EXCISION REPAIR OF UV RADIATION-INDUCED DNA DAMAGE

紫外线辐射引起的 DNA 损伤的切除修复

• 批准号: 2856447
• 负责人: Paul William Doetsch
• 金额: $ 29.61万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-02-01 至 2000-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2856447
• 关键词: DNA damage; DNA repair; autoradiography; carcinogen testing; complementary DNA; endonuclease; enzyme activity; mutagen testing; neoplasm /cancer genetics; oligonucleotides; protein sequence; radiation carcinogenesis; species difference; tissue /cell culture; ultraviolet radiation

DESCRIPTION: The biological effects of UV light irradiation of cells include death, mutation and neoplastic transformation. DNA is the biologically relevant target of UV light exposure, resulting in the formation of primarily cyclobutane pyrimidine dimers (CPDs) and (6-4) photoproducts (6-4 PPs). CPDs and 6-4 PPs have been shown to be cytotoxic, mutagenic, and carcinogenic in cell and animal model systems and are readily formed in human skin cells following exposure to sunlight. Skin cancer, the most frequently occurring cancer in humans, is primarily associated with chronic exposure to solar radiation. The majority of both basal and squamous cell carcinomas of the skin contain mutations in the p53 tumor suppressor gene and are of the type caused by CPDs and 6-4 PPs. An understanding of the components and biochemistry of the repair of CPDs and 6-4 PPS in eukaryotes should provide important insights into the mechanisms of UV carcinogenesis. The fission yeast, Schizosaccharomyces pombe provides an attractive biochemical and genetic eukaryotic DNA repair model system with features that include an abundant source of cells for enzyme purification and characterization, relatively straightforward genetic dissectability, and the characterizing a S. pombe endonuclease that specifically recognizes both CPDs and 6-4 PPs and makes direct 5'incisions at the sites of these UV photoproducts. We have biological and genetic evidence that this enzyme, S. pombe DNA endonuclease (SPDE), represents the initial step of an alternative DNA excision repair system which we have termed the SPDE-dependent DNA repair (SDR) pathway. It now appears that SDR-like pathways are also present in other organisms. The goal of the proposed research will be to characterize the SDR pathway with a significant focus on SPDE. A combination of biochemical and molecular biological approaches will be taken to provide direct information on SPDE and the SDR pathway. The major objectives will be to (1) complete the purification and conduct a detailed enzymological characterization of SPDE; (2) identify and characterize the gene encoding SPDE; (3) identify and characterize other components of the SDR pathway; and (4) screen a selection of candidate organisms, including humans, for a SPDE-like activity to determine the species distribution of the SDR pathway. The information obtained in these studies should greatly increase our understanding of the eukaryotic cellular machinery that reverses carcinogenic UV photoproducts.

描述：紫外线照射细胞的生物学效应 包括死亡、突变和肿瘤转化。 DNA是 紫外线照射的生物相关目标，导致 主要形成环丁烷嘧啶二聚体（CPD）和（6-4） 光产物（6-4 PPs）。 CPD和6-4 PP已被证明具有细胞毒性， 在细胞和动物模型系统中具有致突变性和致癌性， 在人体皮肤细胞暴露于阳光下后形成。 皮肤癌而 人类最常见的癌症，主要与 长期暴露在太阳辐射下 大多数基础和 皮肤鳞状细胞癌含有p53肿瘤突变 抑制基因，并且是由CPD和6-4 PP引起的类型。 一个 了解CPD修复的成分和生物化学， 6-4真核生物中的PPS应该提供重要的见解， 紫外线致癌作用。 裂殖酵母，粟酒裂殖酵母 一个有吸引力的生化和遗传真核DNA修复模型系统 其特征包括酶的丰富细胞来源 纯化和表征，相对简单的遗传 可解剖性和S.粟酒裂殖酵母核酸内切酶， 特异性识别CPD和6-4 PP，并进行直接5 '切口 在这些紫外光产物的位置。 我们有生物学和遗传学上的 有证据表明，这种酶，S.粟酒裂殖酵母DNA内切酶（SPDE），代表了 另一种DNA切除修复系统的初始步骤， SPDE依赖性DNA修复（SDR）途径。 现在看来 SDR样途径也存在于其他生物体中。 的目标 拟议的研究将是以一个显著的 专注于SPDE。 生物化学和分子生物学的结合 将采取措施提供有关SPDE和SDR的直接信息 通路 主要目标将是（1）完成纯化， 对SPDE进行详细的酶学表征;（2）鉴定和 表征编码SPDE的基因;（3）鉴定和表征其他 SDR途径的组成部分;以及（4）筛选候选人的选择 生物体，包括人类，用于SPDE样活性，以确定 SDR途径的物种分布。 在这些文件中获得的信息 这些研究将大大增加我们对真核细胞的理解， 逆转致癌紫外线光产物的机制。