Fig. 1.

Contribution of TMC2 to development of mechanotransduction in OHCs and IHCs. a Examples of maximum MET currents of wild-type apical OHCs during the first postnatal week, ages P2, P5, and P8. Top trace denotes timing of 100 nm amplitude sinusoidal vibration of the hair bundle evoked by a fluid jet stimulator. b MET currents in Tmc2^−/− in apical OHCs. c MET currents in Tmc1^−/− mouse apical OHCs. d MET current amplitudes (mean ± SEM) in wild type (WT; black symbols) and Tmc2^−/− (red symbols) in OHCs from cochlear apex and base. Numbers of OHCs for points with increasing age: apex WT, 13, 6, 5, 8, 6, 6, 5; apex Tmc2^−/−, 3, 3, 3, 5,7, 5, 6, 3, 3; apex Tmc1^−/−: 3, 8, 5, 4, 7, 9, 3, 6, 8, 6, 3; base WT: 7, 7, 4, 7, 9, 12, 7, 3; base Tmc2^−/−: 3, 3, 4, 5, 5, 4, 4, 3. e Expression of TMC2 in apical OHCs, derived as the difference between wild type and Tmc2^−/− (crosses) and from Tmc1^−/− mice (open symbols); points fit with Gaussian curves. Numbers of cells: WT, 5 to 13; Tmc2^−/− mice 3 to 7. Tmc1^−/− mice 5 to 7. f Examples of maximum MET currents during development of wild type apical IHCs at postnatal ages P2, P5 and P8. g MET currents during same period in apical IHCs from Tmc2^−/− mice. h MET currents in apical IHCs from Tmc1^−/− mice at postnatal ages P2, P5, and P8. i MET currents (mean ± SEM) in wild type (black symbols) and Tmc2^−/− (red symbols). j Expression of TMC2 in IHCs, derived as the difference between wild type and Tmc2^−/− (blue crosses, fit with blue dashed line) and from Tmc1^−/− mice (open symbols, fit with black dashed line). Numbers of cells, increasing in age: IHC, WT: 5, 10, 6, 10, 6, 6, 5, 4, 4, 4; IHC Tmc2^−/− 3, 9, 11, 8, 6, 7, 6, 5, 3, 3; IHC Tmc1^−/− 3, 4, 5, 3, 4, 5, 4, 4, 4, 4, 3. Holding potential −84 mV