In situ hybridization with 33P-labeled RNA probes for determination of cellular expression patterns of liver transcription factors in mouse embryos.
Murine hepatocyte nuclear factor-3beta (HNF-3beta) protein is a member of a large family of developmentally regulated transcription factors that share homology in the winged helix/fork head DNA binding domain and that participate in embryonic pattern formation. HNF-3beta also mediates cell-specific transcription of genes important for the function of hepatocytes, intestinal and bronchiolar epithelium, and pancreatic acinar cells. We have previously identified a hepatocyte and pancreatic cut-homeodomain transcription factor, HNF-6, which is required for HNF-3beta promoter activity. In this study, we used in situ hybridization studies of stage-specific embryos to demonstrate that HNF-6 and its target gene, HNF-3beta, are coexpressed in the foregut endoderm and in the pancreatic and hepatic diverticulum. More detailed analysis of HNF-6 and HNF-3beta's developmental expression patterns provides evidence of colocalization in hepatocytes, intestinal epithelium, and pancreatic ductal epithelium and exocrine acinar cells. In support of the role of HNF-6 in regulating HNF-3beta expression in developing hepatocytes, their liver expression levels are both transiently reduced between 14 and 15 days of gestation. At day 18 of gestation and in adult pancreas, HNF-6 and HNF-3beta transcripts remain colocalized in the exocrine acinar cells, but their expression patterns diverge in endocrine cells. HNF-3beta expression is restricted to the endocrine cells of the islets of Langerhans, whereas the ductal epithelium expresses HNF-6. We discuss these expression patterns with respect to specification of hepatocytes and differentiation of the endocrine and exocrine pancreas.
Department of Biochemistry and Molecular Biology, University of Illinois at Chicago, College of Medicine, Chicago, Illinois, 60612-7334, USA.
F M
FM
Rausa
H
H
Ye
L
L
Lim
S A
SA
Duncan
R H
RH
Costa
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D005865:Gestational Age; D051542:Hepatocyte Nuclear Factor 3-beta; D051559:Hepatocyte Nuclear Factor 6; D018398:Homeodomain Proteins / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D007422:Intestines / Q000196:embryology; D008099:Liver / Q000196:embryology; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics; D016376:Oligonucleotides, Antisense / Q000235:genetics; D010179:Pancreas / Q000196:embryology; D010759:Phosphorus Isotopes; D011228:Prealbumin / Q000235:genetics; D011401:Promoter Regions, Genetic; D015347:RNA Probes / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D015534:Trans-Activators / Q000235:genetics; D014157:Transcription Factors / Q000032:analysis*
D004268:DNA-Binding Proteins; C496503:Foxa2 protein, mouse; D051559:Hepatocyte Nuclear Factor 6; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D016376:Oligonucleotides, Antisense; C496606:Onecut1 protein, mouse; D010759:Phosphorus Isotopes; D011228:Prealbumin; D015347:RNA Probes; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; D051542:Hepatocyte Nuclear Factor 3-beta