SPECIFICITY OF DNA REPAIR FOR OXIDIZED ABASIC SITES

描述：自由基对DNA的损伤，这与 癌变，正常的衰老过程，和神经退化，会产生一种 各种损伤。这些损害中的许多是各种基础损害(部位 基本损耗)。包括1-氧化、4-氧化或碎裂 脱氧核糖残留物，如过氧化氢，电离剂的已知产物 放射线和博莱霉素。这种损伤具有细胞毒性和诱变性。 这可能是上述年龄和疾病影响的基础，但 这些氧化脱氧核糖损伤很难测量。 具体地说，通过现有的方法灵敏地和定量地。这 该项目建议为这种分析开发新的方法，重点是 利用DNA修复酶释放特异性损伤进行分析 采用先进的质谱学和毛细管电泳法。 这些方法将被用来探索个体的形成和修复 体内氧化的碱性部位。碱性(AP)内切酶已经被 与这些损伤的修复有关，但这种特异性尚未得到证实 在活体内得到证实。建议的主要研究包括分析染色体 DNA检测大肠杆菌核酸外切酶III在修复中的特殊作用 H_2O_2诱导的DNA损伤及大肠杆菌核酸内切酶IV和酵母菌Apn1的损伤 氧化碱性部位的修复。人猿类核酸内切酶活性的研究 纠正大肠杆菌和酵母菌突变株的特异性修复缺陷 将通过新的方法进行评估，核酸内切酶的突变形式也将如此 IV和Apnl.这项工作不仅对今后的工作具有重要意义 了解自由基损伤在衰老、癌症和 神经退化，但它也将在 一类重要的氧化型DNA的分子分析方法 损坏。

DESCRIPTION: Free radical damage to DNA, which has been associated with carcinogenesis, the normal aging process, and neurodegeneration, produces a variety of lesions. Many of these damages are various abasic lesions (sites of base loss). These include 1 -oxidized, 4 -oxidized or fragmented deoxyribose residues, known products of agents such as H2O2, ionizing radiation and bleomycin. Such damages have cytotoxic and mutagenic potential that might underlie the age and disease effects cited above, but these oxidized deoxyribose lesions have been difficult to measure specifically, sensitively and quantitatively by existing methods. This project proposes to develop new methods for such analysis, with an emphasis on the use of DNA repair enzymes to liberate specific damages for analysis by advanced techniques of mass spectrometry and capillary electrophoresis. These methods will be used to explore the formation and repair of individual oxidized abasic sites in vivo. Abasic (AP) endonucleases have been implicated in the repair of these damages, but this specificity has not been demonstrated in vivo. Key proposed studies include analyzing chromosomal DNA to determine the specific role of E. coli exonuclease III in repairing H2O2-induced DNA damage, and of E. coli endonuclease IV and yeast Apnl in the repair of oxidized abasic sites. The ability of human Ape endonuclease to correct specific repair defects in mutant strains of E. coli and yeast will be assessed by the novel methods, as will mutated forms of endonuclease IV and Apnl. Not only will this work be important for future work toward understanding the role of free-radical damage in aging, cancer, and neurodegeneration, but it will also provide quantum improvements in the methodology for molecular analysis of an important class of oxidative DNA damage.