Targeting of sensory axons in the olfactory bulb

描述（由申请人提供）：本提案的目的是了解在胚胎发育期间嗅觉回路的第一个元素是如何正确地连接在一起的。气味感知神经元从嗅上皮向大脑嗅球投射轴突。值得注意的是，从分散在上皮中的神经元延伸而来的轴突，从大量的受体中选择表达相同的气味受体，在球茎内的特定可复制位置聚集在一起。本研究计划探讨嗅觉感觉轴突如何在大脑中定位其正确的目标。本项目利用斑马鱼胚胎相对简单、发育迅速、实验可及性等优势，研究感觉神经元的引导作用。在第一个目标中，我们将气味受体表达与球茎内的目标位置联系起来。气味受体参与嗅觉感觉轴突的引导，第二个目的是研究它们在目标获取的初始阶段或后期的作用是否重要

DESCRIPTION (provided by applicant): The objective of this proposal is to understand how the first elements of olfactory circuitry are correctly wired together during embryonic development. Odorant sensing neurons project axons from the olfactory epithelium to the olfactory bulb in the brain. Remarkably, axons extending from neurons that are scattered in the epithelium but choose to express the same odorant receptor from a large repertoire of receptors, converge together in specific reproducible locations within the bulb. This research proposal addresses how olfactory sensory axons locate their correct targets in the brain. The project takes advantage of the relative simplicity, rapid development, and experimental accessibility of the embryonic zebrafish to study the guidance of sensory neurons. In the first aim we will relate odorant receptor expression to target location within the bulb. Odorant receptors participate in the guidance of olfactory sensory axons and the second aim examines whether their contribution is important during the initial stages of target acquisition or later as sensory axons coalesce into distinct neuropilar structures called glomeruli. The third aim addresses the role of a large and important class of axonal guidance cues, the semaphorins, in olfactory axon targeting. This work will explore how guidance receptors and olfactory receptor expression is coordinated, and how guidance cues determine the target locations of sensory axons in the bulb. Olfactory sensory neurons are constantly being born and making new connections within the mature olfactory bulb. Understanding how these connections form during development will be essential in understanding how this process fails in neurodegenerative diseases.