Identification of essential factors contributing to vector colonization and transmission of relapsing fever spirochetes

回归热螺旋体媒介定植和传播的重要因素的鉴定

• 批准号: 10112814
• 负责人: Job E Lopez
• 金额: $ 39.63万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-03-01 至 2023-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10112814
• 关键词: Address; Area; Arthropods; Black-legged Tick; Blood; Borrelia turicatae; Candidate Disease Gene; Child; Childhood; Chromosome Mapping; Code; Comparative Genomic Analysis; Data; Data Set; Defect; Development; Disease; Environment; Essential Genes; Event; Exhibits; Fever; Gene Expression; Generations; Genes; Genetic; Genome; Genomic approach; Genomics; Goals; Health; Human body; Image; In Vitro; Infection; Infectious Diseases Research; Interruption; Knowledge; Laboratories; Life Cycle Stages; Location; Malaria; Mammals; Measures; Mediating; Membrane Proteins; Midgut; Mind; Mission; Modeling; Molecular; Morbidity - disease rate; Mus; Mutagenesis; National Institute of Allergy and Infectious Disease; Order Spirochaetales; Ornithodoros; Pathogenesis; Pattern; Pediculus humanus humanus; Plasmids; Population; Preventive vaccine; Process; Production; Proteins; Proteome; Public Health; Publishing; Quantitative Reverse Transcriptase PCR; Relapsing Fever; Risk; Role; Salivary Glands; Series; Site-Directed Mutagenesis; Structure; Surface; System; Tick-Borne Relapsing Fever; Ticks; Tuberculosis; United States National Institutes of Health; Vector-transmitted infectious disease; World Health Organization; Zoonoses; biophysical analysis; comparative; comparative genomics; diarrheal disease; functional genomics; gene product; human disease; improved; mortality; mutant; neglect; novel; pathogen; pathogenic microbe; prevent; tick bite; tick feeding; transcriptomics; transmission process; vector; vector tick; vector transmission

Project Summary Understanding the life cycle of a pathogen within different natural environments is a poorly evolved area of infectious disease research. Tick-borne relapsing fever (RF) spirochetes are one such pathogen that have adapted to colonize arthropods and mammalian blood. When a tick imbibes an infectious bloodmeal, spi- rochetes enter the midgut. Within ~ 2 weeks a population subsequently migrates and colonizes the salivary glands. However, the molecular events facilitating vector colonization and subsequent transmission to the mammalian host remain unclear. Consequently, delineating the intricacies of the life cycle of RF spirochetes is particularly relevant to public health. Limitations in RF spirochete genomics, transcriptomics, and genetics have been addressed by develop- ing the Borrelia turicatae-Ornithodoros turicata model. Utilizing a functional genomic approach, two important observations were made that this proposal builds upon: 1) after 220 generations, B. turicatae losses genes es- sential in vector colonization and/or establishing mammalian infection; 2) the 150 kb linear megaplasmid (lp150) is likely important for vector colonization and transmission. A 36 kb locus toward the 3' end of the plas- mid contains a series of genes that coded for surface proteins that are up-regulated in the tick vector compared to infected mammalian blood. The central hypothesis of this application is that there are subsets of B. turicatae genes essential in midgut and salivary gland colonization and establishing early mammalian infection. The fol- lowing aims are purposed: Aim 1: Identify genes that are essential in the tick-mammalian transmission cycle by comparative ge- nomics, and define temporal expression and protein production of B. turicatae genes localized in the 36 kb locus. The objective is to quantify the expression of genes in the 36 kb locus during the pathogens life cycle in the tick vector, and coincide the findings with protein production. Also, a comparative genomic analysis between a wild type spirochetes and noncolonizing/noninfectious strains will identify likely essential genes. Aim 2: Identify and characterize genes essential in vector colonization and transmission by mutagene- sis, imaging, and structural and biophysical analyses. The objective is to generate and evaluate B. tu- ricatae mutants, to identify defects in tick-mediated transmission to mice. The significance of these genes in the tick-mammalian transmission cycle will be further verified by site directed mutagenesis and structural and biophysical analyses. With the surface proteome of RF spirochetes serving essential roles in pathogenesis, these findings will guide strategies to interrupt the pathogen's life cycle in the tick and mammal. The results will be broadly appli- cable to Old and New World species, and address NIAID's mission to better understand and prevent disease.

项目摘要 了解病原体在不同自然环境中的生命周期是一个很差的进化过程。 传染病研究领域。蜱传回归热（RF）螺旋体就是这样一种病原体， 已经适应了节肢动物和哺乳动物的血液。当蜱虫吸收了传染性的血粉时， 罗切特进入中肠。在约2周内，种群随后迁移并在唾液中定植。 腺体然而，促进载体定殖和随后传播到宿主的分子事件是不确定的。 哺乳动物宿主尚不清楚。因此，描绘RF螺旋体生命周期的复杂性是 特别是与公共卫生有关的。 RF螺旋体基因组学、转录组学和遗传学的局限性已经通过开发- 用Borrelia turicatae-Ornithodoros turicata模型。利用功能基因组方法，两个重要的 观察到该提议基于：1）在220代之后，B。尿酸损失基因es- 在载体定殖和/或建立哺乳动物感染中是必需的; 2）150 kb线性巨质粒 （lp 150）可能对病媒定殖和传播很重要。质粒3'端的一个36 kb的位点， mid包含一系列编码表面蛋白的基因，这些蛋白在蜱虫载体中表达上调， 感染的哺乳动物血液本申请的中心假设是存在B的子集。图里克特 中肠和唾液腺定植和建立早期哺乳动物感染所必需的基因。以下是 目的如下： 目的1：通过比较基因组学鉴定蜱-哺乳动物传播周期中必需的基因。 组学，并定义了B的时间表达和蛋白质产生。turic基因定位于 36 kb基因座。目的是定量病原体生命过程中36 kb基因座的基因表达 在蜱虫载体中的循环，并与蛋白质生产的发现相一致。同时，比较基因组分析 野生型螺旋体和非定殖/非感染性菌株之间的差异将确定可能的必需基因。 目的2：鉴定和表征诱变剂在载体定植和传播中所必需的基因- SIS、成像以及结构和生物物理分析。目标是生成和评估B。你， 蓖麻毒素突变体，以确定蜱介导的小鼠传播缺陷。这些基因的重要性 蜱-哺乳动物传播周期将通过定点诱变和结构和 生物物理分析 RF螺旋体的表面蛋白质组在发病机制中起着重要作用，这些发现将 指导策略以中断病原体在蜱和哺乳动物中的生命周期。研究结果具有广泛的应用价值。 电缆到旧的和新的世界物种，并解决NIAID的使命，以更好地了解和预防疾病。