Fig. 4. Sall1-GFP^high mesenchyme differentiates into renal epithelia in organ culture. (A) Three subpopulations in E11.5 mesenchyme (Sall1-GFP^high, Sall1-GFP^low and Sall1-GFP^negative) were cultured on 3T3Wnt4 feeder cells in an organ culture setting. Only Sall1-GFP^high cells (upper panels) differentiated into kidney structure, while Sall1-GFP^low cells (lower) disappeared. (B) Hematoxylin-eosin staining of sections of Sall1-GFP^high aggregates at day 10. Tubule- and glomerulus-like structures are seen. (C) Double staining with Wt1 (red, podocyte marker) and LTL (green, proximal tubule marker) of Sall1-GFP^high aggregates. g, glomerulus-like structure; t, tubule-like structure. Scale bars: 500 µm in A; 25 µm in B,C.