Taste Receptor Genes and Sensory Coding

描述（由申请人提供）：我们的长期目标是了解动物如何识别环境中存在的或由配偶，竞争对手和捕食者释放的化学线索，以及这些线索如何介导先天行为。 化学感觉感知为从细菌到人类的所有生物体提供了有关外部世界化学成分的基本信息。在大多数动物中，这种“化学世界”是通过两种不同的感官方式感知的：味觉（味觉）和嗅觉（嗅觉）。昆虫表现出广泛的取食偏好，可以是非常狭窄的，仅限于单一的宿主植物，或相当广泛，包括许多植物，甚至动物尸体。包括果蝇在内的一些昆虫与哺乳动物有着非常相似的味觉偏好。 我们的总体策略是利用果蝇的遗传顺从系统来研究味觉感知。果蝇味觉神经元表达与非挥发性可溶性配体相互作用的G蛋白偶联受体（GPCR）的不同成员。这些细胞的激活被传播到大脑中的特定味觉中心，在那里接收到的信息被翻译成行为输出（进食/吸吮，回避，求爱）。行为学研究和电生理学研究表明，果蝇具有发达的味觉系统，可以使用编码不同GPCR的约70个味觉受体（Gr）基因的大家族识别大量不同的底物（配体）。少数Gr基因的表达研究表明，给定的基因在一个独特的小集合（1- 4%）的味觉神经元中表达，在昆虫味觉系统中创建了一个外周图。因此，单个味觉受体基因的细胞分离提供了优先被同源受体识别的不同底物的高区分能力的概念。因此，这些观察结果导致了果蝇和其他昆虫比哺乳动物识别和区分更多味觉品质的假设。为了验证这一假设，我们提出了一个系统的分析果蝇味觉受体基因家族，通过确定全球Gr表达谱和配体特异性。此外，我们建议测试是否在外周感觉系统的表达地图翻译成功能地图在食管下神经节。本研究计划已根据评审员的建议、最近发表的报告和我们实验室产生的新数据进行了修改。

DESCRIPTION (provided by applicant): Our long-term objective is to understand how animals recognize chemical cues present in the environment or released by mates, competitors and predators and how these cues mediate innate behaviors. Chemosensory perception provides all organisms, from bacteria to humans, with essential information about the chemical composition of the external world. In most animals, this 'chemical world' is perceived by two distinct sensory modalities: the sense of taste (gustation) and the sense of smell (olfaction). Insects show a wide range of feeding preferences that can be extremely narrow and be restricted on a single host plant, or fairly broad and include many plants and even animal cadavers. Some insects, including Drosophila, have remarkably similar taste preferences as mammals. Our general strategy is to utilize the genetically amenable system of Drosophila melanogaster to study the perception of taste. Drosophila gustatory neurons express divergent members of G-protein coupled receptors (GPCRs) that interact with non-volatile, soluble ligands. Activation of these cells is propagated to specific taste centers in the brain, where the received information is translated into a behavioral output (feeding/sucking, avoidance, courtship). Behavioral investigations and electrophysiological studies have indicated that Drosophila has a well-developed taste sensory system that can recognizes a large number of different substrates (ligands) using a large family of about 70 gustatory receptor (Gr) genes encoding divergent GPCRs. Expression studies of a small number of Gr genes revealed that a given gene is expressed in a distinct small set (1- 4 %) of gustatory neurons, creating a peripheral map in the insect gustatory system. Thus, cellular segregation of individual taste receptor genes provides a concept for high discriminatory power of different substrates that are preferentially recognized by cognate receptors. Hence, these observations have, led to the hypothesis that Drosophila and other insects recognize and distinguish significantly more taste qualities than mammals. To test this hypothesis, we propose a systematic analysis of the Drosophila taste receptor gene family by determining the global Gr expression profile and their ligand specificity. Moreover, we propose to test whether the expression map in the peripheral sensory system is translated into a functional map in the subesophageal ganglion. This research proposal has been modified based on the reviewer's recommendations, recently published reports and new data generated in our laboratory.