Figure 5.

Protection against apical dedifferentiation in double KO kidneys. Double (or triple, Hoechst in blue) confocal fluorescence at 6 months for L. tetragonolobus lectin (LT-lectin) labeling (red), and either (A) NaPi-IIa or (B) SGLT-2 in green. Top panels, GTJs; bottom panels, enlargement of representative proximal tubule sections. On the left, notice in control (CTL) PTCs restriction of NaPi-IIa and SGLT-2 to the brush border but extension of LT-labeling subapically, resulting in apical label stratification. In Ctns^−/− PTCs (central panels), LT-lectin and NaPi-IIa or SGLT-2 signals are greatly decreased or absent (arrowheads indicate sharp boundary with preserved cells). On the right, megalin ablation in Ctns^−/− kidneys preserves apical signal of LT-lectin and NaPi-IIa or SGLT-2; stratification is lost due to atrophy of subapical endocytic apparatus. For whole-cortex views, see Supplemental Figure 6, A and B. For RT-PCR, see Supplemental Figure 7. DIC, differential interference contrast; glom, glomerulus.