Campylobacter jejuni DNA methylation and gene regulation

空肠弯曲杆菌 DNA 甲基化和基因调控

• 批准号: 6810686
• 负责人: STUART A THOMPSON
• 金额: $ 32.05万
• 依托单位: AUGUSTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-30 至 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6810686
• 关键词: Campylobacter; DNA methylation; Guillain Barre syndrome; bacterial genetics; bacterial proteins; biological signal transduction; bioterrorism /chemical warfare; enzyme activity; enzyme mechanism; gastroenteritis; gene environment interaction; gene expression; gene induction /repression; methyltransferase; microarray technology; proteomics; temperature; tissue /cell culture; virulence

DESCRIPTION (provided by applicant): Campylobacter jejuni is a Category B Bioterrorism Agent as classified by the NIH. It is the leading cause of bacterial gastroenteritis in the United States, and is responsible for sporadic disease as well as food-borne and water-borne outbreaks. There are at least 2.4 million cases of C. jejuni gastroenteritis in the U.S. annually, with an incidence exceeding that of Salmonella and Shigella combined (1). C. jejuni infection is also the most common antecedent event to development of Guillain-Barr Syndrome, an acute motor paralysis apparently resulting from an autoimmune response directed at C. jejuni surface antigens. Despite the high prevalence of Campylobacter disease and more than 20 years of study, the mechanisms by which C. jejuni causes disease remain obscure. Several C. jejuni virulence factors have been identified, yet their regulatory mechanisms are largely unknown. Recent evidence implicates DNA methylation as an important signal controlling virulence gene expression in Salmonella and other bacteria. In light of this, our studies on the predicted C. jejuni DNA methylase Cj1461 showed that cj1461 was induced at 37C, the internal temperature of humans, consistent with a role in pathogenic growth adaptation. Further experiments revealed that mutation of cj1461 resulted in the dramatically altered expression of ca. 50-60 proteins, including known virulence factors and additional predicted regulatory proteins such as the orphan response regulator Cj0355. Consequently, Cj1461 appears to be involved in a complex regulatory circuit controlling expression of numerous C. jejuni genes; growth temperature is one of the signals. We now propose further study of gene regulation in C. jejuni, focusing on those proteins that are regulated by the predicted DNA methylase Cj1461 and the orphan response regulator Cj0355. We will use a combination of microarray, proteomics, and biochemical approaches to achieve the goals outlined in these three specific aims: Specific Aim 1. Determine the functional properties of Cj1461 and Cj0355 responsible for modulating virulence gene expression. Specific Aim 2. Identify the downstream targets of Cj1461 and Cj0355 to define their combinatorial impact on gene regulation. Specific Aim 3. Elucidate the upstream factors and signals controlling Cj1461 and Cj0355 expression to reveal the entire regulatory circuit.

描述（由申请人提供）：空肠弯曲菌是 NIH 分类的 B 类生物恐怖主义制剂。它是美国细菌性胃肠炎的主要原因，并导致散发性疾病以及食源性和水源性爆发。美国每年至少有 240 万例空肠弯曲菌胃肠炎病例，发病率超过沙门氏菌和志贺氏菌的总和 (1)。空肠弯曲菌感染也是格林-巴尔综合征发生的最常见先决事件，格林-巴尔综合征是一种急性运动麻痹，显然是由针对空肠弯曲菌表面抗原的自身免疫反应引起的。尽管弯曲杆菌病的患病率很高并且研究已超过 20 年，但空肠弯曲菌引起疾病的机制仍然不清楚。一些空肠弯曲菌毒力因子已被鉴定，但其调节机制很大程度上未知。 最近的证据表明 DNA 甲基化是控制沙门氏菌和其他细菌毒力基因表达的重要信号。有鉴于此，我们对预测的空肠弯曲菌 DNA 甲基化酶 Cj1461 的研究表明，cj1461 在 37°C（人体内部温度）下被诱导，这与致病性生长适应中的作用一致。进一步的实验表明，cj1461 的突变导致 ca 的表达显着改变。 50-60 个蛋白质，包括已知的毒力因子和其他预测的调节蛋白，例如孤儿反应调节因子 Cj0355。因此，Cj1461 似乎参与了控制许多空肠弯曲菌基因表达的复杂调节回路。生长温度是信号之一。 我们现在建议进一步研究空肠弯曲菌的基因调控，重点关注那些受预测的 DNA 甲基化酶 Cj1461 和孤儿反应调节因子 Cj0355 调控的蛋白质。我们将结合使用微阵列、蛋白质组学和生化方法来实现这三个具体目标中概述的目标： 具体目标 1. 确定负责调节毒力基因表达的 Cj1461 和 Cj0355 的功能特性。 具体目标 2. 确定 Cj1461 和 Cj0355 的下游靶标，以确定它们对基因调控的组合影响。 具体目标 3. 阐明控制 Cj1461 和 Cj0355 表达的上游因子和信号，以揭示整个调节回路。