Gene expression pattern The nuclear receptor fetoprotein transcription factor is coexpressed with its target gene HNF-3b in the developing murine liver intestine and pancreas

During organogenesis, the winged helix hepatocyte nuclear factor 3b (HNF-3b ) protein participates in regulating gene transcription in the developing esophagus, trachea, liver, lung, pancreas, and intestine. Hepatoma cell transfection studies identified a critical HNF-3b promoter factor, named UF2-H3b , and here, we demonstrate that UF2-H3b is identical to the fetoprotein transcription factor (FTF). In situ hybridization studies of mouse embryos demonstrate that FTF expression initiates in the foregut endoderm during liver and pancreatic morphogenesis (day 9) and that earlier expression of FTF is observed in the yolk sac endoderm, branchial arch and neural crest cells (day 8). Abundant FTF hybridization signals are observed throughout morphogenesis of the liver, pancreas, and intestine and its expression continues in the epithelial cells of these adult organs. In day 17 mouse embryos and adult pancreas, however, expression of FTF becomes restricted to the exocrine acinar and ductal epithelial cells. q 1999 Elsevier Science Ireland Ltd. All rights reserved.