Distinct sweet taste receptor neurons in the legs of Drosophila

检测和引发对可口刺激的适当行为反应的能力对所有动物的生存都很重要。在果蝇中，甜味化学物质的接触式检测是由分布在整个果蝇身体（包括长鼻和腿）的味觉器官介导的。利用丰富多样的遗传学技术，果蝇已成为研究味觉系统结构和功能基本原理的理想模式系统。然而，一些基本的问题仍有待回答：不同的味觉感觉神经元是否具有特定的功能？甜味是如何在苍蝇大脑中计算出来以引起食欲行为的？糖的检测如何导致食欲行为的不同方面（例如长鼻延伸，食欲强化）？我们的初步观察表明，一个小的子集的形态不同的跗感觉神经元是特别重要的驱动食欲反应蔗糖。使用复杂的遗传干预策略，我建议全面地重复单个跗神经元。为此，我们将产生转基因果蝇，使我们能够特异性地标记和操纵不同的跗骨甜味受体，并确定它们在不同糖反应行为中的功能。作为第一步，对细胞机制的甜味加工的苍蝇，我们的目标是有效地识别下游的糖感觉神经元的神经元，并研究其解剖连接到高阶组件的味觉电路。总之，这些实验将有助于构建果蝇糖反应的功能电路图。

The ability to detect and elicit appropriate behavioural responses to palatable stimuli is important for the survival of all animals. In Drosophila, contact-based detection of sweet chemical substances is mediated by gustatory organs that are distributed throughout the fly body, including the proboscis and legs. Taking advantage of a rich variety of genetic techniques, Drosophila melanogaster has served as an excellent model system to study basic principles of the structure and function of the gustatory system. Nevertheless, fundamental questions remain to be answered: Do different gustatory sensory neurons fulfill specific functions? How is sweet taste computed in the fly brain to elicit appetitive behaviour? How does detection of sugar lead to different aspects of appetitive behaviour (e.g. proboscis extension, appetitive reinforcement)?Our initial observations revealed that a small subset of morphologically distinct tarsal sensory neurons is particularly important in driving appetitive responses to sucrose. Using sophisticated genetic intervention strategies, I propose to comprehensively characterise individual tarsal neurons. To this end, we will generate transgenic flies that allow us to specifically label and manipulate distinct tarsal sweet taste receptors, and identify their functions in different sugar response behaviours. As a first step toward cellular mechanisms of sweet taste processing in the fly, we aim to efficiently identify downstream neurons of the sugar sensory neurons and investigate their anatomical connections to higher-order components of the taste circuit. Taken together, these experiments will contribute to the construction of functional circuit maps underlying sugar response in Drosophila.