Development of olfactory glomeruli

描述（由申请人提供）：嗅觉信息的编码始于动物检测和辨别气味的能力。在小鼠的嗅觉系统中，这是由大约1000个功能性气味受体基因家族完成的，每个基因在数千个神经元中表达。一个成熟的嗅觉神经元只表达来自一个等位基因的一个气味受体基因。气味剂受体（OR）对于数千个相同的轴突会聚成嗅球上的2个对称定位的肾小球从而产生大约2000个肾小球是至关重要的。小鼠遗传学和神经发育的结合允许对这些过程进行分子解剖。本计画继续分析小鼠的嗅觉系统。在目标1中，将确定对应于嗅球表面上空间相关位置的2个高度相关OR的时间发育。该分析将确定肾小球形成的开始是否与其在嗅球上的最终位置相关。一项平行的研究将确定改变给定轴突群体的轴突数量是否会影响其会聚位置。在目标2中，多态性OR蛋白将探测OR中的结构域是否赋予会聚到肾小球中的轴突特异性。这些实验将为嗅球的发育提供基础。产生的结果将详细说明是否有内在的位置上的嗅球是由梯度，如果有一个在嗅觉系统的可塑性不足。嗅觉感觉神经元不断重新建立与嗅球连接的代码的过程，可能会让我们深入了解大脑其他区域的轴突寻路。

DESCRIPTION (provided by applicant): The coding of olfactory information begins with an animal's ability to detect and discriminate odorants. In the mouse olfactory system this is accomplished by a family ofapproximately 1000 functional odorant receptor genes each of which is expressed in thousands of neurons. A mature olfactory neuron expresses only 1 odorant receptor gene from only 1 allele. Odorant receptors (OR) are critical for the convergence of thousands of identical axons into 2 symmetrically located glomeruli on an olfactory bulb thereby creating approximately 2000 glomeruli. The marriage of mouse genetics and neural development has allowed for molecular dissection of these processes. This project continues with the analysis of the mouse olfactory system. In Aim 1, the temporal development will be determined for 2 highly related ORs that correspond to spatially related positions on the surface of the olfactory bulb. This analysis will determine if the onset of glomerular formation correlates with its final position on the olfactory bulb. A parallel study will determine if altering the number of axons for a given axonal population affects its position of convergence. In Aim 2, polymorphic OR proteins will probe if domains in the OR impart specificity to axons that converge into glomeruli. These experiments will provide a foundation for how olfactory glomeruli develop. Results generated will elaborate whether there are intrinsic positions on the olfactory bulb that are laid down by gradients and if there is an under appreciated plasticity in the olfactory system. The process by which olfactory sensory neurons are constantly re-establishing codes of connectivity to the olfactory bulb, may give insights into axonal pathfinding in other regions of the brain.