Hepatocyte nuclear factor 3/fork head or "winged helix" proteins: a family of transcription factors of diverse biologic function.

A family of transcription factors, first identified as hepatocyte nuclear factors (HNF-3 alpha, -3 beta, and -3 gamma) and as a homeotic Drosophila mutant, fork head, has been intensively studied for the past 4 years. Important findings have emerged about the structure of the DNA-binding portion of the proteins as well as biologic discoveries about the diversity of the family and its implied role in early development.