REPAIR OF GENOME DESTABILIZING DNA STRUCTURES

描述：(申请人提供)基因组完整性对细胞至关重要 存活，并由细胞内的DNA修复机制维持。它被认为是 高达90%的人类癌症是由DNA损伤造成的。核苷酸 切除修复(NER)是消除dna损伤的主要修复途径。 暴露于来自太阳的紫外线照射和环境致癌物质。纳 是唯一已知的人类修复系统，用于移除巨大的损伤 由上述类型的损害造成。尽管已经做了很多工作 要定义人类的内分泌机制，人们对前者知之甚少。 以及限速步骤，DNA损伤识别。已知的发挥作用的蛋白质 识别过程中的重要角色包括XPA、RPA和XPC-hHR23B。它 有人提出，这些分子通过结合螺旋来识别损伤 DNA的扭曲，从而启动修复过程。长期的 这一应用的目的是确定DNA的分子机制 人类对基因组不稳定DNA结构的损伤识别和修复 内尔。异常DNA引起的DNA螺旋扭曲的诱变潜力 在重复序列上形成的结构，生物化学细节 人类NER中蛋白质-核酸的相互作用以及螺旋的作用 DNA损伤识别中的失真将通过解决 以下问题：异常的DNA结构是否被DNA识别为损伤 修理机器？DNA螺旋中的结构变化是否被 修复蛋白？哪一种假定的损害识别复合体最先起作用 在DNA损伤部位，它们在损伤识别中的作用是什么？ 螺旋扭曲的程度是否存在相关性 损伤以及识别和修复它的效率，以及 这些特性决定了诱变能力吗？具体来说，我们建议 确定具有螺旋扭曲的异常DNA结构和 三链形成寡核苷酸诱导基因组的复杂病变 不稳定和突变，NER在这些过程中的作用 基因组不稳定的螺旋扭曲，以及损伤的分子细节 人XPA-RPA和XPC-hHR23B损伤识别复合体的识别。

DESCRIPTION: (PROVIDED BY APPLICANT) Genomic integrity is essential for cell survival and is maintained by DNA repair mechanisms in cells. It is thought that up to 90 percent of human cancer results from DNA damage. Nucleotide excision repair (NER) is a major repair pathway to remove DNA damage resulting from exposure to UV irradiation from the sun and environmental carcinogens. NER is the only known human repair system for removing bulky lesions that are caused by the types of damage mentioned above. Although much work has been done to define the mechanism of NER in humans, very little is known about the first and rate-limiting step, DNA damage recognition. Proteins known to play important roles in the recognition process include XPA, RPA, and XPC-hHR23B. It is has been proposed that these molecules recognize damage by binding helical distortions in the DNA, thereby initiating the repair process. The long-term objective of this application is to determine the molecular mechanisms of DNA damage recognition and repair of genome-destabilizing DNA structures by human NER. The mutagenic potential of DNA helical distortions induced by unusual DNA structures formed at repeat sequences, the biochemical details of the protein-nucleic acid interactions in human NER, and the role of helical distortions in DNA damage recognition will be ascertained by addressing the following questions: Are unusual DNA structures recognized as damage by the DNA repair machinery? Are structural alterations in the DNA helix recognized by the repair proteins? Which of the putative damage recognition complexes act first at the site of DNA damage and what is the role of each in damage recognition? Is there a correlation between the extent of helical distortion induced by a lesion and the efficiency with which it is recognized and repaired, and do these properties determine the mutagenic capacity? Specifically, we propose to determine the ability of unusual DNA structures with helical distortions and complex lesions directed by triplex-forming oligonucleotides to induce genomic instability and mutagenesis, the role of NER in the processing of these genome-destabilizing helical distortions, and the molecular details of damage recognition by human XPA-RPA and XPC-hHR23B damage recognition complexes.