GENETIC ANALYSIS OF CHEMOSENSATION IN C ELEGANS

这项拟议的研究的目标是了解细胞、基因、 以及对Dauer诱导的化学敏感反应的分子机制 秀丽隐杆线虫信息素达尔幼虫是一种发育中的 截然不同的交替第三幼虫阶段(L3)，专门用于长时间 在恶劣条件下长期生存。在正常L3和L3之间选择 达尔幼虫的控制主要是通过对 一种分泌型达尔诱导信息素的环境浓度。更多 目前已鉴定出超过25个控制DAUER过程的基因 形成，它们被置于一个复杂的上位性途径。一些人 这些基因本身与化学感觉过程有关，而 其他人可能在化学感受器的下游作用来激活达尔- 幼虫发育程序。这项建议集中在基因上。 与达尔信息素的功能和发育有关 化学感觉细胞。其中一个目标是严格测试感官的作用 与控制信息素反应有关的神经元。 信息素反应性将在动物身上进行测量，在这些动物中，个体 识别出的神经元已经用激光微束消除。另一个 目标是完成对重要基因突变的彻底搜索 这些感觉细胞的功能和发育。基因突变 已经牵涉到信息素化学传感将被用来识别 其他这类基因使用了各种经典的遗传方法。一 基因，daf-11，已经在信息素的过程中有特殊的牵连 化学传感，将通过转座子标签克隆。各种各样的 将采用分子生物学和遗传学方法来定义 Daf-11的功能，包括DNA序列分析、基因产物 定位和遗传镶嵌分析。另一个基因daf-19是 与大量感觉神经元的发育有关，包括 那些控制达尔队形的人。DAF-19将使用详细的 遗传和物理作图以及DNA转化。克隆的基因将 用来测试daf-19是否参与了 对感觉细胞进行DNA序列分析和表达研究。 线虫Dauer形成的感觉调节提供了极好的 感官和环境影响的调查模型 发展。将广泛的基因分析应用于 这样的问题，并在单个神经元上定义感觉通路 级别是独一无二的。此外，对达尔信息素的反应是 化学感官的一般过程，目前很差 明白了。

The goal of the proposed research is to understand the cellular, genetic, and molecular mechanisms of chemosensory response to the dauer-inducing pheromone of Caenorhabditis elegans. The dauer larva is a developmentally distinct alternative third-larval stage (L3) that is specialized for long- term survival under harsh conditions. The choice between the normal L3 and the dauer larva is controlled primarily by chemosensory assessment of the environmental concentration of a secreted dauer-inducing pheromone. More than 25 genes have been identified that control the process of dauer formation and they have been placed into a complex epistasis pathway. Some of these genes are implicated in the chemosensory process per se, while others probably act downstream of chemosensation to activate the dauer- larval developmental program. This proposal concentrates on the genes implicated in the function and development of the dauer pheromone chemosensory cells. One aim is to rigorously test the role of sensory neurons that have been implicated in controlling pheromone response. Pheromone responsiveness will be measured in animals in which individual identified neurons have been eliminated with a laser microbeam. Another aim is to complete a thorough search for mutations in genes important for the function and development of these sensory cells. Mutations in genes already implicated in pheromone chemosensation will be used to identify other such genes using a variety of classical genetic approaches. One gene, daf-11, already implicated specifically in the process of pheromone chemosensation, will be cloned by transposon tagging. A variety of molecular biological and genetic approaches will be taken to defining the function of daf-11, including DNA sequence analysis, gene product localization, and genetic mosaic analysis. Another gene, daf-19, is implicated in the development of a large set of sensory neurons, including those controlling dauer formation. daf-19 will be cloned using detailed genetic and physical mapping and DNA transformation. The cloned gene will be used to test the involvement of daf-19 in the development of the sensory cells by DNA sequence analysis and expression studies. Sensory modulation of dauer formation in C. elegans provides an excellent model for the investigation of sensory and environmental influences on development. The opportunity to both apply extensive genetic analysis to such a problem and to define the sensory pathway at the single neuron level is unique. In addition, response to dauer pheromone is a model for the general process of chemosensation, which is currently poorly understood.