Figure 4

Abnormal vestibular morphogenesis in whole-mount β-galactosidase stained E11.5 and E14.5 embryos lacking both Dlx5 and Dlx6. Embryonic Dlx5 and Dlx6 expression in the inner ears of heterozygous (A, C) and homozygous (B, D) Dlx5/Dlx6 embryos demonstrates that vestibular morphogenesis is arrested by E11.5 with the absence of presumptive semicircular ducts and endolymphatic duct (ED, asterisk). At E14.5, Dlx5/Dlx6 expression normally defines the majority of the vestibular apparatus, including the anterior (AD), posterior (PD), and lateral (LD) semicircular ducts, ampullae (A) and ED. In contrast, the cell lineage of the presumptive vestibular apparatus is absent (asterisk) from Dlx5/Dlx6 null embryos, which develop a rudimentary pinna (P).