GUIDANCE OF NEURONAL MIGRATION IN EMBRYONIC DEVELOPMENT

描述：定向神经元迁移是脑出血的一个基本特征。 发育神经系统，在此期间未分化的细胞被引导 通过不断变化的膜结合环境、基质相关环境和 可扩散的线索。尽管对其性质进行了广泛的调查 影响迁移行为的信号通路、分子机制 调节神经元迁移的机制仍然是个谜。此问题可能 现在是使用Manduca蛾的肠道神经系统(ENS)来处理的 塞克萨。ENS的形成需要一个已识别的 沿着内脏肌肉系统的300个神经元(EP细胞)； 与其他准备不同的是，神经元及其肌带通路 在整个开发过程中保持可直接访问的操作。外科手术 体内的操作表明，特定于波段的提示既是必要的 并足以支持EP细胞的迁移。最近，一条候选路径 分子已被鉴定为Fasciclin II(MFAs II)，是 免疫球蛋白超家族的嗜同型细胞黏附受体。MFAs II 是由EP细胞及其肌带通路瞬时表达的 在迁移时，当胚胎中MFAs II的扰动 文化对迁徙有明显的抑制作用。对这两人的调查 MFAs II的主要异构体(从已被 从cDNA文库中分离的)将被用来表征发育 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 然后用来确定其在调节EP细胞中的确切功能 在发育中的胚胎内迁移。一种原代细胞培养制剂 将被用来确定外源性MFAs II对神经元的影响 体外迁移行为。EP细胞迁移的开始也是一致的 随着酪氨酸激酶活性的增强，MFAs II现在被证明是 与蛋白酪氨酸激酶密切相关。因此，体内的 而EP细胞的体外制备将用于研究 MFA II依赖的迁移方面是否需要激活 特定的酪氨酸激酶。这些实验将阐明 在胚胎发育过程中，哪些MFAs II会影响EP细胞的迁移，应该 让我们深入了解类似的分子机制是如何调控这类 更复杂系统中的迁徙行为也是如此。

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.