Effects of the knockdown of Arf6 on cell proliferation and neuronal differentiation. A, Representative micrographs showing the distribution of BrdU-positive cells in the VZ. Embryos were electroporated with the indicated shRNAs and EGFP at E14.5 and killed at E15.5 1 h after the intraperitoneal administration of BrdU to pregnant mice. Arrowheads show BrdU-incorporated mCherry-positive cells in the VZ. Note no apparent differences in the cell number or position of BrdU-positive transfected cells between Control and Arf6 knockdown (Arf6 KD). B, Representative micrographs showing the expression of PSA-NCAM in control and Arf6-KD neurons in the IZ at E17.5. C, Representative micrographs showing that the expression of Cux1 in control and Arf6-KD neurons in the superficial cortical layers at P0. Scale bars: A, 25 μm; B, 50 μm; C, 100 μm.