Synapse formation in the C. elegans nervous system

描述（申请人提供）：谷氨酸是大脑中最丰富的兴奋性神经递质，谷氨酸突触在中枢神经系统的学习、记忆和发育可塑性中起着至关重要的作用。了解谷氨酸突触如何在中枢神经系统中形成和调节是至关重要的，以便为神经系统疾病的诊断、治疗和预防开发新的应用。几个基本问题仍未得到解答。谷氨酸受体和信号分子是如何定位到谷氨酸突触的？这些神经元突触在发育过程中是如何形成和修改的？秀丽隐杆线虫是研究体内谷氨酸信号传导的一个很好的模型系统，重点研究谷氨酸突触在发育过程中是如何形成和修饰的。ampa型谷氨酸受体（GluR）亚基GLR-1是谷氨酸能信号传递所必需的，并且定位于秀丽隐杆线虫神经元之间的突触簇。我们感兴趣的是确定GLR-1的定位（以及谷氨酸受体的定位）是如何进行和调节的。通过正向遗传筛选，我们已经确定了几个突变导致GLR-1定位缺陷的基因。这项提议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CaMKll同源物UNC-43进行结构/功能分析。我们将在UNC-43的特定区域引入突变，以测试突变蛋白定位到突触的能力，并挽救UNC-43突变体的GLR-1定位缺陷。其次，我们将描述GLR-1定位所需的两个新发现的基因，glo2和glo11。我们将克隆glo2和glo11，确定在哪些细胞中表达glo2和glo11蛋白，并确定glo2和glo11蛋白在细胞内的定位。第三，我们将完成识别glo2和glo11至饱和的屏幕。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，UNC-43/CaMKII的功能在整个系统发育中是保守的。因此，我们期望我们未来的实验能够揭示中枢神经系统形成和功能的普遍原理，并可能为治疗人类神经系统疾病提供新的策略。

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.