1
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Cui Y, Wang Y. Mass spectrometry-based DNA adductomics. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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2
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Onizuka K, Usami A, Yamaoki Y, Kobayashi T, Hazemi ME, Chikuni T, Sato N, Sasaki K, Katahira M, Nagatsugi F. Selective alkylation of T-T mismatched DNA using vinyldiaminotriazine-acridine conjugate. Nucleic Acids Res 2019; 46:1059-1068. [PMID: 29309639 PMCID: PMC5814796 DOI: 10.1093/nar/gkx1278] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 12/19/2017] [Indexed: 11/25/2022] Open
Abstract
The alkylation of the specific higher-order nucleic acid structures is of great significance in order to control its function and gene expression. In this report, we have described the T–T mismatch selective alkylation with a vinyldiaminotriazine (VDAT)–acridine conjugate. The alkylation selectively proceeded at the N3 position of thymidine on the T–T mismatch. Interestingly, the alkylated thymidine induced base flipping of the complementary base in the duplex. In a model experiment for the alkylation of the CTG repeats DNA which causes myotonic dystrophy type 1 (DM1), the observed reaction rate for one alkylation increased in proportion to the number of T–T mismatches. In addition, we showed that primer extension reactions with DNA polymerase and transcription with RNA polymerase were stopped by the alkylation. The alkylation of the repeat DNA will efficiently work for the inhibition of replication and transcription reactions. These functions of the VDAT–acridine conjugate would be useful as a new biochemical tool for the study of CTG repeats and may provide a new strategy for the molecular therapy of DM1.
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Affiliation(s)
- Kazumitsu Onizuka
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Akira Usami
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Yudai Yamaoki
- Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.,Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Tomohito Kobayashi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Madoka E Hazemi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Tomoko Chikuni
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Norihiro Sato
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Kaname Sasaki
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Masato Katahira
- Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.,Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Fumi Nagatsugi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
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3
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Sato N, Tsuji G, Sasaki Y, Usami A, Moki T, Onizuka K, Yamada K, Nagatsugi F. A new strategy for site-specific alkylation of DNA using oligonucleotides containing an abasic site and alkylating probes. Chem Commun (Camb) 2016; 51:14885-8. [PMID: 26304997 DOI: 10.1039/c5cc03915k] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Selective chemical reactions with DNA, such as its labelling, are very useful in many applications. In this paper, we discuss a new strategy for the selective alkylation of DNA using an oligonucleotide containing an abasic site and alkylating probes. We designed three probes consisting of 2-AVP as a reactive moiety and three kinds of binding moiety with high affinity to duplex DNA. Among these probes, Hoechst-AVP probe exhibited high selectivity and efficient reactivity to thymine bases at the site opposite an abasic site in DNA. Our method is potentially useful for inducing site-directed reactions aimed at inhibiting polymerase reactions.
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Affiliation(s)
- Norihiro Sato
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai-shi, 980-8577, Japan.
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4
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Nagatsugi F. Development of the Strategy for Chemical Modifications to Nucleic Acids. J SYN ORG CHEM JPN 2016. [DOI: 10.5059/yukigoseikyokaishi.74.494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Fumi Nagatsugi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University
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5
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Comparison of gas phase intrinsic properties of cytosine and thymine nucleobases with their O-alkyl adducts: different hydrogen bonding preferences for thymine versus O-alkyl thymine. J Mol Model 2013; 19:2993-3005. [DOI: 10.1007/s00894-013-1813-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2012] [Accepted: 03/03/2013] [Indexed: 12/11/2022]
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6
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van Lier JJC, Stroucken JHM, Buck HM. Molecular aspects of methylated adenine in DNA. A quantum-chemical study. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19841030406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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7
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Gates KS. An overview of chemical processes that damage cellular DNA: spontaneous hydrolysis, alkylation, and reactions with radicals. Chem Res Toxicol 2010; 22:1747-60. [PMID: 19757819 DOI: 10.1021/tx900242k] [Citation(s) in RCA: 351] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The sequence of heterocyclic bases on the interior of the DNA double helix constitutes the genetic code that drives the operation of all living organisms. With this said, it is not surprising that chemical modification of cellular DNA can have profound biological consequences. Therefore, the organic chemistry of DNA damage is fundamentally important to diverse fields including medicinal chemistry, toxicology, and biotechnology. This review is designed to provide a brief overview of the common types of chemical reactions that lead to DNA damage under physiological conditions.
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Affiliation(s)
- Kent S Gates
- Departments of Chemistry and Biochemistry, University of Missouri-Columbia, 125 Chemistry Building, Columbia, Missouri 65211.
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8
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Crean C, Uvaydov Y, Geacintov NE, Shafirovich V. Oxidation of single-stranded oligonucleotides by carbonate radical anions: generating intrastrand cross-links between guanine and thymine bases separated by cytosines. Nucleic Acids Res 2007; 36:742-55. [PMID: 18084033 PMCID: PMC2241916 DOI: 10.1093/nar/gkm1092] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The carbonate radical anion is a biologically important one-electron oxidant that can directly abstract an electron from guanine, the most easily oxidizable DNA base. Oxidation of the 5'-d(CCTACGCTACC) sequence by photochemically generated CO3*- radicals in low steady-state concentrations relevant to biological processes results in the formation of spiroiminodihydantoin diastereomers and a previously unknown lesion. The latter was excised from the oxidized oligonucleotides by enzymatic digestion with nuclease P1 and alkaline phosphatase and identified by LC-MS/MS as an unusual intrastrand cross-link between guanine and thymine. In order to further characterize the structure of this lesion, 5'-d(GpCpT) was exposed to CO3*- radicals, and the cyclic nature of the 5'-d(G*pCpT*) cross-link in which the guanine C8-atom is bound to the thymine N3-atom was confirmed by LC-MS/MS, 1D and 2D NMR studies. The effect of bridging C bases on the cross-link formation was studied in the series of 5'-d(GpC(n)pT) and 5'-d(TpC(n)pG) sequences with n = 0, 1, 2 and 3. Formation of the G*-T* cross-links is most efficient in the case of 5'-d(GpCpT). Cross-link formation (n = 0) was also observed in double-stranded DNA molecules derived from the self-complementary 5'-d(TTACGTACGTAA) sequence following exposure to CO3*- radicals and enzymatic excision of the 5'-d(G*pT*) product.
