Compared to the medial side of the LPR in controls (A–C), hair bundle polarity (arrows) in the medial region of Sox2CreER/+;RosaEmx2/+ (D-F, tamoxifen given at E12.5 and E13.5, gain-of-function (GOF) in the sensory epithelium (SE), GOF-SE early; n = 3) and Gfi1Cre/+;RosaEmx2/+ utricles (J-L, GOF-HC (hair cell); n = 7) are reversed. (G–I) Sox2CreER/+;RosaEmx2/+ utricles (tamoxifen give at E15.5 and E16.5, GOF-SE late) show a mixed phenotype of normal and reversed bundle polarities (white arrows, n = 3). Among the GOF specimen (D,G,J), anti-oncomodulin staining (blue) is only sparsely detectable in the GOF-HC utricles (J) compared to controls (A). (M–N) Quantification of HC density (M; Figure 4—source data 1) and surface area (N; Figure 4—source data 2) in Regions 1 and 3 of utricles from various genotypes (controls, n = 6; GOF-SE, n = 3; GOF-HC, n = 4). Only utricles of GOF-SE early show a significant decrease in HC density and an increase in the apical surface area of HCs compared to controls. Error bars represent SEM. *p<0.05; **p<0.01; ***p<0.001. (O) Schematic diagrams illustrating hair bundle polarity pattern and defined regions in control and Emx2 gain-of-function utricles. (P–Q) Box-plots of hair bundle polarity in regions L (LES) and M (MES) of utricles (Figure 4—source data 3). Region L of controls includes the LPR and thus show HCs with both medial and lateral polarities but only medial-pointing hair bundles are present in all Emx2 GOF utricles except GOF-SE late (control, n = 6; mutant, n = 3). Box represents quartiles 1 to 3. The line within the box is the median and the bar represents maximum and minimum number. **p<0.01, ***p<0.001, compared to controls.
DOI:
http://dx.doi.org/10.7554/eLife.23661.011
Figure 4—source data 1. Quantification of HC density in Emx2 gain-of-function mutants.
Figure 4—source data 2. Quantification of apical surface area of HCs in Emx2 gain-of-function mutants.
Figure 4—source data 3. Quantification of hair bundle orientation in Emx2 gain-of-function mutants.