Target Specificity in the Drosophila Olfactory System

果蝇嗅觉系统的目标特异性

• 批准号: 7154775
• 负责人: S. Lawrence Zipursky
• 金额: $ 25.96万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-12-08 至 2008-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7154775
• 关键词: Affect; Alternative Splicing; Axon; Cadherins; Cell Adhesion Molecule Gene; Cell Surface Proteins; Chromosome Pairing; Class; Defect; Development; Down Syndrome Cell Adhesion Molecule; Drosophila genus; Drosophila melanogaster; Excision; Exhibits; Exons; Extracellular Domain; Genes; Genetic; Genomics; Immunoglobulins; Link; Lobe; Mediating; Mental disorders; Molecular; Mutation; N-Cadherin; Neurologic; Neurons; Odorant Receptors; Olfactory Receptor Neurons; Phenotype; Phosphorus; Play; Protein Isoforms; Protein Overexpression; Protein Tyrosine Phosphatase; RNA Splicing; Role; Specificity; Synapses; System; Testing; Transgenes; Transmembrane Domain; base; fly; gain of function; genetic analysis; homologous recombination; insight; interest; loss of function; mutant; novel; promoter; receptor; research study

DESCRIPTION (provided by applicant): The olfactory system in Drosophila melanogaster provides a unique opportunity to explore the mechanisms by which neurons form connections during development. Olfactory receptor neurons (ORNs) that express the same odorant receptors connect to the same neurons in the antennal lobe, while neurons that express different odorant receptors connect to different neurons. The studies proposed here are directed towards understanding the molecular basis of this specificity. Genetic studies have revealed that different neurons use different constellations of cell surface proteins to control specificity including Dscam, N-cadherin, Lar receptor tyrosine phosphatase and the novel cadherin, Flamingo. Of particular interest is the requirement for Dscam. Dscam is alternatively spliced and comes in many different forms (approximately 38,000) that may contribute to recognition specificity. In this proposal, the role of different forms of Dscam in controlling the specificity of neuronal connections in the olfactory system will be tested. Three sets of experiments are proposed to critically assess the importance of alternative forms of Dscam in ORN targeting. First, a set of deletions has been isolated that remove many different forms of Dscam. The effect of these mutations on a set of three different ORNs will be assessed in these mutants. Additional mutants lacking other forms will be isolated and their affects on ORN targeting will be explored. Second, homologous recombination will be used to introduce a single extracellular domain containing form of Dscam into the endogenous Dscam locus. This will reduce diversity from approximately 38,000 to 2 forms. The phenotypes in three sets of olfactory neurons will be assessed. And finally, single forms of Dscam will be expressed under heterologous promoters in both wild type and mutant backgrounds. Dominant phenotypes induced by these forms will be assessed. Forms that do not induce dominant phenotypes will be assessed for the ability to rescue the complete loss of function Dscam mutations. A better understanding of how neuronal connections are formed during development will provide insight into the mechanisms that may be disrupted in various neurological and psychiatric diseases.

描述（由申请人提供）：果蝇的嗅觉系统为探索神经元在发育过程中形成连接的机制提供了独特的机会。表达相同气味受体的嗅觉受体神经元（ORN）连接到触角叶中的相同神经元，而表达不同气味受体的神经元连接到不同的神经元。这里提出的研究旨在了解这种特异性的分子基础。遗传学研究表明，不同的神经元使用不同的细胞表面蛋白群来控制特异性，包括 Dscam、N-钙粘蛋白、Lar 受体酪氨酸磷酸酶和新型钙粘蛋白 Flamingo。特别令人感兴趣的是 Dscam 的要求。 Dscam 是选择性剪接的，有许多不同的形式（大约 38,000 种），可能有助于识别特异性。在该提案中，将测试不同形式的 Dscam 在控制嗅觉系统神经元连接特异性方面的作用。提出了三组实验来严格评估 Dscam 替代形式在 ORN 靶向中的重要性。首先，一组删除已被隔离，删除了许多不同形式的 Dscam。将在这些突变体中评估这些突变对一组三种不同 ORN 的影响。将分离出缺乏其他形式的其他突变体，并探讨它们对 ORN 靶向的影响。其次，同源重组将用于将包含 Dscam 形式的单个细胞外结构域引入内源性 Dscam 基因座。这将使多样性从大约 38,000 种减少到 2 种。将评估三组嗅觉神经元的表型。最后，单一形式的 Dscam 将在野生型和突变体背景下在异源启动子下表达。将评估这些形式诱导的显性表型。将评估不诱导显性表型的形式挽救完全丧失功能的 Dscam 突变的能力。更好地了解神经元连接在发育过程中如何形成，将有助于深入了解各种神经和精神疾病中可能被破坏的机制。