Molecular mechanisms of neuron motility and axon guidance

神经元运动和轴突引导的分子机制

• 批准号: 9904764
• 负责人: John G Flanagan
• 金额: $ 38.36万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9904764
• 关键词: 3' Untranslated Regions; Actins; Adenomatous Polyposis Coli Protein; Adult; Amyloid beta-Protein Precursor; Axon; Basement membrane; Binding; Binding Sites; Brain; Complex; Cues; Cytoplasmic Tail; Cytoskeleton; Development; Disease; Distal; Floor; Gene Expression; Genetic Translation; Goals; Growth Cones; Health; Human; Image; In Vitro; Injury; Investigation; Lead; Ligand Binding; Ligands; Mediating; Mental disorders; Messenger RNA; Microtubules; Modeling; Molecular; Mutation; Natural regeneration; Nerve Regeneration; Neurodegenerative Disorders; Neurodevelopmental Disorder; Neurons; Pathway interactions; Pattern; Phenotype; Play; Plus End of the Microtubule; RNA; RNA Transport; RNA-Binding Proteins; Regulation; Regulatory Pathway; Role; Site; Specificity; Spinal; Spinal Cord; Structure; Synapses; Testing; Time; Translations; Tubulin; Vertebral column; Work; alpha Tubulin; axon guidance; axonal pathfinding; base; cell motility; cohort; design; differential expression; disability; field study; in vivo; migration; nervous system disorder; novel; protein expression; receptor; repaired; selective expression; social; time use

The brain relies for its function on a precise and complex pattern of axonal connections. The broad long-term goal of this project is to understand how this pattern of axon connections is set up during development. When such connections fail to form properly, or are subsequently lost, this can lead to a broad range of neurodevelopmental, psychiatric and neurodegenerative disorders. This proposal focuses particularly on RNA-based regulatory mechanisms. A key advantage of regulating gene expression at the mRNA level is that protein expression can be directed to specific subcellular regions with temporal and spatial specificity – an important advantage in neurons, which have a high degree of spatial organization. Accordingly, RNA-based regulation plays key roles in axon guidance, neuron migration and synapse plasticity, although the specific mechanisms remain poorly understood. Here, RNA-based mechanisms will be studied in regulation of the microtubule cytoskeleton (Aim 1), and in axon pathway selection at a complex choice point (Aim 2). Aim 1 focuses on the microtubule cytoskeleton, which has crucial roles in neuron structure and motility. Our recent work has now identified a mechanism for RNA-based regulation of microtubules. Specifically, microtubule plus-end protein APC binds tubulin Tubb2b mRNA, at a site required for Tubb2b translation in axons, formation of dynamic microtubules in the growth cone, and neuron migration in vivo. This opens up a new field of investigation into RNA-based regulation of the microtubule cytoskeleton. One goal will be to investigate coordinated regulation of specific tubulin mRNAs which have APC binding sites in their 3'UTR and cause most human tubulinopathies. Another objective will use time-lapse imaging to understand specifically how RNA-based regulation controls microtubule dynamics, including fundamental new models for both microtubule initiation at the minus end, and assembly at the plus- end. In addition to axons, these mechanisms will be characterized in formation of synaptic spines. Aim 2 will continue studies of commissural axon guidance at the spinal cord midline, a well-characterized model of developmental axon pathfinding. RNA-based regulation is known to occur within commissural axons, including upregulated translation of mRNAs in distal axon segments that have crossed the midline intermediate target. However, little has been known of the mechanisms, including the RNA-binding proteins involved, their downstream mRNA targets, or upstream regulatory pathways. This Aim will characterize specific RNA-binding proteins that display highly selective expression on axon segments, strong and distinct phenotypes in midline guidance, and interactions with mRNAs regulated in axons at the midline; as well as upstream ligands and receptors that interact physically and functionally with these RNA based regulatory mechanisms. These studies will provide novel information on fundamental mechanisms of axon development, and RNA-based regulation.

大脑的功能依赖于精确而复杂的轴突连接模式。宽泛的长期 这个项目的目标是了解这种轴突连接模式是如何在发育过程中建立的。什么时候 这种连接不能正确形成或随后丢失，这可能导致广泛的 神经发育、精神和神经退行性疾病。 该提案特别侧重于基于RNA的调控机制。基因调控的一个关键优势 在mRNA水平上的表达是蛋白质的表达可以被定向到特定的亚细胞区域 时间和空间特异性-神经元的一个重要优势，它具有高度的空间性 组织。因此，基于RNA的调控在轴突引导、神经元迁移和 突触可塑性，尽管具体的机制仍然知之甚少。这里，基于RNA的 机制将在微管细胞骨架的调节(目标1)和轴突途径进行研究。 在复杂的选择点进行选择(目标2)。目的1重点研究微管细胞骨架，它具有重要的 在神经元结构和运动性中的作用。我们最近的工作现在确定了一种基于RNA的机制 微管的调节。具体地说，微管正端蛋白APC在a结合微管蛋白Tubb2b的mRNA. 轴突中Tubb2b翻译所需的位置，生长锥体中动态微管的形成，以及 神经元在体内的迁移。这为基于RNA的基因调控开辟了一个新的研究领域。 微管细胞骨架。一个目标是研究特定微管蛋白mRNAs的协调调节 它们在其3‘端非编码区具有APC结合位点，可导致大多数人类微管蛋白病变。另一个目标将使用 时间推移成像，以具体了解基于RNA的调控如何控制微管动力学， 包括微管在负端启动和在正端组装的基本新模型 结束。除了轴突，这些机制的特点是形成突触棘突。目标2将 继续研究脊髓中线连合轴突引导，这是一个特征良好的模型 发育性轴突寻路。已知基于RNA的调节发生在连合轴突内，包括 在穿过中线中间靶点的远端轴突片段中，mRNAs的翻译上调。 然而，人们对其机制知之甚少，包括所涉及的RNA结合蛋白、它们的 下游的信使核糖核酸靶点，或上游调控通路。这一目标将表征特定的RNA结合 在轴突片段上表现出高度选择性表达的蛋白质，在中线表现出强烈而独特的表型 引导，以及与中线轴突中调节的mRNAs的相互作用；以及上游配体和 与这些基于RNA的调节机制相互作用的物理和功能上的受体。这些研究 将提供有关轴突发育和基于RNA的调控的基本机制的新信息。