GUIDANCE OF NEURONAL MIGRATION IN EMBRYONIC DEVELOPMENT

描述：定向神经元迁移是神经元迁移的一个基本特征。 发育中的神经系统，在此期间，未分化的细胞被引导 通过不断变化的环境膜结合，基质相关， 可扩散的线索 尽管广泛调查的性质， 可能影响迁移行为的信号通路， 调节神经元迁移的机制仍然是个谜。 这个问题可以 现在使用蛾的肠神经系统（ENS）来解决， 六。 ENS的形成需要一个已识别的 沿着内脏肌肉组织的300个神经元（EP细胞）的群体; 与其他制备不同的是，神经元和它们的肌带通路 在整个开发过程中仍然可以直接进行操作。 手术 在体内的操作已经表明，带特异性的线索都是必要的， 并且足以用于EP细胞迁移。 最近，一个候选路径 分子已被鉴定为成束蛋白II（MFas II），其是 嗜同性细胞粘附受体免疫球蛋白超家族。 MFas II 由EP细胞和它们的肌带通路瞬时表达 在迁移的时候，而扰动MFas II在胚胎 文化对迁移有明显的抑制作用。 针对两人的调查 MFas II的主要同种型（从已被克隆的全长克隆制备） 分离自cDNA文库）将用于表征发育的 MFas II基因在通路形成和EP细胞中的表达 迁移 正义和反义探针的组合，单克隆和 针对MFas II的多克隆抗体和合成肽将 然后用于确定其在调节EP细胞中的确切功能作用， 在发育中的胚胎中迁移。 一种原代细胞培养制备物， 然后将被用来定义外源性MFas II对神经元的影响。 离体迁移行为 EP细胞迁移的开始也与 具有增强的酪氨酸激酶活性，MFas II现已被证明是 与蛋白酪氨酸激酶密切相关。 因此，体内 EP细胞的体外制备将用于研究 依赖MFas II的迁移方面是否需要激活 特异性酪氨酸激酶。 这些实验将阐明 MFas II在胚胎发生过程中影响EP细胞迁移， 让我们深入了解类似的分子机制如何调节这种类型的 更复杂系统中的迁移行为。

DESCRIPTION: Directed neuronal migration is an essential feature of the developing nervous system, during which undifferentiated cells are guided through a changing environment of membrane-bound, matrix-associated, and diffusible cues. Despite extensive investigations into the nature of pathway cues that can affect migratory behavior, the molecular mechanisms that regulate neuronal migration have remained enigmatic. This issue can now be addressed using the enteric nervous system (ENS) of the moth, Manduca sexta. The formation of the ENS requires the migration of an identified population of 300 neurons (the EP cells) along the visceral musculature; unlike other preparations, both the neurons and their muscle band pathways remain directly accessible to manipulation throughout development. Surgical manipulations in vivo have shown that band-specific cues are both necessary and sufficient for EP cell migration. Recently, one candidate pathway molecule has been identified as fasciclin II (MFas II), a member of the immunoglobulin superfamily of homophilic cell adhesion receptors. MFas II is transiently expressed by both the EP cells and their muscle band pathways at the time of migration, while perturbations of MFas II in embryonic culture cause a marked inhibition of migration. Probes against the two major isoforms of MFas II (prepared from full-length clones that have been isolated from a cDNA library) will be used to characterize the developmental expression of the MFas II gene during pathway formation and EP cell migration. A combination of sense and antisense probes, monoclonal and polyclonal antibodies, and synthetic peptides directed against MFas II will then be used to determine its precise functional role in regulating EP cell migration within the developing embryo. A primary cell culture preparation will then be used to define the effects of exogenous MFas II on neuronal migratory behavior in vitro. The onset of EP cell migration also coincides with enhanced tyrosine kinase activity, and MFas II has now been shown to be closely associated with protein tyrosine kinases. Accordingly, the in vivo and in vitro preparations of the EP cells will be used to investigate whether MFas II -dependent aspects of migration require the activation of specific tyrosine kinases. These experiments will clarify the manner in which MFas II affects EP cell migration during embryogenesis, and should lend insight into how similar molecular mechanisms regulate this type of migratory behavior in more complex systems, as well.