Role of mPAR6 Polarity CNS Neuronal Migration

年轻神经元从它们产生的位置迁移到它们产生的位置 他们建立的成人大脑回路是发育过程中的关键一步。迁移缺陷 导致一系列人类出生缺陷，从严重的智力障碍到微妙的学习 残疾，以及大量的癫痫病。我们的实验室致力于了解 控制迁移的基因，希望深入了解正常发育的这一关键步骤。 我们使用小脑颗粒神经元的迁移作为模型系统来检查 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关键 启动神经元沿着神经胶质引导迁移的步骤。筛选在颗粒中起作用的基因 神经元迁移揭示极性信号复合物 mPar6a 的高水平表达 神经元退出循环并建立极性。在秀丽隐杆线虫中，一组 6 种 PAR 蛋白建立 前/后不对称并控制随后的不对称细胞分裂。 PAR 蛋白是 在整个进化过程中保守。 在初步研究中（Solecki 等，2004），我们发现 mParGa 信号复合物是 定位于迁移的小脑颗粒神经元的中心体，在那里它协调 当神经元沿着神经胶质纤维迁移时，中心体和细胞核的运动。在 拟议的研究，我们将研究 mParGa 复合体的其他组成部分，aPKC^ 和 Par3， 迁移颗粒神经元的极性。 mPartxx 在细胞分裂中的作用表明 靶向功能丧失突变体和 shRNA 实验将不可行。因此我们将 使用Roger Tsien开发的一种新方法来整合结合基因标签（TC） 将 ReAshS 染色到 mParGq 中，并使用单色光进行发色团辅助光灭活 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，可用于颗粒细胞和皮质神经元的研究。在最后一组 实验中，我们将研究颗粒细胞中表达的受体/配体系统，该系统与 mParGa 复合物、EphB 配体肝配蛋白-B1 和肝配蛋白-B2。这些实验共同将 提供有关发育中皮质区域神经元迁移调节的新信息 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.