Fig. 3

Immunolocalization of polycystin in rat fetal kidney (18 day gestation) (a), human fetal kidney (12 week gestation) (b and c), and human adult kidney (d)

Staining was carried out using AP1 (a, b, and d) and AP2 (c). (a) Branching ureteric buds are stained brightly at the basal surface (arrow), and faintly at the apical surface. Bright staining is observed in developing glomeruli (G), at the level of the glomerular basement membrane, with weak staining of Bowman’s capsule. Moderate staining of an S-shaped body (S) is also seen. Bar = 20 µm. (b) Intense staining of human fetal glomeruli (G) at the level of the basement membrane, with occasional staining of parietal epithelium and moderate staining of the apical pole (arrows) of a collecting duct. Bar = 20 µm. (c) AP2 staining of parietal epithelium but not the glomerular tuft, and moderate staining (arrows) of a collecting duct. The tissue was first denatured with 6 M urea prior to staining. Bar = 20 µm. (d) Bright staining at the level of the basement membrane of a glomerulus, but no staining of Bowman’s capsule. Moderate apical and basolateral staining of intercalated cells (arrows) is also observed. Bar = 20 µm.