Confocal microscopy images of merged stainings from kidney tissue following UUO. (a) Glomeruli from the contralateral kidneys in R26R × γGT.Cre mice 10 days after unilateral UUO have no reaction product. Unfloxed LacZ⁺ tubular epithelium stained red with anti-LacZ antibodies as evidence of recombination, and floxed LacZ^– interstitial fibroblasts formed before day P7 stained green (FSP1⁺) with anti-FSP1 antibodies. ×630. (b) A representative cortical tubule undergoing EMT in kidney harvested 10 days after UUO stained with anti-FSP1 (green) and anti-LacZ (red). The merged confocal image demonstrates unfloxed FSP1⁺, LacZ⁺ epithelial cells staining yellow as double-positive cells. The tubule is disaggregating, with cellular elements assuming the shape of new interstitial FSP1⁺, LacZ⁺ fibroblasts. ×630. (c) Renal cortical interstitium from kidney harvested 10 days after UUO demonstrated that floxed FSP1⁺, LacZ^– fibroblasts formed before day P7 were stained green (FSP1⁺), and adjacent and newly formed unfloxed FSP1⁺, LacZ⁺ fibroblasts (those created after day P7) stained yellow (double positive for FSP1 and LacZ) after local EMT. ×400. (d) Tubular EMT in kidney cortical tissue harvested 10 days after UUO demonstrated that floxed FSP1⁺, LacZ^– fibroblasts formed before day P7 were stained green (FSP1⁺), some cortical FSP1⁺, LacZ⁺ tubular epithelial cells undergoing EMT were yellow (double positive for FSP1 and LacZ), and adjacent and newly formed, unfloxed FSP1⁺, LacZ⁺ fibroblasts stained yellow after EMT. ×630. (e) Day 10 UUO kidney sections stained with anti-LacZ (green) and (f) anti-HSP47 (red). (g) Merged kidney section in yellow demonstrates colocalization of HSP47 (collagen type I production) in unfloxed tubular LacZ⁺, HSP47⁺ epithelium undergoing EMT and in new unfloxed LacZ⁺, HSP47⁺ fibroblasts. ×400.