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Affiliation(s)
- Conor Crean
- Chemistry Department and Radiation and Solid State Laboratory, 31 Washington Place, New York University, New York, NY 10003-5180, USA
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9
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Pedroso E, Fernández D, Palom Y, Eritja R. Syhthesis of Oligonucleotides Containing 4-0-Ethylthymidine. ACTA ACUST UNITED AC 2007. [DOI: 10.1080/07328319108046551] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- E. Pedroso
- a Department of Organic Chemistry , University of Barcelona , Marti i Franques 1-11, E-08028 , Barcelona , Spain
| | - D. Fernández
- a Department of Organic Chemistry , University of Barcelona , Marti i Franques 1-11, E-08028 , Barcelona , Spain
| | - Y. Palom
- a Department of Organic Chemistry , University of Barcelona , Marti i Franques 1-11, E-08028 , Barcelona , Spain
| | - R. Eritja
- a Department of Organic Chemistry , University of Barcelona , Marti i Franques 1-11, E-08028 , Barcelona , Spain
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10
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11
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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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12
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Shipova E, Gates KS. A fluorimetric assay for the spontaneous release of an N7-alkylguanine residue from duplex DNA. Bioorg Med Chem Lett 2005; 15:2111-3. [PMID: 15808479 DOI: 10.1016/j.bmcl.2005.02.058] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2005] [Revised: 02/09/2005] [Accepted: 02/10/2005] [Indexed: 11/28/2022]
Abstract
A fluorimetric assay for monitoring depurination of the N7-alkylguanine adduct derived from the anticancer natural product leinamycin is described. This general approach could potentially provide the foundation for a high throughput assay that detects DNA-alkylating agents or a convenient continuous fluorimetric assay for base excision repair enzymes.
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Affiliation(s)
- Ekaterina Shipova
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211, USA
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13
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Richter SN, Menegazzo I, Fabris D, Palumbo M. Concerted bis-alkylating reactivity of clerocidin towards unpaired cytosine residues in DNA. Nucleic Acids Res 2004; 32:5658-67. [PMID: 15494453 PMCID: PMC524306 DOI: 10.1093/nar/gkh898] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Clerocidin (CL) is a topoisomerase II poison, which cleaves DNA irreversibly at guanines (G) and reversibly at cytosines (C). Furthermore, the drug can induce enzyme-independent strand breaks at the G and C level. It has been previously shown that G-damage is induced by alkylation of the guanine N7, followed by spontaneous depurination and nucleic acid cleavage, whereas scission at C is obtained only after treatment with hot alkali, and no information is available to explain the nature of this damage. We present here a systematic study on the reactivity of CL towards C both in the DNA environment and in solution. Selected synthetic derivatives were employed to evaluate the role of each chemical group of the drug. The structure of CL-dC adduct was then characterized by tandem mass spectrometry and NMR: the adduct is a stable condensed ring system resulting from a concerted electrophilic attack of the adjacent carbonyl and epoxide groups of CL towards the exposed NH(2) and N3, respectively. This reaction mechanism, shown here for the first time, is characterized by faster kinetic rates than alkylation at G, due to the fact that the rate-determining step, alkylation at the epoxide, is an intramolecular process, provided a Schiff base linking CL and C can rapidly form, whereas the corresponding reaction of G N7 is intermolecular. These results provide helpful hints to explain the reversible/irreversible nature of topoisomerase II mediated DNA damage produced by CL at C/G steps.
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Affiliation(s)
- Sara N Richter
- Department of Pharmaceutical Sciences, University of Padova, 35131 Padova, Italy
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14
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Shi J, Ray AS, Mathew JS, Anderson KS, Chu CK, Schinazi RF. 2 ′ ,3 ′ -Didehydro-2 ′ ,3 ′ -dideoxynucleosides are degraded to furfuryl alcohol under acidic conditions. Bioorg Med Chem Lett 2004; 14:2159-62. [PMID: 15081000 DOI: 10.1016/j.bmcl.2004.02.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2003] [Accepted: 02/06/2004] [Indexed: 11/19/2022]
Abstract
2('),3(')-Didehydro-2('),3(')-dideoxynucleosides are clinically relevant antiviral agents. These nucleosides could be degraded under acidic conditions. Acidic stability studies showed the D4N had the following increasing stability order: D4G<cyclo-D4G#10877;RVT<D4T with half-lives ranging from less than 2 min to 35 days. A concerted A-1 mechanism has been proposed for the acidic cleavage of D4-nucleosides. The cleavage products were characterized as furfuryl alcohol and the corresponding nucleobase. Furfuryl alcohol is an agent found in many everyday food products. The biological results demonstrated that furfuryl alcohol had neither anti-HIV activity nor cytotoxicity in vitro, suggesting the acid instability of D4-nucleosides is unlikely to have an impact on the toxicity of these nucleoside analogs in humans.
