Background of the antigen
HNF-1 (a and b), HNF-3 (a, b and g), HNF-4 (a and g) and HNF-6 compose, in part, a homoeprotein family designated the hepatocyte nuclear factor family. The various HNF-1 isoforms regulate transcription of genes in the liver as well as in other tissues such as kidney, small intestine and thymus. HNF-3a, HNF-3b and HNF-3g regulate the transcription of numerous hepatocyte genes in adult liver. HNF-3a and HNF-3b have also been shown to be involved in gastrulation events such as body axis formation. HNF-4a and HNF-4g have been shown to be important for early embryo development. HNF-4a is expressed in liver, kidney, pancreas, small intestine, testis and colon; and HNF-4g is expressed in each of these tissues except liver. HNF-6 has been shown to bind to the promoter of HNF-3b, which indicates a potential role of HNF-6 in gut endoderm epithelial cell differentiation. Evidence suggests that HNF-6 may also be a transriptional activator for at least 22 other hepatocyte-enriched genes, including cytochrome P450 2C13 and a-1 antitrypsin.