Fig. 8: IHC stereocilia degenerate in Myo7a-ΔC mice. | Nature Communications

Fig. 8: IHC stereocilia degenerate in Myo7a-ΔC mice.

From: Myosin-VIIa is expressed in multiple isoforms and essential for tensioning the hair cell mechanotransduction complex

Fig. 8

a, b SEM analysis at 3, 6, and 8 weeks. The first, second, and third row of stereocilia are shown in red, yellow, and blue, respectively. Number of third row stereocilia in Myo7a-ΔC IHCs decreases progressively: mean third row stereocilia number ± SD per cell (number of cells; animals): 3 weeks WT = 25.64 ± 7.25 (14;3), Myo7a-ΔC = 12.44 ± 3.26 (18;3), p = 7.28e−23. 6 weeks WT = 22.65 ± 2.79 (36;6), Myo7a-ΔC = 4.50 ± 3.03 (20;5), p = 7.28e−23. 8 weeks WT = 20.83 ± 4.54 (35;3), Myo7a-ΔC = 3.84 ± 2.54 (31;3), p = 9.41e−26. c, d First and second row stereocilia of Myo7a-ΔC IHCs are longer than WT counterparts. SEM images are collected from the middle turn. Mean stereocilia lengths at 6 weeks (averaged by cell) ± SD. First row: WT = 3.41 ± 0.47, Myo7a-ΔC = 3.78 ± 0.35, p = 0.021; analyzed numbers (stereocilia; cells; animals) for WT (95;15;5) and Myo7a-ΔC (86;16;5). Second row: WT = 1.83 ± 0.17, Myo7a-ΔC = 1.96 ± 0.21, p = 0.033. Analyzed numbers (stereocilia; cells; animals) for WT (116;20;3) and Myo7a-ΔC (159;21;3). e, f Loss of prolate tips in second row stereocilia in Myo7a-ΔC IHC. Stereocilia tips were traced and superimposed. g, h OHC bundles at 8 weeks were not affected in Myo7a-ΔC mice. SEM-based quantification of stereocilia lengths: basal OHCs: First row: WT = 1.27 ± 0.094, Myo7a-ΔC = 1.34 ± 0.12, p = 0.089. Second row: WT = 1.01 ± 0.050, Myo7a-ΔC = 1.032 ± 0.096, p = 0.52. Third row: WT = 0.57 ± 0.031, Myo7a-ΔC = 0.55 ± 0.069, p = 0.58. Analyzed numbers (stereocilia; cells; animals) for WT (188;14;5) and for Myo7a-ΔC (153;12;4). Apical OHCs: First row: WT = 2.01 ± 0.10, Myo7a-ΔC = 1.99 ± 0.13, p = 0.688. Analyzed numbers (stereocilia; cells; animals) for WT (131;13;3) and for Myo7a-ΔC (137;18;4). Second row: WT = 1.43 ± 0.082, Myo7a-ΔC = 1.39 ± 0.082, p = 0.21. Analyzed numbers (stereocilia; cells; animals) for WT (99;13;4) and for Myo7a-ΔC (94;14;3). Third row: WT=0.80 ± 0.049, Myo7a-ΔC = 0.80 ± 0.045, p = 0.95. Analyzed numbers (stereocilia; cells; animals) for WT (99;13;4) and for Myo7a-ΔC (94;14;3). Boxplots show medians, 25th and 75th percentiles as box limits, and minima and maxima as whiskers. p values in b, d, and h were derived from two-tailed, unpaired t-tests (error bars indicate SD and n = number of cells). All scale bars: 1 μm (except in e and f: 0.2 μm). Source data are provided in the Source Data file.

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