TRANSPOSITION OF TN7

TN7 的移位

• 批准号: 3131715
• 负责人: NANCY Craig CRAIG
• 金额: $ 10.44万
• 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 1987-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3131715
• 关键词: Caulobacter; DNA repair; Escherichia coli; R factors; bacterial DNA; bacterial genetics; chromosome translocation; gel electrophoresis; gene complementation; gene mutation; genetic markers; mutagens; nucleic acid sequence; point mutation; prophages; Caulobacter; DNA repair; Escherichia coli; R factors; bacterial DNA; bacterial genetics; chromosome translocation; gel electrophoresis; gene complementation; gene mutation; genetic markers; mutagens; nucleic acid sequence; point mutation; prophages

Tn7 is an E. coli transposable element that encodes resistance to trimethoprim, spectinomycin and streptomycin. In contrast to most transposable elements, Tn7 transposes with high efficiency to a specific site called attTn7. Tn7 also transposes with reduced specificity and efficiency to secondary (2 degrees) sites. This work will define the components of Tn7 transposition and examine the mechanism of this novel transposition reaction. The basic strategy to define the components will be to examine the transposition properties of variants of the components. The target and donor sites will be analyzed by defining the nucleotide sequences that promote the activity of attTn7 and the ends of Tn7. The critical features of target sites will also be analyzed by examining the structure of 2 degrees sites including one preferred site in Caulobacter crescentus. The donor site will also be analyzed by comparing the activities of the left and right ends of Tn7 and by determining whether the sequences that flank these ends in the donor site participate directly in transposition. The genetic organization of Tn7 will be analyzed by identifying Tn7-encoded functions that promote transposition. The roles of these functions will be explored by determining what steps in transposition they mediate. The mechanism of transposition will also be analyzed by examining the formation of cointegrates and by looking directly at DNA breakage and joining reactions at the target and donor sites. Elucidation of the mechanism of Tn7 transposition will contribute to the understanding of the rapid dispersal of antibiotic resistance. It will also provide insights into the mechanisms of other DNA rearrangements that underlie a wide variety of important cellular processes in both procaryotes and eucaryotes. Comparison of the basis of site-specificity in this replicative recombination with the basis of site-specificity in conservative recombination should be particularly interesting.

TN7是一个大肠杆菌转座元件，它编码对 甲氧苄啶，光霉素和链霉素。 与大多数 转座元素，TN7以高效率向特定 名为atttn7的网站。 TN7还以降低的特异性和 辅助（2度）位点的效率。 这项工作将定义 TN7换位的组成部分并检查了这种新颖的机制 转座反应。 定义组件的基本策略是检查 组件变体的换位特性。 目标和 将通过定义核苷酸序列来分析供体位点 促进ATTTN7的活性和TN7的末端。 关键功能 还将通过检查2的结构来分析目标位点的 学位位点，包括在花椰菜牙周膜中的一个首选地点。 这 还将通过比较左侧的活动来分析捐助者站点 和TN7的右端，并确定侧翼的序列是否 这些结束在供体站点直接参与换位。 这 TN7的遗传组织将通过识别TN7编码来分析 促进换位的功能。 这些功能的作用将是 通过确定介导的转换步骤来探索。 这 换位机理也将通过检查形成来分析 协整并直接查看DNA断裂和加入 目标和供体部位的反应。 阐明TN7换位机理将有助于 了解抗生素抗性的快速分散。 会 还提供有关其他DNA重排机制的见解 两种丙烯酸酯中的多种重要蜂窝过程的基础 和桉树。 比较现场特异性的基础 复制重组与场地特异性的基础 保守的重组应该特别有趣。