Repair, Replication, and Detection of Oxidatively Damaged DNA

描述（由申请人提供）：核酸氧化在疾病的病因学和治疗中很重要。例如，电离辐射会导致癌症，并通过破坏 DNA 来破坏肿瘤细胞。 DNA 损伤还与衰老和多种其他疾病（例如色素性干皮病、囊性纤维化、心肌梗塞）有关。这项研究的目的是了解由于氧化应激而在 DNA 中产生的损伤如何被修复、复制以及如何反应形成其他损伤。我们还在开发选择性检测 DNA 损伤的工具。我们的大部分努力都集中在氧化无碱基损伤上，这些损伤无法形成沃森-克里克氢键。与之前所认为的相反，氧化脱碱基损伤与聚合酶以不同的方式相互作用，并通过核苷酸糖苷键正式水解产生的脱碱基位点（AP）相互作用。因此，无法形成沃森-克里克氢键并不意味着损伤没有指导意义。我们将使用合成化学来合成类似物，使用快速猝灭动力学来确定聚合酶机制，以及穿梭载体实验来确定单个病变的哪些结构特性会在细胞中产生观察到的效应。我们还将检查似乎需要 DNA 修复酶进行异常处理的损伤的修复。最后，我们将开发和使用使我们能够选择性检测氧化无碱基损伤的试剂。这些工具将使科学家能够将病变的独特生物效应与各种氧化剂形成的病变联系起来。与公共健康的相关性：氧化核酸损伤在衰老以及癌症等遗传性疾病的病因和治疗中发挥着重要作用。这项基础研究对于了解癌症等疾病的病因和治疗很有价值。此外，我们开发的用于选择性检测氧化无碱基位点的试剂将是有价值的生物技术工具。

DESCRIPTION (provided by applicant): Nucleic acid oxidation is important in the etiology and treatment of disease. For instance, ionizing radiation causes cancer and destroys tumor cells by damaging DNA. DNA damage is also involved in aging and a variety of other diseases (e.g. Xeroderma Pigmentosum, cystic fibrosis, myocardial infarction). The goals of this research are to understand how lesions produced in DNA as a result of oxidative stress are repaired, replicated, and react to form other lesions. We are also developing tools for selectively detecting DNA lesions. Much of our effort focuses on oxidized abasic lesions, which are incapable of forming Watson-Crick hydrogen bonds. Contrary to what was previously believed, oxidized abasic lesions interact with polymerases in distinct ways from each other and from an abasic site (AP) resulting from formal hydrolysis of a nucleotide's glycosidic bond. Hence, the inability to form Watson-Crick hydrogen bonds does not mean that a lesion is noninstructive. We will use synthetic chemistry to synthesize analogues, rapid-quench kinetics to determine polymerase mechanisms, as well as shuttle vector experiments to determine what structural properties of the individual lesions give rise to their observed effects in cells. We will also examine the repair of lesions that would appear to require unusual handling by DNA repair enzymes. Finally, we will develop and employ reagents that enable us to selectively detect oxidized abasic lesions. These tools will enable scientists to correlate unique biological effects of lesions with their formation by various oxidizing agents. Relevance to public health: Oxidative nucleic acid damage plays an important role in aging, as well as the etiology and treatment of genetic diseases, such as cancer. This fundamental research is valuable to understanding the etiology and treatment of diseases such as cancer. Furthermore, the reagents developed by us for selectively detecting oxidized abasic sites will be valuable biotechnology tools.