Fig. 3. Mispositioning of the kinocilium in Ush1 mutant hair cells. (A) Basal view of E18.5 cochlear whole-mounts from wild-type, Ush1c^-/- and Cdh23^v2J/v2J mice were stained with an antibody that labels the kinocilia (green), and with phalloidin to reveal F-actin in stereocilia (red). (B) Schematic of the method used to measure the angular deviation of the kinocilium with respect to the PCP axis on SEM images. A P0 wild-type OHC is taken as an example. (C) Evaluation of the kinocilium position on P0 wild-type and Ush1 mutant hair cells. For each mouse strain, kinocilia were falsely labeled orange (using Adobe Photoshop) to facilitate their visualization on SEM images of control and mutant OHCs. Mean absolute positions (±s.e.m.) of the kinocilia for the total population of hair cells (orange) and per hair cell row (blue to purple) are represented on the bar charts. P-values, which were determined with respect to the positions of kinocilia in wild-type mice using the Welch's t-test, are indicated by asterisks (^*P0.05, ^**P0.01, ^***P0.001). The pie charts present the percentage of hair cells in which the kinocilium is mispositioned by 0-14° (white), 15-44° (light-gray), 45-89° (medium-gray), or 90-180° (dark-gray) from its expected location at the lateral-most edge of the cell surface. Scale bars: 2 µm in A; 1 µm in C.