Figure 1 .

Semithin section of the renal stem/progenitor cell niche underneath the organ capsule (CF). Accurate orientation of parenchyma is obtained by sectioning in parallel to the lumen of a collecting duct (CD). Epithelial stem/progenitor cells are found within the tip of a ureteric bud derived CD ampulla (A). A thin layer of nephrogenic mesenchymal stem/progenitor cells is found between the tip of a CD ampulla and the organ capsule. Epithelial and mesenchymal stem/progenitor cells are separated by a wide interstitial space (lined asterisk). Coordinate for electron microscopy is labeled by a cross (+).