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：
9795616
负责人：
Kimberley Diane Seed
金额：
$ 2.71万
依托单位：
UNIVERSITY OF CALIFORNIA BERKELEY
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-11-01 至 2021-08-31
项目状态：
已结题

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 in vulnerable areas where infrastructure has been compromised and populations have been displaced. 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). Knowledge of the molecular consequences of phage predation on the selection of epidemic strains is needed to enhance our understanding of the forces impacting the evolution and epidemiology of V. cholerae. We found that a novel group of mobile genetic elements called PLEs (phage-inducible chromosomal island-like elements) are a key weapon that epidemic V. cholerae uses to protect against phage attack. Our hypothesis is that PLEs are potent, highly specific, antiviral barriers that act through two distinct mechanisms to ensure that phage do not propagate and spread to neighboring V. cholerae cells. Our data indicate that PLEs act by inhibiting the production of essential phage proteins and by rupturing the infected bacterial cell before all progeny phage complete their replication cycle. To understand PLE activity in mechanistic detail we will pursue the following specific aims: 1) We will define the regulatory network that permits the rapid stimulation of PLE activity when V. cholerae is under attack by phage and determine how specificity is imparted onto PLE-phage interactions. 2) We will determine how PLE interferes with the ability of phage to produce essential proteins. Under this aim we will use a combination of functional genomic approaches and mutational analyses to separate this aspect of PLE activity from PLE-mediated cell lysis. 3) We will determine the molecular basis for PLE-mediated bacterial cell lysis. We will characterize suppressors that are insensitive to cytotoxic PLE-encoded products to understand how PLE efficiently kills phage-infected V. cholerae. The proposed studies will establish how phage predation shapes the genome of epidemic V. cholerae. This knowledge will enhance our understanding of phage-mediated perturbations to microbial populations in healthy and diseased states, and further our ability to manipulate these communities for therapeutic or prophylactic benefit.

霍乱弧菌等水传播病原体对全球健康构成重大威胁。霍乱弧菌可以持续存在水生环境，它可能会在霍乱流行地区和地区造成毁灭性的霍乱疫情基础设施遭到破坏、人口流离失所的脆弱地区。主人- 决定疾病结果和霍乱传播动态的病原体相互作用发生在复杂的微生物生态系统，包括捕食性细菌病毒（噬菌体）。分子知识需要了解噬菌体捕食对流行菌株选择的影响，以加强我们的研究了解影响霍乱弧菌进化和流行病学的力量。我们发现有一本小说称为 PLE（噬菌体诱导染色体岛样元件）的一组可移动遗传元件是关键流行性霍乱弧菌用来防御噬菌体攻击的武器。我们的假设是 PLE 是有效的、高度特异性的抗病毒屏障，通过两种不同的机制发挥作用，以确保噬菌体不会繁殖并传播到邻近的霍乱弧菌细胞。我们的数据表明，PLE 通过抑制产生必需的噬菌体蛋白，并在所有子代噬菌体之前破坏受感染的细菌细胞完成它们的复制周期。为了详细了解 PLE 活动的机制，我们将采取以下措施具体目标： 1）我们将定义监管网络，以允许在 V 时快速刺激 PLE 活动。霍乱弧菌受到噬菌体的攻击，并决定如何将特异性赋予 PLE-噬菌体相互作用。 2）我们将确定 PLE 如何干扰噬菌体生产必需蛋白质的能力。在这个目标下我们将结合使用功能基因组方法和突变分析来分离这方面的 PLE 介导的细胞裂解产生 PLE 活性。 3）我们将确定PLE介导的细菌的分子基础细胞裂解。我们将表征对细胞毒性 PLE 编码产物不敏感的抑制剂，以了解 PLE 如何有效杀死噬菌体感染的霍乱弧菌。拟议的研究将确定如何噬菌体捕食塑造了流行性霍乱弧菌的基因组。这些知识将增强我们的理解噬菌体介导的对健康和患病状态下微生物种群的干扰，并进一步提高我们的能力操纵这些社区以获得治疗或预防益处。