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Affiliation(s)
- Junxing Shi
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520-8066, USA
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15
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Koskinen M, Calebiro D, Hemminki K. Styrene oxide-induced 2'-deoxycytidine adducts: implications for the mutagenicity of styrene oxide. Chem Biol Interact 2000; 126:201-13. [PMID: 10862818 DOI: 10.1016/s0009-2797(00)00165-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The reaction between 2'-deoxycytidine and styrene 7,8-oxide (SO) resulted in alkylation at the 3-position and at the O(2)-position through the alpha- and beta-carbons of the epoxide but at the N(4)-position only through the alpha-carbon. The 3-alkylated adducts were found to deaminate to the corresponding 2'-deoxyuridine adducts (37 degrees C, pH 7.4) with half-lives of 6 min and 2.4 h for the alpha- and beta-isomers, respectively. The N(4)-alkylated products were stable at neutral pH. The O(2)-alkylated products were unstable being prone to depyrimidation and to isomerisation between alpha- and beta-isomers. In SO-treated double-stranded DNA, enzymatic hydrolysis allowed the identification of the beta3-deoxyuridine and alphaN(4)-deoxycytidine adducts (1.9 and 0.5% of total alkylation, respectively), in addition to the previously identified DNA-adducts. The 3-substituted uracil may have implications for the mutagenicity of SO.
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Affiliation(s)
- M Koskinen
- Center for Nutrition and Toxicology, Department of Biosciences at Novum, Karolinska Institute, S-141 57, Huddinge, Sweden.
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16
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Masaoka A, Terato H, Kobayashi M, Honsho A, Ohyama Y, Ide H. Enzymatic repair of 5-formyluracil. I. Excision of 5-formyluracil site-specifically incorporated into oligonucleotide substrates by alka protein (Escherichia coli 3-methyladenine DNA glycosylase II). J Biol Chem 1999; 274:25136-43. [PMID: 10455195 DOI: 10.1074/jbc.274.35.25136] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
5-Formyluracil (fU) is a major thymine lesion produced by reactive oxygen radicals and photosensitized oxidation. We have previously shown that fU is a potentially mutagenic lesion due to its elevated frequency to mispair with guanine. Therefore, fU can exist in DNA as a correctly paired fU:A form or an incorrectly paired fU:G form. In this work, fU was site-specifically incorporated opposite A in oligonucleotide substrates to delineate the cellular repair mechanism of fU paired with A. The repair activity for fU was induced in Escherichia coli upon exposure to N-methyl-N'-nitro-N-nitrosoguanidine, and the induction was dependent on the alkA gene, suggesting that AlkA (3-methyladenine DNA glycosylase II) was responsible for the observed activity. Activity assay and determination of kinetic parameters using purified AlkA and defined oligonucleotide substrates containing fU, 5-hydroxymethyluracil (hU), or 7-methylguanine (7mG) revealed that fU was recognized by AlkA with an efficiency comparable to that of 7mG, a good substrate for AlkA, whereas hU, another major thymine methyl oxidation products, was not a substrate. (1)H and (13)C NMR chemical shifts of 5-formyl-2'-deoxyuridine indicated that the 5-formyl group caused base C-6 and sugar C-1' to be electron deficient, which was shown to result in destabilization of the N-glycosidic bond. These features are common in other good substrates for AlkA and are suggested to play key roles in the differential recognition of fU, hU, and intact thymine. Three mammalian repair enzymes for alkylated and oxidized bases cloned so far (MPG, Nth1, and OGG1) did not recognize fU, implying that the mammalian repair activity for fU resided on a yet unidentified protein. In the accompanying paper (Terato, H., Masaoka, A., Kobayashi, M., Fukushima, S., Ohyama, Y., Yoshida, M., and Ide, H., J. Biol. Chem. 274, 25144-25150), possible repair mechanisms for fU mispaired with G are reported.
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Affiliation(s)
- A Masaoka
- Graduate Department of Gene Science, Faculty of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan
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17
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Berdal KG, Johansen RF, Seeberg E. Release of normal bases from intact DNA by a native DNA repair enzyme. EMBO J 1998; 17:363-7. [PMID: 9430628 PMCID: PMC1170387 DOI: 10.1093/emboj/17.2.363] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Base excision repair is initiated by DNA glycosylases removing inappropriate bases from DNA. One group of these enzymes, comprising 3-methyladenine DNA glycosylase II (AlkA) from Escherichia coli and related enzymes from other organisms, has been found to have an unusual broad specificity towards quite different base structures. We tested whether such enzymes might also be capable of removing normal base residues from DNA. The native enzymes from E.coli, Saccharomyces cerevisiae and human cells promoted release of intact guanines with significant frequencies, and further analysis of AlkA showed that all the normal bases can be removed. Transformation of E. coli with plasmids expressing different levels of AlkA produced an increased spontaneous mutation frequency correlated with the expression levels, indicating that excision of normal bases occurs at biologically significant rates. We propose that the broad specificity 3-methyladenine DNA glycosylases represent a general type of repair enzyme 'pulling' bases in DNA largely at random, without much preference for a specific structure. The specificity for release of damaged bases occurs because base structure alterations cause instability of the base-sugar bonds. Damaged bases are therefore released more readily than normal bases once the bond activation energy is reduced further by the enzyme. Qualitatively, the model correlates quite well with the relative rate of excision observed for most, if not all, of the substrates described for AlkA and analogues.
