Figure 4

Cerebellar neural stem cell multipotency was not abolished in Sox9-null cerebellum under both En1-Cre and Pax2-Cre mediated Sox9 inactivation as shown by immunofluorescence staining on cerebellar sagittal sections. (A-D, F-I) No defects in the neurogenesis of VZ-derivatives including Purkinje cells (PCs) and GABAergic interneurons was observed, as indicated by the normal distribution of Lhx1⁺ PCs (A-D) and Pax2⁺ interneurons (F-I) between control and Sox9 mutant cerebella at E16.5. Both the number of Lhx1+ PCs and Pax2+ interneurons appeared normal in the Sox9 mutants (E; p = 0.6870 and J; p = 0.9980). (K-S) Specification of the RL-derived progenitors committed to become granule cells was also normal, as exemplified by robust expression of Pax6 at the EGL. The differentiation of progenitors into different neuronal subtypes suggests that the multipotency of neural stem cells in cerebellum was retained upon Sox9 inactivation. Abbreviations: egl, external granular layer; pwm, prospective white matter; vz, ventricular zone. Scale bar: 100 μm.