(A) A representative E12.5 Pax2-eYFP kidney injected with Six2 TGC +/tg; Rosa +/tdTomato nephron progenitors at two different sites. Dotted line marks the branching UB. (B). A recipient kidney 96hrs after injection. Six2 antibody (green) labels the progenitor cells in the periphery. Cytokeratine-8 antibody (Cyto8, white) labels the collecting duct. (C). Enlarged image of one injection site (yellow frame in B). Arrow indicating injected progenitors in the CM and arrowheads pointing at differentiated descendants in the nephron epithelia. (D). 3hr pulse labeling of injected kidneys with EdU by the end of 48hrs (white). Magenta arrows point at triple positive (Six2+; tdTom+; EdU+) cells. (E, F) TUNEL staining of a kidney explant 24hrs (E) and 48hrs (F) after transplantation. Six2 antibody stains all CM (white), tdTomato (Red) labels injected cells, and TUNEL (green) labels apoptotic cells. (G). tdTomato+ progenitors differentiated into podocytes precursor [green, Wilm's tumor 1 (Wt1)], proximal tubule [white, Lotus Tetragonolobus Lectin (LTL)], (H) distal tubule (white, ECadLO) and (I) thick ascending limb of Loop of Henle [green, Tamm-Horsfall Protein (THP)] but not UB (white, ECadHI and Cyto8) or (J) stroma (green, PDGFRβ). Scale bar, 1mm in A, 200μm in B, 30 μm in C and D, 20μm in E and F and 30μm in G-I. See also .