Genes in the Yersinia pestis lifecycle

鼠疫耶尔森氏菌生命周期中的基因

• 批准号: 8891359
• 负责人: Olaf Schneewind
• 金额: $ 24.37万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8891359
• 关键词: Aerosols; Affect; Amino Acids; Antigens; Bacteria; Biochemical; Biological Assay; Bite; Blood; Breathing; Bubonic Plague; Calcium; Calcium ion; Cell Culture Techniques; Cells; Chromosomes; Collaborations; Complex; Defect; Development; Disease; Disease Outbreaks; Domestic Animals; Drops; Felis catus; Fleas; Gastrointestinal tract structure; Gene Expression Profile; Genes; Genome; Goals; Growth; Human; Immune; Immune response; In Vitro; Infection; Insecta; Invaded; Label; Lesion; Libraries; Ligand Binding; Mammals; Maps; Measures; Microbial Biofilms; Modeling; Needles; Obstruction; Open Reading Frames; Organelles; Pathogenesis; Peptide Hydrolases; Phenotype; Plague; Plasmids; Population; Prairie Dog; Proteins; Proteome; Proventriculus; Pseudogenes; Rattus; Recombinants; Regulator Genes; Rodent; Role; Signal Transduction; Small RNA; Surface; Technology; Temperature; Testing; United States; Variant; Virulence; Virulent; Work; Yersinia pestis; comparative; epizootic; extracellular; feeding; gastrointestinal; gene function; macrophage; mouse model; mutant; pathogen; response; tissue/cell culture; tool; transmission process; vector; weapons of mass destruction

Yersinia pestis is the causative agent of plague, a disease that affects many different mammalian species. Plague is transmitted by fleas, which are infected during blood meals and colonized via a gastrointestinal biofilm. Transmission occurs when colonized insects feed on new hosts, typically rodents. Historically, epizootic outbreaks in rodents have triggered flea-born transmission of plague into human populations with devastating consequences. For this reason, Y. pestis is considered the single most virulent bacterial pathogen and weapon of mass destruction. Y. pestis is a clonal pathogen with a genome of 4,012 chromosomal genes and three virulence plasmids. The pCDI plasmid encodes the type III secretion machine for delivery of Yop effectors into host immune cells. This essential virulence strategy is regulated by two environmental signals: temperature shift, as bacteria are transferred from fleas (18-30°C) to mammals (37°C), and a drop in extracellular calcium ions, perceived as type III needle complexes penetrate host immune cells (LCR, low-calcium response). The functions of most genes on the virulence plasmids have been revealed, however very little is known about chromosomal genes and their contributions to the unique lifecycle of Y. pestis. The transcriptome of Y. pestis grown in vitro has been compared with bacteria in a flea biofilm and Y. pestis invading a rat bubo: 214 genes are specifically upregulated in the flea gut, whereas 119 genes are specifically expressed in the rat bubo. Here we will investigate the function of uncharacterized Y. pestis genes upregulated in either the flea gut or the rat bubo. Towards this goal, we have isolated 7,832 mutants with mapped insertional lesions on the Y. pestis C092 chromosome (PEST-Library). Mutants with lesions in unknown ORFs, hypothetical genes and small RNAs will be analyzed for defects in flea colonization, the LCR, type 111 secretion and effector translocation into host immune cells. Selected mutants will be analyzed for the pathogenesis of bubonic plague and the histopathological features of this disease. Mutants with defects in flea biofilm or plague pathogenesis will be subjected to biochemical studies, thereby exploring the specific functions of unknown gene products and small RNAs in the Y. pestis lifecycle.

鼠疫耶尔森氏菌是鼠疫的病原体，鼠疫是一种影响许多不同哺乳动物物种的疾病。鼠疫是通过跳蚤传播的，跳蚤在血餐过程中感染，并通过胃肠道生物膜定居。当被殖民的昆虫以新宿主(通常是啮齿动物)为食时，就会发生传播。从历史上看，鼠疫在啮齿动物中的暴发曾引发鼠疫通过跳蚤传播到人类人口中，造成毁灭性的后果。出于这个原因，鼠疫杆菌被认为是唯一最致命的细菌病原体和大规模杀伤性武器。鼠疫耶尔森氏菌是一种克隆病原菌，其基因组由4,012个染色体基因和3个毒力质粒组成。PCDI质粒编码III型分泌机，用于将YOP效应器输送到宿主免疫细胞。这种基本的毒力策略受两种环境信号的调节：温度变化，因为细菌从跳蚤(18-30℃)转移到哺乳动物(37℃)，以及细胞外钙离子的下降，被认为是III型针状复合体穿透宿主免疫细胞(LCR，低钙反应)。大多数基因在毒力质粒上的功能已被揭示，但对染色体基因及其在鼠疫菌独特生命周期中的作用知之甚少。将体外培养的鼠疫杆菌转录组与跳蚤生物膜中的细菌和入侵大鼠肠道的鼠疫杆菌进行比较：214个基因在跳蚤肠道中特异上调，而119个基因在大鼠肠道中特异表达。在这里，我们将研究未鉴定的鼠疫耶尔森氏菌基因在跳蚤肠道或大鼠肠道中上调的功能。为了实现这一目标，我们已经分离到7832个在鼠疫耶尔森氏菌C092染色体上具有定位插入损伤的突变体(PEST-文库)。具有未知ORF、假设基因和小RNA损伤的突变体将被分析跳蚤定植、LCR、111型分泌和效应器转位到宿主免疫细胞中的缺陷。选定的突变体将分析腺鼠疫的发病机制和这种疾病的组织病理学特征。具有跳蚤生物膜缺陷或鼠疫致病机制的突变株将接受生化研究，从而探索未知基因产物和小RNA在鼠疫菌生命周期中的特定功能。