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Nakamura J, Nakamura M. DNA-protein crosslink formation by endogenous aldehydes and AP sites. DNA Repair (Amst) 2020; 88:102806. [PMID: 32070903 DOI: 10.1016/j.dnarep.2020.102806] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 01/22/2020] [Accepted: 01/22/2020] [Indexed: 12/19/2022]
Abstract
Covalent binding between proteins and a DNA strand produces DNA-protein crosslinks (DPC). DPC are one of the most deleterious types of DNA damage, leading to the blockage of DNA replication and transcription. Both DNA lesions and endogenous products with carbonyl functional groups can produce DPC in genomic DNA under normal physiological conditions. For example, formaldehyde, the most abundant endogenous human carcinogen, and apurinic/apyrimidinic (AP) sites, the most common type of endogenous DNA lesions, has been shown to crosslink proteins and/or DNA through their carbonyl functional groups. Unfortunately, compared to other types of DNA damage, DPC have been less studied and understood. However, a recent advancement has allowed researchers to determine accurate yields of various DNA lesions including formaldehyde-derived DPC with high sensitivity and specificity, paving the way for new developments in this field of research. Here, we review the current literature and remaining unanswered questions on DPC formation by endogenous formaldehyde and various aldehydic 2-deoxyribose lesions.
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Affiliation(s)
- Jun Nakamura
- Laboratory of Laboratory Animal Science, Graduate School of Life and Environmental Biosciences, Osaka Prefecture University, Izumisano, Osaka, Japan.
| | - Mai Nakamura
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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2
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Comparative Analysis of UV Irradiation Effects on Escherichia coli and Pseudomonas aeruginosa Bacterial Cells Utilizing Biological and Computational Approaches. Cell Biochem Biophys 2016; 74:381-9. [DOI: 10.1007/s12013-016-0748-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 06/09/2016] [Indexed: 01/27/2023]
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Roginskaya M, Moore TJ, Ampadu-Boateng D, Razskazovskiy Y. Efficacy and site specificity of hydrogen abstraction from DNA 2-deoxyribose by carbonate radicals. Free Radic Res 2015; 49:1431-7. [PMID: 26271311 DOI: 10.3109/10715762.2015.1081187] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The carbonate radical anion CO(3)(•-) is a potent reactive oxygen species (ROS) produced in vivo through enzymatic one-electron oxidation of bicarbonate or, mostly, via the reaction of CO(2) with peroxynitrite. Due to the vitally essential role of the carbon dioxide/bicarbonate buffer system in regulation of physiological pH, CO(3)(•-) is arguably one of the most important ROS in biological systems. So far, the studies of reactions of CO(3)(•-) with DNA have been focused on the pathways initiated by oxidation of guanines in DNA. In this study, low-molecular products of attack of CO(3)(•-) on the sugar-phosphate backbone in vitro were analyzed by reversed phase HPLC. The selectivity of damage in double-stranded DNA (dsDNA) was found to follow the same pattern C4' > C1' > C5' for both CO(3)(•-) and the hydroxyl radical, though the relative contribution of the C1' damage induced by CO(3)(•-) is substantially higher. In single-stranded DNA (ssDNA) oxidation at C1' by CO3(•-) prevails over all other sugar damages. An approximately 2000-fold preference for 8-oxoguanine (8oxoG) formation over sugar damage found in our study identifies CO(3)(•-) primarily as a one-electron oxidant with fairly low reactivity toward the sugar-phosphate backbone.
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Affiliation(s)
- M Roginskaya
- a Department of Chemistry , East Tennessee State University , Johnson City , USA
| | - T J Moore
- a Department of Chemistry , East Tennessee State University , Johnson City , USA
| | - D Ampadu-Boateng
- a Department of Chemistry , East Tennessee State University , Johnson City , USA
| | - Y Razskazovskiy
- b Department of Physics and Astronomy , East Tennessee State University , Johnson City , USA
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Chen SH, Byrne RT, Wood EA, Cox MM. Escherichia coli radD (yejH) gene: a novel function involved in radiation resistance and double-strand break repair. Mol Microbiol 2015; 95:754-68. [PMID: 25425430 DOI: 10.1111/mmi.12885] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2014] [Indexed: 11/28/2022]
Abstract
A transposon insertion screen implicated the yejH gene in the repair of ionizing radiation-induced damage. The yejH gene, which exhibits significant homology to the human transcription-coupled DNA repair gene XPB, is involved in the repair of double-strand DNA breaks. Deletion of yejH significantly sensitized cells to agents that cause double-strand breaks (ionizing radiation, UV radiation, ciprofloxacin). In addition, deletion of both yejH and radA hypersensitized the cells to ionizing radiation, UV and ciprofloxacin damage, indicating that these two genes have complementary repair functions. The ΔyejH ΔradA double deletion also showed a substantial decline in viability following an induced double-strand DNA break, of a magnitude comparable with the defect measured when the recA, recB, recG or priA genes are deleted. The ATPase activity and C-terminal zinc finger motif of yejH play an important role in its repair function, as targeted mutant alleles of yejH did not rescue sensitivity. We propose that yejH be renamed radD, reflecting its role in the DNA repair of radiation damage.
