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.

活性氧簇(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引起的DNA氧化损伤。因此，了解RIS引起DNA损伤的性质是很重要的。这一提议的中心假设指出，氧化DNA损伤的真实性质在几个重要方面与普遍接受的观点不同。这一论点的基础来自对DNA寡聚体中ROS损伤的研究。低聚物中的DNA损伤分析已经完成，而不会进一步降解受损的低聚物。这些分析表明，许多主要的ROS诱导的损害是两个相邻的核苷都受到损害的损害。另一个发现是，如果有氧气来调节损伤过程，嘧啶碱基裂解产物很可能是主要的嘧啶碱基损伤。如果不存在氧作为介质，则6-羟基-5，6-二氢胸腺嘧啶修饰是主要损害。最近的一项观察表明，链断裂是与附近鸟嘌呤损伤的氧化作用一起产生的。我们的假设是，在寡聚体中观察到的这些和其他标志性病变也是由细胞中的ROS产生的。这项拟议的研究将分析暴露在ROS培养中的细胞中的这些标志性损伤。大多数检测将使用32P-后标记进行检测，并将通过使用本实验室合成的载体使其明确无误。两个细胞系将被检查被认为最能代表DNA氧化损伤性质的损伤。将使用三种不同的方法使细胞承受氧化应激。