Mechanistic Dissection of Pheromone-Dependent Regulation of Group A Streptococcal

A 组链球菌信息素依赖性调节的机制剖析

• 批准号: 8293002
• 负责人: MICHAEL J FEDERLE
• 金额: $ 39.25万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8293002
• 关键词: Animals; Bacterial Genes; Binding; Biological Assay; Cell Communication; Cells; Chromatography; Communication; Cysteine Protease; DNA; Data; Disease; Dissection; Foundations; Future; Gene Expression; Gene Expression Regulation; Genetic; Genetic Screening; Genetic Transcription; Goals; Gram-Positive Bacteria; Growth; In Vitro; Infection; Luciferases; Modeling; Mutagenesis; Organism; Orthologous Gene; Pathogenesis; Pathway interactions; Pattern; Peptide Hydrolases; Peptide Signal Sequences; Peptides; Phase; Pheromone; Play; Process; Production; Property; Proteins; Regulation; Regulatory Pathway; Research; Role; Severity of illness; Signal Transduction; Streptococcus; Streptococcus pyogenes; Structure; System; Systemic infection; Testing; Virulence; Virulence Factors; antimicrobial; base; design; environmental change; in vivo; insight; paralogous gene; pathogen; quorum sensing; research study; response; reversed phase chromatography; therapy design/development; transcription factor

DESCRIPTION (provided by applicant): Group A Streptococcus (GAS), a pathogen capable of both localized and systemic infection, is known to secrete numerous virulence factors in temporal patterns during growth in vitro and in vivo, indicating the presence of intricate regulatory circuits. An inverse relationship exists between expression levels of the secreted cysteine protease, SpeB, and severity of disease [1-3]. The so-called "stand-alone" regulator Rgg (also known as RopB) is required, but is not sufficient, for expression of SpeB. An unknown growth-phase-dependent factor is additionally required, but has remained elusive [4-6]. Our preliminary data demonstrate that the unknown factor is a bacterially-produced pheromone with properties consistent with a small peptide. Additionally, analysis predicts that Rgg is a peptide-binding transcription factor with structural homology to PlcR and PrgX of other quorum sensing systems. The overall hypothesis to be tested is that a pheromone modulates the activity of Rgg for the purpose of controlling speB transcription. This is a departure from the paradigm that the Rgg-dependent pathway responds to environmental changes; instead, we provide compelling evidence that GAS produces its own impetus to induce speB. Our preliminary results demonstrate that Rgg paralogs found in GAS are indeed responsive to small peptide pheromones, providing a convincing precedent for our hypothesis and are the first examples that Rgg proteins are quorum sensing effectors. The goal of our research will be to define the signaling pheromone(s) present in culture supernatants and characterize the mechanism for its production and recognition by GAS. Genetic disruption of these systems will be tested for their contributions in localized and invasive infection models. Demonstration that GAS utilizes Rgg proteins for cell-to-cell signaling will provide a foundation for future development of therapies designed to interfere with intercellular signaling in GAS and in other Rgg-containing organisms.

描述（由申请人提供）：已知A组（气体）是一种能够局部感染和全身感染的病原体，可以分泌体外和体内生长期间时间模式中的许多毒力因子，表明存在复杂的调节循环。分泌半胱氨酸蛋白酶，SPEB和疾病严重程度的表达水平存在反比关系[1-3]。需要所谓的“独立”调节剂RGG（也称为ROPB），但不足以表达SPEB。另外还需要一个未知的生长期依赖性因子，但仍然难以捉摸[4-6]。我们的初步数据表明，未知因子是细菌生产的信息素，具有与小肽一致的特性。 此外，分析预测RGG是一种肽结合转录因子，具有与PLCR的结构同源性和其他Quorum传感系统的PRGX。要测试的总体假设是，信息素调节RGG的活性是为了控制SPEB转录。这与RGG依赖性途径对环境变化做出反应是与范式不同的。取而代之的是，我们提供了令人信服的证据，表明天然气会产生自己的动力诱导SPEB。我们的初步结果表明，在气体中发现的RGG旁系同源物确实对小肽信息素有反应，这为我们的假设提供了令人信服的先例，并且是RGG蛋白是群体感应效应子的第一个例子。我们研究的目的是定义培养上清液中存在的信号信息素（S），并表征其通过气体生产和识别的机制。这些系统的遗传破坏将在局部和侵入性感染模型中的贡献进行测试。证明气体利用RGG蛋白进行细胞到细胞信号的证明将为未来开发旨在干扰气体和其他含RGG的生物中细胞间信号传导的疗法提供基础。