Mechanisms of Purkinje cell migration

 描述(申请人提供)：小脑协调并同步平衡、运动、情绪和认知。小脑缺陷导致运动控制、平衡、姿势和学习障碍，是癫痫和自闭症常见的病理征象。小脑结构的表面简单性掩盖了其发育的复杂性，两种主要细胞类型--浦肯野细胞和颗粒细胞之间的相互作用。 由此产生的细胞非自主效应一直是理解发育机制的障碍。教科书上的观点一直认为浦肯野细胞是通过沿着放射状神经胶质纤维移动而迁移的，缺乏环境线索Reelin会抑制从放射状神经胶质细胞的脱离。然而，有理由对这一观点提出质疑。首先，最近发现浦肯野细胞穿过而不是沿着放射状胶质细胞移动。其次，尽管Reelin调节前脑中的神经元迁移，但它也调节神经胶质细胞无关的迁移。此外，我们最近发现E3泛素连接酶CRL5调节Purkinje细胞的迁移，但其细胞机制仍不清楚。这些问题目前很难解决，因为从基因上操纵单个浦肯野细胞并观察它们在正常环境中的迁移是具有挑战性的。因此，我们的直接目标是采用方法来跟踪和遗传改变浦肯野细胞在小脑中的迁移和分化。然后，我们将把这些新方法与我们在新皮质中研究神经元迁移的经验结合起来，以解决浦肯野细胞如何迁移以及Reelin和CRL5如何调节它们的关键问题。这项拟议研究的一个附带好处是，我们开发的方法将对未来研究出生前和出生后小脑发育、疾病和退化的研究具有非常重要的价值。

 DESCRIPTION (provided by applicant): The cerebellum coordinates and synchronizes balance, movement, emotion and cognition. Cerebellar defects contribute to disorders in motor control, equilibrium, posture and learning and are frequent pathological signs in epilepsy and autism. The seeming simplicity of cerebellar structure belies its developmental complexity, with reciprocal interactions between the two principal cell types, the Purkinje cells and granule cells. The resulting cell non-autonomous effects have been an obstacle to understanding the developmental mechanisms. The textbook view has been that Purkinje cells migrate by locomotion along radial glia fibers, and absence of an environmental cue, Reelin, inhibits detachment from the radial glia. However, there are reasons to question this view. First, Purkinje cells were recently seen to move across rather than along radial glia. Second, even though Reelin regulates neuron migrations in the forebrain, it regulates glia-independent migration. In addition, we recently found that an E3 ubiquitin ligase, CRL5, regulates Purkinje cell migration, but, again, the cellular mechanism is unknown. These issues are currently difficult to address because it is challenging to genetically manipulate individual Purkinje cells and observe their migrations in a normal environment. Therefore, our immediate goal is to adapt methods to track and genetically alter Purkinje cells as they migrate and differentiate in the cerebellum. Then, we will combine these new methods with our experience studying neuron migration in the neocortex in order to address key questions of how Purkinje cells migrate and how they are regulated by Reelin and CRL5. An ancillary benefit of the proposed research is that the methods we develop will be invaluable for future investigation of pre- and post-natal cerebellar development, disease and degeneration.