Pax6 regulates the epidermal growth factor-responsive neural stem cells of the subventricular zone.

Neural stem/progenitor cells transit from fibroblast growth factor-responsive to epidermal growth factor (EGF)-responsive stem cells in the subventricular zone (SVZ). Here, we provide evidences that Pax6 plays a crucial role in the regulation of the EGF-responsive stem cell pool of the SVZ. Using Pax6 homozygous mutant mice (E18.5d), we found that the neurospheres were formed less than that from the wild-type mice, and the expression of EGF receptor in these neurospheres is downregulated very much. The amount of EGF-responsive cells in the mutant dorsal cortex SVZ (E18.5d) was also decreased from 16.8 (wild) to 4.5% (mutant), by flow cytometry method. Immunostaining of the cortex showed a downregulation of EGF receptor expression. All these results suggest that Pax6 regulate the EGF-responsive stem cells in the SVZ.