The mechanistic basis of how symbionts assist vector control

项目摘要： 世界卫生组织最近建议部署感染沃尔巴克氏体的 蚊子进行试点生物控制工作，以遏制寨卡病毒和登革热病毒向人类的传播。这 该建议主要基于沃尔巴克氏体生物学的两个方面。首先，这些母亲传播的， 内共生细菌通过改变蚊子作为病原体的能力而引起病原体阻断， 病毒复制的有效宿主。其次，沃尔巴克氏体通过一种称为细胞质的过程改变精子和卵子 - 用于种群抑制（减少蚊子种群大小）的不相容性（CI），以及 人口替换（病原体阻断沃尔巴克氏体传播到未感染的人口）战略。 具体地说，CI导致胚胎死亡时，感染的男性与未感染的女性交配。的 修改后的精子使未感染的卵子受精，然而受精后的缺陷随后发生，跨越复制失败 父亲的DNA，父亲的核膜和细胞周期激活的延迟破裂，以及失败的， 父本染色体分离。重要的是，精子在受精前的变化仍然存在， 神秘的，即沃尔巴克氏体在睾丸中如何表达和使用细胞质的毒素基因产物， 不相容因子（cif）A和B以确定CI的发作。由于这两种基因产物代表了 作为对CI理解的突破，所提出的研究的中心假设是原噬菌体WO cifA和cifB基因编码蛋白质产物，这些蛋白质产物可以逃离睾丸中的沃尔巴克氏体膜， 真核宿主配体，最终修饰精子完整性导致CI。在目标1中，我将使用DNA细胞化学 和酶测定以确定Cif蛋白在体内引起的精子修饰的类型。在Aim中 2，我将研究定位模式和潜在的配体，以测试病毒颗粒 运输蛋白质与精子核DNA相互作用。到目前为止，考试尚未得出任何结果 最初的CI缺陷的机制性进展，以及部署Wolbachia来遏制虫媒病毒的兴趣日益增加 传播需要解释沃尔巴克氏体的驱动系统。如果成功，这项研究将开创 Wolbachia诱导的生殖寄生的机制研究，告知Wolbachia的功效和交付， 一种控制多种人畜共患病的工具，并为发现 CI的生化基础

Project Summary: The World Health Organization recently recommended the deployment of Wolbachia-infected mosquitoes for pilot biocontrol efforts that curb the transmission of Zika and dengue viruses to humans. This recommendation is based principally on two facets of Wolbachia biology. First, these maternally-transmitted, endosymbiotic bacteria cause pathogen blocking by altering the competency of mosquitoes to serve as effective hosts for viral replication. Second, Wolbachia alter sperm and egg via a process termed cytoplasmic incompatibility (CI) that is used for population suppression (reduction in mosquito population size) and population replacement (spread of pathogen-blocking Wolbachia into an uninfected population) strategies. Specifically, CI results in embryonic lethality when an infected male mates with an uninfected female. The modified sperm fertilize the uninfected egg, however post-fertilization defects ensue spanning failed replication of paternal DNA, delayed breakdown of paternal nuclear envelope and cell cycle activation, and a failure of segregation of paternal chromosomes. Importantly, the pre-fertilization modifications of sperm remain enigmatic, namely how Wolbachia in the testes express and use the toxin gene products of cytoplasmic incompatibility factors (cif) A and B to establish the onset of CI. As these two gene products represent a breakthrough in the understanding of CI, the central hypothesis of the proposed research is that prophage WO genes, cifA and cifB, encode protein products that escape the Wolbachia membrane in testes to interact with eukaryotic host ligands, ultimately modifying sperm integrity to cause CI. In Aim 1, I will use DNA cytochemistry and enzymatic assays to determine the types of sperm modifications inflicted by the Cif proteins in vivo. In Aim 2, I will investigate localization patterns and potential ligands to test the presumption that viral particles transport the proteins to interact with sperm nuclear DNA. Examinations thus far have yet to yield any mechanistic advance for the initial CI defects, and the rising interest in deploying Wolbachia to curb arbovirus transmission necessitates an explanation of Wolbachia's drive system. If successful, this research will pioneer mechanistic studies of Wolbachia-induced reproductive parasitism, inform Wolbachia's efficacy and delivery as a tool to control diverse zoonotic diseases, and provide multiple lines of evidence for the discovery of the biochemical basis of CI.