微管正端追踪蛋白SLAIN1在新皮质投射神经元迁移过程中的作用研究

神经元迁移是构筑大脑皮层有序板层结构的必要步骤。微管骨架是神经细胞极化、迁移的重要调节者。微管正端追踪蛋白在动态调控微管的组成和功能中至关重要。迄今仅有少量微管正端追踪蛋白的作用在神经元迁移中得到验证。有报道SLAIN1在神经元极化过程中发挥重要作用。我们前期研究发现SLAIN1在神经元迁移高峰期高表达，敲除SLAIN1会导致神经元迁移阻滞，SLAIN1下游互作蛋白ch-TOG（微管正端聚合酶）的共表达能部分补救SLAIN1敲除造成的迁移异常，初步证实SLAIN1通过影响微管聚合来调节神经元迁移。本课题拟通过系统的体内和体外实验检验SLAIN1对神经迁移过程的调节作用，并通过酵母双杂交和免疫共沉淀实验找出上游调控SLAIN1蛋白稳定性的分子，最后通过建立相关小鼠模型，剖析SLAIN1上下游通路在大脑皮层构建中的协同作用。本课题研究成果将为阐明泛素化修饰参与调节神经元迁移提供新的理论依据。

Proper neuronal migration is critical for the lamination of the six-layered neocortex in the mammalian brain. The microtubule skeleton is an important regulator of this process. Microtubule plus-end tracking proteins specifically recognize and locate at the plus end of the microtubule, and regulate the composition and function of the microtubule. However, only few of microtubule plus-end tracking proteins have been shown to functions in neuronal migration. Previous studies showed that the microtubule plus-end tracking protein SLAIN1 is an important regulatory protein for the plus-end polymerization of microtubules. Our own studies have demonstrated that SLAIN1 is expressed at the peak level during neuronal migration, and knockout of SLAIN1 dramatically delays neuronal migration. Notably, the migration delay is partially rescued by the expression of ch-TOG, a member of processive microtubule polymerase that is generally assumed to be directly responsible for the high rates of microtubule polymerization, which confirms our hypothesis that SLAIN1 regulate neuronal migration by affecting microtubule polymerization. In the proposed grant, we will characterize the roles of SLAIN1 in neuronal migration, and reveal the upstream molecules that regulate the stability of SLAIN1 using yeast two-hybrid and co-immunoprecipitation. Eventually we will try to analyze the impact of SLAIN1 on neocortex establishment. Results from this proposal may contribute to a better understanding of cellular basis of the ubiquitination in neuronal migration.