<p>(A-I) Immunofluorescence demonstrating β-catenin spatial and temporal expression in stromal cells. (A) At E11.5 Pbx1 is expressed in the nucleus of stromal cells (arrow head-inset) surrounding the condensing mesenchyme. Some Pbx1 positive stromal cells locate within the condensing mesenchyme, directly adjacent to epithelial cells (arrows). (B,C) At E11.5 β-catenin is expressed in the condensing mesenchyme and ureteric epithelium, and co-localizes with Pbx1 demonstrating expression in the renal stroma. At E11.5, some Pbx1 cells co-localize with β-catenin in the nuclear compartment of stromal cells (arrowhead-inset). (D) At E13.5, Pbx1 is expressed in capsular and cortical stroma surrounding the condensing mesenchyme. (E, F) At E13.5, β-catenin co-localizes in the cytoplasm of capsular stromal cells. The stromal cells located between developing nephrons express β-catenin in the cytoplasmic (arrow-inset) and nuclear compartment (arrowhead-inset). (G) At E17.5, Pbx1 marks the capsular, cortical, and medullary stroma. (H-I) β-catenin is expressed in the medullary stroma and co-localizes strongly with Pbx1 in the nuclear compartment (arrowhead-inset). (scale bar = 100μm, s = stroma, cm = condensing mesenchyme, ub = ureteric epithelium, rc = renal capsule, ms = medullary stroma, rp = renal pelvis).</p