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Affiliation(s)
- Stefanie H Chen
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
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Escherichia coli genes and pathways involved in surviving extreme exposure to ionizing radiation. J Bacteriol 2014; 196:3534-45. [PMID: 25049088 DOI: 10.1128/jb.01589-14] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To further an improved understanding of the mechanisms used by bacterial cells to survive extreme exposure to ionizing radiation (IR), we broadly screened nonessential Escherichia coli genes for those involved in IR resistance by using transposon-directed insertion sequencing (TraDIS). Forty-six genes were identified, most of which become essential upon heavy IR exposure. Most of these were subjected to direct validation. The results reinforced the notion that survival after high doses of ionizing radiation does not depend on a single mechanism or process, but instead is multifaceted. Many identified genes affect either DNA repair or the cellular response to oxidative damage. However, contributions by genes involved in cell wall structure/function, cell division, and intermediary metabolism were also evident. About half of the identified genes have not previously been associated with IR resistance or recovery from IR exposure, including eight genes of unknown function.
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Chan W, Chen B, Wang L, Taghizadeh K, Demott MS, Dedon PC. Quantification of the 2-deoxyribonolactone and nucleoside 5'-aldehyde products of 2-deoxyribose oxidation in DNA and cells by isotope-dilution gas chromatography mass spectrometry: differential effects of gamma-radiation and Fe2+-EDTA. J Am Chem Soc 2010; 132:6145-53. [PMID: 20377226 DOI: 10.1021/ja910928n] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The oxidation of 2-deoxyribose in DNA has emerged as a critical determinant of the cellular toxicity of oxidative damage to DNA, with oxidation of each carbon producing a unique spectrum of electrophilic products. We have developed and validated an isotope-dilution gas chromatography-coupled mass spectrometry (GC-MS) method for the rigorous quantification of two major 2-deoxyribose oxidation products: the 2-deoxyribonolactone abasic site of 1'-oxidation and the nucleoside 5'-aldehyde of 5'-oxidation chemistry. The method entails elimination of these products as 5-methylene-2(5H)-furanone (5MF) and furfural, respectively, followed by derivatization with pentafluorophenylhydrazine (PFPH), addition of isotopically labeled PFPH derivatives as internal standards, extraction of the derivatives, and quantification by GC-MS analysis. The precision and accuracy of the method were validated with oligodeoxynucleotides containing the 2-deoxyribonolactone and nucleoside 5'-aldehyde lesions. Further, the well-defined 2-deoxyribose oxidation chemistry of the enediyne antibiotics, neocarzinostatin and calicheamicin gamma(1)(I), was exploited in control studies, with neocarzinostatin producing 10 2-deoxyribonolactone and 300 nucleoside 5'-aldehyde per 10(6) nt per microM in accord with its established minor 1'- and major 5'-oxidation chemistry. Calicheamicin unexpectedly caused 1'-oxidation at a low level of 10 2-deoxyribonolactone per 10(6) nt per microM in addition to the expected predominance of 5'-oxidation at 560 nucleoside 5'-aldehyde per 10(6) nt per microM. The two hydroxyl radical-mediated DNA oxidants, gamma-radiation and Fe(2+)-EDTA, produced nucleoside 5'-aldehyde at a frequency of 57 per 10(6) nt per Gy (G-value 74 nmol/J) and 3.5 per 10(6) nt per microM, respectively, which amounted to 40% and 35%, respectively, of total 2-deoxyribose oxidation as measured by a plasmid nicking assay. However, gamma-radiation and Fe(2+)-EDTA produced different proportions of 2-deoxyribonolactone at 7% and 24% of total 2-deoxyribose oxidation, respectively, with frequencies of 10 lesions per 10(6) nt per Gy (G-value, 13 nmol/J) and 2.4 lesions per 10(6) nt per microM. Studies in TK6 human lymphoblastoid cells, in which the analytical data were corrected for losses sustained during DNA isolation, revealed background levels of 2-deoxyribonolactone and nucleoside 5'-aldehyde of 9.7 and 73 lesions per 10(6) nt, respectively. Gamma-irradiation of the cells caused increases of 0.045 and 0.22 lesions per 10(6) nt per Gy, respectively, which represents a approximately 250-fold quenching effect of the cellular environment similar to that observed in previous studies. The proportions of the various 2-deoxyribose oxidation products generated by gamma-radiation are similar for purified DNA and cells. These results are consistent with solvent exposure as a major determinant of hydroxyl radical reactivity with 2-deoxyribose in DNA, but the large differences between gamma-radiation and Fe(2+)-EDTA suggest that factors other than hydroxyl radical reactivity govern DNA oxidation chemistry.
