Investigations of DNA Damage and Repair

描述（由申请人提供）：拟议研究的总体目标 是为了探测DNA的致突变性和三种损伤的修复， 在核酸中通过各种氧化应激机制。这些病变 都缺乏核碱基的存在，并且是由核碱基的形式氧化产生的。 碳水化合物部分这些氧化脱碱基损伤在DNA中的存在， 体内与癌症和衰老有关。尽管它们很重要， 在分子水平上，这些碱基损伤对DNA功能的影响并不 很好理解。 利用从这些和以前的相关研究中获得的基本知识， 我们正在设计DNA修复过程的酶抑制剂。第一代 抑制碱基切除修复（BER）酶的裂解酶步骤的分子是 在这个提案中提出。 我们的一般实验方法涉及明确的合成（和 表征）的寡核苷酸的方法 病变部位具体纳入。病变对双功的影响 使用这些化学合成的化合物检测稳定性和酶活性。 印刷受体.具体目标包括： 1.病变的体外和体内致突变性研究。 2. BER酶在体外和体内修复这些损伤的研究 vivo. 3.在E.大肠杆菌和酵母中。 4. BER自杀抑制剂的设计。 增加了对氧化脱碱基病变对核酸的影响的理解， 酸的结构和功能将有助于了解协会 核酸损伤和衰老之间的关系，以及疾病的病因， 癌症这些研究的应用，如酶的设计 抑制剂可以提供新的治疗剂。

DESCRIPTION (provided by applicant): The overall goal of the proposed research is to probe the DNA mutagenicity and repair of three lesions that are produced in nucleic acids via a variety of oxidative stress mechanisms. These lesions all lack the presence of a nucleobase, and result from formal oxidation of the carbohydrate moiety. The presence of these oxidized abasic lesions in DNA in vivo is associated with cancer and aging. Despite their importance, the effects of these abasic lesions on the function of DNA at the molecular level are not well understood. Using the fundamental knowledge gained from these and previous related studies, we are designing enzyme inhibitors of DNA repair processes. First generation molecules that inhibit the lyase step of base excision repair (BER) enzymes are presented in this proposal. Our general experimental approach involves the unambiguous synthesis (and characterization) of oligonucleotides containing individual oxidized abasic lesions site specifically incorporated. The effects of the lesions on duplex stability and enzyme activity are examined using these chemically synthesized substrates. Specific aims include: 1. Investigation of the in vitro and in vivo mutagenicity of the lesions. 2. Investigation of the repair of these lesions by BER enzymes in vitro and in vivo. 3. Examination of the lethality of these lesions in E. coli and in yeast. 4. Design of suicide inhibitors of BER. Increased understanding of the effects of oxidized abasic lesions on nucleic acid structure and function will be useful for understanding the association between nucleic acid damage and aging, as well as the etiology of diseases such as cancer. Application of these studies, such as the design of enzyme inhibitors may provide new therapeutic agents.