Natural and Synthetic Small-Molecule Modulators of Dauer Development in Nematodes

描述（由申请人提供）：在秀丽隐杆线虫和相关线虫中，水信息素是进入发育受阻、水幼虫阶段的主要线索，其活性被一种未表征的“食物信号”所拮抗。在许多方面与群体感应分子相似，信息素是由线虫分泌到环境中的组成部分，从而使线虫能够感知其种群密度。水信息素和食物信号被认为调节TGFP和胰岛素/IGF-1通路，这两种通路调节水发育，也控制秀丽隐杆线虫和高等生物的代谢和衰老。一些成分的水信息素已被确定为衍生物的二脱氧糖ascarylose，但额外的未知成分的水信息素有助于其活性。此外，所产生的成分因环境条件而异。为了研究道尔费洛蒙的性质，我们将1)确定道尔费洛蒙所有有效成分的化学结构和调节其产生的环境条件，2)利用上位性分析研究其作用机制，3)通过生物合成突变体的表征和对其他生物合成基因进行候选RNAi筛选来研究其生物合成。4)鉴定了几种相近线虫种的水信息素的化学结构和跨种活性。为了研究拮抗强力信息素的食物信号，我们将利用上位性分析鉴定其化学结构并探讨其作用机制。最后，为了鉴定靶向TGFP和胰岛素/IGF- 1途径的合成小分子，我们将对抑制daer形成或诱导daer恢复的分子进行高通量筛选。这一筛选有可能鉴定出新的驱虫药。总之，识别强信息素和食物信号并描述它们的作用机制对于我们理解来自环境的化学感觉信号如何影响线虫和高等生物的发育、代谢和衰老等基本过程至关重要。

DESCRIPTION (provided by applicant): In Caenorhabditis elegans and related nematodes, the dauer pheromone is the primary cue for entry into the developmentally arrested, dauer larval stage, and its activity is antagonized by an uncharacterized 'food signal'. Similar in many respects to a quorum-sensing molecule, the dauer pheromone is constitutively secreted into the environment by the nematode, and thus enables the nematode to sense its population density. Dauer pheromone and food signal are thought to modulate the TGFP and insulin/IGF-1 pathways, which regulate dauer development and also control metabolism and aging in C. elegans and in higher organisms. Several components of the dauer pheromone have been identified as derivatives of the dideoxy sugar ascarylose, but additional unidentified components of the dauer pheromone contribute to its activity. Furthermore, the components that are produced vary depending on environmental conditions. In order to investigate the nature of the dauer pheromone, we will 1) identify the chemical structures of all active components of the dauer pheromone and the environmental conditions that modulate their production, 2) investigate their mechanism of action using epistasis analysis, 3) investigate their biosynthesis by characterization of biosynthetic mutants and by performing a candidate RNAi screen for additional biosynthetic genes, and 4) identify the chemical structures and cross-species activities of the dauer pheromone from several related nematode species. In order to characterize the food signal that antagonizes the dauer pheromone, we will identify its chemical structure and investigate its mechanism of action using epistasis analysis. Lastly, in order to identify synthetic small molecules that target the TGFP and insulin/IGF- 1 pathways, we will perform a high-throughput screen for molecules that either suppress dauer formation or induce dauer recovery. This screen could potentially identify novel anthelmintics. In summary, identifying the dauer pheromone and the food signal and characterizing their mechanism of action are critical to our understanding of how chemosensory cues from the environment can influence such fundamental processes as development, metabolism, and aging in nematodes and in higher organisms. Relevance: Environmental signals such as pheromones and food-based cues control the development, metabolism, and aging process in the small roundworm C. elegans. We will investigate the chemical nature of these signals and how they modulate development in roundworms. This work will provide insights into the influence of environmental factors on metabolism and aging in humans.