Fig. 4. Smo^c/–;Foxg1^Cre mutants show complete dorsalization. (A-L) E12.5 coronal sections of the wild-type (A,C,E,G,I,K) and Smo^c/–;Foxg1^Cre mutant (B,D,F,H,J,L) telencephalon stained by in situ hybridization. Foxg1 staining of the mutant telencephalon shows the morphological absence of all three ventral eminences (B). Both Ngn2 and Emx2, which are normally restricted to the developing cortical fields (C,E), are expanded throughout the entire ventral extent of the mutant telencephalon (D,F). Nkx2.1, Gsh2 and Mash1 are all expressed within overlapping domains of the ventral telencephalon (G,I,K). These three markers are absent from the Smo^c/–;Foxg1^Cre mutant telencephalon (H,J,L). Note that the ventral staining for Nkx2.1 and Mash1 is not telencephalic (asterisks, compare with asterisk in B). Scale bars: 300 µm in A-L.