Molecular Biology of the Odorant Receptors

描述（由申请人提供）：人类疾病的昆虫媒介每年感染数亿人致命的传染病，包括疟疾、登革热、黄热病和西尼罗河脑炎。昆虫被特定的感官信号吸引到人类宿主身上，其中嗅觉信号起着主导作用。该提案的长远目标是了解嗅觉系统允许昆虫瞄准人类宿主的机制。这些知识可以转化为一类新的化学制剂，作用于昆虫的嗅觉系统，以中断媒介昆虫的寻宿主行为。对PA-05-154的响应，本项目的总体目标是增加对介导昆虫气味识别的气味受体（ORs）的分子结构和功能的理解。在初步研究中，我们已经记录了OR83b独特的伴随共受体功能。OR83b在体内的大多数嗅觉感觉神经元中与常规的ORs共表达并形成OR/OR83b异源二聚体，这对于在发生气味转导的纤毛树突中靶向和维持ORs是必要的。这些初步研究导致了OR/OR83b复合物对昆虫嗅觉功能至关重要的假设。为了验证这一假设，我们提出了3个具体目标：1)确定介导OR83b靶向嗅纤毛的蛋白结构域；2)确定介导异质OR/OR83b复合物形成的蛋白结构域；3)描述调节OR/OR83b复合物的翻译后修饰。研究设计包括OR83b的靶向诱变，以发现转运、OR/OR83b异质化和翻译后修饰所必需的基序。使用的方法是利用电生理、成像、细胞生物学、生化和行为技术对体内和体外果蝇OR功能进行表型分析。对昆虫OR功能的分子理解可能有助于设计新的化学制剂，选择性地破坏昆虫的OR，从而中断昆虫疾病媒介（如蚊子）的寻宿主行为。这一建议的健康相关性是，这些化学制剂可能在未来减少媒介昆虫的传染病传播。

DESCRIPTION (provided by applicant): Insect vectors of human disease infect hundreds of millions of individuals annually with deadly infectious diseases, including Malaria, Dengue and Yellow Fever, and West Nile Encephalitis. Insects are attracted to human hosts by specific sensory cues, with olfactory cues playing a dominant role. The Broad," Long-Term Objectives of this proposal are to understand the mechanisms by which the olfactory system allows insects to hone in on human hosts. Such knowledge could be translated to a new class of chemical agents that act on the insect olfactory system to interrupt vector insect host-seeking behavior. Responsive to PA-05-154, the overall goal of this specific project is to increase understanding of the molecular structure and function of the odorant receptors (ORs) that mediate odor recognition in insects. In preliminary studies, we have documented a unique chaperoning co-receptor function for OR83b. OR83b is co-expressed and forms OR/OR83b heterodimers with conventional ORs in most olfactory sensory neurons in vivo and is necessary for the targeting and maintenance of ORs in ciliated dendrites where odor transduction occurs. These preliminary studies have led to the hypothesis that the OR/OR83b complex is essential for insect olfactory function. To test this hypothesis, 3 Specific Aims are proposed: 1) Identify protein domains that mediate OR83b targeting to olfactory cilia; 2) Define protein domains that mediate the formation of heteromeric OR/OR83b complexes; 3) Characterize post-translational modifications that modulate the OR/OR83b complex. The Research Design involves targeted mutagenesis of OR83b to uncover motifs necessary for trafficking, OR/OR83b heteromerization, and post-translational modifications. The Methods used are phenotypic analysis of Drosophila OR function in vivo and in vitro employing electrophysiological, imaging, cell biological, biochemical, and behavioral techniques. A molecular understanding of insect OR function may aid in the design of novel chemical agents that selectively disrupt insect ORs and thus interrupt host- seeking behaviors of insect disease vectors such as mosquitoes. The Health-Relatedness of this proposal is that such chemical agents may act to reduce infectious disease transmission by vector insects in the future.