Liver Receptor Homolog 1 (LRH1)

By means of yeast 1-hybrid screening of a liver cDNA library, Li et al. (1998) cloned a cDNA encoding a novel hepatocyte transcription factor, which they called HB1F for human B1-binding factor. The deduced 495-amino acid protein, which has a molecular mass of 54 kD, belongs to the fushi tarazu factor-1 (FTZ-F1) subfamily of orphan nuclear receptors and is closely related to steroidogenic factor-1 (SF1), another member of this subfamily.

HB1F contains a DNA-binding domain with 2 zinc finger motifs, an FTZ-F1 box, and a ligand-binding domain. Northern blot analysis revealed that HB1F is expressed in liver, pancreas, and lung as a 5.2-kb transcript. An additional transcript of 3.8 kb was present in hepatoma cells HepG2. The authors identified 2 HB1F isoforms which differ in their A/B region.