Fig. 5.

Gradation of stereocilia diameters is lost in Myo15^sh2/sh2 but not Myo15^∆N/∆N OHCs. a–c Magnified SEM images of stereocilia in control (a), Myo15^sh2/sh2 (b), and Myo15^∆N/∆N (c) OHCs at different postnatal ages. Scale bars: 0.5 μm. d–g Quantification of stereocilia diameters (D, nm) in the first (circles, dotted lines), second (squares, dashed lines), and third (triangles, solid lines) stereocilia rows of the Myo15^sh2/sh2 (different shades of red) and Myo15^∆N/∆N (different shades of blue) OHC bundles, as well as in corresponding heterozygous controls (different shades of gray/black). Other details of the layout are as in Fig. 4. Statistical analysis was performed with P0-P10 data, since both Myo15^sh2/sh2 and Myo15^∆N/∆N OHCs show some signs of stereocilia diameter degradation at P16–21 (see panels e–g). All cells were from the middle of the cochlea, and stereocilia at the very edges of the rows were excluded from analysis. Number of cells: 4–15 from at least two different mice per age/genotype