Analysis of a Large Family of Candidate Taste Receptors

描述（来自申请人摘要）：本项目的长期目标 是阐明味觉功能的基本原理。详细分析 提出了最近发现的候选味觉受体的GR家族。的 建议解决受体功能的基本问题，利用 果蝇作为实验系统的优势了解昆虫 味道还可用于控制人类疾病昆虫媒介， 从人类宿主那里接收味觉线索 第一个目标是识别和分类OR基因家族的所有成员， 并描述它们的基因组结构。影响OR的现存突变 基因将被寻找。 将分析GR基因的表达。最初，RT-PCR分析将 用于确定有多少家族成员在味觉器官中表达， 果蝇作为特异性的测试，缺乏 将检查化学感觉神经元以及某些非味觉组织。一 主要目的是通过其他方法证实和扩展RT-PCR分析的结果。 手段，特别是通过指示哪些细胞表达个体或 基因.原位杂交、免疫组织化学和报告基因融合 将进行实验，以确定个体或 基因在味觉神经元的亚群中表达，无论个体的味觉 神经元表达多个OR基因，OR蛋白是否定位于神经元， 味觉神经元的树突，正如味觉受体所预期的那样。 OR蛋白实际上是味觉受体的假设将得到验证 直接，通过分析两个已经存在的OR突变体， 过表达个别OR基因的果蝇。对品味小组的回应 刺激将被测试，最初通过敏感的行为范例。如果突变 检测到表型后，将通过生理分析对其进行检查， 单个味觉神经元。如果低表达或 GR基因的过表达产生了特定的味觉表型， 该项目将提供强有力的证据，证明GR蛋白实际上是味道 受体，受体的配体将被鉴定，并且关于 将获得味觉感受器的特异性。

DESCRIPTION (From the Applicant's Abstract): The long-term goal of this project is to elucidate basic principles of gustatory function. A detailed analysis of the recently discovered GR family of candidate taste receptors is proposed. The proposal addresses fundamental issues of receptor function, taking advantage of the strengths of Drosophila as an experimental system. Understanding of insect taste may also be useful in controlling insect vectors of human disease, which receive gustatory cues from their human hosts. The first aim is to identify and classify all members of the OR gene family, and to characterize their genomic organization. Extant mutations affecting OR genes will be sought. The expression of GR genes will be analyzed. Initially, RT-PCR analysis will be used to determine how many family members are expressed in the taste organs of Drosophila. As a test of specificity, the taste organs of a mutant lacking chemosensory neurons will be examined, as will certain non-gustatory tissues. A major goal is to confirm and extend the results of RT-PCR analysis by other means, especially by means that indicate which cells express individual OR genes. In situ hybridization, immunohistochemistry, and reporter gene fusion experiments will be performed with a view to determining whether individual OR genes are expressed in subsets of taste neurons, whether individual taste neurons express multiple OR genes, and whether OR proteins localize to the dendrites of taste neurons, as expected of taste receptors. The hypothesis that OR proteins are in fact taste receptors will be tested directly, by analysis of two OR mutants that are already available, and of flies that overexpress individual OR genes. Responses to a panel of taste stimuli will be tested, initially by a sensitive behavioral paradigm. If mutant phenotypes are detected, they will be examined by physiological analysis of individual taste neurons, in vivo. If either the underexpression or overexpression of a GR gene produces a specific taste phenotype, then the project will provide strong evidence that GR proteins are in fact taste receptors, a ligand for a receptor will be identified, and information about the specificity of a taste receptor will be gained.