THE TRUE NATURE OF OXIDATIVE DNA DAMAGE

DNA 氧化损伤的真正本质

• 批准号: 6475853
• 负责人: HAROLD C BOX
• 金额: $ 15.4万
• 依托单位: ROSWELL PARK CANCER INSTITUTE CORP
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-12-16 至 2003-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6475853
• 关键词: DNA damage; DNA repair; chemical transfer reaction; diol; electrochemistry; formamide; free radical oxygen; gas chromatography mass spectrometry; guanine nucleoside; neoplastic process; neural degeneration; nucleolus; oxidative stress; oxygen tension; phosphorus; protein degradation; protein structure; pyrimidine nucleosides; radionuclides; thymine; tissue /cell culture

Reactive oxygen species (ROS) and oxidative stress have been implicated in cancer, aging and in several neurodegenerative diseases. The molecular mechanism underlying these disease etiologies likely involves oxidative DNA damaged engendered by ROS. Consequently, it is important to know the nature if RIS-induced DNA damage. The central hypothesis of this proposal states that the true nature of oxidative DNA damage differs in several important aspects from generally accepted views. The basis for this contention comes from studies of ROS damage in DNA oligomers. The analyses of DNA damage in oligomers has been accomplished without further degradation of the damaged oligomers. These analyses indicate that many of the main ROS-induced lesions are lesions in which two adjacent nucleosides are both damaged. Another finding is that pyrimidine base breakdown products are by all odds the main pyrimidine base damage if oxygen is available to mediate the damage process. If oxygen is not present as mediator, the 6-hydroxyl-5,6-dihydrothymine modification is a principal lesion. A recent observation is that strand breaks are produced in conjunction with oxidation of a nearby guanine lesion. Our hypothesis is that these and other hallmark lesions observed in oligomers are produced by ROS in cells as well. The proposed research will assay for these hallmark lesions in cells exposed in culture to ROS. Most assays will employ 32p-post-labeling for detection and will be made unequivocal through the use of carriers synthesized in this laboratory. Two cell lines will be examined for the lesions deemed most representative of the nature of oxidative DNA damage. Three different methods for subjecting cells to oxidative stress will be utilized.

活性氧（ROS）和氧化应激与癌症，衰老和几种神经退行性疾病有关。这些疾病病因的分子机制可能涉及ROS损坏的氧化DNA。因此，重要的是要了解RIS诱导的DNA损伤的性质。该提议的中心假设指出，氧化DNA损伤的真实本质在几个重要方面与普遍接受的观点不同。这种争论的基础来自对DNA低聚物中ROS损伤的研究。在没有进一步损害的低聚物降解的情况下，已经完成了低聚物中DNA损伤的分析。这些分析表明，许多主要的ROS诱导的病变是病变，其中两个相邻的核苷都受损。另一个发现是，如果有氧气可用于介导损伤过程，嘧啶基碱基分解产物的主要嘧啶基碱损伤。如果不作为氧气作为介体，则6-羟基-5,6-二氢氨基氨酸的修饰是主要病变。最近的一个观察结果是，链断裂是与附近鸟嘌呤病变的氧化一起产生的。我们的假设是，在低聚物中观察到的这些和其他标志性病变也由细胞中的ROS产生。拟议的研究将在培养物中暴露于ROS的细胞中测定这些标志性病变。大多数测定方法将采用32p-ost-post标记进行检测，并通过在本实验室中合成的载体而明确地进行检测。将检查两种细胞系的病变，以证明氧化性DNA损伤的性质最具代表性。将利用三种不同的方法来使细胞受到氧化应激。