Molecular Characterization of Insect Pheromone Chemosensory Mutants in Nematodes

描述（由申请人提供）：考虑到大量与无脊椎动物和脊椎动物宿主相关的线虫，甲虫相关的太平洋隐杆线虫代表了自由生活的土壤线虫秀丽隐杆线虫和许多引起疾病的丝状线虫，如马来布鲁贾线虫和bancrofti Wucheria之间急需的知识桥梁。虽然昆虫信息素识别的最新进展是在昆虫种内相互作用方面进行的，主要是在交配方面，但我们对介导线虫和昆虫之间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。具体来说，在物种形成过程中，对特定化合物的化学感觉是如何被重新编程的，这对线虫对宿主的偏好有多大影响？除了秀丽隐杆线虫外，太平洋假单胞线虫是唯一可行的正向遗传方法。因此，我们首次对太平洋p.p ificus进行了对已知东方甲虫信息素ZTDO缺乏趋化性的行为遗传筛选，并分离出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具有特异性趋化性，但对其他引诱剂具有野生型趋化性。我们将利用秀丽隐杆线虫有翼两栖动物神经元启动子如odr-7和str-2（分别针对AWA和AWC特异性）鉴定obi-1和obi-3的分子病变，并错误表达太平洋p.p ificus野生型基因，寻找秀丽隐杆线虫对ZTDO的功能获得性吸引趋化表型。因此，我们将尝试设计一种新的化学感觉输出到秀丽隐杆线虫中，从而确定重新编程化学感觉行为所需的基因。人类寄生线虫如何感知宿主环境的分子机制在很大程度上是从自由生活的线虫中推断出来的，但可能更接近于与节肢动物相关的感知昆虫宿主信息素的太平洋线虫。本研究概述了太平洋拟蚊的第一次嗅觉行为筛选，旨在利用分子和遗传相结合的方法了解拟蚊对信息素吸引的特定发育和神经生理因素。

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.