Repair and Biological Consequences of Alkylated Thymidine Lesions

 描述（由申请人提供）：环境暴露和内源性代谢都会引起DNA的烷基化，并且DNA烷基化代表了许多常用的癌症化疗药物的主要作用机制。因此，评估烷基化 DNA 损伤如何通过改变 DNA 复制和转录的效率和保真度来损害遗传信息流，以及这些损伤如何发生 修复将为理解 DNA 烷基化在人类疾病病因学中的影响提供重要的知识。这些知识也将成为制定更好的癌症化疗策略的基础。本申请的重点是一组烷基化胸苷损伤，这些损伤已被证明在哺乳动物组织中持续存在，或者在暴露于香烟烟雾的人类淋巴细胞样本中检测到其水平显着升高。我们将采用创新和多管齐下的方法，包括合成有机化学、基于质谱的生物分析化学和分子生物学，以在分子水平上了解尚未研究的烷基化胸苷损伤组如何阻碍细胞中的DNA复制和转录，并在这些过程中诱导突变。我们还将评估核苷酸切除修复和碱基切除修复途径在细胞损伤修复中的影响。拟议研究的结果将使我们对这组很大程度上被忽视的烷基化 DNA 损伤的理解达到一个显着更高的水平。

 DESCRIPTION (provided by applicant): Environmental exposure and endogenous metabolism both give rise to the alkylation of DNA, and DNA alkylation represents the major mechanism of action for a number of commonly prescribed cancer chemotherapeutic agents. Thus, assessing how alkylated DNA lesions compromise the flow of genetic information by altering the efficiency and fidelity of DNA replication and transcription and how these lesions are repaired will provide important knowledge for understanding the implications of DNA alkylation in the etiology for developing human diseases. Such knowledge will also form the basis for developing better strategies for cancer chemotherapy. The emphasis of this application is placed on a group of alkylated thymidine lesions which have been shown to persist in mammalian tissues or have been detected at substantially elevated levels in lymphocyte samples of humans exposed to cigarette smoke. We will employ an innovative and multi- pronged approach, including synthetic organic chemistry, mass spectrometry-based bioanalytical chemistry, and molecular biology to achieve a molecular-level understanding about how the under-investigated group of alkylated thymidine lesions impede DNA replication and transcription in cells, and induce mutations in these processes. We will also assess the implications of nucleotide excision repair and base excision repair pathways in the repair of these lesions in cells. The outcome of the proposed research will bring our understanding of this largely overlooked group of alkylated DNA lesions to a significantly higher level.