Figure 9.

The number of SCs that downregulate E-cadherin and convert into HCs after DAPT treatments declines with postnatal maturation, so that by P16 SCs no longer convert into HCs. Whole mount utricles harvested from P8, P12 and P16, treated with DAPT for 72 h and labeled for E-cadherin (green), N-cadherin (red) and myosin VIIA (purple). A, Images of whole utricles showing regions of E-cadherin depletion. Scale bars are 50 μm. Please note that E-cadherin levels are not comparable between the different age group images in this figure. Image intensity was individually optimized for each age. Although E-cadherin levels appear to be lower in the striolar regions at all ages, E-cadherin is completely absent only in the P8 and P12 shown. B, Higher magnification images taken at the level of the striola, showing that the regions of conversion become progressively smaller until disappearing at P16. Scale bars are 10 μm. C, Quantification of area exhibiting SC-to-HC conversion as a function of postnatal age (n = 4 for P4 and P8, n = 5 for P12, n = 3 for P16 and n = 3 for P82).