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Affiliation(s)
- K G Berdal
- Department of Molecular Biology, Institute of Medical Microbiology, The National Hospital, University of Oslo, Norway
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18
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Venkateswarlu D, Lyngdoh R. Deglycosylation of alkylated nucleosides: a molecular orbital study. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0166-1280(97)00063-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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19
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Rokita SE, Yang J, Pande P, Greenberg WA. Quinone Methide Alkylation of Deoxycytidine. J Org Chem 1997; 62:3010-3012. [PMID: 11671669 DOI: 10.1021/jo9700336] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Steven E. Rokita
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, and Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794
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20
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21
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Lafortune F, Buchko GW, Hruska FE, Sadana KL, Standing KG, Westmore JB. Time-of-Flight Secondary Ion Mass Spectrometry of Isomeric O-Alkylthymidines. ACTA ACUST UNITED AC 1992. [DOI: 10.1080/07328319208021175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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22
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Loechler EL. Molecular modeling studies of O2-alkylthymines and O4-alkylthymines in DNA: structures that may be pertinent to the incorporation of the corresponding dAlkTTP into DNA by DNA polymerases in vitro. Mutat Res 1990; 233:39-44. [PMID: 2233811 DOI: 10.1016/0027-5107(90)90149-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- E L Loechler
- Department of Biology, Boston University, MA 02215
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23
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Fernandez-Forner D, Palom Y, Ikuta S, Pedroso E, Eritja R. Synthesis and characterization of oligodeoxynucleotides containing the mutagenic base analogue 4-O-ethylthymine. Nucleic Acids Res 1990; 18:5729-34. [PMID: 2216766 PMCID: PMC332307 DOI: 10.1093/nar/18.19.5729] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
A method for the preparation of oligonucleotides containing the mutagenic base 4-O-ethylthymine is described for the first time. Use of p-nitrophenylethyl type base protecting groups together with phosphitetriester solid-phase methodology makes possible the rapid and efficient preparation of oligonucleotides bearing 4-O-ethylthymine, while standard base protecting groups are not compatible with the presence of this base. Possible applications of this methodology are discussed.
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24
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Klein JC, Bleeker MJ, Lutgerink JT, van Dijk WJ, Brugghe HF, van den Elst H, van der Marel GA, van Boom JH, Westra JG, Berns AJ. Use of shuttle vectors to study the molecular processing of defined carcinogen-induced DNA damage: mutagenicity of single O4-ethylthymine adducts in HeLa cells. Nucleic Acids Res 1990; 18:4131-7. [PMID: 2377457 PMCID: PMC331169 DOI: 10.1093/nar/18.14.4131] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We developed a simian virus 40 based shuttle vector system to study the molecular consequences of distinct carcinogen-induced DNA lesions in human cells. To establish the mutagenicity of O4-ethylthymine adducts, oligonucleotides carrying a single O4-ethylthymine adduct at a unique position were ligated into the vector molecules. Following replication in HeLa cells on average 23% of the progeny molecules carried a mutation in the region of modification. The vast majority of these mutations represented single T----C transitions at the position of the modified base, most probably as a consequence of mispairing of the O4-ethylthymine residues during replication. To a minor extent the O4-ethylthymine adduct may also induce T----A transversions or double point mutations. The in vivo mutation frequency of the adduct was found to be comparable to that of a C-A mismatch at the same position, but was lower than that expected from in vitro experiments with adducted DNA templates and purified DNA polymerases.
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Affiliation(s)
- J C Klein
- Division of Chemical Carcinogenesis, The Netherlands Cancer Institute, Amsterdam
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25
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Church KM, Wurdeman RL, Zhang Y, Chen FX, Gold B. N-(2-chloroethyl)-N-nitrosoureas covalently bound to nonionic and monocationic lexitropsin dipeptides. Synthesis, DNA affinity binding characteristics, and reactions with 32P-end-labeled DNA. Biochemistry 1990; 29:6827-38. [PMID: 2168742 DOI: 10.1021/bi00481a011] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The synthesis and characterization of a series of compounds that contain an N-alkyl-N-nitrosourea functionality linked to DNA minor groove binding bi- and tripeptides (lexitropsins or information-reading peptides) based on methylpyrrole-2-carboxamide subunits are described. The lexitropsins (lex) synthesized have either a 3-(dimethylamino)propyl or propyl substituent on the carboxyl terminus. The preferred DNA affinity binding sequences of these compounds were footprinted in 32P-end-labeled restriction fragments with methidiumpropyl-EDTA.Fe(II), and in common with other structural analogues, e.g., distamycin and netropsin, these nitrosoureas recognize A-T-rich runs. The affinity binding of the compound with the dimethylamino terminus, which is ionized at near-neutral pH, appeared stronger than that observed for the neutral dipeptide. The sequence specificity for DNA alkylation by (2-chloroethyl)nitrosourea-lex dipeptides (Cl-ENU-lex), with neutral and charged carboxyl termini, using 32P-end-labeled restriction fragments, was determined by the conversion of the adducted sites into single-strand breaks by sequential heating at neutral pH and exposure to base. The DNA cleavage sites were visualized by polyacrylamide gel electrophoresis and autoradiography. The alkylation of DNA by Cl-ENU-lex was compared to that by N-(2-chloroethyl)-N'-cyclohexyl-N-nitrosourea (CCNU), which has no DNA affinity binding properties. While all the Cl-ENU compounds generate DNA breaks as a consequence of the formation of N7-alkyl-guanine, the Cl-ENU-lex compounds induced, in a time- and dose-dependent fashion, intense DNA cleavage bands at adenine, cytosine, and thymine residues associated with affinity binding sites. These non-G cleavages induced by Cl-ENU-lex were inhibited by the coaddition of distamycin at concentrations that did not affect G alkylation break sites. CCNU, even at much higher concentrations, does not generate any similar detectable lesions at non-G sites. Therefore, linking the Cl-ENU moiety to minor groove binders is a viable strategy to qualitatively and quantitatively control the delivery and release of the ultimate DNA alkylating agent in a sequence-dependent fashion.
