Gene expression profiling of GABA neurons to reveal synaptic remodeling genes

描述（由申请人提供）：神经元采用极化形态来指导神经系统中的信息流。不同的突触前和突触后区域的组装是信号从一个神经元传递到另一个神经元所必需的。这些区域可能通过改变轴突和树突隔室的发育事件而重塑。神经元重塑极性的能力在进化上是保守的，但控制这一过程的机制在很大程度上是未知的。秀丽隐杆线虫的gaba能运动神经元显示了一个显著的发育调节突触重塑的例子。背侧D （DD）运动神经元最初支配腹侧肌肉，但在孵化成与背侧肌肉突触后极性转换。在此期间出现的腹侧D （VD）运动神经元被UNC-55阻止重塑，UNC-55是保守的COUP转录因子家族的成员。这个项目的目标是利用这个模型系统来识别控制运动神经元重塑的分子因素。在Aim 1中，我将验证一种独立于已知突触原蛋白SYD-1和SAD-1的新机制驱动DD运动神经元重塑的假设，以及UNC-55阻止VD运动神经元采用这一途径。为了确定DD重新布线的潜在新决定因素，我使用了一种强大的细胞特异性微阵列分析方法来检测体内约200个由UNC-55调节的转录本。在Aim 2中描述的实验中，我将使用特定的rnai依赖分析来测试这些候选基因在DD突触重塑中的作用。在该数据集中选定的基因的先导筛选揭示了刺猬相关基因在突触组装中的独立作用。目的3旨在明确刺猬相关蛋白在GABA运动神经元突触发生中的作用机制。在这项研究中，我希望揭示突触重塑机制中的保守因素。因此，这些结果可能导致我们对突触可塑性的理解取得重大进展，从而为开发破坏突触组装的人类疾病的治疗方法提供基础。

DESCRIPTION (provided by applicant): Neurons adopt polarized morphologies to direct information flow in the nervous system. The assembly of distinct presynaptic and postsynaptic regions is necessary for the transmission of signals from one neuron to the next. These domains may be remodeled by developmental events that alter both axonal and dendritic compartments. The capacity of neurons to remodel polarity is evolutionarily conserved but the mechanisms that govern this process are largely unknown. The GABAergic motor neurons in the nematode C. elegans display a striking example of developmentally regulated synaptic remodeling. Dorsal D (DD) motor neurons initially innervate ventral muscles but switch polarity after hatching to synapse with dorsal muscle. Ventral D (VD) motor neurons that arise during this period are prevented from remodeling by UNC-55, a member of the conserved family of COUP transcription factors. The goal of this project is to exploit this model system to identify molecular factors that govern motor neuron remodeling. In Aim 1, I will test the hypothesis that a novel mechanism, independent of known synaptogenic proteins SYD-1 and SAD-1, drives DD motor neuron remodeling and that UNC-55 prevents VD motor neurons from adopting this pathway. To identify the potentially novel determinants of DD rewiring, I have used a powerful cell-specific microarray profiling method to detect ~200 transcripts that regulated by UNC-55 in vivo. In experiments described in Aim 2, I will use specific RNAi-dependent assays to test these candidate genes for roles in DD synaptic remodeling. A pilot screen of selected genes in this data set revealed an independent role for Hedgehog-related genes in synaptic assembly. Aim 3 is designed to define the mechanism of Hedgehog-related protein function in GABA motor neuron synaptogenesis. In this study, I expect to uncover conserved elements in the mechanism of synaptic remodeling. Thus, these results could lead to significant advances in our understanding of synaptic plasticity and thereby provide a foundation for developing therapeutic approaches for human diseases that disrupt synaptic assembly.