Effects of forced expression of Rbfox3-full on progenitors in the VZ. The expression constructs indicated at the top were transfected and sections of the neural tube were stained for markers indicated on the left and nuclei (DAPI). The right side in each panel is the transfected side, as demonstrated by GFP in A and B. A–L are E3 embryos, and M–R are E4 embryos. Arrowheads in E and F indicate some of the TUNEL⁺ apoptotic cells. Arrowheads and an arrow in H and I indicate precocious expression of Isl1 in motor neuron progenitor and D2 neuron progenitor domains, respectively. Arrowheads in N and O indicate precocious expression of the interneuron marker Lim1/2 in the VZ. Expression of the postmitotic cell marker p27kip1 is not increased in the VZ (K, L, Q, and R). F, I, L, O, and R show only red fluorescence signals without DAPI, which is shown in E, H, K, N, and Q. Bars, 50 µm.