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Affiliation(s)
- K M Church
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha 68198-6805
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26
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Weinfeld M, Liuzzi M, Paterson MC. Selective hydrolysis by exo- and endonucleases of phosphodiester bonds adjacent to an apurinic site. Nucleic Acids Res 1989; 17:3735-45. [PMID: 2543953 PMCID: PMC317854 DOI: 10.1093/nar/17.10.3735] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Partial depurination of d-ApA produced two UV260nm-absorbing isomers, d-SpA and d-ApS (where S represents the depurinated deoxyribose sugar), that provided simple model compounds with which to examine, by HPLC, the response of nucleases to phosphodiester bonds flanked 3' or 5' by an apurinic site. The structural identity of each compound was established by (i) reaction with methoxyamine to confirm the presence of an abasic deoxyribose group, and (ii) degradation of d-SpA under mild alkaline conditions to distinguish it from d-ApS. At an enzyme concentration which led to complete hydrolysis of d-ApA, snake venom phosphodiesterase readily cleaved d-SpA to 5'-dAMP but had no discernible effect on d-ApS. Calf spleen phosphodiesterase also failed to act on one isomer, in this instance d-SpA, but additionally reacted at a much slower rate (approximately 100 fold) with d-ApS than with d-ApA. Three single-strand specific endonucleases, nuclease P1, nuclease S1 and mung bean nuclease, all responded in an identical manner, hydrolysing d-ApS but not d-SpA. The possibility that the aldehyde group at the AP sites might be responsible for some of these observations was rejected after repeating the enzyme digestions with the methoxyamine-capped molecules and observing no differences from the reactions with d-SpA and d-ApS.
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Affiliation(s)
- M Weinfeld
- Department of Medicine, Cross Cancer Institute, Edmonton, Alberta, Canada
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Milligan JR, Hirani-Hojatti S, Catz-Biro L, Archer MC. Methylation of DNA by three N-nitroso compounds: evidence for sequence specific methylation by a common intermediate. Chem Biol Interact 1989; 72:175-89. [PMID: 2555071 DOI: 10.1016/0009-2797(89)90026-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Methylation in vitro of calf thymus DNA, a supercoiled plasmid, poly(dG).poly(dC), and poly(dGdC).poly(dGdC) by N-nitroso(acetoxy-methyl)methylamine and N-nitroso(acetoxybenzyl)methylamine in the presence of esterase, and by N-nitrosomethylurea was investigated. Although there were differences in the amounts of 7-methylguanine and O6-methylguanine formed in the various DNA substrates, the methylation pattern was the same for each of these methylating agents. The three compounds reacted identically when methylation of a portion of a 345 bp restriction fragment of the plasmid pBR322 was examined at nucleotide resolution by a sequencing assay. They also showed a tendency to react preferentially with particular guanines. These data suggest that the three N-nitroso compounds methylate DNA via a common intermediate such as the methyl diazonium ion, which exhibits some sequence specificity.
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Affiliation(s)
- J R Milligan
- Department of Medical Biophysics, University of Toronto, Ontario, Canada
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29
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Schutte HH, van der Schans GP, Lohman PH. Comparison of induction and repair of adducts and of alkali-labile sites in human lymphocytes and granulocytes after exposure to ethylating agents. Mutat Res 1988; 194:23-37. [PMID: 3386656 DOI: 10.1016/0167-8817(88)90053-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A comparative study has been made of the induction and repair of adducts and alkali-labile sites in the DNA of human lymphocytes and granulocytes exposed to the ethylating agents N-ethyl-N-nitrosourea (ENU) and diethyl sulphate (DES). To evaluate these damages, the human blood cells were treated with highly 3H-labelled ENU and DES, and the resulting 3H-ethyl adducts were analysed via HPLC. Alkali-labile sites introduced in the DNA during treatment with non-radioactive ENU and DES were detected by alkaline elution with fluorometric quantitation of the DNA in the eluted fractions. All known adducts induced by ENU and DES could be detected by the HPLC methods applied. Furthermore, these adducts were separated from a number of unidentified compounds, because of the improved resolution on the columns used. Most of the adducts were rather persistent during a subsequent incubation period of up to 20 h after treatment, but some partly disappeared (7-ethyladenine and 3-ethyladenine). The induction of alkali-labile sites in lymphocytes and granulocytes was very similar, but the kinetics of the removal of these sites appeared to be quite different. In granulocytes there was hardly any repair, whereas in lymphocytes, particularly after ENU treatment, a substantial and relatively fast repair was observed. Induction of alkali-labile sites in human lymphocytes and granulocytes occurred also at 0 degrees C; the data suggest that this kind of damage is not a result of enzymic repair processes. A comparison of the induction and the repair of alkali-labile sites in lymphocytes and granulocytes with those of the various ethyl adducts did not give a clue as to the identity of the adduct that could be responsible for the lability towards alkali.
