Function of Neuroligin in Synapse Formation in the CNS

这些研究的长期目标是了解突触形成的分子机制和 中枢神经系统中的目标识别。本申请中提出的研究目标 主要内容有：(1)剖析突触后黏附--神经连接素--突触生成活性的结构基础 能够在接触轴突时触发突触前元件组装的分子，(2)识别 神经连接素在突触前细胞中的受体，以及(3)分析神经连接素在体内的作用。目标1和 目标2将在体外用基于功能细胞的分析进行研究，允许直接操作前 以及突触后机制。我们将作为候选研究对象来研究神经毒素家族。 神经连接蛋白受体，但同时我们将对所有 在突触形成过程中可能与神经连接素相关的分子。分析神经连接蛋白的功能 在体内，将产生锤头状核酶，专门降解神经连接蛋白mRNAs。这些 核酶将在小鼠的小脑中表达，要么通过基因转移到选定的细胞中 病毒载体或转基因动物。 突触的形成是大脑中神经元回路产生的关键过程。反常的 突触形成和突触功能障碍会导致严重的神经系统疾病，如癫痫， 精神分裂症和智力低下。神经连接素类本身与精神疾病有牵连 人类的智力迟缓。除了神经系统障碍，了解突触的机制 形成对控制或刺激突触回路的再生也是最重要的 损伤后，例如脊髓在损伤后的连通性，导致瘫痪。

The long-term goal of these studies is to understand the molecular mechanism of synapse formation and target recognition in the central nervous system. The aims of the research proposed in this application are: (1) to dissect the structural basis for the synaptogenic activity of neuroligin, a post-synaptic adhesion molecule that can trigger the assembly of pre-synaptic elements in contacting axons, (2) to identify receptors for neuroligin in the pre-synaptic cell, and (3) to analyze the role of neuroligin in vivo. Aim 1 and Aim 2 will be studied with functional cell-based assays in vitro that permit direct manipulation of the pre- and post-synaptic machinery. The neurexin family of proteins will be studied as candidate neuroligin-receptors, but at the same time we will perform an unbiased biochemical purification of all molecules that might associate with neuroligin during synapse formation. To analyze neuroligin function in vivo, hammer-head ribozymes will be generated that specifically degrade neuroligin mRNAs. These ribozymes will be expressed in the cerebellum of mice, either by gene transfer into selected cells with a viral vector or in a transgenic animal. Synapse formation is a crucial process in the generation of neuronal circuits in the brain. Aberrant synapse formation and synaptic dysfunction lead to severe nervous system disorders such as epilepsy, schizophrenia, and mental retardation. Neuroligins themselves have been implicated in mental retardation in humans. Besides nervous system disorders, understanding the mechanism of synapse formation will also be most important for controlling or stimulating the regeneration of synaptic circuits after injury, as for example the connectivity in the spinal cord after injuries that lead to paralysis.