Loss of Kcnq1 expression in marginal cells. The time course of marginal cell reorganization during development was determined by confocal immunohistochemistry of Kcnq1 (red) and phalloidin-staining of α-actin (green) of stria vascularis in whole-mounts. Top, images from Slc26a4
+/- mice of various ages. Bottom, images from Slc26a4
-/- mice. Note that marginal cells of Slc26a4
+/- mice expressed Kcnq1 homogeneously in their apical membrane and that apical membrane surface areas displayed little variation in size. Marginal cells of Slc26a4
-/- mice at P10 and P15 expressed Kcnq1 homogeneously, too, and apical membrane surface areas showed little variation in size. However, surface areas were larger compared to Slc26a4
+/- mice. At P37, expression of Kcnq1 in Slc26a4
-/- mice was reduced in some marginal cells and maintained in others. Loss of Kcnq1 expression correlated with an enlargement of the apical membrane surface area and maintenance of Kcnq1 expression correlated with a reduction in the apical membrane surface area. This segregation of marginal cells was more drastic at P96. The scale bar shown in the bottom right image represents 10 μm and pertains to all images in this figure.