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Affiliation(s)
- H H Schutte
- TNO Medical Biological Laboratory, Rijswijk, The Netherlands
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30
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Preston BD, Singer B, Loeb LA. Comparison of the relative mutagenicities of O-alkylthymines site-specifically incorporated into phi X174 DNA. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(19)76499-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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31
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Saffhill R. The Large Scale Synthesis and Chromatographic and Spectral Properties of a Series of Alkylated Thymine and Uracil-Containing Nucleosides. O2-, 3- and O4-Alkylpyrimidine Derivatives. ACTA ACUST UNITED AC 1987. [DOI: 10.1080/15257778708073418] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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32
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LaFortune F, Ens W, Hruska FE, Sadana KL, Standing KG, Westmore JB. Metastable ion studies with a secondary ion time-of-flight mass spectrometer. Enhanced distinction between isomers of O-alkylated thymidines. ACTA ACUST UNITED AC 1987. [DOI: 10.1016/0168-1176(87)87048-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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33
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Zielonacka-Lis E. Possible relevance of the stability of the glycosyl bond of undesired nucleosides in DNA to the mechanism of their repair. Chem Biol Interact 1987; 61:199-201. [PMID: 3829143 DOI: 10.1016/0009-2797(87)90040-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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34
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Richardson FC, Beauchamp RO, Swenberg JA. Properties and biological consequences of alkylpyrimidine deoxyribonucleosides. Pharmacol Ther 1987; 34:181-213. [PMID: 3317451 DOI: 10.1016/0163-7258(87)90011-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- F C Richardson
- Department of Biochemical Toxicology and Pathobiology, Chemical Industry Institute of Toxicology, Research Triangle Park, NC 27709
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35
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Kiriasis L, Farkas S, Pfleiderer W. Nucleosides, XLIII1)Synthesis and Properties of 04-Alkylthymidines. ACTA ACUST UNITED AC 1986. [DOI: 10.1080/07328318608068694] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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36
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Preston BD, Singer B, Loeb LA. Mutagenic potential of O4-methylthymine in vivo determined by an enzymatic approach to site-specific mutagenesis. Proc Natl Acad Sci U S A 1986; 83:8501-5. [PMID: 3464967 PMCID: PMC386958 DOI: 10.1073/pnas.83.22.8501] [Citation(s) in RCA: 103] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
O4-Alkylthymine-DNA adducts have been implicated as causative lesions in chemical mutagenesis and carcinogenesis. To directly assess the mutagenic potential of these adducts in vivo, we have designed an enzymatic technique for introducing nucleotide analogues at predetermined sites of biologically active DNA. Escherichia coli DNA polymerase I was used in vitro to incorporate a single O4-methylthymine residue at the 3' terminus of an oligonucleotide primer opposite the adenine residue of the amber codon in bacteriophage phi X174 am3 DNA. After further extension of the primer with unmodified nucleotides, the partial-duplex product was transfected into E. coli spheroplasts. Replication of the site-specifically methylated DNA in E. coli deficient in O4-methylthymine-DNA methyltransferase (ada-) yielded 10-fold more mutant progeny phage than replication of nonmethylated DNA; no increase in mutation frequency was observed after replication in repair-proficient (ada+) E. coli. The DNA from 20 independently isolated mutant plaques all contained A.T----G.C transitions at the original site of O4-methylthymine incorporation. These data demonstrate that O4-methylthymine induces base-substitution mutations in E. coli and suggest that this adduct may be involved in mutagenesis by N-nitroso methylating agents. This enzymatic technique for site-specific mutagenesis provides an alternative to the chemical synthesis of oligonucleotides containing altered bases.
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37
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Teo I, Sedgwick B, Kilpatrick MW, McCarthy TV, Lindahl T. The intracellular signal for induction of resistance to alkylating agents in E. coli. Cell 1986; 45:315-24. [PMID: 3009022 DOI: 10.1016/0092-8674(86)90396-x] [Citation(s) in RCA: 167] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The E. coli ada gene positively controls its own expression and that of other genes (alkA, alkB, aidB) involved in repair of DNA alkylation damage. The cloned ada and alkA genes and purified Ada protein have been used in cell-free systems to identify the inducing signal. Self-methylation of the Ada protein by transfer of a methyl group from a phosphotriester in alkylated DNA to a cysteine residue in the protein converts it to an activator of transcription. The covalently modified Ada protein binds specifically to promoter regions containing the sequence d(AAANNAAAGCGCA) immediately upstream of the RNA polymerase binding sites. This is apparently the first example of conversion of a regulatory gene product to a transcriptional activator by a posttranslational modification event.
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Singer B, Spengler SJ, Fraenkel-Conrat H, Kuśmierek JT. O4-Methyl, -ethyl, or -isopropyl substituents on thymidine in poly(dA-dT) all lead to transitions upon replication. Proc Natl Acad Sci U S A 1986; 83:28-32. [PMID: 3455756 PMCID: PMC322784 DOI: 10.1073/pnas.83.1.28] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In a previous paper, we reported that O4-methyl dTTP can be incorporated into poly(dA-dT) in place of thymidine without distortion of the helical structure, but on replication it could behave as deoxycytidine and misincorporate dGTP. Only weak interactions are possible for any O4-modified T X A pair. While O4-alkyl T X G pairing should be favored, experiments to detect the ability of Escherichia coli DNA polymerase I (pol I) to utilize the triphosphate as dCTP were ambiguous. dTTPs with larger alkyl groups (ethyl, isopropyl) have now been synthesized and tested for their recognition as dTTP by pol I. Enhanced steric hindrance could be expected, particularly for O4-isopropyl dTTP, which has a three-carbon branched chain. However, both compounds behaved qualitatively like O4-methyl dTTP, being incorporated into poly(dA-dT) and then directing deoxyguanosine misincorporation by pol I. Quantitative comparisons of mutagenicity were not possible because of the finding that, unlike polymers made with O4-methyl dTTP, those made with ethyl or isopropyl dTTP were resistant to hydrolysis by using a variety of nucleases. The frequent misincorporations of dGTP would be expected to produce transitions in vivo. O4-ethyldeoxythymidine is very poorly repaired in vivo, which would also be expected for repair of O4-isopropyldeoxythymidine. Therefore, under suitable conditions, these particular carcinogen products are likely to be initiators of carcinogenesis.
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39
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Singer B. In vivo formation and persistence of modified nucleosides resulting from alkylating agents. ENVIRONMENTAL HEALTH PERSPECTIVES 1985; 62:41-8. [PMID: 4085444 PMCID: PMC1568687 DOI: 10.1289/ehp.856241] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Alkylating agents are ubiquitous in the human environment and are continuously synthesized in vivo. Although many classes exist, interest has been focused on the N-nitroso compounds, since many are mutagens for bacteria, phage, and cells, and carcinogens for mammals. In contrast to aromatic amines and polyaromatic hydrocarbons which can react at carbons, simple alkylating agents react with nitrogens and oxygens: 13 sites are possible, including the internucleotide phosphodiester. However, only the N-nitroso compounds react extensively with oxygens. In vivo, most possible derivatives have been found after administration of methyl and ethyl nitroso compounds. The ethylating agents are more reactive toward oxygens than are the methylating agents and are more carcinogenic in terms of total alkylation. This is true regardless of whether or not the compounds require metabolic activation. It has been hypothesized that the level and persistence of specific derivatives in a "target" cell correlates with oncogenesis. However, no single derivative can be solely responsible for this complex process, since correlations cannot be made for even a single carcinogen acting on various species or cell types. Some derivatives are chemically unstable, and the glycosyl bond is broken (3- and 7-alkylpurines), leaving apurinic sites which may be mutagenic. These, as well as most adducts, are recognized by different enzymatic activities which remove/repair at various rates and efficiencies depending on the number of alkyl derivatives, as well as enzyme content in the cell and recognition of the enzyme. Evaluation of human exposure requires early and sensitive methods to detect the initial damage and the extent of repair of each of the many promutagenic adducts.
