LAUSR

We have examined the relationship between interkinetic nuclear migration (INM) and cell‐cycle progression of apical progenitors in the ventricular zone (VZ) at different stages of mouse cerebral corticogenesis. We report stage‐specific changes in INM due to a significant alteration of the nuclear apical movement dynamics with respect to cell‐cycle phases. While at early stages, the apical nuclear movement corresponds to the G2 phase, cell‐cycle phase specific immunostaining and real‐time imaging of PCNA expressing apical progenitors revealed that at midcorticogenesis, the nuclear apical movement is initiated well before the entry into G2, during S phase. We observed that the S phase and G2 phase segments of the nuclear apical movement exhibit different velocities. Experimental shortening of cell‐cycle duration via cyclin E overexpression in APs at midcorticogenesis leads to congruent INM behavior changes. This suggests that INM dynamics are under cell‐cycle related constraints.