Identity, function and control of Francisella effectors encoded outside its pathogenicity island

弗朗西斯菌致病岛外编码的效应子的身份、功能和控制

• 批准号: 10668260
• 负责人: SIMON L DOVE
• 金额: $ 79.56万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10668260
• 关键词: Aerosols; Aggressive course; Animals; Bacteria; Biochemical; Bioinformatics; Biology; Cell membrane; Cells; Classification; Data; Disease; Distal; Distant; Dose; Elements; Enzymes; Family; Francisella; Francisella tularensis; Gene Expression; Genes; Genetic; Genetic Screening; Genome; Gram-Negative Bacteria; Growth; Homologous Gene; Human; Infection; Legionella; Life Style; Link; Location; Manuscripts; Mediating; Modeling; Molecular; Mutagenesis; Names; Organism; PIK3CG gene; Paper; Pathogenesis; Pathogenicity; Pathogenicity Island; Pathway interactions; Phosphatidylinositols; Phosphotransferases; Play; Protein Secretion; Proteins; Publishing; Regulation; Reporting; Research; Research Personnel; Rickettsia; Role; Route; System; Testing; Tularemia; Variant; Vesicle; Vibrio; Virulence; Virulence Factors; Virulent; Work; experimental study; fitness; functional plasticity; guided inquiry; human pathogen; in vivo; insight; member; pathogen; pathogenic bacteria; phosphatidylinositol 3-phosphate; promoter; protein function; response; screening; trafficking

Summary The Francisella constitute a genus of Gram-negative bacteria that occupy intracellular niches within a wide range of metazoan hosts. This group includes Francisella tularensis subsp. tularensis, a highly virulent human pathogen that has been classified as a Tier 1 select agent due to its low infectious dose, aerosol route of inoculation, and aggressive course of infection. Several studies have suggested that the key virulence factor of these bacteria is the Francisella pathogenicity island (FPI), which encodes a variant of the bacterial type VI secretion system (T6SS). However, the FPI is conserved among Francisella spp with diverse host ranges and variable capacity to cause disease. In preliminary data accompanying this proposal, we demonstrate that genes encoding substrate effector proteins of the FPI T6SS can be found at distal locations in the genome. We further find that although these effectors are variably present in Francisella spp, they play important, direct roles in promoting the virulence strategies of the bacteria that harbor them. These findings lead us to hypothesize that the FPI-encoded T6SS serves as a versatile platform for the delivery of diverse effector molecules encoded elsewhere within the genome. In our first aim we will define the molecular mechanism by which one T6SS effector of F. tularensis, OpiA, facilitates intracellular replication. Importantly, the mode of action of an FPI effector protein has not been identified to date. We show herein that OpiA is the founding member of a family of bacterial phosphatidylinositol kinases with representatives in diverse pathogens including Vibrio, Legionella, and Rickettsia spp. These data and additional preliminary findings suggest that OpiA acts by manipulating host cell membrane trafficking. In our second aim, we seek to identify the proteins required for targeting effectors to the T6SS in Francisella, as well as to define the mechanism by which the secretory apparatus and its substrates are coordinately regulated. Finally, in the third aim we propose to identify additional substrates of FPI-encoded T6SSs belonging to multiple F. tularensis subspecies and to characterize their contribution to the pathogenesis of F. tularensis subsp. tularensis. Collectively, the proposed research will provide insight into the virulence mechanisms of an important group of human and animal pathogens.

概括 弗朗西斯氏菌是革兰氏阴性菌的一个属，在广泛的细胞内占据着生态位。 后生动物宿主的范围。该组包括土拉弗朗西斯菌亚种。 tularensis，一种剧毒人类 由于感染剂量低、气溶胶途径传播，该病原体已被列为一级选择病原体 接种和侵袭性感染过程。多项研究表明，该病的关键毒力因子 这些细菌是弗朗西斯菌致病岛 (FPI)，它编码 VI​​ 型细菌的变体 分泌系统（T6SS）。然而，FPI 在具有不同宿主范围的弗朗西斯菌属中是保守的，并且 导致疾病的可变能力。在该提案附带的初步数据中，我们证明 编码 FPI T6SS 底物效应蛋白的基因位于基因组的远端位置。我们 进一步发现，尽管这些效应器在弗朗西斯菌属中存在不同程度的存在，但它们发挥着重要、直接的作用 在促进含有它们的细菌的毒力策略中发挥作用。这些发现引导我们 假设 FPI 编码的 T6SS 作为传递不同效应器的多功能平台 基因组内其他地方编码的分子。在我们的第一个目标中，我们将通过以下方式定义分子机制： F. tularensis 的一种 T6SS 效应子 OpiA 促进细胞内复制。重要的是，模式 迄今为止，FPI 效应蛋白的作用尚未确定。我们在此表明​​ OpiA 是创始者 细菌磷脂酰肌醇激酶家族的成员，在多种病原体中具有代表性 包括弧菌、军团菌和立克次体。这些数据和其他初步调查结果表明 OpiA 通过操纵宿主细胞膜运输发挥作用。在我们的第二个目标中，我们寻求鉴定蛋白质 需要将效应器靶向弗朗西斯拉中的 T6SS，以及定义该效应的机制 分泌装置及其底物是协调调节的。最后，在第三个目标中，我们建议 鉴定属于多个 F. tularensis 亚种的 FPI 编码的 T6SS 的其他底物，并 描述它们对 F. tularensis subsp. 发病机制的贡献。图拉伦西斯。总的来说，拟议的 研究将深入了解人类和动物的重要群体的毒力机制 病原体。