Regulation of Odorant Receptor Gene Expression in Olfactory Sensory Neurons

描述(由申请人提供)：嗅觉识别是通过气味受体(OR)的化学特异性及其刻板印象的嗅觉连接实现的。ORs是G蛋白偶联受体(GPCR)大亚家族的成员。小鼠基因组中大约有1000个OR基因。每个嗅觉神经元(OSN)选择只表达一种OR，并根据其OR身份将其轴突会聚为一个刻板的小球。目前尚不清楚如何在OSN内进行和维护OR选择。OR蛋白似乎在OSN的OR表达和轴突靶向中起着关键作用。本研究的目的是剖析OR蛋白序列中的调控基序，以确定OR介导的转录调控机制。为了进行这项研究，我们建立了一个体外系统，允许在其固有的细胞环境OSN内对OR表达进行有效的基因操作。利用这个体外系统，在目标1中，我们将检测外源OR表达是否以序列特异性的方式抑制内源OR转录。在目标2中，我们将研究OR表达是否调节OSN中黏附分子的表达。通过对OR序列及其调控功能的剖析，我们希望能够深入了解OR表达选择和OSN轴突引导的机制。OR调控基序的确定将为未来的体内研究奠定基础，并有助于临床干预措施的设计。公共卫生相关性：这项研究旨在了解控制嗅觉感觉神经元在气味受体选择中的身份以及它们为轴突靶向表达黏附分子的调控机制。

DESCRIPTION (provided by applicant): Olfactory discrimination is achieved through chemical specificity of odorant receptors (OR) and their stereotypic olfactory connections. ORs are members of a large subfamily of G-protein coupled receptors (GPCR). There are about 1000 OR genes in the mouse genome. Each olfactory sensory neuron (OSN) chooses to express only one OR and converges its axon according to its OR identity to a stereotypic glomerulus. It is not clear how the OR selection is made and maintained within the OSN. OR proteins appear to play critical roles in OSN specificity in its OR expression and axon targeting. The goal of this study is to dissect the regulatory motif within the OR protein sequence in order to define the mechanism of OR- mediated transcription regulation. To carry out this study, we established an in vitro system which allows efficient genetic manipulation of OR expression within its intrinsic cellular environment, the OSN. Utilizing this in vitro system, in Aim 1, we will examine whether exogenous OR expression suppresses endogenous OR transcription in a sequence specific manner. In Aim 2, we will examine whether OR expression regulates adhesion molecule expression in OSNs. Through dissecting OR sequence and their regulatory function, we hope to gain insights into the mechanisms of OR expression choice and OSN axon guidance. Identification of the OR regulatory motif will lay foundations for future in vivo investigations and aid in the design of clinical interventions. PUBLIC HEALTH RELEVANCE: This study aims to understand the regulatory mechanism that controls the identity of olfactory sensory neurons in their odorant receptor choice and their expression of adhesion molecules for axon targeting.