Supplemental Figure S2.

In P21 control and Six2creFrs2α knock-out (KO) kidneys, phosphorylated Creb (p-Creb) is present in the thick ascending limbs of the Henle loop and collecting ducts. Co-immunofluorescence for p-Creb (red) with Tamm-Horsfall protein (THP) (green) or dolichos biflorus agglutinin (DBA) (green) on serial sections from P21 control and Six2creFrs2αKO kidneys. A and B: In both control and Six2creFrs2αKO kidneys, comparable p-Creb signal is present in subsets of THP-positive cells of the thick ascending limbs of the Henle loop (arrows). C and D: In both control and Six2creFrs2αKO kidneys, comparable p-Creb signal is present in DBA-positive collecting ducts (arrows). Note that the p-Creb staining cyst lining cells (B and D, concave arrowheads) are neither THP nor DBA positive and were found by lotus tetragonolobus lectin (LTL) staining to be proximal tubule in origin (data not shown). Arrrowhead indicates p-Creb–positive tubules that are THP-positive in A. Scale bars: 50 μm.