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Affiliation(s)
- Wan Chan
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Fate of DNA Sugar Radicals. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/s1872-0854(10)04004-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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Zu Y, Liu H, Zhang Y, Hu N. Electrochemical detection of in situ DNA damage with layer-by-layer films containing DNA and glucose oxidase and protection effect of catalase layers against DNA damage. Electrochim Acta 2009. [DOI: 10.1016/j.electacta.2008.11.041] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Affiliation(s)
- Peter C. Dedon
- Department of Biological Engineering and Center for Environmental Health Sciences, Massachusetts Institute of Technology, NE47-277, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139
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Chen B, Zhou X, Taghizadeh K, Chen J, Stubbe J, Dedon PC. GC/MS methods to quantify the 2-deoxypentos-4-ulose and 3'-phosphoglycolate pathways of 4' oxidation of 2-deoxyribose in DNA: application to DNA damage produced by gamma radiation and bleomycin. Chem Res Toxicol 2007; 20:1701-8. [PMID: 17944541 PMCID: PMC2529375 DOI: 10.1021/tx700164y] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
DNA oxidation plays a substantive role in the pathophysiology of human diseases, such as cancer. While the chemistry of nucleobase lesions has dominated studies of DNA damage, there is growing evidence that the oxidation of 2-deoxyribose in DNA plays a critical role in the genetic toxicology of oxidative stress. As part of an effort to define the spectrum of 2-deoxyribose oxidation products arising in vitro and in vivo, we now describe methods for quantifying products arising from 4' oxidation of 2-deoxyribose in DNA. The chemistry of 4' oxidation partitions between either of two pathways to form either a 2-deoxypentos-4-ulose abasic site (oxAB) or a strand break comprised of a 3'-phosphoglycolate (3PG) residue and a 5'-phosphate, with the release of either malondialdehyde and free base or a base propenal. Highly sensitive gas chromatography/mass spectrometry (GC/MS) methods were developed to quantify both lesions. The abasic site was converted to a 3'-phosphoro-3-pyridazinylmethylate derivative by treatment of the damaged DNA with hydrazine, which was released from DNA as 3-hydroxymethylpyridazine (HMP) by enzymatic hydrolysis. Similarly, 3PG was released as 2-phosphoglycolic acid (PG) by enzymatic hydrolysis. Following HPLC prepurification, both PG and HMP were silylated and quantified by GC/MS, with limits of detection of 100 and 200 fmol and sensitivities of 2 and 4 lesions per 10(6) nucleotides (nt) in 250 microg of DNA, respectively. Following validation of the methods with oligodeoxynucleotides containing the two lesions, the methods were applied to DNA damage produced by bleomycin and gamma radiation. As expected for an agent known to produce only 4' oxidation of DNA, the quantities of 3PG and oxAB accounted for all 2-deoxyribose oxidation events, as indicated by slopes of 0.8 and 0.3, respectively, in plots of the lesion frequency against total 2-deoxyribose oxidation events, with the latter determined by a plasmid-nicking assay. 3PG residues and oxAB were produced at the rate of 32 and 12 lesions per 10(6) nt per microM, respectively. For gamma radiation, on the other hand, 4' oxidation was found to comprise only 13% of 2-deoxyribose oxidation chemistry, with 3% oxAB (4 per 10(6) nt per Gy) and 10% 3PG (13 per 10(6) nt per Gy).
