Investigations of DNA Damage and Repair

描述(申请人提供)：拟议研究的总体目标是探索DNA的致突变性和修复产生的三个病变 通过各种氧化应激机制在核酸中的作用。这些损伤 它们都缺乏核苷酸碱基的存在，并且是由 碳水化合物部分。这些氧化的基本损伤在DNA中的存在 VIVE与癌症和衰老有关。尽管它们很重要，但它们的影响 在这些分子水平上对DNA功能的基本损伤中， 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)酶裂解酶步骤的分子有 在本提案中提出。 我们的一般实验方法涉及明确的综合(和 含单个氧化碱基的寡核苷酸的表征) 病变部位具体并入。病变对双联畸形的影响 使用化学合成的这些化合物来检测稳定性和酶活性 底物。具体目标包括： 1.研究病变的体内外致突变性。 2.BER酶在体外和体内修复这些损伤的实验研究 活着。 3.检测这些病变在大肠杆菌和酵母菌中的致死性。 4.误码率自杀抑制剂的设计。 加深对氧化性基底细胞损伤对细胞核影响的认识 酸的结构和功能将有助于理解这种缔合 核酸损伤与衰老之间的关系，以及诸如 就像癌症一样。这些研究的应用，例如酶的设计 抑制剂可能会提供新的治疗药物。

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.