The human intestinal fatty acid binding protein (hFABP2) gene is regulated by HNF-4alpha.

The cytosolic human intestinal fatty acid binding protein (hFABP2) is proposed to be involved in intestinal absorption of long-chain fatty acids. The aim of this study was to investigate the regulation of hFABP2 by the endodermal hepatocyte nuclear factor 4alpha (HNF-4alpha), involved in regulation of genes of fatty acid metabolism and differentiation. Electromobility shift assays demonstrated that HNF-4alpha binds at position -324 to -336 within the hFABP2 promoter. Mutation of this HNF-4 binding site abolished the luciferase reporter activity of hFABP2 in postconfluent Caco-2 cells. In HeLa cells, this mutation reduced the activation of the hFABP2 promoter by HNF-4alpha by about 50%. Thus, binding element at position -336/-324 essentially determines the transcriptional activity of promoter and may be important in control of hFABP2 expression by dietary lipids and differentiation. Studying genotype interactions of hFABP2 and HNF-4alpha, that are both candidate genes for diabetes type 2, may be a powerful approach.