Although cadherins and catenins are known to play important roles during neural development, the types of alpha-catenin present in the developing telencephalon are still unknown. Here, we show that the ventricular zones (VZ) of the cortex and the ganglionic eminences express alphaE-catenin and alphaN-catenin, respectively, in a complementary manner. In the cortex, alpha-catenin is switched from alphaE-catenin in the VZ to alphaN-catenin II in the intermediate zone (IMZ).