affiliation(s)
- Helen Budworth
- MRC Radiation and Genome Stability Unit, Harwell, Oxfordshire OX11 0RD, UK
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Parsons JL, Zharkov DO, Dianov GL. NEIL1 excises 3' end proximal oxidative DNA lesions resistant to cleavage by NTH1 and OGG1. Nucleic Acids Res 2005; 33:4849-56. [PMID: 16129732 PMCID: PMC1196207 DOI: 10.1093/nar/gki816] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Base excision repair is the major pathway for the repair of oxidative DNA damage in human cells that is initiated by a damage-specific DNA glycosylase. In human cells, the major DNA glycosylases for the excision of oxidative base damage are OGG1 and NTH1 that excise 8-oxoguanine and oxidative pyrimidines, respectively. We find that both enzymes have limited activity on DNA lesions located in the vicinity of the 3′ end of a DNA single-strand break, suggesting that other enzymes are involved in the processing of such lesions. In this study, we identify and characterize NEIL1 as a major DNA glycosylase that excises oxidative base damage located in close proximity to the 3′ end of a DNA single-strand break.
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Affiliation(s)
| | - Dmitry O. Zharkov
- SB RAS Institute of Chemical Biology and Fundamental MedicineNovosibirsk 630090, Russia
| | - Grigory L. Dianov
- To whom correspondence should be addressed. Tel: +44 1235 841 134; Fax: +44 1235 841 200;
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