GABAERGIC NEURON DIFFERENTIATION IN C ELEGANS

线虫中的伽巴能神经元分化

• 批准号: 6209274
• 负责人: Yishi Jin
• 金额: $ 36.8万
• 依托单位: UNIVERSITY OF CALIFORNIA SANTA CRUZ
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-07-18 至 2004-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6209274
• 关键词: Caenorhabditis elegans; biological signal transduction; cell differentiation; confocal scanning microscopy; developmental genetics; developmental neurobiology; gamma aminobutyrate; genetic library; genetic mapping; genetic regulatory element; genetic screening; glutamate decarboxylase; guanine nucleotide exchange factors; guanosinetriphosphatases; immunocytochemistry; molecular cloning; morphometry; motor neurons; neurogenetics; protein tyrosine phosphatase; suppressor mutations; synaptic vesicles; synaptogenesis; transmission electron microscopy

Chemical synapses are composed of specialized subcellular structures. Presynaptic terminals contain an organized cytoskeletal architecture to facilitate neurotransmitter release. Most known presynaptic proteins are associated with synaptic vesicles and function in vesicle exocytosis and endocytosis. Few proteins are shown to play roles in organizing presynaptic structure. Work in this laboratory has focused on the molecular events controlling the differentiation of GABAergic motor neurons in the nematode C. elegans. A genetic screen identified several syd genes (for synapse defective) that affect the morphology and organization of the presynaptic terminals in these neurons. Our analysis has suggested that signaling via small GTPases and receptor protein tyrosine phosphatases may function at different steps in the presynaptic structural formation. This proposal focuses on dissecting the signaling pathway involving syd-3, a putative guanine nucleotide exchanger with a Ring-H2 finger. Specifically, we will clone syd-5 and syd-8, both exhibit similar mutant phenotypes as syd-3, suggesting that they may function in the same pathway. We will systematically analyze the ultrastructural defects in selected syd mutants using transmission electron microscopy. This study is the key for understanding how syd genes function in synapse formation. Genes that are involved in the same pathway may be identified as genetic suppressors or enhancers. We have isolated six semi-dominant suppressors of syd-3 and will continue their molecular and genetic characterization. In addition, we will perform a dominant enhancer screen on a temperature sensitive syd-3 mutation, which may identify genes that are sensitive to the dosage of syd-3. GABAergic neurons are essential for brain function. The use of model organisms is invaluable to the studies of the human nervous system. Our results may provide insights into the understanding of synapse formation in all organisms, and may shed light to the search of causes for cancer and other diseases that are associated with synapse malformation.

化学突触由专门的亚细胞结构组成。突触前末梢包含有组织的细胞骨架结构，以促进神经递质的释放。大多数已知的突触前蛋白与突触小泡相关，并在小泡胞吐作用和内吞作用中发挥作用。很少有蛋白质被证明在组织突触前结构中发挥作用。该实验室的工作重点是控制线虫中 GABA 能运动神经元分化的分子事件。遗传筛选发现了几个影响这些神经元突触前末梢形态和组织的 syd 基因（突触缺陷）。我们的分析表明，通过小 GTP 酶和受体蛋白酪氨酸磷酸酶发出的信号可能在突触前结构形成的不同步骤中发挥作用。该提案的重点是剖析涉及 syd-3 的信号传导途径，syd-3 是一种具有 Ring-H2 指的假定鸟嘌呤核苷酸交换器。具体来说，我们将克隆syd-5和syd-8，两者都表现出与syd-3相似的突变表型，表明它们可能在相同的途径中发挥作用。我们将使用透射电子显微镜系统地分析所选 syd 突变体的超微结构缺陷。这项研究是理解 syd 基因如何在突触形成中发挥作用的关键。参与同一途径的基因可被鉴定为遗传抑制子或增强子。我们已经分离出 syd-3 的 6 个半显性抑制因子，并将继续对其进行分子和遗传表征。此外，我们将对温度敏感的syd-3突变进行显性增强子筛选，这可能会识别对syd-3剂量敏感的基因。 GABA 能神经元对于大脑功能至关重要。模型生物的使用对于人类神经系统的研究具有无价的价值。我们的结果可能为理解所有生物体中的突触形成提供见解，并可能为寻找癌症和其他与突触畸形相关的疾病的原因提供线索。