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.

总结 弗朗西斯菌属构成革兰氏阴性细菌的一个属，其占据广泛的细胞内的细胞内小生境。 一系列的后生动物宿主。这组包括Francisella tularensis subsp.土拉热，一种高度致命的人类 由于其感染剂量低，气溶胶途径， 接种和侵袭性感染过程。一些研究表明， 这些细菌是弗朗西斯菌致病岛（FPI），它编码细菌VI型的变体 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， 导致疾病的可变能力。在伴随这一提议的初步数据中，我们证明， 编码FPIT6SS的底物效应蛋白的基因可以在基因组的远端位置发现。我们 进一步发现，尽管这些效应子在弗朗西斯菌属中不存在，但它们在弗朗西斯菌属中起着重要的、直接的、 在促进携带它们的细菌的毒力策略中的作用。这些发现使我们 假设FPI编码的T6SS作为一个多功能平台，用于递送不同的效应物， 基因组中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，OpiA，促进细胞内复制。重要的是， 迄今为止还没有鉴定出FPI效应蛋白的作用。我们在此表明，Opia是 细菌磷脂酰肌醇激酶家族的一员，在多种病原体中具有代表性 包括弧菌属、军团菌属和立克次氏体属。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起作用。在我们的第二个目标中，我们试图识别蛋白质 需要靶向效应子到弗朗西斯菌中的T6SS，以及定义靶向效应子的机制。 分泌器和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.土拉热亚种， 描述了它们在F.土拉热亚种土拉热。总体而言，拟议的 这项研究将深入了解一个重要的人类和动物群体的毒力机制， 病原体