Figure 5

Ngn2-/- embryos have normal cortical lamination. (A-L) To assess any changes in cortical lamination upon the loss of Ngn2, we harvested Ngn2+/- embryos and Ngn2-/- embryos at E18.5 (A-F), and at the last possible time point, P0 (G-L). To assess deep layer formation, we immunostained sections with CTIP2, which strongly labels layer 5 and weakly labels layer 6a (A,D,G,J), and Tbr1 (B,E), which labels layer 6a. Merged images (C,F) revealed no difference in size or location of layers V and VI between Ngn2+/- (A-C) and Ngn2-/- embryos (D-F). To compare any differences in superficial layer formation, we immunostained sections with Cux1 (H,K), which labels layers 2 to 4. Again we observed no obvious difference in laminar formation when Ngn2+/- (G-I) and Ngn2-/- sections were stained for superficial layer markers. (I,L) Merged images. Immunostaining for laminar markers did reveal the presence of heterotopias in the intermediate zon of the Ngn2 knockout (arrowheads, J,L) and the presence of Cux1-positive neurons in deep layers (bracket, K).