MECHANISMS FOR REPAIR OF RADIATION DAMAGE IN HUMAN CELLS

人体细胞辐射损伤的修复机制

• 批准号: 2871831
• 负责人: Priscilla K. Cooper
• 金额: $ 34.06万
• 依托单位: UNIVERSITY OF CALIF-LAWRENC BERKELEY LAB
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-05-19 至 2001-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2871831
• 关键词: DNA damage; DNA directed DNA polymerase; DNA repair; N glycosidase; RNA biosynthesis; endonuclease; enzyme activity; enzyme inhibitors; free radical oxygen; genetic library; human tissue; hydrogen peroxide; intermolecular interaction; ionizing radiation; mutant; proliferating cell nuclear antigen; protein biosynthesis; radiation genetics; radiation sensitivity; syndrome; tissue /cell culture; transcription factor; xeroderma pigmentosum; yeast two hybrid system

DESCRIPTION: (Adapted from the applicant's abstract): Many human genetic diseases that involve defects in processing DNA damage are associated with severe developmental, neurological and immunological abnormalities as well as frequent cancer predisposition. These facts imply an as-yet poorly understood requirement for DNA repair in normal development in addition in its better documented role in prevention of carcinogenesis. This requirement is proposed to be related to damage to DNA from reactive oxygen species generated during metabolism. Because of qualitative similarity in the lesions induced by ionizing radiation and cellular oxidation, understanding the mechanisms for repair of ionizing radiation damage can contribute to understanding this vital role of repair processes. The broad objective of this research program is to elucidate the molecular mechanisms involved in transcription-coupled repair in mammalian cells of DNA lesions induced by ionizing radiation and other agents that produce oxidative damage. In addition, the relationship of transcription-coupled repair of oxidative damage to other DNA transactions and to normal growth and development will be investigated. The hypotheses to be tested are 1) that transcription-coupled repair of oxidative base damage proceeds by utilizing components of both base excision repair (BER) and nucleotide excision repair (NER) pathways, which have classically been regarded as distinct, and 2) that failure to rapidly repair such damage in critical active genes contributes both to cellular end points and to the profound clinical abnormalities of Cockayne syndrome (CS). It has recently been shown that the xeroderma pigmentosum group G (XPG) gene product is essential for removal of the oxidatively damaged base TG from active DNA and that defects in this repair process correlate with the clinical appearance of CS. It is proposed to continue these studies to determine the role of XPG in the transcription-coupled repair of TGs, to identify other required functions, to assess the generality of the process in repair of other oxidatively damaged bases, and to further explore the relationship between defective repair of oxidative damage and the severe abnormalities of CS. Immediate objectives include 1) investigation of the mechanism of XPG-dependent TG removal to distinguish between a role of XPG in assembly of proteins for base excision repair vs. a direct role in incision; 2) examination of a possible overlap between this process and a PCNA-dependent pathway of base excision repair; and 3) investigation of normal and mutant cellular responses to ionizing radiation to evaluate possible mechanisms by which defective transcription-coupled repair of oxidative lesions in DNA could produce developmental defects.

描述：（改编自申请人的摘要）：许多人类遗传基因 涉及 DNA 损伤处理缺陷的疾病与 严重的发育、神经和免疫异常 作为常见的癌症倾向。 这些事实表明，目前的情况还很糟糕。 了解正常发育中 DNA 修复的需求 它在预防癌变方面的作用已有更详细的记录。 这 提出的要求与活性氧对 DNA 的损伤有关 新陈代谢过程中产生的物种。 由于质的相似性 电离辐射和细胞氧化引起的损伤， 了解电离辐射损伤的修复机制可以 有助于理解修复过程的这一重要作用。 广义的 该研究计划的目的是阐明分子机制 参与哺乳动物细胞 DNA 损伤的转录偶联修复 由电离辐射和其他产生氧化的物质引起 损害。 此外，转录偶联修复的关系 对其他 DNA 处理和正常生长的氧化损伤 将调查发展情况。 要检验的假设是 1) 氧化碱基损伤的转录偶联修复通过利用 碱基切除修复 (BER) 和核苷酸切除修复的组成部分 (NER) 路径，传统上被认为是不同的，并且 2) 未能快速修复关键活性基因的此类损伤 有助于细胞终点和深刻的临床 科凯恩综合征（CS）的异常。 最近有研究表明 着色性干皮病 G 组 (XPG) 基因产物对于 从活性 DNA 中去除氧化损伤的碱基 TG 并导致缺陷 此修复过程与 CS 的临床表现相关。 这是 建议继续这些研究以确定 XPG 在 TG 的转录耦合修复，以确定其他所需的功能， 评估修复其他氧化过程的一般性 损坏的碱基，并进一步探讨缺陷之间的关系 修复氧化损伤和严重异常的CS。 即时 目标包括1）研究XPG依赖性TG的机制 去除以区分 XPG 在蛋白质组装中的作用 基底切除修复与切口直接作用； 2）检查 该过程与 PCNA 依赖的碱基途径之间可能存在重叠 切除修复； 3) 正常和突变细胞的研究 对电离辐射的反应，以评估可能的机制 DNA 氧化损伤的转录偶联修复缺陷可能 产生发育缺陷。