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40
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Yang NC, Chang CW. Selective alkylation of carcinogenic 9-anthryloxirane at the N-3 position of adenine in DNA. Proc Natl Acad Sci U S A 1985; 82:5250-4. [PMID: 3860860 PMCID: PMC390545 DOI: 10.1073/pnas.82.16.5250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Carcinogenic 9-anthryloxirane binds covalently to calf thymus DNA and poly(dA-dT). Application of the technique for DNA sequence determination shows that acid cleavage of the modified DNA frees approximately half of the anthryl groups from the DNA. HPLC analysis indicates that an adenine adduct and the glycol derived from 9-anthryloxirane are the major acid-labile products. Spectroscopic analyses establish that the adenine adduct is the N-3 adduct of 9-anthryloxirane to adenine. Similar analyses of modified poly(dA-dT) indicate that the binding of 9-anthryloxirane takes place selectively at the N-3 position of adenine. The significance of this finding is briefly discussed.
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41
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Golankiewicz B, Zielonacka-Lis E, Folkman W. Kinetics and mechanism of the acid-catalyzed hydrolysis of a hypermodified nucleoside wyosine and its 5'-monophosphate. Nucleic Acids Res 1985; 13:2443-9. [PMID: 4000960 PMCID: PMC341166 DOI: 10.1093/nar/13.7.2443] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The rates of acid-catalyzed hydrolysis of a hypermodified nucleoside, wyosine and its 5'-monophosphate were determined at various pH, temperature and buffer concentrations. The results show that despite distinct differences in structure and the glycosyl bond stability, the hydrolysis of wyosine proceeds via cleavage of the C-N bond by A-1 mechanism, analogously to simple nucleosides. Unlike majority of other monophosphates studied so far, wyosine 5'-monophosphate is not more stable than respective nucleoside.
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Abstract
A series of poly(dT,RdT) polynucleotides containing O2-, 3- and O4-methyl- or ethyldeoxythymines have been prepared and used as templates for Pol I, Pol alpha and Pol R to investigate the miscoding properties of these modified bases with the different nucleotide polymerising enzymes. Only O4-alkylthymine (O4-RT) leads to a large number of errors (incorporation of dGMP with a mutagenic efficiency approaching unity). O2-RT has a very much lower, but none-the-less significant, mutagenic efficiency and 3-RT does not lead to errors with the DNA polymerases. All alkylthymines lead to significant errors with the RNA polymerase. The results confirm conclusions concerning the promutagenic nature of the alkylthymines and that the reported differences in their promutagenicity with the various polymerases reflect different specificities of the nucleotide polymerising enzymes used.
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Djurić Z, Sinsheimer JE. Characterization and quantitation of 3-alkylthymidines from reactions of mutagenic propylene oxides with thymidine. Chem Biol Interact 1984; 52:243-53. [PMID: 6391705 DOI: 10.1016/0009-2797(84)90077-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Thymidine was reacted in methanol with four epoxides of varying mutagenicities: propylene oxide, glycidol, epichlorohydrin and trichloropropylene oxide. A single product was detected with each epoxide, and these products had the same retention times on silica high pressure liquid chromatography (HPLC). UV spectra of the products identified them as 3-alkylthymidines, and this was confirmed by infrared (IR) and nuclear magnetic resonance (NMR) spectra. Mass spectra (MS) analysis showed the products to be consistent with attachment at the least substituted carbon of the epoxide. Formation of 3-alkylthymidines correlated to Taft sigma electron withdrawing values for the substituents on the epoxides and mutagenicities in strain TA100 of the Ames Assay.
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La Belle M, Linn S, Thompson LH. Apurinic/apyrimidinic endonuclease activities appear normal in the CHO-cell ethyl methanesulfonate-sensitive mutant, EM9. Mutat Res 1984; 141:41-4. [PMID: 6482894 DOI: 10.1016/0165-7992(84)90035-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A study of the apurinic/apyrimidinic (AP) endonuclease activities of a mutant line of CHO cells, EM9, and its parental cell line, AA8, was undertaken to determine if the defective DNA repair exhibited by the mutant cell line after exposure to ethyl methanesulfonate was due to a defective AP endonuclease activity. Phosphocellulose chromatography of cell extracts resolved the AP endonuclease activities of both cell lines into two peaks as seen previously in mouse and human cells. No difference was found between the mutant and parental cell lines in the relative amount of AP endonuclease activity present in the two peaks.
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Djuric Z, Sinsheimer JE. Reactivity of propylene oxides towards deoxycytidine and identification of reaction products. Chem Biol Interact 1984; 50:219-31. [PMID: 6744466 DOI: 10.1016/0009-2797(84)90098-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Deoxycytidine was reacted with four epoxides of varying alkylating rates: propylene oxide, glycidol, epichlorohydrin and trichloropropylene oxide. Deoxycytidine was chosen to compare the reactivities of these epoxides as all sites of possible alkylation, the oxygen and both nitrogens, are involved in base pairing in DNA. Reaction products were separated on HPLC. Products of the least and most reactive epoxides, propylene oxide and trichloropropylene oxide, were characterized by UV, IR, 360 MHz NMR and MS analysis. For the epichlorohydrin and glycidol reactions and all analytical separations, products were characterized by their HPLC retention times and UV spectra. While differences in reactivity among the epoxides towards specific nitrogen and oxygen sites were found, total reactivity correlated with Taft sigma-values of the substituent groups.
