Development of a C. elegans model for axonal regeneration

项目总结/摘要 描述：很少有研究利用遗传学和功能基因组学的力量来理解 损伤后轴突再生的机制。我们开发了飞秒激光轴突切断术， 完整的活C.优雅的动物。切断几个C.线虫细胞类型显示出强大的 再生和功能恢复。我们已经证明了几个因素，包括细胞类型，轴突切断的位置， 和生命阶段，可以调节损伤后轴突是否再生。保守的信号通路，包括循环 AMP信号和ephrin信号调节轴突的再生生长。我们还发现了一个意想不到的角色 突触分支在调节轴突再生中的作用。利用C. 秀丽隐杆线虫有利于大规模筛选新的再生基因。一个试点屏幕已经发现了几个新的 促进或抑制再生生长的基因。我们的三个具体目标建立在这些初步结果的基础上： 首先，我们将剖析突触分支调节再生的机制， 机械感觉神经元我们假设突触分支点包含一个分类区， 在损伤后调节膜和细胞器的运输。我们将分析汽车和货物的运输 这是再生所需的，并将专门测试Liprin途径在促进再生中的作用。 其次，我们将确定cAMP信号如何促进C。神经再生我们将测试 cAMP或其效应物是否是再生所必需的。我们将检查轴突切断对cAMP的影响 体内动力学我们将测试一个假定的cAMP调节转录因子的作用，我们已经发现， 对于再生至关重要。 第三，我们将进行大规模的功能基因组筛选，以确定新的基因与作用， 再生轴突生长。将研究具有强促或抗再生作用的基因的机制 详细 相关性：这项工作将产生一个系统的理解的途径，调节轴突再生 在一个简单的模型系统中。对轴突再生保守机制的认识 将允许它们在神经系统疾病和损伤的治疗中被操纵。

Project Summary / Abstract Description: Few studies have exploited the power of genetics and functional genomics to understand the mechanisms of regrowth of axons following injury. We have developed femtosecond laser axotomy to cut single axons in intact living C. elegans animals. Severed axons of several C. elegans cell types show robust regrowth and functional recovery. We have shown that several factors, including cell type, position of axotomy and life stage, can regulate whether axons regrow after injury. Conserved signaling pathways, including cyclic AMP signaling and ephrin signaling, regulate regenerative growth of axons. We also found an unexpected role for synaptic branches in regulating axon regrowth. The tractable genetic and genomic tools available in C. elegans facilitate large scale screens for new regeneration genes. A pilot screen has uncovered several new genes that promote or repress regenerative growth. Our three specific Aims build on these preliminary results: First, we will dissect the mechanism by which the synaptic branch regulates regeneration in mechanosensory neurons. We hypothesize that the synaptic branch point contains a sorting area that regulates membrane and organelle traffic after injury. We will analyze the transport of motors and cargoes required for regrowth and will specifically test the role of the Liprin pathway in promoting regrowth. Second we will define how cAMP signaling promotes C. elegans neuronal regeneration. We will test whether cAMP or its effectors are required for regrowth. We will examine the effects of axotomy on cAMP dynamics in vivo. We will test the role of a putative cAMP-regulated transcription factor that we have found is essential for regeneration. Third, we will perform a large scale functional genomic screen to identify new genes with roles in regenerative axon growth. The mechanisms of genes with strong pro- or anti-regeneration roles will be studied in detail. Relevance: This work will yield a systematic understanding of the pathways that regulate axon regeneration after injury in a simple model system. Knowledge of the conserved mechanisms controlling axon regeneration will allow their manipulation in therapies for nervous system disease and injury.