Synapse formation in the C. elegans nervous system

描述（由申请人提供）：谷氨酸是大脑中最丰富的兴奋性神经递质，谷氨酸能突触在中枢神经系统的学习、记忆和发育可塑性中起关键作用。为了开发用于诊断、治疗和预防神经系统疾病的新应用，了解神经元突触在CNS中如何形成和调节是至关重要的。有几个基本问题仍然没有答案。谷氨酸受体和信号分子是如何特异性地定位于谷氨酸能突触的？在发育过程中，这些神经元-神经元突触是如何形成和改变的？C. elegans一直是研究体内谷氨酸信号传导的极好模型系统，重点是谷氨酸能突触在发育过程中如何形成和修饰。AMPA型谷氨酸受体（GluR）亚单位GLR-1是谷氨酸能信号传导所必需的，并定位于C。秀丽神经元。我们感兴趣的是确定GLR-1定位（以及谷氨酸受体的定位）如何进行和调节。通过正向遗传筛选，我们已经确定了几个基因，当突变导致GLR-1定位缺陷。该提案旨在描述通过这些筛选确定的三个基因。首先，我们将对GLR-1定位所需的CaMK 11同源物--GLR-43进行结构/功能分析。我们将在UNC-43的特定结构域中引入突变，以测试突变蛋白定位于突触的能力，并拯救unc-43突变体的GLR-1定位缺陷。其次，我们将描述两个新发现的基因，glo-2和glo-11，这是GLR-1定位所需的。我们将克隆glo-2和glo-11，确定GLO-2和GLO-11蛋白在哪些细胞中表达，并确定GLO-2和GLO-11蛋白在细胞内的定位。第三，我们将完成筛选，确定glo-2和glo-11达到饱和。候选基因将受到严格的标准，以确定哪些基因值得进一步研究。有趣的是，β-43/CaMKII的功能在整个胚胎发育过程中是保守的。因此，我们希望我们未来对该系统的实验能够揭示中枢神经系统形成和功能的普遍原则，并可能为治疗人类神经系统疾病提出新的策略。

DESCRIPTION (provided by applicant): Glutamate is the most abundant excitatory neurotransmitter in the brain, and glutamatergic synapses play a critical role in learning, memory, and developmental plasticity of the central nervous system. It is critical to understand how glutamatergic synapses are formed and regulated in the CNS in order to develop novel applications for the diagnosis, treatment, and prevention of neurological disorders. Several fundamental questions remain unanswered. How are glutamate receptors and signaling molecules localized specifically to glutamatergic synapses? How are these neuron-neuron synapses made and modified during development? C. elegans has been an excellent model system for studying glutamate signaling in vivo with an emphasis on how glutamatergic synapses are formed and modified during development. The AMPA-type glutamate receptor (GluR) subunit GLR-1 is required for glutamatergic signaling and is localized to synaptic clusters between C. elegans neurons. We are interested in determining how GLR-1 localization (and the localization of glutamate receptors in general) is conducted and regulated. By forward genetic screening, we have identified several genes that when mutated result in defects in GLR-1 localization. This proposal aims to characterize three genes identified through those screens. First, we will conduct a structure/function analysis of UNC-43, a CaMKll homolog required for GLR-1 localization. We will introduce mutations into specific domains of UNC-43 to test the ability of the mutant proteins to localize to synapses and to rescue unc-43 mutants for GLR-1 localization defects. Second, we will characterize two newly-identified genes, glo-2 and glo-11, that are required for GLR-1 localization. We will clone glo-2 and glo-11, determine in which cells GLO-2 and GLO-11 proteins are expressed, and determine where GLO-2 and GLO-11 proteins are localized within the cell. Third, we will complete the screen that identified glo-2 and glo-11 to saturation. Candidate genes will be subjected to rigorous criteria to determine which genes merit further study. Interestingly, the function of UNC-43/CaMKII is conserved across phylogeny. Thus, we expect our future experiments with this system to reveal universal principles about the formation and function of the central nervous system, and perhaps suggest new strategies for the treatment of human neurological disorders.