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A molecular switch of the type III secretion system in Chlamydia trachomatis

沙眼衣原体III型分泌系统的分子开关

基本信息

批准号：
8509139
负责人：
LI SHEN
金额：
$ 35.54万
依托单位：
LSU HEALTH SCIENCES CENTER
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-08-01 至 2015-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8509139
关键词：
Affect Bacteria Binding Biological Assay Cell membrane Cell-Free System Cells Chlamydia Chlamydia Infections Chlamydia trachomatis Complex Coupled Cytosol DNA-Directed RNA Polymerase Data Disease Drug Delivery Systems Ectopic Pregnancy Escherichia coli Event Gene Expression Genes Genetic Genetic Transcription Genital system Gram-Negative Bacteria Hela Cells Immunity In Vitro Infection Infertility Knowledge Mediating Membrane Modeling Molecular Molecular Chaperones Mutagenesis Needles Operon Pathogenesis Pelvic Inflammatory Disease Polymerase Process Property Proteins Public Health Regulation Regulon Research Role Sexually Transmitted Diseases Signal Transduction System Testing Transcriptional Regulation Type III Secretion System Pathway Virulence Woman Work base enteropathogenic Escherichia coli genetic manipulation insight member mutant novel pathogen promoter protein complex protein protein interaction reconstitution tool

项目摘要

DESCRIPTION (provided by applicant): A molecular switch of the type III secretion system in Chlamydia trachomatis The obligate intracellular bacterium C. trachomatis is the causative agent of the most common sexually transmitted disease worldwide and represents a significant public health burden. The severe sequelae of genital chlamydial infections in women include pelvic inflammatory disease, ectopic pregnancy and tubal infertility. A key virulence mechanism of C. trachomatis is the type III secretion system (T3SS) that directly delivers protein effectors into the host cell cytosol to subvert host immunity and enables bacterial survival in hosts. The objective of this project is to study the mechanism by which C. trachomatis controls type III secretion and gene expression, contributing to disease pathogenesis. We hypothesize that T3SS activity is regulated and coupled to gene transcription during C. trachomatis infection by a molecular switch, consisting of CT663 and its protein partners. This hypothesis is strongly supported by our novel finding that chlamydial CT663 is a bi-functional protein acting as both a transcription regulator that interacts with RNA polymerase containing ? 66 and a T3SS chaperone for CopN, which is a regulator as well as an effector of the T3SS. Our specific aims are: Aim 1. To test the hypothesis that CT663 forms a protein complex necessary for type III secretion activity. We will characterize the dynamic interactions of CT663 and its partners, and how these interactions impact the secretion activity using quantitative assays for protein-protein interactions, immunodetection, and an enteropathogenic Escherichia coli (EPEC) system. Aim 2. To test the hypothesis that CT663 differentially regulates the gene transcription. This aim will be achieved using our established transcription assays with reconstituted ?66RNA polymerase in vitro and in E. coli. These studies will uncover how T3SS activity affects gene expression during C. trachomatis infection and vice versa. This project will provide important insights into how C. trachomatis utilizes T3SS to survive in an intracellular niche by coordinating the regulatory events of the T3SS and gene expression during infection. Our research will significantly expand current knowledge of the C. trachomatis infection process and contribute to the identification of potential drug targets for new therapies that could significantly reduce the public health burden caused by C. trachomatis infection.

描述（由申请人提供）：沙眼衣原体III型分泌系统的分子开关专性细胞内细菌沙眼衣原体是世界范围内最常见的性传播疾病的病原体，并且代表着重大的公共卫生负担。女性生殖器衣原体感染的严重后遗症包括盆腔炎、宫外孕和输卵管性不孕。沙眼衣原体的一个关键毒力机制是 III 型分泌系统 (T3SS)，该系统直接将蛋白质效应物传递到宿主细胞胞浆中，破坏宿主免疫并使细菌在宿主中生存。该项目的目的是研究沙眼衣原体控制 III 型分泌和基因表达从而促进疾病发病机制的机制。我们假设，在沙眼衣原体感染期间，T3SS 活性受到分子开关（由 CT663 及其蛋白伴侣组成）的调节并与基因转录耦合。我们的新发现有力地支持了这一假设，即衣原体 CT663 是一种双功能蛋白，既充当转录调节因子，又与含有 ? 的 RNA 聚合酶相互作用。 66 和 CopN 的 T3SS 伴侣，它是 T3SS 的调节器和效应器。我们的具体目标是：目标 1. 检验 CT663 形成 III 型分泌活性所需的蛋白质复合物的假设。我们将使用蛋白质-蛋白质相互作用的定量测定、免疫检测和肠病原性大肠杆菌 (EPEC) 系统来描述 CT663 及其伙伴的动态相互作用，以及这些相互作用如何影响分泌活性。目标 2. 检验 CT663 差异调节基因转录的假设。这一目标将可以使用我们在体外和大肠杆菌中使用重构的 ?66RNA 聚合酶建立的转录测定法来实现。这些研究将揭示 T3SS 活性如何影响沙眼衣原体感染期间的基因表达，反之亦然。该项目将为沙眼衣原体如何通过协调 T3SS 的调控事件和感染期间的基因表达来利用 T3SS 在细胞内生存提供重要见解。我们的研究将显着扩展目前对沙眼衣原体感染过程的了解，并有助于确定新疗法的潜在药物靶点，从而显着减轻沙眼衣原体感染造成的公共卫生负担。