Figure 8. Rfx1/3 are not necessary for the early differentiation of OHCs.

(a) SEM images of the middle turns from P8 Rfx1/3 cKO mice and their wild-type controls showing normal appearance of the cochlear sensory epithelia with one row of IHCs and three rows of OHCs. All HCs have kinocilia. (b) Higher magnification lateral views of IHCs and OHCs of Rfx1/3 cKO and littermate P8 controls showing properly formed kinocilia. (c) Higher magnification medial views of IHCs; Inset show the tip links at higher magnification from the regions indicated in the dashed boxes. (d) Basal turns of P8 cochlear ducts from Rfx1/3 cKO and controls stained with an antibody for prestin (red) and phalloidin (green). All OHCs express prestin in their lateral wall. (e) A functional assay for the presence of an intact transduction channel was performed using the uptake of FM1-43 dye. HCs throughout the cochleae of the wild-type and double cKO mice internalized the dye within 10 s. Scale bars for a,d,e: 5 μm; Scale bars for b,c: 0.5 μm. n=3 for P8 SEM analysis, n=4 for prestin staining and n=8 for FM1-43 analysis.