FIGURE 3.

Both SMAD1 and SMAD4 can regulate CRMP2 transcription directly in the developing neocortex. A, both SMAD1 and SMAD4 bind to the CRMP2 promoter region as evaluated by ChIP analysis as described under “Experimental Procedures.” B, a diagram illustrates the CRMP2 promoter-driven EGFP expression vector. There are SMAD1 and SMAD4 binding sites in the CRMP2 promoter region. C, ectopic expression of either SMAD1 or SMAD4 can suppress the expression of CRMP2.EGFP. Images of cortices co-transfected with CRMP2.EGFP (green) and DsRed (as a transfection efficiency control, red) together with control vector (upper panel), SMAD1 (middle panel), or SMAD4 (lower panel) expression vector and counterstained with Hoechst dye (for nuclei, blue) 2 days after electroporation. D, quantification of the ratio of EGFP/DsRed fluorescence intensities as analyzed by ImageJ. Error bars represent S.E. t test, *, p < 0.01. Ctrl, control.