GENETIC ANALYSIS OF OLFACTION

这项研究的目的是了解 果蝇嗅觉系统中的潜在信号转导 利用分子、遗传、行为和 生理学方法。果蝇是一个强大的模型系统进行研究 嗅觉，因为它可以识别基因负责 嗅觉感觉和处理的每一步，以及它们的分配， 特定的生理和行为功能。的结果予以 研究将绘制出生物化学和细胞途径， 果蝇的嗅觉信号，并应指导未来的分子 在类似但更复杂的系统中进行遗传学研究。 1)我将使用增强子捕获技术分离出调节嗅觉的基因， 一组在嗅觉结构中特异性表达的基因。 我将首先使用cDNA序列，表达模式和 无效突变的表型，以表明这些突变的生化功能， 基因产物对于选定的基因，将分离调节序列 并用来表达这些基因的分子修饰形式， 结构-功能关系。我已经用这个策略， 分离编码一种新的气味结合蛋白（odorant-binding protein-1，OBP-1）基因， 果蝇气味结合蛋白家族成员。苍蝇缺乏 OBP-1改变了嗅觉行为。这是第一次展示 这个蛋白质家族的任何成员在任何系统中的功能作用。 2)果蝇嗅觉的信号转导机制 没有特征。我克隆了一个新的G蛋白α亚基，dGq- α-3，在嗅觉系统中表达。dGq-α-3在人乳腺癌中的表达 初级嗅觉神经元的树突表明， 介导嗅觉反应的子集。我直接测试一下 通过研究突变体的嗅觉行为， dGq-α-3有缺陷此外，其他几类G蛋白 α亚基在嗅觉结构中表达， 将类似地确定对嗅觉信号的贡献。 3)在果蝇突变体中检测嗅觉表型一直受到阻碍 由于缺乏同时筛选大量气味剂的测定 化合物.我设计了一种新的行为分析方法 筛选大量具有化学吸引力的化合物。我会 继续鉴定用于该测定的化学吸引化合物。

The goal of this proposed research is to understand the mechanisms underlying signal transduction in the olfactory system in Drosophila melanogaster utilizing a combination of molecular, genetic, behavioral and physiological approaches. Drosophila is a powerful model system to study olfaction because it allows the identification of genes responsible for each step of olfactory sensation and processing, and their assignment to specific physiologic and behavioral functions. The results of these studies will map the biochemical and cellular pathways necessary for olfactory signaling in Drosophila, and should direct future molecular genetic studies in analogous but more complex systems. 1) I will use enhancer trapping to isolate genes mediating olfaction from a collection of genes specifically expressed in the olfactory structures. I will initially use the cDNA sequences, patterns of expression and phenotypes of null mutations to suggest biochemical functions for these gene products. For selected genes, regulatory sequences will be isolated and used to express molecularly modified forms of these genes to define structure-function relationships. I have already used this strategy to isolate a gene, OBP-1 (odorant-binding protein-1), that encodes a novel member of the Drosophila odorant-binding protein family. Flies lacking OBP-1 have altered olfactory behavior. This is the first demonstration of a functional role for any member of this protein family in any system. 2) Signal transduction mechanisms mediating olfaction in Drosophila are not characterized. I have cloned a novel G protein alpha subunit, dGq- alpha-3, expressed in the olfactory system. Expression of dGq-alpha-3 in the dendrites of a subset of primary olfactory neurons suggests that it mediates a subset of olfactory responses. I will directly test this hypothesis by studying olfactory behavior in mutants specifically defective for dGq-alpha-3. In addition, several other classes of G protein alpha subunits are expressed in olfactory structures, and their contributions to olfactory signaling will be similarly determined. 3) Detecting olfactory phenotypes in Drosophila mutants has been hampered by the lack of an assay to simultaneously screen large numbers of odorant compounds. I have devised a novel behavioral assay to simultaneously screen large numbers of compounds for chemoattractive properties. I will continue to identify chemoattractive compounds for use in this assay.