Mutagenic hot spots & 3-D structure of damaged DNA

这项研究的长期目标有两个；建立 选择环境诱变剂的诱变潜力和探索环境诱变剂 识别和修复DNA损伤的分子基础。 在过去的项目期内，取得了很好的进展。 已经开发出了定量方法，使我们能够在 体外和体内已定义的DNA加合物的诱变图谱。 基本原则已经出现，这将有助于分析 环境诱变剂产生的突变谱。例如，使用 特定部位的技术，我们可以预测核苷酸序列上下文 突变热点。我们还发现DNA聚合酶不同 令人惊讶的是，它们相对于 某些DNA加合物。我们还描述了一种新的修复途径 大肠杆菌中的氧化DNA损伤。 在接下来的项目期间，我们将寻求确定诱变剂 修饰后的PhIP和8-氨基鸟嘌呤在体内外的应用 DNA碱基在2-甲基-4-羟基苯乙酸乙酯处理的动物的肝脏中积累 硝基丙烷。我们将使用我们的实验系统来探索分子 ABASIC的碱基替换和缺失突变机制 中心、氨基荧加成物和四个衍生于 苯并(A)芘。这个项目的一部分致力于DNA修复的研究 酶；我们建议分离和纯化FPG蛋白的同源物和 来自哺乳动物的MutY蛋白。最后，我们将研究 FpG蛋白衍生的单个锌指与损伤的相互作用 DNA

The long-range goals of this research are two-fold; to establish the mutagenic potential of selected environmental mutagens and to explore the molecular basis for recognition and repaired of damaged DNA. Excellent progress has been made during the past project period. Quantitative methods have been developed that allowed us to establish in vitro and in vivo the mutagenic profiles of defined DNA adducts. Fundamental principles have emerged that will facilitate analyses of mutational spectra produced by environmental mutagens. For example, using site-specific techniques, we can predict nucleotide sequence contexts of mutational hot spots. We also discovered that DNA polymerases differ strikingly from one another in their miscoding potential with respect to certain DNA adducts. We also describe a new pathway for repair of oxidative DNA damage in E. coli. In the next project period, we will seek to determine the mutagenic potential in vitro and in vivo for PhIP and 8-aminoguanine, a modified DNA base which accumulates in the liver of animals treated with 2- nitropropane. We will use our experimental systems to explore molecular mechanisms of base substitutions and deletion mutagenesis for abasic sites, aminofluorene adducts and four stereoisomers derived from benzo(a)pyrene. Part of this project is devoted to studies of DNA repair enzymes; we propose to isolate and purify homologs of Fpg protein and MutY protein from mammalian sources. Finally, we will study the interaction of a single zinc finger derived from Fpg protein with damaged DNA.