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46
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Ahmmed Z, Laval J. Enzymatic repair of O-alkylated thymidine residues in DNA: involvement of a O4-methylthymine-DNA methyltransferase and a O2-methylthymine DNA glycosylase. Biochem Biophys Res Commun 1984; 120:1-8. [PMID: 6370256 DOI: 10.1016/0006-291x(84)91405-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Alkylation of poly(dT) by N-[methyl-3H] (N-nitrosomethylurea) and subsequent annealing with poly(dA) yield a substrate containing O2 and O4-methylthymidine, 3-methylthymidine and phosphotriesters. In an in vitro assay using this substrate, cell extracts from Escherichia coli catalyse i) the transfer of the O4-methyl present in O4 methylthymidine to a protein which becomes alkylated; ii) the release of O2-methylthymine by a glycosylase activity. The two DNA repair activities described above appear to be involved in the adaptive response.
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Singer B, Sági J, Kuśmierek JT. Escherichia coli polymerase I can use O2-methyldeoxythymidine or O4-methyldeoxythymidine in place of deoxythymidine in primed poly(dA-dT).poly(dA-dT) synthesis. Proc Natl Acad Sci U S A 1983; 80:4884-8. [PMID: 6348776 PMCID: PMC384151 DOI: 10.1073/pnas.80.16.4884] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
O2-and O4-alkyldeoxythymidine are among the four O-alkyl base-modified derivatives produced by the reaction of N-nitroso alkylating agents with nucleic acids in vitro and in vivo. We find that both O2- and O4-methyl-dTTP can substitute for dTTP in alternating poly(dA-dT)-primed DNA synthesis. Up to 22% of the pyrimidines in the newly synthesized polymer were found by HPLC analysis to be O-methyldeoxythymidine. Little polymer synthesis was observed in the absence of dTTP. However, the O-methyl-dTTPs did not inhibit polymerization of dATP and dTTP. Polymers containing O2- or O4-methyldeoxythymidine were obtained in good yield, retaining the secondary structure of alternating poly(dA-dT). This was shown by the data for thermal transition under different conditions. In contrast, poly(dA-dT).poly(dA-dT) methylated or ethylated to less than 4% total modification by alkylnitrosoureas had a distinctly less stable structure. Neither O2- nor O4-methyldeoxythymidine can form more than one hydrogen bond with adenosine. The unchanged secondary structure of polymers containing these modified thymidines indicates that stacking interactions must play a major role in helix stabilization. O-Alkyldeoxythymidine may be formed by N-nitroso carcinogens that react intracellularly. We have shown that the triphosphates can be utilized by Escherichia coli DNA polymerase I as dTTP. The incorporated O4-methyl-dT causes misincorporation of G, both in transcription and synthesis. When O2-methyl-dT is present, less, but definite, misincorporation results.
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Su CM, Brash DE, Chang MJ, Hart RW, D'Ambrosio SM. Induction of single-strand breaks plus alkali-labile bonds by N-nitrosoureas in rat tissues in vivo: ethylnitrosourea versus benzylnitrosourea. Mutat Res 1983; 108:1-12. [PMID: 6835219 DOI: 10.1016/0027-5107(83)90105-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Alkaline sucrose sedimentation procedures were used to quantitate the amount of single-strand breaks plus alkali-labile bonds (SSB + ALB) induced and repaired following a single intraperitoneal injection of the neurocarcinogen N-ethyl-N-nitrosourea (ENU) and its non-neurocarcinogenic analog N-benzyl-N-nitrosourea (BNU) in the brain, liver and kidney of female Sprague-Dawley rats. SSB + ALB were measured and used as an indicator of apurinic/apyrimidinic sites, phosphotriesters and in situ breaks. ENU induced a dose-dependent increase in the number of SSB + ALB at the doses studied (0, 0.39, 0.77, 1.54 mmoles/kg) in all 3 tissues. At 1 h postinjection with 0.77 mmoles/kg of these compounds there were 50-70% fewer breaks induced by BNU than ENU. The SSB + ALB induced by ENU persisted over a 7-day period, while those induced by BNU did not. Thus, these studies showed that 2 homologues of nitrosoureas, ENU and BNU, exhibited different potentials to induce and to persist SSB + ALB in vivo.
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49
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Singer B, Brent TP. Human lymphoblasts contain DNA glycosylase activity excising N-3 and N-7 methyl and ethyl purines but not O6-alkylguanines or 1-alkyladenines. Proc Natl Acad Sci U S A 1981; 78:856-60. [PMID: 6940152 PMCID: PMC319902 DOI: 10.1073/pnas.78.2.856] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cultured human lymphoblasts (CCRF-CEM line) have DNA glycosylase activities, the specificities of which were investigated by using high-performance liquid chromatography. In addition to 3-methyladenine, 3-ethyladenine, 7-methylguanine, 7-ethylguanine, 3-methylguanine, and 3-ethylguanine also were excised from alkylated double-stranded DNA and deoxypolynucleotides, but 1-methyladenine, 1-ethyladenine, O6-methylguanine, and O6-ethylguanine were not. The glycosylase activity was generally greater for the methylated than for the corresponding ethylated purines and was also greater toward 3-alkyladenine than toward 3-alkyladenine than toward 3-alkylguanine. 7-Methylguanine and 7-ethylguanine were excised to similar but low extents. However, in molar terms, the release of 7-methylguanine was similar to that of 3-methyladenine.
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