Figure 5.

Adult Alk3^UB−/− kidneys exhibit medullary hypoplasia. (A and B) P21 Alk3^UB−/− kidneys exhibit cortical cysts, loss of the renal papilla, and medullary hypoplasia. (C and D) Malformation of medullary collecting ducts, identified with anti-calbindin_28K antibody, in Alk3^UB−/− kidneys (boxed areas in A and B). (E and F) Nuclear phospho-Smad1 expression is not detected in the medulla of Alk3^UB−/− kidneys. (G and H) Cytosolic β-catenin expression is increased in Alk3^UB−/− kidneys compared with Wt. (I and J) De novo nuclear MYC expression is observed in Alk3^UB−/− kidneys. (K) Reduced ALK3 and phospho-Smad1 protein, together with increased β-catenin and MYC proteins, are observed in P21 Alk3^UB−/− whole-kidney lysates compared with Wt. Scale bars: (A and B) 1 mm, (C through F) 50 μm, (G and H) 500 μm, (I and J) 50 μm.