(A) Wide distribution of STC1 protein in the kidney and strong staining in blood vessels and some cortical tubules. Formalin-fixed and EDTA-treated WT kidney sections were stained with goat anti-STC1. Upper panel shows wide distribution of STC1 immunoreactivity (albeit with variable staining intensity); note strong staining in some cortical tubules, possibly representing CD and blood vessels including medullary rays. No staining is observed in preimmune serum-treated sections (lower panel). G, glomerulus; IM, inner medulla; VR, vasa recta. (B) Wide distribution of STC1 mRNA in the kidney. Upper panels: scrambled shRNA Tg kidneys harvested 4 days after the delivery of pTie2-Cre and probed with antisense STC1 probe reveal expression of STC1 mRNA (brown color) in the entire kidney; left upper corner inset in the cortical panel shows expression of STC1 mRNA in the endothelium and adventitia of a midsize artery. Middle panels: consecutive sections from scrambled shRNA Tg kidneys, shown in the upper panels, were probed with sense STC1 probe and show minimal background signal. Lower panel: sections from STC1 shRNA Tg kidneys harvested 4 days after the delivery of pTie2-Cre and probed with anti-sense STC1 probe; note diminished expression of STC1 mRNA in the entire kidney. A, artery; G, glomerulus; V, vein.