Control of Bacterial Toxins by Viruses and Plasmids

通过病毒和质粒控制细菌毒素

• 批准号: 8432443
• 负责人: Randall K Holmes
• 金额: $ 51.15万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 1976
• 资助国家: 美国
• 起止时间: 1976-09-30 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8432443
• 关键词: Anabolism; Assimilations; Attenuated; Bacillus (bacterium); Bacteria; Bacterial Infections; Bacterial Toxins; Biological; Cessation of life; Deferoxamine; Diphtheria; Diphtheria Toxin; Disease; Drug Targeting; Epidemic; Family; Ferrichrome; Gene Expression; Gene Expression Regulation; Generations; Genes; Genetic; Homeostasis; Homologous Gene; Hyperactive behavior; Ions; Iron; Lead; Maintenance; Mediating; Metals; Methods; Molecular; Mycobacterium tuberculosis; Oxidative Stress Pathway; Pathway interactions; Peptides; Pharmaceutical Preparations; Plasmids; Proteins; Proteomics; Recombinants; Regulon; Reporter Genes; Role; Russia; Siderophores; Sigma Factor; Structure; System; Testing; Toxin; Tuberculosis; USSR; Variant; Virulence; Virus; acid fast bacteria; antimicrobial; base; chemotherapeutic agent; corynebactin; design; genetic regulatory protein; inhibitor/antagonist; insight; novel; promoter; prototype; receptor; response; small molecule; synthetic peptide; tuberculosis treatment; uptake

Diphtheria, which re-emerged as a major epidemic disease in Russia andthe Newly Independent States of the former Soviet Union during the 1990s, is a paradigm for toxin-mediated bacterial disease. Tuberculosis, which causes more deaths worldwide than any other bacterial infection, is a paradigm for intracellular bacterial infection. Very similar iron-activated regulatory proteins, called the diphtheria toxin repressor (DbcR) and the iron-dependent regulator (IdeR), control virulence in C. diphtheriae and M. tuberculosis, respectively. Db<R and IdeR are prototypes for a family of metal-dependent global regulators predominantly found in Gram-positive and acid-fast bacteria. During the current project period, we used genetic and biochemcial methods to identify iron-regulated genes and gene products in C. diphtheriae, and we developed lead compounds that promote activation of DbcR or IdeR at lower concentrations of ferrous ions than are needed to activate DtxR or IdeR by itself. During the next project period we will extend these studies in several important ways. In Aim 1, using C. diphtheriae, we will characterize the structure and function of several important iron-regulated genes, determine the molecular basis for DtxR-dependent and Db<R-independent regulation of gene expression by iron, investigate the roles of specific sigma factors within the iron regulon, and investigate oxidative stress pathways and their interactions with iron-dependent gene regulation. In Aim 2, we will characterize the multiple siderophore-dependent iron-uptake pathways in C. diphtheriae that participate in maintenance of iron homeostasis. We will characterize interaction of diphtheriabactin (the siderophore produced by C. diphtheriae) with its dip0582/ciuA receptor, and we will identify the genetic systems that enable C. diphtheriae to use other siderophores (e.g., desferrioxamine, ferrichrome, rhizoferrin and the recently discovered siderophores from C. pseudotuberculosis). In Aim 3, we will apply structure- based methods to develop "second-generation" peptides and other molecules with high potency for stimulating or inhibiting Db<R or IdeR activity. We will test these novel compounds for biological activity, first in pound coli or C. glutamicum systems in which recombinant IdeR controls expression of reporter genes, and then in M. tuberculosis. Because ideR is essential in M. tuberculosis, and because expression of a "hyper- repressor" variant of DtxR attenuates the virulence of M. tuberculosis, we will determine whether the novel activators and inhibitors of IdeR that we are developing have antimicrobial activity against M. tuberculosis and potential value as chemotherapeutic agents for treatment of tuberculosis.

白喉重新成为俄罗斯和新独立国家的主要流行病 20 世纪 90 年代的前苏联，是毒素介导的细菌性疾病的典范。结核， 它在全球范围内造成的死亡人数比任何其他细菌感染都要多，是细胞内感染的范例 细菌感染。非常相似的铁激活调节蛋白，称为白喉毒素阻遏蛋白 (DbcR) 和铁依赖性调节因子（IdeR）分别控制白喉杆菌和结核分枝杆菌的毒力。 Db<R 和 IdeR 是一系列依赖于金属的全球调节器的原型，主要存在于 革兰氏阳性和抗酸细菌。在当前的项目期间，我们使用了遗传和生化技术 鉴定白喉杆菌中铁调节基因和基因产物的方法，我们开发了铅 在低于所需浓度的亚铁离子浓度下促进 DbcR 或 IdeR 活化的化合物 自行激活 DtxR 或 IdeR。在下一个项目期间，我们将在几个方面扩展这些研究 重要途径。在目标 1 中，我们将利用白喉棒状杆菌来表征几种细菌的结构和功能。 重要的铁调节基因，确定 DtxR 依赖性和 Db<R 独立性的分子基础 铁对基因表达的调节，研究铁调节子中特定西格玛因子的作用， 并研究氧化应激途径及其与铁依赖性基因调控的相互作用。瞄准 2，我们将描述白喉杆菌中多种铁载体依赖性铁吸收途径 参与铁稳态的维持。我们将表征白喉菌素（白喉菌素）的相互作用。 白喉杆菌产生的铁载体）及其dip0582/ciuA受体，我们将鉴定遗传 使白喉杆菌能够使用其他铁载体（例如去铁胺、铁铬、根铁蛋白）的系统 以及最近发现的来自假结核杆菌的铁载体）。在目标 3 中，我们将应用结构- 基于方法来开发“第二代”肽和其他具有高效能的分子 刺激或抑制 Db<R 或 IdeR 活性。我们将首先测试这些新型化合物的生物活性 在磅大肠杆菌或谷氨酸棒杆菌系统中，重组 IdeR 控制报告基因的表达，以及 然后是结核分枝杆菌。因为 ideR 在结核分枝杆菌中是必需的，并且因为“超- DtxR 的阻遏物”变体减弱了结核分枝杆菌的毒力，我们将确定新的 我们正在开发的 IdeR 激活剂和抑制剂对结核分枝杆菌具有抗菌活性 以及作为治疗结核病的化疗剂的潜在价值。