HNF1a was shown to bind a 3'-region of the Foxa3 (Hnf3g) gene by chromatin immunoprecipitation (Boj et al. 2001). The deletion in mice of an enhancer region that binds HNF1a located in the 3' region of the Foxa3 gene was shown to affect Foxa3 gene expression in liver, pancreas and gut (Hiemisch et al. 1997). Genetic evidence exists that HNF1a regulates Foxa3 in Hnf1alpha -/- mice (Boj et al. 2001).