Pax6 transcription factor is required for the interkinetic nuclear movement of neuroepithelial cells.

The mammalian cerebral cortex develops from proliferative neuroepithelial cells that exhibit a cell cycle-dependent nuclear movement (interkinetic nuclear migration; INM). Pax6 transcription factor plays pivotal roles in various aspects of corticogenesis. From live observation using cultured cortical slices from the Pax6 mutant rat, we identified the premature descent of S phase cells, the unsteady ascent or descent of G2 phase cells, and ectopic cell division within the basal side of the ventricular zone (VZ). The centrosome normally stayed at the most apical side, apart from the nucleus, in the neuroepithelial cell during the S to G2 phase, while the Pax6 mutant showed unstable movement of the centrosome associated with an abnormal INM. Our results suggest the possibility that Pax6 regulates the INM by stabilizing the centrosome at the apical side.