Figure 1

SOX2 and SOX9 expression in human fetal cochlea around the onset of first hair cell differentiation. (A) Hematoxylin and eosin (H&E) staining of a cochlea at W10.4 (week 10 and 4 days) with higher magnification (right panel) of the basal turn cochlear duct. (B) Basal turn of a W10.4 cochlea immunostained for SOX2, and magnification of the prosensory domain (bottom panels). Cell nuclei were visualized with TO-PRO-3 (red). (C) Basal turn of a W10.4 cochlea immunostained for SOX9, and magnification of the prosensory domain (bottom panels). Cell nuclei were visualized with TO-PRO-3 (red). (D) H&E staining of a W12 (week 12) cochlea with higher magnification (right panel) of the basal turn cochlear duct. (E) Basal turn of a W12 cochlea immunostained for SOX2, and magnification of the prosensory domain (bottom panels). Cell nuclei were visualized with TO-PRO-3 (red). (F) Basal turn of a W12 cochlea immunostained for SOX9 (green) and MYO7A (red), and magnification of the prosensory domain (bottom panels). Cell nuclei were visualized with DAPI (blue). #Tissue artifact; *, cytoplasmic SOX2 staining in the cochlear duct; $, SOX9 staining in the otic capsule; bracket, the prosensory domain; white arrow, Schwann cells of the spiral ganglion; arrowhead, inner hair cell. Abbreviations: cd, cochlear duct; KO, Kölliker’s organ; sv, scala vestibuli; st, scala tympani. Scale bars = 100 μm (all lower magnifications) or 50 μm (all higher magnifications).