MITOCHONDRIAL DNA DAMAGE AND REPAIR

线粒体 DNA 损伤与修复

• 批准号: 6352912
• 负责人: DANIEL F. BOGENHAGEN
• 金额: $ 21.9万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-04-10 至 2001-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6352912
• 关键词: DNA damage; DNA directed DNA polymerase; DNA repair; DNA replication; adenine; cytosine; endonuclease; environmental toxicology; enzyme activity; mitochondrial DNA; mitochondrial disease /disorder; molecular genetics; oxidative stress

Mitochondrial DNA is a frequent target of chemical damage. Base loss, oxidative damage and reaction with carcinogenic compounds such as benzo(a)pyrene and aflatoxin are thought to occur at rates equal to or greater than the corresponding rates of damage to nuclear DNA. Mitochondria are able to repair some types of DNA damage, such as abasic sites and oxidative lesions (e.g., 8-oxo-dG), but probably not others. Very little is known concerning the enzymology of DNA repair in mitochondria. Replication through DNA adducts or attempts at repair may contribute to the incidence of point mutations and deletions observed in a growing list of human diseases. These diseases range from point mutations associated with rare neuromuscular diseases identified with the acronyms MELAS, MERRF, and NARP to large deletions observed in Kearns Sayre Syndrome. Recent studies have found a correlation between mtDNA damage and type 11 diabetes, Parkinson's disease and aging, although more research is required to establish a role for mtDNA damage in the etiology of these conditions. We propose to investigate the effects of specifically localized lesions in DNA templates prepared by our collaborators in this project on DNA replication by the purified mitochondrial DNA polymerase gamma. These studies will employ templates containing abasic sites, 8-oxo-dG, aminofluorene and benzo(a)pyrene adducts. We will also search for accessory factors that may facilitate translesional synthesis by DNA polymerase gamma. We propose experiments to characterize enzymes involved in mtDNA repair and to attempt to reconstitute repair of abasic sites or 8-oxo-dG lesions in mtDNA. Certain lesions, such as cyclobutane pyrimidine dimers in mtDNA are not thought to be repaired efficiently. We will attempt to increase the efficiency of repair by using molecular genetic techniques to direct repair enzymes such as photolyase or T4 endonuclease (denV) to mitochondria.

线粒体DNA是化学损伤的常见靶标。基本损失， 氧化损伤和与致癌化合物的反应， 苯并（a）芘和黄曲霉毒素被认为以等于或 比相应的核DNA损伤率要高。 线粒体能够修复某些类型的DNA损伤，如脱碱基 位点和氧化损伤（例如，8-氧代-dG），但可能不是其他人。 关于DNA修复的酶学知之甚少， 线粒体通过DNA加合物或修复的尝试进行复制， 有助于在细胞中观察到的点突变和缺失的发生率。 越来越多的人类疾病这些疾病的范围从点 与罕见神经肌肉疾病相关的突变， 首字母缩略词MELAS、MERRF和NARP与Kearns中观察到的大缺失 塞尔综合征。最近的研究发现线粒体DNA 损伤和11型糖尿病，帕金森病和衰老，虽然更多 需要研究确定mtDNA损伤在病因学中的作用 这些条件。我们建议调查的影响 在我们制备的DNA模板中， 合作者在这个项目上的DNA复制的纯化 线粒体DNA聚合酶γ这些研究将采用模板 含有脱碱基位点、8-氧代-dG、氨基芴和苯并（a）芘 加合物我们还将寻找辅助因素， 通过DNA聚合酶γ的跨损伤合成。我们提出实验 以表征参与mtDNA修复的酶，并试图 线粒体DNA中脱碱基位点或8-oxo-dG损伤的修复。某些 线粒体DNA中的环丁烷嘧啶二聚体等损伤， 有效修复。我们将努力提高效率 通过使用分子遗传技术来指导修复酶 如光裂合酶或T4内切核酸酶（denV）。