CONTROL AND EXPRESSION OF TYPE 1 PILI IN E. COLI

大肠埃希菌和其他革兰氏阴性肠杆菌的1型皮利 细菌是丝状的，蛋白质的附属物， 主要是一种叫做菌毛蛋白的亚基。 1型皮利介导 甘露糖敏感粘附E.大肠杆菌到各种真核生物 细胞，是促进在较低的殖民化的因素 泌尿系统 该项目的长期目标是建立 基因控制、组装和 受体结合活性的1型皮利，并在这样做，有助于 对控制和组装的理解 超分子结构和受体-配体相互作用 将军 此外，希望这项研究将导致更好的 了解细菌粘附在发病机制中的作用 传染性疾病。 本文提出的研究使用各种 遗传和生物化学技术：1）识别因素 影响pilA表达。 pilA基因编码主要的 皮利的亚基，并受到至少两种类型的 转录调控 一种类型是一种压抑， 一种是相邻基因的产物，另一种是亚稳态（ON 或OFF）控制。 提出了创建和分析影响这些病变的方法 两种类型的转录控制 2)识别分子 菌毛组装所需的相互作用。 方法建议 用于分析在pilE中具有点突变的突变体， 编码受体所需的皮利的次要成分 约束力 项目包括分离基因外的 补偿突变，条件pilE突变分析 和pilE蛋白的定位。 此外，用于 分离和检查具有影响两种疾病的病变的突变体， 其他组装相关基因，其中之一影响菌毛长度， 被提议。 3)识别所需的分子相互作用， 受体结合 概述了分离和分析的方法 具有改变的受体特异性的突变体 另外， 分离pilE基因产物并评估pilE的作用 蛋白质受体结合概述。 此外， 受体结合和菌毛长度对纤毛E. 检查具有巨噬细胞的大肠杆菌。

Type 1 pili of Escherichia coli and other gram negative enteric bacteria are filamentous, proteinaceous appendages composed primarily of a subunit called pilin. Type 1 pili mediate the mannose-sensitive adhesion of E. coli to a variety of eucaryotic cells and are a factor in promoting colonization in the lower urinary tract. The long term goal of this project is to establish the molecular nature of the genetic control, assembly and receptor binding activity of type 1 pili and in doing so, contribute to the understanding of the control and assembly of supramolecular structures and receptor-ligand interactions in general. Also, it is hoped that this research will lead to a better understanding of the role of bacterial adhesion in the pathogenesis of infectious disease. The research herein proposed uses a variety of genetic and biochemical techniques to: 1) Discern the factors effecting pilA expression. The pilA gene encodes the major subunit of pili and is subject to at least two types of transcriptional control. One type is a repression effected by the product of an adjacent gene, the other type is a metastable (ON or OFF) control effected by the inversion of the pilA promotor. Ways are proposed to create and analyze lesions affecting these two types of transcriptional control. 2) Discern the molecular interactions required for pilus assembly. Methods are suggested for the analysis of mutants having point mutations in pilE, a gene encoding a minor component of pili that is required for receptor binding. Projects include the isolation of extrageneic compensatory mutations, analysis of conditional pilE mutations and localization of the pilE protein. In addition, methods for isolating and examining mutants having lesions affecting two other assembly related genes, one of them affecting pilus length, are proposed. 3) Discern the molecular interactions required for receptor binding. Methods are outlined for isolating and analyzing mutants with an altered receptor specificity. Also, ways for isolating the pilE gene product and assessing the role of the pilE protein in receptor binding are outlined. In addition, the role of receptor binding and pilus length on the interaction of piliated E. coli with macrophages is examined.