Fig. 2.

Two progenitor zones generate all the cerebellar cell types. (A) During embryonic development, the RL gives rise to excitatory cerebellar nuclei neurons (eCNs), unipolar brush cells (UBCs) and granule cell progenitors (GCPs) and the ventricular zone gives rise to Purkinje cells, inhibitory neurons located in the cerebellar nuclei (CN) and nestin-expressing progenitors (NEPs), which give rise to the inhibitory neurons of the cerebellar cortex and the astroglia. (B-D) During postnatal growth (until ∼P14 in mice), RL-derived GCPs give rise to granule cells (C) and ventricular zone-derived NEPs produce astroglia (Bergmann glia and astrocytes) and molecular layer (ML) interneurons (D). Black arrows show the migration routes of lineages. The double-headed arrows between the Hopx⁺ and Ascl1⁺ WM-NEPs denotes the presence of multipotent progenitors at birth, which mostly give rise to Ascl1⁺ WM-NEPs. Both the GCPs and the three populations of NEPs during postnatal development proliferate in response to SHH secreted (dotted arrows) by Purkinje cells. A, anterior; BgL, Bergmann glia layer; D, dorsal; EGL, external granule layer; IGL, internal granule layer; L, lateral; M, medial; P, posterior; PC, Purkinje cell; PCL, Purkinje cell layer; V, ventral; WM, white matter.