MECHANISM OF BASE EXCISION REPAIR IN HIGHER EUKARYOTES

高等真核生物碱基切除修复机制

• 批准号: 2376918
• 负责人: YOSHIHIRO MATSUMOTO
• 金额: $ 9.49万
• 依托单位: FOX CHASE CANCER CENTER
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-05-01 至 1999-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2376918
• 关键词: DNA damage; DNA directed DNA polymerase; DNA repair; Xenopus oocyte; adduct; cell cycle proteins; complementary DNA; endonuclease; enzyme activity; enzyme mechanism; exonuclease; furans; ion exchange chromatography; laboratory mouse; laboratory rabbit; molecular cloning; nucleic acid sequence; nucleotide analog; phosphoester ligase; tissue /cell culture

The induction of DNA damages by physical and chemical agents is an early step for mutagenesis, carcinogenesis and cell inactivation by most cancer therapies. Cells have evolved eloquent enzyme systems for recognition and elimination of such damages as a defense against genetic alteration. Consequently, a comprehensive understanding of DNA repair mechanisms will be important for the design of novel interventions for cancer prevention and treatment. This research project aims at defining the fundamental reaction of base- excision repair in higher eukaryotes. Base-excision repair is a major pathway in most living organisms to correct various types of modified bases. Many modified bases can be cytotoxic and mutagenic unless they are repaired. The base-excision repair consists of a sequential process of multistep reactions. The study of this repair reaction will be facilitated by development of an in vitro system. In an initial part of this project, Xenopus laevis oocytes will be used as a model system. The extracts prepared from them have shown high activity in repairing apurinic/apyrimidinic sites which are one of major lesions generated by several damaging agents and are also common intermediate products in base-excision repair. The repair factors participating in this reaction will be isolated by fractionation of these extracts and used to develop a reconstituted system. Factors essential for repair and their interactions during the repair reaction will be characterized in this reconstituted system. Subsequently the results obtained from the study with the Xenopus oocytes will be applied to investigation of the base- excision repair in mammalian systems. Mammalian homologs to the Xenopus repair factors will be obtained on the basis of functional similarity or homology of their amino acid sequences. Characterization of these factors will be performed with human or rodent cultured cells. The results of this study will contribute to a number of aspects in cancer biology such as the mechanism of carcinogenesis and generation of tumor cells resistant to drugs and radiation used for cancer therapy.

物理和化学剂诱导DNA损伤是早期的 大多数癌症的诱变，癌变和细胞失活的步骤 疗法。细胞已经进化出雄辩的酶系统，以识别和 消除这种损害，以防御遗传改变。 因此，对DNA修复机制的全面了解 对于预防癌症的新干预措施的设计很重要 和治疗。 该研究项目旨在定义基础的基本反应 - 较高真核生物的切除修复。基础拆卸维修是主要的 大多数活生物体中的途径以纠正各种类型的修改 基地。除非它们是细胞毒性和诱变，否则许多修饰的碱都可以是 修理。基础拆卸维修包括一个顺序的过程 多步反应。该修复反应的研究将得到促进 通过开发体外系统。 在该项目的最初部分，Xenopus laevis卵母细胞将用作 模型系统。从它们中准备的摘录表现出很高的活性 在修复肾上腺素/阿吡啶素位点，这是主要病变之一 由几种有害代理产生，也是常见的中间体 基础外观维修的产品。参与此的维修因素 反应将通过分馏这些提取物分离，并用于 开发一个重构的系统。维修至关重要的因素 修复反应期间的相互作用将在此表征 重构系统。随后从研究中获得的结果 与爪蟾卵母细胞一起研究 哺乳动物系统中的切除修复。 Xenopus的哺乳动物同源物 维修因素将根据功能相似性或 其氨基酸序列的同源性。这些因素的表征 将使用人或啮齿动物培养的细胞进行。 这项研究的结果将有助于癌症的许多方面 生物学，例如癌变机制和肿瘤的产生 细胞对癌症治疗的药物和辐射有抵抗力。