MOLECULAR MECHANISMS OF GRANULE CELL MIGRATION

描述（来自申请人摘要）：拟议的总体目标 研究的目的是了解脊椎动物神经元迁移的机制 个脑袋两大目标是发现迁移所需的基因， 中枢神经系统神经元的胶质基质，并开发一种实验方法， 对大量迁移的神经元进行原位真实的实时成像。于过往 研究人员发现了一种基因astrotactin（Aestrophin）， 作为颗粒细胞沿沿着神经胶质迁移的神经元配体发挥作用 套.预测的蛋白质结构中有一个细胞外区域 含有两个潜在的糖基化位点，以及与 纤连蛋白III家族的粘附分子和EGF受体。的 建议研究的第一个目的是进行定量分析， 靶向删除Abla 3，检查一级结构的大小， 两个主要的小脑神经元，颗粒细胞和 浦肯野细胞。在初步研究中，他们发现了一个Astn 2， 寻找其他家庭成员。在另一组实验中，他们将 用生化方法分离ASTN的胶质受体。最后他们 将把他们对迁移的长期兴趣扩展到体内环境， 使用新开发的基于计算机的方法来跟踪大型 用GFP标记物的逆转录病毒转移标记的颗粒细胞群，或 用GFP-A基因“敲入”小鼠。新的成像实验应该提供 第一个关于颗粒细胞在体内运动的信息，使用3D 大量细胞的延时记录。 这些实验将共同产生关于神经胶质配体的信息 astrotactin及其在迁移中的作用。因为发现了另外三个 astrotactin基因表明，Aestrophin是一个基因家族的一部分，他们将 检查这些基因功能的冗余性。神经胶质细胞的发现 受体将提供神经胶质细胞的机制的基本信息， 分化，对大脑发育和大脑发育至关重要的信息 外伤最后，能够真实的观察颗粒细胞的运动 原位将告知轴突（平行纤维）之间的关系 颗粒神经元沿Bergmann胶质细胞的延伸和运动 光纤

DESCRIPTION (from applicant's abstract): The overall goal of the proposed research is to understand the mechanism of neuronal migration in the vertebrate brain. Two broad goals are to discover the genes required for the migration of CNS neurons on glial substrates and to develop an experimental approach to imaging large cohorts of migrating neurons, in situ, in real time. In prior cycles of this grant, the investigator discovered a gene astrotactin (Astn), that functions as a neuronal ligand for granule cell migration along glial guides. The predicted protein structure of Astn has an extra cellular region containing two potential glycosylation sites, and regions of homology to adhesion molecules of the fibronectin III family and the EGF receptor. The first aim of the proposed research is to carry out a quantitative analysis of a targeted deletion of Astn, examining the size of primary structures, and the development of the two principal cerebellar neurons, the granule cell and the Purkinje cell. In preliminary studies, they discovered an Astn2 and are searching for other family members. In another group of experiments, they will use biochemical methods to isolate the glial receptor for ASTN. Finally, they will extend their long-standing interest in migration to the in vivo setting, using newly developed computer-based methods to follow the migration of large cohorts of granule cells, labeled with retroviral transfer of the GFP marker or with GFP-Astn "knock-in" mice. The new imaging experiments should provide the first information on the movements of granule cells in vivo, using 3D time-lapse recordings of large cohorts of cells. Together these experiments will generate information on the neuron-glial ligand astrotactin, and its role in migration. As the discovery of a three more astrotactin genes demonstrates that Astn is part of a gene family, they will examine the redundancy in function of these genes. The discovery of the glial receptor will provide fundamental information on mechanisms of glial differentiation, information critical to both brain development and brain trauma. Finally, being able to view the movements of granule cells in real time in situ will inform about the relationship between axon (parallel fiber) extension and the locomotion of the granule neuron down the Bergmann glial fiber.