title: The onecut transcription factor HNF6 is required for normal development of the biliary tract.
abstract: During liver development, hepatoblasts differentiate into hepatocytes or biliary epithelial cells (BEC). The BEC delineate the intrahepatic and extrahepatic bile ducts, and the gallbladder. The transcription factors that control the development of the biliary tract are unknown. Previous work has shown that the onecut transcription factor HNF6 is expressed in hepatoblasts and in the gallbladder primordium. We now show that HNF6 is also expressed in the BEC of the developing intrahepatic bile ducts, and investigate its involvement in biliary tract development by analyzing the phenotype of Hnf6(-/-) mice. In these mice, the gallbladder was absent, the extrahepatic bile ducts were abnormal and the development of the intrahepatic bile ducts was perturbed in the prenatal period. The morphology of the intrahepatic bile ducts was identical to that seen in mice whose Hnf1beta gene has been conditionally inactivated in the liver. HNF1beta expression was downregulated in the intrahepatic bile ducts of Hnf6(-/-) mice during development. Furthermore, we found that HNF6 can stimulate the Hnf1beta promoter. We conclude that HNF6 is essential for differentiation and morphogenesis of the biliary tract and that intrahepatic bile duct development is controlled by a HNF6-->HNF1beta cascade.
authors.affiliation: Hormone and Metabolic Research Unit, Institute of Cellular Pathology and Université catholique de Louvain, Avenue Hippocrate 75, B-1200 Brussels, Belgium.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Clotman
authors.forename: Vincent J
authors.initials: VJ
authors.lastname: Lannoy
authors.forename: Michael
authors.initials: M
authors.lastname: Reber
authors.forename: Silvia
authors.initials: S
authors.lastname: Cereghini
authors.forename: David
authors.initials: D
authors.lastname: Cassiman
authors.forename: Patrick
authors.initials: P
authors.lastname: Jacquemin
authors.forename: Tania
authors.initials: T
authors.lastname: Roskams
authors.forename: Guy G
authors.initials: GG
authors.lastname: Rousseau
authors.forename: Frédéric P
authors.initials: FP
authors.lastname: Lemaigre
mesh_terms: D000818:Animals; D017734:Bile Ducts, Extrahepatic / Q000002:abnormalities / Q000166:cytology / Q000196:embryology*; D001653:Bile Ducts, Intrahepatic / Q000002:abnormalities / Q000166:cytology / Q000196:embryology*; D001659:Biliary Tract / Q000166:cytology / Q000196:embryology; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics; D004847:Epithelial Cells / Q000378:metabolism; D005704:Gallbladder / Q000002:abnormalities / Q000166:cytology / Q000196:embryology*; D005786:Gene Expression Regulation; D051539:Hepatocyte Nuclear Factor 1-beta; D051559:Hepatocyte Nuclear Factor 6; D022781:Hepatocytes / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D008099:Liver / Q000378:metabolism / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D009024:Morphogenesis; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; C496495:HNF1B protein, human; D051559:Hepatocyte Nuclear Factor 6; C496496:Hnf1b protein, mouse; D018398:Homeodomain Proteins; C496605:ONECUT1 protein, human; C496606:Onecut1 protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors; D051539:Hepatocyte Nuclear Factor 1-beta