Function of Neuroligin in Synapse Formation in the CNS

描述（由申请人提供）：这些研究的长期目标是了解中枢神经系统中突触形成和靶点识别的分子机制。本申请中提出的研究的目的是：（1）剖析神经连接素的突触发生活性的结构基础，神经连接素是一种突触后粘附分子，其可以触发突触前元件在接触轴突中的组装，（2）鉴定突触前细胞中神经连接素的受体，以及（3）分析神经连接素在体内的作用。目的1和目的2将研究与功能细胞为基础的体外试验，允许直接操纵的前和突触后机制。neurexin家族的蛋白质将作为候选神经连接素受体进行研究，但在同一时间，我们将执行一个公正的生化纯化的所有分子，可能与神经连接素在突触形成。为了分析体内神经连接蛋白的功能，将产生特异性降解神经连接蛋白mRNA的锤头状核酶。这些核酶将在小鼠的小脑中表达，或者通过用病毒载体将基因转移到选定的细胞中，或者在转基因动物中表达。突触的形成是大脑中神经元回路产生的关键过程。异常的突触形成和突触功能障碍导致严重的神经系统疾病，如癫痫、精神分裂症和精神发育迟滞。神经胶质素本身与人类的智力迟钝有关。除了神经系统疾病之外，了解突触形成的机制对于控制或刺激损伤后突触回路的再生也是最重要的，例如导致瘫痪的损伤后脊髓中的连接。

DESCRIPTION (provided by applicant): 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.