Repair mechanism of oxidative DNA damage on the mitochondrial genome

线粒体基因组DNA氧化损伤的修复机制

• 批准号: 13680618
• 负责人: MASASHI Takao
• 金额: $ 2.3万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13680618/
• 关键词: Reactive oxygen species; Mitochondrion; DNA repair; Aging; Cancer; Knock-out mouse; Base excision repair; DNAグリコシラーゼ

This research is a basic investigation to evaluate the importance of DNA repair on the mitochondrial genome in view of cancer protection and aging process. For this purpose mutant mice that lack NTH1, a key enzyme removing oxidative pyrimidine base lesions from mitochondrial and nuclear DNA, was generated. The Nth1 knock-out did not lead to any abnormal mouse phenotype nor to sensitivity against oxidative stress. These results provoked us to find residual repair activities in the mutant mouse cells. With a biochemical approach, one residual DNA glycosylase activity in the mitochondrial extracts and, at least, two activities in the nuclear extracts were found. We analyzed three candidate genes in the database for the biochemically detected activities, and found that a gene named Neil1 encodes one of the nuclear DNA glycosylases. These results clearly indicate that mammalian base excision repair for oxidative pyrimidines can be initiated by multiple DNA glycosylases in both nucleus and mitochondrion, raising questions toward further studies, such as why and how the cells use different enzymes.

这项研究是一项基础研究，旨在评估线粒体基因组DNA修复在癌症保护和衰老过程中的重要性。为此，产生了缺乏NTH 1的突变小鼠，NTH 1是从线粒体和核DNA中去除氧化嘧啶碱基损伤的关键酶。Nth1基因敲除未导致任何异常小鼠表型，也未导致对氧化应激的敏感性。这些结果促使我们在突变小鼠细胞中发现残留的修复活性。通过生化方法检测到线粒体中有一个残留的DNA糖基化酶活性，核中至少有两个残留的DNA糖基化酶活性，我们对数据库中的三个候选基因进行了生化分析，发现Neil 1基因编码核中的一个DNA糖基化酶。这些结果清楚地表明，哺乳动物的碱基切除修复氧化嘧啶可以启动多个DNA糖基化酶在细胞核和细胞外基质，提出了进一步的研究问题，如为什么和如何细胞使用不同的酶。

项目成果

Takao M., Kanno S.et al.: "Novel nuclear and mitochondrial glycosylases revealed by disruption of the mouse Nth1 gene encoding an endonuclease III homolog for repair of thymine glycols"EMBO J.. 21・13. 3486-3493 (2002)

Takao M.、Kanno S.等人：“通过破坏编码核酸内切酶 III 同源物的小鼠 Nth1 基因揭示用于修复胸腺嘧啶二醇的新型核糖基化酶和线粒体糖基化酶”EMBO J.. 21・13 (2002)。

Takao M. et al.: "Novel nuclear and mitochondrial glycosylases revealed by disruption of the mouse Nth1 gene encoding an endonuclease III homolog for repair of thymine glycols"EMBO J.. 20-13. 3486-3493 (2002)

Takao M. 等人：“通过破坏编码内切核酸酶 III 同源物的小鼠 Nth1 基因揭示了用于修复胸腺嘧啶二醇的新型核糖基酶和线粒体糖基化酶”EMBO J.. 20-13。

Miyabe I. et al.: "Identification of 5-formyluracil DNA glycosylase activity of human hNTH1 protein"Nucleic Acids Res.. 30-15. 3443-3448 (2002)

Miyabe I.等人：“人hNTH1蛋白的5-甲酰尿嘧啶DNA糖基化酶活性的鉴定”核酸研究30-15。

Takao M. et al.: "A back-up glycosylase in Nth1 knock-out mice is a functional Nei (endonuclease VIII) homologue"J. Biol. Chem.. 277・44. 42205-42213 (2002)

Takao M. 等：“Nth1 敲除小鼠中的备用糖基化酶是功能性 Nei（核酸内切酶 VIII）同源物”J. Biol. 277・44 (2002)。

Matsumoto Y. et al.: "Escherichia coli Nth and human hNTH1 DNA glycosylase are involved in removal of 8-oxoguanine from 8-oxoguanine/guanine mispairs in DNA"Nucleic Acids Res.. 29・9. 1975-1981 (2001)

Matsumoto Y. 等人：“大肠杆菌 Nth 和人 hNTH1 DNA 糖基化酶参与从 DNA 中的 8-氧代鸟嘌呤/鸟嘌呤错配中去除 8-氧代鸟嘌呤”，Nucleic Acids Res. 1975-1981 (2001)。