Fig. 1

The human cochlear prosensory domain. a Three stages of human cochlear development (W8 (E1202), W10 (E1201), and W12 (E1210)). Shown are overview modiolar cyosections, immunolabeled with antibodies to p27Kip1. F-actin was labeled with phalloidin and cell nuclei were stained with DAPI. Scale bar = 1 mm. b Cochlea at W8 (E1202) of development, immunostained for p27Kip1 and Ki67. Right and left cochleae from the same fetus are shown. The prosensory domain (PSD) and the spiral ganglion (SG) are indicated. Pink dashed lines indicate the lack of KI67 positivity in the PSD in apical and middle turn. Scale bar = 100 μm. c Characterization of the W8.4 (E1251) PSD by immunostaining for SOX2 and p27Kip1. Scale bar = 100 μm. Apical and basal turns are shown as indicated. d Characterization of W12 (E1210 top and E1203 bottom) PSDs with immunostaining for SOX2 and p27Kip1. Upper panel shows the basal turn, lower panel shows the localization of the two markers in the base, middle, and apex. Scale bar = 50 μm. e Schematic comparison of the timing of cell cycle exit between mouse and human. f Immunostaining for SOX2, LGR5, and MYO7A of human fetal cochlear PSDs at W8 (E1202), W10 (E1201), and W12 (E1210) of development. Basal turns are shown for all-time points. Scale bar = 100 μm. g In situ hybridization (brown dots) with a LGR5-specific RNAscope probe at W9.2 of development (E1276) Basal, middle, and apical turns are shown. Sections are counterstained with haematoxylin (blue) to visualize tissue morphology. Scale bar = 50 μm. h Immunostaining for SOX2 and MYO7A of cochlear PSDs at W11 (E1195) and W12 (E1203). The basal, middle, and apical turns are shown. Scale bar = 50 μm. i Schematic comparison of the timing of hair cell differentiation between mouse and human. j Immunostaining of the entire cochlear duct for EPCAM (red) and p27Kip1 (green) at W10. Scale bar = 100 μm