Robo receptor control of lateral position of axons in the Drosophila CNS

Robo 受体控制果蝇中枢神经系统轴突的横向位置

• 批准号: 7760962
• 负责人: Timothy A. Evans
• 金额: $ 5.22万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7760962
• 关键词: Affinity; Animals; Arthropods; Axon; Behavioral; Binding; Biological; Biological Assay; Dendrites; Development; Drosophila genus; Elements; Evolution; Exhibits; Family; Family member; Flour; Insecta; Lateral; Mediating; Membrane; Molecular; Mutation; Nematoda; Nervous system structure; Neuraxis; Orthologous Gene; Positioning Attribute; Recording of previous events; Role; Series; Site; Specific qualifier value; Surface Plasmon Resonance; Testing; Tribolium; axon guidance; base; in vivo; insight; novel; receptor; response; trend

DESCRIPTION (provided by applicant): The behavioral sophistication and plasticity of animals has been facilitated by evolutionary trends favoring increased central nervous system nervous system complexity and requires precise developmental control of axon and dendrite position within the CMS. The Roundabout (Robo) family of axon guidance receptors performs an ancient role in regulating midline crossing in response to the secreted repellant Slit. In Drosophila, Robo2 and RoboS specify mediolateral position of axons in the CNS, a novel function not shared by Robo. This proposal seeks to understand the molecular and functional bases and evolutionary origins of Robo receptor control of lateral position in the Drosophila CNS. The specific aims are to: 1. Identify the molecular basis for differential activity of Robo and Robo2 in lateral positioning. The Robo2 axon guidance receptor is able to dictate mediolateral position of axons within the Drosophila CNS, while the closely related Robo receptor cannot. To define the minimal sequence elements distinguishing Robo and Robo2 activity in lateral positioning, I will assay a comprehensive series of chimeric Robo receptors for their ability to dictate lateral position in vivo. 2. Determine the biological basis for Robo receptor control of lateral position. To test the hypothesis that differential Slit affinity is responsible for the distinct activities of Robo and Robo2 in lateral positioning, I will (1) test the assumption that a graded distribution of Slit is required for Robo receptor control of lateral position by examining the effects of a membrane-tethered form of Slit on lateral position; (2) use sitedirected mutations to test the effects of disrupted Slit binding on lateral shifting activity of Robo2 and Robo3; and (3) assess whether Robo receptor lateral positioning activity correlates with Slit affinity by comparing the Slit affinities of wild type and chimeric Robo receptors using surface plasmon resonance. 3. Examine the evolutionary origins of Robo receptor control of lateral position. The third aim will test the hypothesis that control of lateral position is a novel function acquired by Robo receptors during the evolution of insects. Robo2 and Robo3 regulate lateral position of CNS axons in Drosophila. Notably, Robo2 and Robo3 orthologs appear restricted to insects, raising the possibility that control of lateral position is a novel activity that first appeared during insect evolution. To gain insight into the evolutionary origins of Robo receptor control of lateral position, I will: (1) assay arthropod and nematode Robo receptors for conserved lateral positioning activity in Drosophila, and (2) investigate the function of Robo orthologs in the flour beetle Tribolium, an insect that retains a primitive set of Robo receptors.

描述(申请人提供)：动物的行为成熟和可塑性是由有利于增加中枢神经系统神经系统复杂性的进化趋势促进的，需要对CMS内轴突和树突位置的精确发育控制。回旋(Robo)轴突引导受体家族在调节中线交叉方面发挥着古老的作用，以回应分泌的排斥性缝隙。在果蝇中，Robo2和Robos指定了中枢神经系统中轴突的内侧外侧位置，这是Robo没有共享的一项新功能。这一建议试图了解在果蝇中枢神经系统中控制侧向位置的Robo受体的分子和功能基础及其进化起源。具体目的是：1.确定Robo和Robo2在侧向定位时活性不同的分子基础。Robo2轴突引导受体能够决定果蝇中枢神经系统内轴突的内侧外侧位置，而与其密切相关的Robo受体则不能。为了确定在侧向定位中区分Robo和Robo2活性的最小序列元素，我将测试一系列嵌合的Robo受体在体内决定侧向位置的能力。2.确定Robo受体控制侧位的生物学基础。为了验证差异狭缝亲和力导致Robo和Robo2在横向定位中的不同活动的假设，我将(1)通过检测膜栓系形式的狭缝对横向位置的影响来检验Robo受体控制横向位置需要狭缝的渐变分布的假设；(2)使用定点突变来测试缝隙结合中断对Robo2和Robo3侧移活性的影响；以及(3)通过利用表面等离子共振比较野生型和嵌合型Robo受体的狭缝亲和力来评估Robo受体横向定位活动是否与狭缝亲和力相关。3.探讨ROBO受体控制侧位的进化起源。第三个目标将检验这样一种假设，即控制侧向位置是昆虫进化过程中由Robo受体获得的一种新功能。Robo2和Robo3调控果蝇中枢神经系统轴突的侧向位置。值得注意的是，Robo2和Robo3直系物似乎仅限于昆虫，这增加了控制侧向位置是在昆虫进化过程中首次出现的一种新活动的可能性。为了深入了解Robo受体控制侧向位置的进化起源，我将：(1)检测节肢动物和线虫的Robo受体在果蝇中保守的侧向定位活动，(2)研究Robo同源基因在面粉甲虫Tribolium中的功能，Tribolium是一种保留了一套原始Robo受体的昆虫。