权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

ENZYMATIC REPAIR OF CARCINOGENIC DAMAGE TO HUMAN DNA

人类 DNA 致癌损伤的酶修复

基本信息

批准号：
3458946
负责人：
PATRICIA E GALLAGHER
金额：
$ 9.04万
依托单位：
WEST VIRGINIA UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1987
资助国家：
美国
起止时间：
1987-08-15 至 1993-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/3458946
关键词：
DNA damage adenine autoradiography cellular oncology chemical carcinogen chemical carcinogenesis circular DNA clone cells gel electrophoresis high performance liquid chromatography human tissue methylguanidine molecular oncology nitrosourea protein sequence radiotracer

项目摘要

Cells are continuously exposed to chemical and physical agents that can alter the structure and coding properties of DNA. Alkylating chemicals represent the largest class of DNA- damaging agents found in the environment and can result in cellular carcinogenesis, mutagenesis and lethality. Three predominant lesions, 7-methylguanine, O6-methylguanine and 3- methyladenine, are formed in DNA exposed to simple monofunctional alkylating agents. Studies have shown that O6- methylguanine is a mutagenic lesion in DNA, while 3- methyladenine results in cell lethality. Mammalian cells have evolved efficient mechanisms for recognizing and repairing alkylation-induced DNA damages. This proposal describes a comprehensive study of the human 3-methyladenine-DNA glycosylase; the enzyme responsible for the excision of 3- methyladenine from alkylated DNA. The glycosylase will be purified to homogeneity from human lymphoblasts and the substrate specificity against alkylated DNA characterized by high pressure liquid chromatography. Using this purified enzyme as a probe, the effects of DNA base sequence on the formation of 3- methyladenine and its subsequent in vitro and in vivo repair will be quantitated. The cDNA coding for the human 3-methyladenine -DNA glycosylase will be isolated and from that the amino acid sequence of the protein deduced. Further studies will be performed at the molecular level to examine the cellular regulation of gene expression in response to low level exposure to alkylating agents. The repair of alkylation damage in cells from patients with genetic disorders will be analyzed by alkaline sucrose density gradients and compared to that of normal controls to analyze cellular sensitivity to toxic doses of alkylating chemicals. The results of these studies should lead to a better understanding of the molecular processes that constitute the human cellular response to alkylating agents.

细胞持续暴露在化学和物理介质中这会改变DNA的结构和编码特性。烷基化化学品代表了DNA中最大的一类- 在环境中发现的破坏性物质，可能导致细胞致癌、诱变和致命性。三优势病变：7-甲基鸟嘌呤、O6-甲基鸟嘌呤和3-甲基鸟嘌呤甲基腺嘌呤，是在暴露于简单DNA中形成的单官能团烷基化剂。研究表明，O6- 甲基鸟嘌呤是DNA中的一种突变损伤，而3- 甲基腺嘌呤会导致细胞死亡。哺乳动物细胞有进化出高效的识别和修复机制烷基化引起的DNA损伤。本提案描述了一种人3-甲基腺嘌呤-DNA的综合研究糖基酶；负责切除3-羟色胺的酶。烷基化DNA中的甲基腺嘌呤。糖基酶将是从人淋巴母细胞纯化至均一对烷基化DNA的底物专一性高加压液相色谱。用这种纯化的酶作为一种 DNA碱基序列对3-脱氧核糖核酸形成的影响甲基腺嘌呤及其随后的体外和体内修复被量化。人3-甲基腺嘌呤基因的编码区 -DNA糖基酶将被分离出来，并从中提取氨基酸推导出该蛋白的序列。进一步的研究将是在分子水平上进行，以检查细胞低水平暴露对基因表达的调节作用烷基化试剂。细胞中烷基化损伤的修复遗传性疾病的患者将进行碱性分析蔗糖密度梯度及与正常对照组的比较分析细胞对烷基化毒性剂量的敏感性化学制品。这些研究的结果应该会带来更好的对构成分子过程的理解人类细胞对烷基化剂的反应。