Neural stem cells directly or indirectly generate all neurons and macroglial cells and guide migrating neurons by using a palisade-like scaffold made of their radial fibers. Here, we describe an unexpected role for the radial fiber scaffold in directing corticospinal and other axons at the junction between the striatum and globus pallidus. The maintenance of this scaffold, and consequently axon pathfinding, is dependent on the expression of an atypical RHO-GTPase, RND3/RHOE, together with its binding partner ARHGAP35/P190A, a RHO GTPase-activating protein, in the radial glia-like neural stem cells within the ventricular zone of the medial ganglionic eminence. This role is independent of RND3 and ARHGAP35 expression in corticospinal neurons, where they regulate dendritic spine formation, axon elongation, and pontine midline crossing in a FEZF2-dependent manner. The prevalence of neural stem cell scaffolds and their expression of RND3 and ARHGAP35 suggests that these observations might be broadly relevant for axon guidance and neural circuit formation.

神经干细胞直接或间接地产生所有神经元和大胶质细胞，并通过使用由它们的径向纤维制成的栅栏状支架来引导迁移的神经元。在这里，我们描述了径向纤维支架在引导纹状体和苍白球之间的交界处的皮质脊髓和其他轴突方面的意外作用。该支架的维持以及轴突寻路取决于非典型 RHO-GTPase、RND3/RHOE 及其结合伙伴 ARHGAP35/P190A（一种 RHO GTPase 激活蛋白）在径向胶质细胞样神经中的表达。内侧神经节隆突心室区内的干细胞。这种作用独立于皮质脊髓神经元中 RND3 和 ARHGAP35 的表达，在那里它们调节树突棘形成、轴突伸长、和脑桥中线以 FEZF2 依赖性方式交叉。神经干细胞支架的流行及其 RND3 和 ARHGAP35 的表达表明这些观察结果可能与轴突引导和神经回路形成广泛相关。