Phage resistance and mobile genetic elements in Vibrio cholerae

霍乱弧菌的噬菌体抗性和移动遗传元件

基本信息

批准号：
10682489
负责人：
Kimberley Diane Seed
金额：
$ 47.65万
依托单位：
UNIVERSITY OF CALIFORNIA BERKELEY
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-09-27 至 2026-08-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10682489
关键词：
Area Bacterial Chromosomes Bacteriophages Biochemical Biological Models Capsid Cells Cholera Chromosomes Clustered Regularly Interspaced Short Palindromic Repeats Complex Cryoelectron Microscopy DNA biosynthesis Data Defense Mechanisms Disease Disease Outbreaks Disease Outcome Ecosystem Electron Microscopy Elements Environment Epidemic Evolution Excision Gene Expression Genes Genetic Genetic Materials Genome Genomics Goals Human Infection Infection Control Infrastructure Island Life Cycle Stages Lytic Measures Mediating Mobile Genetic Elements Modification Molecular Nature Open Reading Frames Outcome Parasites Predatory Behavior Process Production Proteomics Receptor Cell Regulation Resistance Role Sanitation Small RNA System Tail Techniques Transcript Untranslated RNA Vibrio cholerae Virion Water Work clinically relevant driving force gene product global health improved inhibitor microbial novel pathogen pathogenic bacteria response targeted nucleases transmission process waterborne pathogen

项目摘要

Waterborne pathogens like Vibrio cholerae pose significant threats to global health. V. cholerae can persist in the aquatic environment, and it can emerge to cause devastating cholera outbreaks in endemic regions and vulnerable areas lacking adequate water and sanitation infrastructure. The host-pathogen interactions that dictate disease outcome and cholera transmission dynamics occur in the context of a complex microbial ecosystem that includes predatory bacterial viruses (phages). Phages profoundly impact the evolution of their bacterial hosts, both through predation, which selects for hosts with defenses that overcome phage killing and through mobilization and dissemination of genetic material. Certain mobile elements called the phage satellites have evolved sophisticated mechanisms to exploit phages for their own selfish spread. Such elements interfere with the replication of the phages they parasitize, and as such, provide their cellular hosts with a means to limit phage predation. Our lab discovered PLEs (for phage-inducible chromosomal island-like elements) in V. cholerae that provide specific and robust defense against ICP1, the dominant lytic phage co-circulating with V. cholerae in cholera endemic regions. Upon infection by ICP1, PLEs excise from the V. cholerae chromosome, replicate to high copy and are assembled into virions to spread the PLE genome to new cells while concurrently abolishing phage production. PLEs are uniquely potent, highly specific, anti-phage barriers that act through multiple mechanisms to ensure that ICP1 does not propagate and spread to neighboring V. cholerae cells. However, few mechanisms of direct interference with ICP1 are known, and none are essential for PLE activity, indicating that additional mechanisms await discovery in this system. This proposal builds on our prior work defining the PLE lifecycle in response to phage infection to gain a mechanistic understanding of how PLEs execute their unusually potent anti-phage activity. Our data indicate that PLE’s most potent anti- phage inhibitors are focused on blocking virion assembly. To understand PLE activity in mechanistic detail, we will pursue the following specific aims: 1) We will define the structural composition of virions and capsid assembly intermediates for ICP1 and PLE 2) We will Interrogate the functions of three PLE-encoded ORFs that are each sufficient to inhibit phage 3) We will determine how a PLE-encoded small RNA perturbs phage gene expression. The proposed studies are expected to reveal novel mechanistic paradigms not previously documented in phage satellites or other anti-phage defense systems. The long-term coevolution of V. cholerae PLE and ICP1 serves as a powerful model system to understand clinically relevant phage defense mechanisms to inform phage therapy efforts and understand the forces driving the evolution of bacterial pathogens.

霍乱弧菌等水传播病原体可能持续存在，对全球健康构成重大威胁。水生环境，它可能会在流行地区和地区造成毁灭性的霍乱疫情缺乏足够的水和卫生基础设施的脆弱地区。决定疾病结果和霍乱传播动态发生在复杂的微生物环境中包括捕食性细菌病毒（噬菌体）的生态系统对其进化产生深远影响。细菌宿主，通过捕食，选择具有克服噬菌体杀伤和防御能力的宿主通过遗传物质的动员和传播，某些称为噬菌体卫星的移动元件。已经进化出复杂的机制来利用噬菌体进行自私的传播，这些因素会干扰。随着它们寄生的噬菌体的复制，为它们的细胞宿主提供了一种限制的方法我们的实验室在 V 中发现了 PLE（噬菌体诱导的染色体岛样元素）。霍乱弧菌对 ICP1（与霍乱弧菌共同循环的主要裂解噬菌体）提供特异性和强大的防御。霍乱流行区的霍乱弧菌感染 ICP1 后，PLE 会从霍乱弧菌染色体上切除，复制到高拷贝并组装成病毒粒子，将 PLE 基因组传播到新细胞，同时同时消除噬菌体产生是独特有效的、高度特异性的抗噬菌体屏障。通过多种机制来确保ICP1不会传播和扩散到邻近的V。然而，直接干扰 ICP1 的机制知之甚少，而且没有一个是必需的。对于 PLE 活动，表明该系统中还有其他机制等待发现。我们之前的工作定义了响应噬菌体感染的 PLE 生命周期，以获得对 PLE 如何执行其异常有效的抗噬菌体活性。我们的数据表明，PLE 具有最有效的抗噬菌体活性。噬菌体抑制剂专注于阻断病毒粒子组装。为了详细了解 PLE 活性，我们进行了研究。将追求以下具体目标：1）我们将定义病毒体和衣壳的结构组成 ICP1 和 PLE 的组装中间体 2) 我们将询问三个 PLE 编码的 ORF 的功能，这些 ORF 每一个都足以抑制噬菌体 3) 我们将确定 PLE 编码的小 RNA 如何扰乱噬菌体基因所提出的研究有望揭示以前没有的新机制范式。噬菌体卫星或其他抗噬菌体防御系统记录了霍乱弧菌的长期共同进化。 PLE 和 ICP1 作为强大的模型系统来了解临床相关的噬菌体防御为噬菌体治疗工作提供信息并了解驱动细菌进化的力量的机制病原体。