Fig. 3

Progressive hair cell impairment during postnatal development. Hair cell staining on whole-mount preparation of basilar membrane from P3 (a–c), P7 (d–f), P14 (g–i) cochleae of WT, Het, and KO mice. Figures of each timepoint included apical, middle, and basal turn, from top to bottom. At P3, both IHCs and OHCs were intact in KO mice. Scattered HC loss was seen at P7, with more severe lost in the apical turn in KO mice. There were rarely any HCs left in KO cochleae, while the HCs were relatively normal in Het cochleae. Red shows F-actin, blue shows myosinVIIa. j Comparison of the hair cells in KO and WT mice on cross section. The bodies of HCs were rounded at the bottom and an obvious narrowed “neck” was seen on each HC between the cuticular plate and cell body. Green shows myosin VIIa, blue shows DAPI. k, l Quantitative analysis of IHCs (k) and OHCs (l) at different developmental stages. Scale bar in i, 30 μm (for a–i). Scale bar in j, 15 µm. Error bars indicate the standard error of the mean. In k, l, N = 4