(a–f) Indirect immunofluorescence of mouse renal cortex sections. Mouse anti-synaptopodin staining (a and d) visualized with FITC-conjugated anti-mouse IgG; rabbit anti-Smad7 (b and e) visualized with Cy3-conjugated anti-rabbit IgG in 2-week-old WT (a–c) and TG mice (d–f). Podocytes, blue arrows; endocapillary/mesangial cells, white arrows; artifact (red blood cell), yellow arrows. (g–i) Mouse anti-smooth muscle actin (α-SMA) IgG labeling (g) and anti-Smad7 staining (h). (j) Northern blot shows Smad7 mRNA levels after TGF-β treatment in podocytes cultured under permissive (33°C) or nonpermissive (37°C) conditions. GAPDH is shown for loading control.