Role of mPAR6 Polarity CNS Neuronal Migration

年轻神经元从它们产生的部位迁移到 他们建立成人大脑的回路是发育的关键一步。迁移中的缺陷 导致许多人类先天缺陷，从严重的智力低下到微妙的学习 残疾，以及大量的癫痫。我们的实验室一直致力于了解 控制迁移的基因，希望能洞察这一正常发育的关键步骤。 我们以小脑颗粒神经元的迁移为模型系统来考察 神经胶质引导的神经元迁移的分子控制。神经元极性的建立是一个关键 启动神经元沿神经胶质导向器的迁移。筛选颗粒中起作用的基因 神经元迁移显示极性信号复合体mPar6a的高水平表达 神经元退出周期并建立极性。在线虫中，一组6个PAR蛋白建立 前/后不对称和控制随后的不对称细胞分裂。PAR蛋白是 在整个进化过程中都是保守的。 在初步研究中(Solecki等人，2004)，我们发现mParGa信号复合体是 定位于迁移中的小脑颗粒神经元的中心体，在那里它协调 当神经元沿神经胶质纤维迁移时，中心体和细胞核的运动。在 在拟议的研究中，我们将研究mParGa复合体的其他成分，aPKC^和Par3， 在迁移的颗粒神经元的极性中。MPartxx在细胞分裂中的作用表明 靶向功能缺失突变体和shRNA实验将是不可行的。因此，我们将 使用罗杰·钱存训开发的一种新方法来整合基因标签(TC)，该标签结合了 将ReAshS染色成mParGq，并使用生色团辅助的光灭活单色 激光灭活中心体中的mParGa。对于这些实验，我们将生成TC-mPar6a BAG转基因小鼠，使颗粒细胞和皮质神经元的研究成为可能。在最后一组 在实验中，我们将研究在颗粒细胞中表达的受体/配体系统，它与 MParGa复合体、EphB配体ePhin-B1和ePhin-B2。总而言之，这些实验将 为大脑皮质发育区神经元迁移的调控提供新的信息 大脑。

The migration of young neurons from sites where they are generated into the positions where they establish the circuitry of the adult brain is a critical step in development. Defects in migration cause a host of human birth defects, ranging from severe mental retardation to subtle learning disabilities, as well as a large number of the epilepsies. Our lab has focused on understanding the genes that control migration, in the hope that insights into this key step in normal development. We use the migration of the cerebellar granule neuron as a model system to examine the molecular control of glial-guided neuronal migration. The establishment of neuronal polarity is a key step in initiating neuronal migration along the glial guide. Screens for genes that function in granule neuron migration revealed high levels of expression of the polarity signaling complex mPar6a neurons exiting the cycle and establishing polarity. In C. elegans, a set of 6 PAR proteins establish anterior/posterior asymmetries and control subsequent asymmetric cell divisions. PAR proteins are conserved throughout evolution. In Preliminary Studies (Solecki et al, 2004), we discovered that the mParGa signaling complex is localized in the centrosome of migrating cerebellar granule neurons, where it coordinates the movement of the centrosome and the nucleus as the neuron migrates along the glial fiber. In the proposed research, we will study the other components of the mParGa complex, aPKC^ and Par3, in the polarity of migrating granule neurons. The role of mPartxx in cell division suggests that targeted loss of function mutants and shRNA experiments will not be feasible. We will therefore use a novel method developed by Roger Tsien to incorporate a genetic tag (TC) which binds the dye ReAshS, into mParGq and use chromophore-assisted light inactivation with a monochromatic laser to inactivate mParGa in the centrosome. For those experiments, we will generate TC-mPar6a BAG transgenic mice, enabling studies on granule cells and cortical neurons. In a final group of experiments, we will study a receptor/ligand system expressed in granule cells which interacts with the mParGa complex, the EphB ligands ephrin-B1 and ephrin-B2. Together, these experiments will provide novel information on the regulation of neuronal migration in cortical regions of developing brain.