Molecular Characterization of Insect Pheromone Chemosensory Mutants in Nematodes

描述(申请人提供)：鉴于大量的线虫与无脊椎动物和脊椎动物宿主相关，与甲虫相关的Pristionchus pacphaus线虫代表着自由生活的土壤线虫秀丽线虫和许多引起丝虫线虫(如Brgia Malayi和Wucheria bancrofti)之间亟需的知识桥梁。虽然昆虫信息素识别的最新进展是关于昆虫的种内相互作用，主要是在交配方面，但我们对线虫和昆虫之间介导种间相互作用所需的成分知之甚少，后者是传播人类疾病的重要媒介。具体地说，在物种形成过程中，对特定化合物的化学感觉是如何重新编程的，这对线虫的宿主偏好有多大影响？除了线虫外，太平洋线虫是唯一一种采用正向遗传方法可行的线虫。因此，我们对已知的东方甲虫信息素ZTDO缺乏趋化性进行了首次行为遗传学筛选，并分离到两个东方甲虫信息素不敏感突变体：OBI-1和OBI-3。OBI-1和OBI-3对ZTDO无趋化作用，但对其他引诱剂的趋化作用为野生型。我们将利用线虫有翼双栖神经元启动子ODR-7和str-2(分别针对AWA和AWC)来鉴定OBI-1和OBI-3的分子损伤，并错误表达太平洋线虫野生型基因，并寻找线虫对ZTDO的功能获得性趋化表型。因此，我们将尝试设计一种新的化学感觉输出到线虫中，从而确定重新编程化学感觉行为所需的基因。人类寄生线虫感知寄主环境的分子机制在很大程度上是从自由生活的线虫推断出来的，但可能更接近于与节肢动物相关的感知昆虫寄主信息素的太平洋拟线虫。这项建议概述了太平洋拟青蛙的第一个嗅觉行为筛选，旨在通过分子和遗传方法的结合来了解特定的发育和神经生理学因素调节斜纹夜蛾对信息素的吸引。 公共卫生相关性：昆虫信息素吸引的分子生理学将直接影响我们对线虫嗅觉的理解，以及总体上的化学感觉。我们的建议有可能被转化为通过针对寄生线虫感知环境的方式来改进治疗方法，并阐明动物化学感受中分子途径的整体多样性。

DESCRIPTION (provided by applicant): Given the multitude of nematodes associations with invertebrate and vertebrate hosts, the beetle associated Pristionchus pacificus nematode represents a much needed knowledge bridge between the free-living soil nematode Caenorhabditis elegans and many disease causing filarial nematodes such as Brugia malayi and Wucheria bancrofti. While recent advances in insect pheromone recognition were conducted on insects regarding intraspecies interactions, primarily in mating, we know very little about the components needed to mediate interspecies interactions between nematodes and insects, the latter being a significant vector for spreading human diseases. Specifically, how does chemosensation toward a particular compound become reprogrammed during speciation, and how much does this influence the nematodes' host preferences? Aside from C. elegans, P. pacificus is the only other nematode in which a forward genetic approach is feasible. We have therefore carried out the first behavioral genetic screen in P. pacificus for lack of chemotaxis toward a known oriental beetle pheromone, ZTDO, and isolated two Oriental Beetle pheromone Insensitive mutants: obi-1 and obi-3. Obi-1 and obi-3 are specifically unable to chemotaxis toward ZTDO but are wildtype in chemotaxis toward other attractants. We will identify the molecular lesions of obi-1 and obi-3 and mis-express the P. pacificus wildtype genes using C. elegans winged amphid neuron promoters such as odr-7 and str-2 (specific for AWA and AWC, respectively) and look for gain-of-function attraction chemotaxis phenotype towards ZTDO in C. elegans. Thus we will attempt to engineer a new chemosensory output into C. elegans and thereby determine the genes required for reprogramming chemosensory behavior. The molecular mechanisms for how human parasitic nematodes sense their host environments has largely been extrapolated from the free-living C. elegans, but may be more closely modeled by the arthropod associated P. pacificus that senses insect host pheromones. This proposal outlines the first olfaction behavioral screen in P. pacificus and aims to understand the specific developmental and neurophysiological factors mediating Pristionchus attraction to a pheromone using a combination of molecular and genetic approaches. PUBLIC HEALTH RELEVANCE: The molecular physiology of insect pheromone attraction will have a direct impact on our understanding of olfaction in nematodes, as well as chemosensation in general. Our proposal has the potential to be translated into improving treatments against parasitic nematodes by targeting their means of perceiving their environment and to elucidate the overall diversity of molecular pathways in animal chemosensation.