Role of N-cadherin in synapse formation and maintenance

描述（由申请人提供）：本提案的目的是研究粘附分子 N-钙粘蛋白在哺乳动物大脑中发育中的突触中的定位和作用。突触前和突触后特化的形成以及信号转导必需蛋白质的分子编排发生在轴突与目标接触之后，并且现在已知在没有神经传递的情况下发生。目前尚不清楚该过程需要哪些蛋白质和相互作用，但怀疑粘附分子将发挥至关重要的作用。钙粘蛋白在细胞形态发生、神经突生长和轴突引导过程中介导重要的粘附相互作用，但钙粘蛋白在神经突触中的重要性仍然未知。 N-钙粘蛋白的分布和时间表达模式表明这种粘附分子参与突触形成。因此，在这项研究中，我们希望更精确地确定 N-钙粘蛋白在突触位点聚集的定位和时间，并确定它是否是突触形成所必需的。这些实验将在活体大鼠海马切片中进行，并包括多种技术，包括免疫细胞化学、GFP 和 DsRed 融合蛋白的基因枪转染、使用显性失活蛋白构建体和延时共聚焦显微镜。这里提出的研究将进一步我们对细胞粘附分子的作用的理解，并阐明发育中的哺乳动物大脑中突触形成和维持的机制。

DESCRIPTION (provided by applicant): The aim of this proposal is to investigate the localization and role of the adhesion molecule N-cadherin at the developing synapse in the mammalian brain. Formation of pre- and postsynaptic specializations and the molecular orchestration of essential proteins for signal transduction follows contact of an axon with a target and is now known to occur in the absence of neurotransmission. It is not yet known what proteins and interactions are required for this process, but it is suspected that adhesion molecules will play a crucial role. Cadherins mediate important adhesive interactions during cellular morphogenesis, neurite outgrowth, and axonal guidance, but the importance of cadherins at the neural synapse remains unknown. The distribution and temporal expression patterns of N-cadherin implicate this adhesion molecule in synapse formation. Therefore, in this study we hope to determine more precisely the localization and timing of N-cadherin aggregation at synaptic sites and also determine if it is necessary for synapse formation. These experiments will be conducted in live rat hippocampal slices and will include a variety of techniques including immunocytochemistry, biolistic transfection of GFP and DsRed-fusion proteins, use dominant negative protein constructs, and time-lapse confocal microscopy. The studies proposed here will further our understanding of the roles of cell adhesion molecules and also elucidate mechanisms of synapse formation and maintenance in the developing mammalian brain.