Repair, Replication, and Detection of Oxidatively Damaged DNA

描述（申请人提供）：核酸氧化在疾病的病因和治疗中具有重要意义。例如，电离辐射会导致癌症，并通过破坏DNA来摧毁肿瘤细胞。DNA损伤也与衰老和多种其他疾病有关（如着色性干皮病、囊性纤维化、心肌梗死）。这项研究的目的是了解氧化应激在DNA中产生的损伤是如何修复、复制和反应形成其他损伤的。我们也在开发选择性检测DNA损伤的工具。我们的大部分工作都集中在氧化的碱性损伤上，这些损伤不能形成沃森-克里克氢键。与之前所认为的相反，氧化基灶以不同的方式与聚合酶相互作用，并与碱基位点（AP）相互作用，这是由核苷酸的糖苷键的形式水解产生的。因此，不能形成沃森-克里克氢键并不意味着病变没有指导意义。我们将使用合成化学来合成类似物，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导致其在细胞中观察到的效应。我们还将检查似乎需要DNA修复酶异常处理的病变的修复。最后，我们将开发和使用试剂，使我们能够选择性地检测氧化的基本病变。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。与公共卫生相关：核酸氧化损伤在衰老以及遗传疾病（如癌症）的病因和治疗中发挥重要作用。这项基础研究对了解癌症等疾病的病因和治疗有价值。此外，我们开发的选择性检测氧化碱基位点的试剂将成为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.