Development and Function of Mammalian Chemosensory Systems

分子神经生物学的研究目标是确定哺乳动物化学感受系统的发展和功能的分子机制。其中一个重点领域是识别分子，直接建立精确的模式之间观察到的外周嗅觉感觉神经元和它们的目标神经元的嗅球突触连接。 先前的研究导致了sema 4g基因的鉴定，该基因编码一种新的轴突导向分子，在发育中的嗅觉和犁鼻系统的化学感觉神经元中高度表达。 在过去的一年中获得的结果表明，其他成员的sema家族，基于其早期发育的感觉神经元的表达模式，可能会采取行动与Sema 4g协调一致，介导轴突靶向。 人们对味觉感知的细胞和分子机制知之甚少。在过去的一年中，旨在确定味觉系统功能的重要分子的研究开始了。 在试图确定新的基因表达的味蕾味觉信息处理的初始步骤发生，超过200个新的EST克隆来自大鼠味觉组织cDNA文库的表达模式进行了检查，通过原位杂交。在分析的基因中观察到几种表达谱，包括在所有味蕾中大量表达的基因以及表达仅限于味蕾子集的基因。 这些基因将为未来的发育和功能研究提供急需的味蕾特异性标记。此外，基于RT-PCR的方法和数据库分析已经确定了候选基因，目前正在研究中，可能编码味觉信号转导机制的组成部分。

The research goals of the Section of Molecular Neurobiology are to define the molecular mechanisms underlying the development and function of mammalian chemosensory systems. One area of emphasis is the identification of molecules that direct the establishment of the precise patterns of synaptic connectivity observed between peripheral olfactory sensory neurons and their target neurons in the olfactory bulb. Previous studies led to the identification of the sema4g gene that encodes a novel axonal guidance molecule highly expressed in chemosensory neurons of the developing olfactory and vomeronasal systems. Results obtained during the past year indicate that other members of the sema family, based on their early developmental expression patterns in sensory neurons, may act in concert with Sema4g to mediate axonal targeting. There is very little known about the cellular and molecular mechanisms critical for taste perception. During the past year, studies aimed at identifying molecules important for gustatory system function were initiated. In an attempt to identify novel genes expressed in taste buds where the initial step of gustatory information processing occurs, the expression patterns of over 200 novel EST clones derived from a rat taste tissue cDNA library were examined by in situ hybridization. Several expression profiles were observed among the genes analyzed including genes abundantly expressed in all taste buds as well as genes whose expression was limited to a subset of taste buds. Such genes will provide much needed taste bud specific markers for future developmental and functional studies. In addition, RT-PCR based approaches and database analysis have identified candidate genes, currently under study, that may encode components of the gustatory signal transduction machinery.