G-Protein Coupled Receptors and Axon Guidance in the Drosophila Embryonic Nerve C

描述(申请人提供)：轴突通路的发展是一个复杂的信号转导过程，将细胞外的指导信号与细胞内的信号联系起来，调节轴突的生长和导向。指导错误会导致神经系统的结构性出生缺陷，从而导致身体、精神或行为障碍。研究人员实验室的长期目标是了解信号事件如何导致轴突通路和功能连接的发展。果蝇将被用作模型系统，因为它允许分子、遗传和细胞工具应用于轴突引导的活体研究，而基因保守使这项研究与人类发育相关。这项应用的目的是确定G蛋白偶联受体(GPCRs)在果蝇胚胎神经系统发育过程中轴突途径形成中的作用。GPCRs是一种跨膜受体，可以激活三聚体G蛋白来调节几个关键的细胞内信号通路。GPCRs可能直接作为引导线索受体发挥作用，或改变第二信使水平以间接影响在引导选择点工作的其他配体-受体系统的信号潜力。基于脊椎动物和果蝇的研究，推测GPCRs在发育中的果蝇神经索中起着引导轴突到达靶点的作用。具体目标1将通过系统地评价GPCRs在果蝇胚胎轴突途径形成中的作用来检验这一假说，具体目标2将通过基因改变典型的GPCRs信号通路的组成部分来系统地评价GPCRs在果蝇胚胎轴突途径形成中的作用；以及特定目标2将确定引导轴突途径发育的GPCRs。目的1测试不同基因突变在GPCR信号通路中的功能如何单独或与其他引导分子结合改变轴突通路的形成。它记录了GPCR信号对途径形成的重要性，并阐述了它们是如何做到这一点的。目的2用标准的RNA杂交方法鉴定神经索中表达的GPCRs。新的初步数据使研究人员将重点放在了玛土撒拉及其类似的近亲身上，其中两个在轴突发生期间在神经索中表达。这些基因的突变被用来评估表达对轴突引导的重要性。未来的R01应用程序将利用果蝇“工具箱”来描绘GPCR参与轴突引导决策的分子机制。了解轴突通路形成的基本过程，以及它们与结构性出生缺陷的关联，是NIH任务的关键组成部分。阐明GPCR活性的机制也有助于我们理解几种神经和行为病理学。 NARRATVE项目：轴突路径发育的错误会导致结构性出生缺陷，进而导致身体、精神和行为障碍，严重影响一个人的生活方式和国民经济。这项应用使用果蝇胚胎的发育作为模型系统，以了解脊髓轴突通路发育的基本过程。了解这些过程是设计治疗干预措施和提高受影响个人生活质量的重要一步。

DESCRIPTION (Provided by Applicant): The development of axon pathways is a complex signal transduction process linking extracellular guidance cues to intracellular signals regulating axon outgrowth and steering. Guidance errors lead to structural birth defects in the nervous system that cause physical, mental, or behavioral impairment. The long-term goal of the investigator's laboratory is to understand how signaling events lead to the development of axon pathways and functional connectivity. Drosophila will be used as the model system as it allows molecular, genetic, and cellular tools to be applied to the in vivo study of axon guidance, while gene conservation makes the study relevant to human development. The goal of this application is to establish a role for G-protein coupled receptors (GPCRs) in axon pathway formation during development of the Drosophila embryonic nervous system. GPCRs are transmembrane receptors that activate trimeric G-proteins to regulate several key intracellular signaling pathways. GPCRs may directly function as guidance cue receptors, or modify second messenger levels to indirectly affect the signaling potential of other ligand-receptor systems operating at a guidance choice point. Based on vertebrate and Drosophila studies, it is hypothesized that GPCRs function in the developing Drosophila nerve cord to guide axons to their targets. Specific Aim 1 will test this hypothesis by systematically evaluate the role of GPCRs in axon pathway formation in the Drosophila embryo by genetically altering components of the canonical GPCR signaling pathway; and Specific Aim 2 will identify GPCRs that guide the development of axon pathways. Aim 1 tests how mutations in various genes function in GPCR signaling pathways alter axon pathway formation alone or in combination with other guidance molecules. It documents the importance of GPCR signaling to pathway formation and addresses how they do so. Aim 2 uses standard RNA hybridization methods to identify GPCRs expressed in the nerve cord. New preliminary data have led the investigator to focus on Methuselah and its Methuselah-like cousins, two of which are expressed in the nerve cord during axonogenesis. Mutations in these genes are used to assess the importance of expression to axon guidance. Future R01 applications will harness the Drosophila "toolbox" to delineate the molecular mechanism by which a GPCR participates in axon guidance decisions. Understanding the fundamental processes underlying axon pathway formation, and their association with structural birth defects, is a critical component of the NIH mission. Elucidating the mechanisms of GPCR activity also contributes to our understanding of several neurological and behavioral pathologies. PROJECT NARRATVE: Errors in the development of axon pathways lead to structural birth defects, which in turn lead to physical, mental, and behavioral impairments significantly impacting a person's lifestyle and the national economy. This application uses the development of the Drosophila embryo as a model system to understand the fundamental processes underlying development of axon pathways in the spinal cord. Understanding these processes is an important step in devising therapeutic interventions and improving the quality of life of affected individuals.