Mutagenesis and repair mechanism of DNA base lesions induced by nitrogen oxides

• Project/Area Number: 15510054
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Risk sciences of radiation/Chemicals
• Research Institution: HIROSHIMA UNIVERSITY
• Principal Investigator: TERATO Hiroaki Hiroshima University, Graduate School of Science, Research Associate, 大学院・理学研究科, 助手 (00243543)
• Project Period (FY): 2003 – 2004
• Project Status: Completed (Fiscal Year 2004)
• Budget Amount: ¥3,200,000 (Direct Cost: ¥3,200,000); Fiscal Year 2004: ¥1,600,000 (Direct Cost: ¥1,600,000); Fiscal Year 2003: ¥1,600,000 (Direct Cost: ¥1,600,000)
• Keywords: nitrogen oxides / deamination / base damage / crosslink / DNA replication / base pairing / base excision repair(BER) / nucleotide excision repair(NER) / オキザニン / 付加体形成 / DNAグリコシラーゼ / 損傷乗り越え複製 / ヒストン

Research Abstract

(1)Mutagenesis of deamination products derived from guanine induced by nitrogen oxide
I investigated activities of Escherichia coli DNA polymerase I Klenow fragmen (Pol I Kf)for xanthin (Xan), oxanin (Oxa) and its crosslink-product(Oxa-Sp with spermine for their mutagenesis abilities. The relative activities of translesional elongation of Pol I Kf were for G(1)>Oxa (0.19)>Xan (0.12)>AP site (0.088)>Oxa-Sp(0.035). For insertion abilities of Pol I Kf, Xan in template preferred TM (16% and dGM (14% than other nucleotides, and Oxa in template preferred TMP(49%)than other nucleotides. On the other hand, Oxa-Sp highly inhibited DNA polymerization of the enzyme. These results indicate that their lesions show severe mutagenic properties with respective manner.
(2)Repair activities for Oxa and its crosslink-lesion
I investigated repair activities for Oxa and its crosslink-lesion using purified enzymes and defined oligonucleotide substrates containing these lesions. Firstly, I investigated any DNA glycosylases for these lesions. However, all enzymes I tried showed poor activities to remove these lesions from DNA. The result indicates that base excision repair(BER)is not effective to these lesions. Then, I tied UvrABC complex derived from Bacillus cardotenax for these lesions. The enzyme of nucleotide excision repair(NER)showed nicking activity for DNA substrate containing Oxa-Sp. The nuclear extracts of HeLa cells also showed simlar NER activity for the substrate. These results indicate that Oxa easily converts secondary crosslink lesions such as Oxa-Sp in vivo, and the crosslink lesions can be removed by NER process.

Research Products

• [Journal Article] Assessment of the genotoxic potential of nitric oxide-induced guanine lesions by in vitro reactions with Eschericia coli DNA polymerase I. (2005)
  • Author(s): Toshiaki Nakano
  • Journal Title: Mutagenesis 20 Pages: 209-216
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Repair activity of base and nucleotide excision repair enzymes for guanine lesions induced by nitrosative stress. (2005)
  • Author(s): Toshiaki Nakano
  • Journal Title: Nucleic Acids Research 33 Pages: 2181-2191
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Assessment of the genotoxic potential of nitric oxide-induced guanine lesions by in vitro reactions with Eschericia coli DNA polymerase I.
  • Author(s): Nakano, T.
  • Journal Title: Mutagenesis (in press)
• [Journal Article] Repair activity of base and nucleotide excision repair enzymes for guanine lesions induced by nitrosative stress.
  • Author(s): Nakano, T.
  • Journal Title: Nucleic Acids Res. (in press)
• [Publications] Nakano, Toshiaki: "DNA-protein cross-link formation mediated by oxanine. A novel genotoxic mechanism of nitric oxide-induced DNA damage"The Journal of Biological Chemistry. 278・27. 25264-25272 (2003)