Fig. 7. Reduced Lu/B-CAM expression and p27Kip1 nuclear localization in KO/Tg distal small intestine. (A-D) Sections of distal small intestines (A,B) and proximal small intestines (C,D) from Het/Tg and KO/Tg mice were stained with an antibody against Lu/B-CAM (Lu). Lu/B-CAM expression was high in smooth muscle, medium in the villus core, and very low at the basal surface of intestinal epithelial cells in the Het/Tg DSI (A and inset). Lu/B-CAM expression in the villus core and at the basal surface of intestinal epithelial cells was reduced in the KO/Tg DSI (B and inset). Lu/B-CAM was detected at higher levels on the basal surface of intestinal epithelial cells in Het/Tg PSI than Het/Tg DSI (A,C and insets), and this expression was reduced in the KO/Tg PSI (D and inset). Arrowheads in A and C point to the basal expression of Lu/B-CAM. (E,F) Sections of distal small intestines were stained with an antibody against p27Kip1. p27Kip1 was detected in the nuclei of differentiated intestinal epithelial cells at the bottom of crypts and on the villi in Het/Tg small intestine (E and inset). Nuclear staining was dramatically reduced in KO/Tg distal small intestine (F and inset). Bars, 100 µm.