Analysis of the activity and specificity of promoters/enhancers. (A) Luciferase activity from the different intestine-specific promoters was analyzed by transient transfection in SW480 cells. (B) Influence of the HSI and RITF enhancer on human mucin-2 promoter (HMUC2) activity. (C) Luciferase activity of indicated plasmids in intestinal cells (SW480) and non-intestinal cells (CHO, HeLa, NIH-3T3, HepG2 and 293T). Data are presented as the relative activity of Firefly luciferase to Renilla luciferase in order to normalize transfection efficiency among different wells. The means ± SEM of luciferase expression driven from the selected intestine-specific promoter/enhancers are represented. Different letters represent significant difference, P < 0.01.