TRANSPOSITION OF TN7

TN7 的移位

• 批准号: 3131718
• 负责人: NANCY Craig CRAIG
• 金额: $ 13.61万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-07-01 至 1991-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3131718
• 关键词: Escherichia coli; R factors; affinity chromatography; antibiotics; bacterial DNA; bacterial genetics; bacterial proteins; chemical binding; chromosome translocation; coliphages; gel electrophoresis; gene expression; gene induction /repression; gene mutation; gene redundancy; genetic manipulation; genetic promoter element; mutagens; nucleic acid probes; nucleic acid sequence; point mutation; protein structure; regulatory gene; streptomycin; transcription factor; transposon /insertion element; trimethoprim

The long-range goal of this project is to understand the mechanism and control of a recombination reaction, the transposition of the bacterial transposition Tn7 which encodes resistances to trimethoprim and to streptomycin and spectinomycin. In contrast to most other transposable elements which move at low frequency and show little target site selectivity, Tn7 inserts at high frequency into a specific site called attTn7. When attTn7 is unavailable, Tn7 inserts at low frequency into many other sites. Tn7 is an elaborate element: it encodes five transposition genes which mediate several distinct recombination reactions and utilizes large DNA segments at the ends of Tn7 and at its target sites as recombination substrates. A specific aim of the studies proposed here is to use biochemical methods develop an in vitro Tn7 transposition system in which purified proteins direct the recombination of defined DNA substrates. This will allow the identification of both Tn7- and host-encoded transposition recombination proteins. Another specific aim is to use this purified system to dissect the transposition reaction mechanism at the molecular level. Genetic methods will be used to achieve two other related specific aims: 1) identification of host genes encoding proteins either directly involved in Tn7 recombination or which regulate this process, and 2) production of mutant transposition proteins whose altered activities will allow identification of key steps in recombination. Genetic methods will also be used to pursue another specific aims, understanding cellular responses to Tn7 transposition. The result of these studies will provide important insights into protein- DNA interaction and DNA structure. They will also contribute to a deeper understanding of the interactions between mobile elements and their hosts and of the rapid dispersal of antibiotic resistance determinants.

该项目的远程目标是了解机制和 控制重组反应，细菌的转位 转置TN7，该TN7编码对甲氧苄啶的电阻和对 链霉素和舒张霉素。 与大多数其他转座相反 低频移动并显示几乎没有目标位点的元素 选择性，TN7以高频插入到一个名为的特定站点中 atttn7。 当atttn7不可用时，TN7以低频插入许多 其他站点。 TN7是一个精心设计的元素：它编码五个换位 介导几种不同重组反应并利用的基因 TN7及其目标位点的末端的大型DNA段作为 重组底物。 这里提出的研究的具体目的是使用生化方法 开发一个体外TN7换位系统，其中纯化的蛋白质 指导定义的DNA底物的重组。 这将允许 识别TN7-和宿主编码的转座重组 蛋白质。 另一个具体目的是使用此纯化系统进行剖析 分子水平的转座反应机制。 遗传 方法将用于实现其他两个相关的特定目的：1） 识别编码蛋白质直接参与的蛋白质的宿主基因 TN7重组或调节此过程的重组，以及2）生产 突变换位蛋白的改变活动将允许 识别重组的关键步骤。 遗传方法也将是 用于追求另一个特定目标，了解蜂窝的响应 TN7换位。 这些研究的结果将为蛋白质提供重要的见解。 DNA相互作用和DNA结构。 他们还将为更深的 了解移动元素及其主机之间的相互作用 以及抗生素耐药性决定因素的快速分散。