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Affiliation(s)
- Bingzi Chen
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA
| | - Xinfeng Zhou
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA
| | - Koli Taghizadeh
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA
| | - Jingyang Chen
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA
| | - JoAnne Stubbe
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA
| | - Peter C. Dedon
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA
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Regulus P, Duroux B, Bayle PA, Favier A, Cadet J, Ravanat JL. Oxidation of the sugar moiety of DNA by ionizing radiation or bleomycin could induce the formation of a cluster DNA lesion. Proc Natl Acad Sci U S A 2007; 104:14032-7. [PMID: 17715301 PMCID: PMC1955805 DOI: 10.1073/pnas.0706044104] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bleomycin, a radiomimetic drug currently used in human cancer therapy, is a well known carcinogen. Its toxicity is mostly attributed to its potentiality to induce DNA double strand breaks likely arising from the formation of two vicinal DNA strand breaks, initiated by C4-hydrogen abstraction on the 2-deoxyribose moiety. In this work we demonstrate that such a hydrogen abstraction reaction is able to induce the formation of a clustered DNA lesion, involving a 3' strand break together with a modified sugar residue exhibiting a reactive alpha,beta-unsaturated aldehyde that further reacts with a proximate cytosine base. The lesion thus produced was detected as a mixture of four isomers by HPLC coupled to tandem mass spectrometry subsequent to DNA extraction and enzymatic digestion. The modified nucleosides that constitute new types of cytosine adducts were identified as the likely two pairs of diastereomers of 6-(2-deoxy-beta-D-erythro-pentofuranosyl)-2-hydroxy-3(3-hydroxy-2-oxopropyl)-2,6-dihydroimidazo[1,2-c]-pyrimidin-5(3H)-one as inferred from mass spectrometry and NMR analyses of the chemically synthesized nucleosides. We demonstrate that bleomycin, and to a minor extent ionizing radiation, are able to induce significant amounts of the cytosine damage in cellular DNA. In addition, the repair kinetic of the lesion in a human lymphocyte cell line is rather slow, with a half-life of 10 h. The 2'-deoxycytidine adducts thus characterized that represent the first example of complex DNA lesions isolated and identified in cellular DNA upon one radical hit are likely to play an important role in the toxicity of bleomycin.
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Affiliation(s)
| | | | - Pierre-Alain Bayle
- Laboratoire de Résonnance Magnétique, Laboratoire de Chimie Inorganique et Bioinorganique (Unité Mixte de Recherche E3, Commissariat à l'Energie Atomique–Université Joseph Fourier), Département de Recherche Fondamentale sur la Matière Condensée, Commissariat à l'Energie Atomique–Grenoble, 17 Avenue des Martyrs, 38054 Grenoble Cedex 9, France
| | - Alain Favier
- *Laboratoire des Lésions des Acides Nucléiques and
| | - Jean Cadet
- *Laboratoire des Lésions des Acides Nucléiques and
| | - Jean-Luc Ravanat
- *Laboratoire des Lésions des Acides Nucléiques and
- To whom correspondence should be addressed. E-mail:
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Datta K, Weinfeld M, Neumann RD, Winters TA. Determination and analysis of site-specific 125I decay-induced DNA double-strand break end-group structures. Radiat Res 2007; 167:152-66. [PMID: 17390723 DOI: 10.1667/rr0629.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
End groups contribute to the structural complexity of radiation-induced DNA double-strand breaks (DSBs). As such, end-group structures may affect a cell's ability to repair DSBs. The 3'-end groups of strand breaks caused by gamma radiation, or oxidative processes, under oxygenated aqueous conditions have been shown to be distributed primarily between 3'-phosphoglycolate and 3'-phosphate, with 5'-phosphate ends in both cases. In this study, end groups of the high-LET-like DSBs caused by 125I decay were investigated. Site-specific DNA double-strand breaks were produced in plasmid pTC27 in the presence or absence of 2 M DMSO by 125I-labeled triplex-forming oligonucleotide targeting. End-group structure was assessed enzymatically as a function of the DSB end to serve as a substrate for ligation and various forms of end labeling. Using this approach, we have demonstrated 3'-hydroxyl (3'-OH) and 3'-phosphate (3'-P) end groups and 5'-ends (> or = 42%) terminated by phosphate. A 32P postlabeling assay failed to detect 3'-phosphoglycolate in a restriction fragment terminated by the 125I-induced DNA double-strand break, and this is likely due to restricted oxygen diffusion during irradiation as a frozen aqueous solution. Even so, end-group structure and relative distribution varied as a function of the free radical scavenging capacity of the irradiation buffer.
