TRANSPOSITION AND DNA REPAIR IN DROSOPHILA

目标：果蝇有丝分裂中双链DNA断裂的修复 将对细胞进行遗传分析。这样的断裂可以由两个人修复 机制的主要类别：重组和末端连接。这些 不同类别的维修产品种类有很大不同， 制作。在每个班级中，有多条单独的路径被认为 才能存在。目标是对这些基因进行基因解剖 机械装置。对于每条主要途径，遗传后果和 修理产品的结构将被确定。审查 这些参数在修复过程中涉及的一系列基因座突变中 流程将揭示这些路径的不同之处以及修复类型 这是受影响的。 方法：切除P转座元件提供了一种有用的方法 在特定的已知位置产生双链断裂 基因组。这些切除可以由P转座酶调控。在……里面 此外，两种位点特异性内切酶HO和I-SCEI已经被 在果蝇身上发挥作用。这三种方法将用于 在明确定义的情况下在体内产生特定的双链断裂 遗传条件。使用这些特定于站点的休息时间进行的一系列测试 将在不同的遗传背景下应用提供详细的 描述双链断裂修复的后果。 不同的修复途径将通过突变基因来区分 被认为与一种或多种机制有关。七个遗传基因座 涉及维修工作人员被选择来包括各种这样的 功能。将使用两种最新开发的方法来获得 突变：第一个在靶标中或其附近产生P插入 基因，而第二个利用这些插入来获得侧翼缺失 这会敲除这些基因。 医学意义：DNA修复被认为是维持 基因组的稳定性，尤指具有复杂基因组的物种。 人类许多DNA修复基因的突变，包括人类同源基因 在本研究中的几个基因座中，导致易感性 癌症。对这些修复过程的更好理解可以来自 用果蝇进行的研究，果蝇和人类一样，有着相对复杂的 基因组和多细胞组织，因此需要高水平的 基因组稳定性。与此同时，果蝇为研究人员提供了 需要基因工具来分析多途径修复系统。

Goals: The repair of double-stranded DNA breaks in Drosophila mitotic cells will be analyzed genetically. Such breaks can be repaired by two main classes of mechanisms: recombinational and end-joining. These classes differ significantly in the kinds of repair products that are produced. Within each class, multiple individual pathways are thought to exist. The goal is to perform a genetic dissection of these mechanisms. For each major pathway, the genetic consequences and the structure of the repair products will be determined. Examination of these parameters in a series of mutations at loci involved in the repair processes will reveal how the pathways differ and the type of repair that is affected. Approach: Excision of P transposable elements provides a useful way to produce double-strand breaks at specific, known, locations in the genome. These excisions can be regulated by P transposase. In addition, two site-specific endonucleases, HO and I-SceI, have been shown to function in Drosophila. These three methods will be used to generate specific double-strand breaks in vivo under well-defined genetic conditions. A series of tests using these site-specific breaks will be applied in different genetic backgrounds to provide a detailed description of the consequences of double-strand break repair. Different pathways for repair will be distinguished by mutating genes thought to be involved with one or more mechanism. Seven genetic loci involved with repair were selected to include a variety of such functions. Two recently-developed methods will be used to obtain mutations: the first generates P insertions in or near the targeted genes, and the second uses these insertions to obtain flanking deletions which knock out the genes. Medical significance: DNA repair is recognized as crucial to maintaining the stability of the genome, especially in species with complex genomes. Human mutations in many DNA repair genes, including the human homologs of several of the loci in the present study, cause predisposition to cancer. A better understanding of these repair processes can come from studies using Drosophila, which, like humans, has a relatively complex genome and multicellular organization, thus requiring a high level of genomic stability. At the same time, Drosophila gives researchers the genetic tools needed to analyze the multi-pathway repair system.