FIGURE 3.

Increased apoptosis and impaired expression of CNCC markers in the Cubn^Sox2-Cre-KO mutant heads around E9.25. A and A′, representative lateral views of control and Cubn^Sox2-Cre-KO embryos stained with Lysotracker (in red) and anti-phospho-histone H3 (in green). Dotted lines demarcate the ventral cephalic region (v), dorsal cephalic region (d), and diencephalic region (di) of E9.25 control (A) and mutant (A′) embryos. B and C, cell proliferation is similar at E9.25 (B), whereas the number of Lysotracker+ (LT) cells (C) is significantly increased in the mutant forehead (mean ± S.E., n = 3 embryos of each genotype; Student's t test, p < 0.05). D–M′, representative whole-mount mRNA staining of control (D–M) and mutant (D′–M′) embryos around E9.25. D and D′, reduced expression domain of Foxg1 in the mutant telencephalon (arrows). E and E′, Fgf8 is normally expressed in the commissural plate (arrow) and the isthmus (ist). F and F′, Fgf17 is normally detected at the commissural plate (arrowheads) and isthmus. G and G′ reduced expression domain of Six3 in the ventral telencephalon (arrow) and eye region (arrowhead). H and H′, Shh is lost in the mutant preoptic area (arrow). I and I′, down-regulation of Nkx2.1 in the mutant preoptic area (arrow) but not the hypothalamus (arrowhead). J and J′, dorsal domain of Emx2 is conserved (arrowheads). K and K′, Tfap2a displays a patchy distribution in the mutant telencephalon and periocular region (arrows). L and L′, patchy Dlx2 expression in the mutant rostral cephalic tissues (arrowheads), and in migratory cephalic neural crest cells that contribute to the neurogenic sensory cranial ganglia (snc; arrows). Dlx2 is normally expressed in the mandibular (md) component of the first branchial arch and in the hyoid (h). M and M′, down-regulation of Dlx5 in the mutant rostro-ventral cephalic tissues (asterisk). Lateral views, anterior is to the left. Scale bars, A, 75 μm; D–M, 200 μm.