Fig. 5. KLF5 influences the differentiation of lung epithelium and mesenchyme. (A-L) Lung sections from Klf5^/ mice and littermate controls were prepared at E18.5 and immunostained for CEBP (A,B), CCSP (C,D), FOXJ1 (E,F), SMA (G,H), PECAM (I,J) and VEGFR2 (K,L). Significantly decreased staining of CEBP (B) and CCSP (D) was detected in the airway epithelial cells, whereas no change in FOXJ1 staining was observed (F). The intensity and distribution of SMA staining were increased in the peripheral lung of the Klf5^/ mice (H). Although staining for PECAM (J) and VEGFR2 (L) was readily detected, the pulmonary mesenchyme was thickened and the blood vessels were not found in close proximity to the adjacent epithelial cells. Insets are higher magnification views of the regions indicated by the arrows. Scale bar: 50 µm.