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Affiliation(s)
- Kamal Datta
- Nuclear Medicine Department, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland 20892, USA
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Lahoud G, Fancher J, Grosu S, Cavanaugh B, Bryant-Friedrich A. Automated synthesis, characterization, and structural analysis of oligonucleotide C-3'-radical precursors. Bioorg Med Chem 2005; 14:2581-8. [PMID: 16338139 DOI: 10.1016/j.bmc.2005.11.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2005] [Revised: 11/19/2005] [Accepted: 11/21/2005] [Indexed: 11/16/2022]
Abstract
C-3'-Acyl-3'-xylothymidine-containing oligonucleotides have been designed and synthesized for their use as radical precursors in the study of oxidative DNA damage initiated by a C-3'-radical. These oligomers were efficiently obtained using automated DNA synthesis techniques based on H-phosphonate chemistry. CD spectra and melting curves of the synthesized oligonucleotides were compared to those of their unmodified and xylomodified counterparts. The conformational analysis and hybridization studies indicate that the combination of the photolabile acyl group and the inversion of configuration at the sugar has no profound effect on the overall conformation of C-3'-acyl-2'-deoxy-3'-xylonucleotides as compared to their natural analogues. These systems should provide excellent tools for the elucidation of DNA damage processes.
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Affiliation(s)
- Georges Lahoud
- Department of Chemistry, Oakland University, Rochester, MI 48309-4477, USA
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Zhou X, Liberman RG, Skipper PL, Margolin Y, Tannenbaum SR, Dedon PC. Quantification of DNA strand breaks and abasic sites by oxime derivatization and accelerator mass spectrometry: application to gamma-radiation and peroxynitrite. Anal Biochem 2005; 343:84-92. [PMID: 15964542 DOI: 10.1016/j.ab.2005.05.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2005] [Revised: 04/26/2005] [Accepted: 05/06/2005] [Indexed: 01/26/2023]
Abstract
We report a highly sensitive method to quantify abasic sites and deoxyribose oxidation products arising in damaged DNA. The method exploits the reaction of aldehyde- and ketone-containing deoxyribose oxidation products and abasic sites with [(14)C]methoxyamine to form stable oxime derivatives, as originally described by Talpaert-Borle and Liuzzi [Reaction of apurinic/apyrimidinic sites with [(14)C]methoxyamine. A method for the quantitative assay of AP sites in DNA, Biochim. Biophys. Acta 740 (1983) 410-416]. The sensitivity of the method was dramatically improved by the application of accelerator mass spectrometry to quantify the (14)C, with a limit of detection of 1 lesion in 10(6) nucleotides in 1 microg of DNA. The method was validated using DNA containing a defined quantity of abasic sites, with a >0.95 correlation between the quantities of abasic sites and those of methoxyamine labels. The original applications of this and similar oxyamine derivatization methods have assumed that abasic sites are the only aldehyde-containing DNA damage products. However, deoxyribose oxidation produces strand breaks and abasic sites containing a variety of degradation products with aldehyde and ketone moieties. To assess the utility of methoxyamine labeling for quantifying strand breaks and abasic sites, the method was applied to plasmid DNA treated with gamma-radiation and peroxynitrite. For gamma-radiation, there was a 0.99 correlation between the quantity of methoxyamine labels and the quantity of strand breaks and abasic sites determined by a plasmid nicking assay; the abasic sites comprised less than 10% of the radiation-induced DNA damage. Studies with peroxynitrite demonstrate that the method, in conjunction with DNA repair enzymes that remove damaged bases to produce aldehydic sugar residues or abasic sites, is also applicable to quantifying nucleobase lesions in addition to strand break products. Compared to other abasic site quantification techniques, the modified method offers the advantage of providing a straightforward and direct measurement of aldehyde- and ketone-containing strand breaks and abasic sites, with the potential for direct labeling in cells prior to DNA isolation.
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Affiliation(s)
- Xinfeng Zhou
- Biological Engineering Division, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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