The SOX3 protein is expressed in the ventricular zones of the developing cerebellum but is absent in the adult ventricular zone. Sagittal sections of the cerebellum at 14.5 dpc (A), 16.5 dpc (B), 18.5 dpc (C), postnatal-day 0 (P0) (D), and P21 (E). A–D SOX3 signals are observed in the ventricular zone (VZ) and in the cerebellar mantle zone. Aiii–Ax In 14.5 dpc cerebella, SOX3 (green) expression overlaps with the Ki67+ proliferating cells, SOX2+ neural progenitors (red), and GLAST+ radial glial cells (red) [yellow staining in (Avi) (Aiii), and (Ax) respectively]. E Neural stem cells in the thin ventricular zone lining the fourth ventricle (4th V) of the adult cerebellum expressed SOX2 expression (red) but not Sox3 (green). *Autofluorescence of red blood cells within choroid plexus (cp). Scale bar for Ai, Aii, C–E = 100 um; Aiii–Ax = 500 µm.