Between Slit and repulsion: Molecular mechanisms underlying Robo-mediated midline

描述（由申请人提供）：中枢神经系统的适当连接允许半球之间的交流，这是运动和语言处理等多种功能所必需的。清楚地了解单个轴突生长锥在发育过程中如何做出指导决策，对于了解在正常发育中如何完成可复制的连接模式是必要的。了解轴突引导受体如何将细胞外信号转化为引导选择，对于指导发育性疾病、神经退行性疾病或损伤状态下的重新布线的长期目标至关重要。本研究旨在为轴突引导受体Roundabout （Robo）的信号调控如何影响其排斥性引导指令提供机制上的见解。确定激活机器人的时空分布是否以及如何影响生长锥引导是一个很大程度上未被探索的话题，并可能为引导受体调节的一般机制提供见解。本实验采用果蝇遗传学、生物化学和细胞培养方法来验证Robo的配体依赖性内化（通过蛋白水解和内吞作用）在排斥引导过程中调节生长锥内信号的时空动态的假设。了解激活的受体通知连接决定的机制，将为损伤或神经退行性疾病后的错误连接和修复的发育性疾病的治疗干预的最佳点提供见解。

DESCRIPTION (provided by applicant): Proper connectivity of the central nervous system allows for communication between hemispheres necessary for such diverse functions as locomotion and linguistic processing. A clear understanding of how an individual axon growth cone makes a guidance decision during development is necessary to learn how reproducible connectivity patterns are accomplished in normal development. Knowledge as to how axon guidance receptors convert extracellular cues into a guidance choice will be essential to serve the long-term goal of guiding rewiring in developmental disease, neurodegenerative disease or injury states. This proposal is designed to provide mechanistic insight into the how the regulation of signaling of one axon guidance receptor, Roundabout (Robo) affects its repulsive guidance instruction. Determining whether and how the spatiotemporal profile of activated Robo affects growth cone guidance is a largely unexplored topic and may provide insight into general mechanisms of guidance receptor regulation. The proposed experiments use Drosophila genetics, biochemistry, and cell culture approaches to test the hypothesis that ligand-dependent internalization of Robo, by proteolysis and endocytosis, regulates the spatiotemporal dynamics of signaling within a growth cone during repulsive guidance. Knowledge of the mechanism by which an activated receptor informs wiring decisions will provide insight into optimal points of therapeutic intervention in developmental diseases of miswiring and repair following injury or neurodegenerative disorder. PUBLIC HEALTH RELEVANCE: This proposal is designed to further our understanding of the genetic programs regulating proper wiring of nervous systems during development by uncovering the factors necessary for regulating the axon guidance receptor Roundabout (Robo). Understanding the mechanisms controlling Robo signaling in Drosophila growth cones will provide insight into human health and disease. Robo's role in shaping nervous system connectivity is conserved in humans; understanding its normal mode of action in development will help us to develop therapeutics for a human genetic disorder of aberrant nervous system wiring- Horizontal Gaze Palsy and Progressive Scoliosis- and will help us understand the pathophysiology of common-disease common-variant syndromes such as autism, schizophrenia, dyslexia and periventricular nodular heterotopia. Learning how normal growth cones navigate during development will also be essential to guiding rewiring in regeneration and transplantation therapeutics.