Regulation of the gene for human dipeptidyl peptidase IV by hepatocyte nuclear factor 1α

Hepatocyte nuclear factor 1 was identified as the transcription factor binding to a 20 bp (®150 to ®131) region of the gene for human dipeptidyl peptidase IV, which has been shown to be important for the expression of dipeptidyl peptidase IV in the human intestinal and hepatic epithelial cell lines Caco-2 and HepG2. Functional analysis of the hepatocyte nuclear factor 1 site was performed with two minimal dipeptidyl peptidase IV promoter constructs (®250 to ®41, and ®150 to ®41) with and without a 3 bp mutation in the hepatocyte nuclear factor 1 sequence, and used in transient transfection experiments with Caco-2 cells. The results show that the mutated constructs were able to drive transcription at only 5–10% of the activity of the