Conditional deletion of Sox10 with Wnt1-cre eliminates Sox10 expression in neural crest but not placode-derived cells.

These images of E13.5 mice show that Sox10 expression is retained in the ear (A, B) and some other cranial placode-derived ganglia (C, D). Sox10 is in the Schwann cells of spinal dorsal root ganglia (DRG) in the control (C) but no cervical DRGs are Sox10 positive in the Wnt1-cre; Sox10 conditional mutant mice (D). Trigeminal ganglion neurons (V) innervate the anterior part of the ear lobes (E, F) whereas the posterior aspect of the ear lobes is innervated by the greater auricular nerve of the DRGs in control animals (arrow in E), but not in the mutants (arrow in F). Mmp-24 is an early neuronal marker and in situ hybridization (G, H) shows reduction of the remaining ganglia (G, H). Some Mmp-24 positive DRG neurons but no autonomic ganglia remain in Sox10 mutants (H). Abbreviations: OC, organ of Corti; PC, posterior crista; AC, anterior crista; HC, horizontal crista; U, utricle; S, saccule; DRG, dorsal root ganglia. Dotted line indicates where the ear was removed in G, H; bar indicates 0.5 mm in A, B, and 1 mm in C–H.