title: Elements and factors involved in tissue-specific and embryonic expression of the liver transcription factor LFB1 in Xenopus laevis.
abstract: LFB1 (HNF1) is a tissue-specific transcription factor found in the livers, stomachs, intestines, and kidneys of vertebrates. By analyzing the promoter of the Xenopus LFB1 gene, we identified potential autoregulation by LFB1 and regulation by HNF4, a transcription factor with a tissue distribution similar to that of LFB1. Injection of LFB1 promoter-chloramphenicol acetyltransferase constructs into Xenopus eggs revealed embryonic activation that is restricted to the region of the developing larvae expressing endogeneous LFB1. Proper embryonic activation was also observed with a rat LFB1 promoter. Deletion analysis of the Xenopus and rat promoters revealed that in both promoters embryonic activation is absolutely dependnet on the presence of an element that contains CCNCTCTC as the core consensus sequence. Since this element is recognized by the maternal factor OZ-1 previously described by N. Ovsenek, A. M. Zorn, and P. A. Krieg (Development 115:649-655, 1992), we might have identified the main constituents of a hierarchy that leads via LFB1 to the activation of tissue-specific genes during embryogenesis.
authors.affiliation: Institut für Zellbiologie (Tumorforschung), Universitätsklinikum Essen, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Zapp
authors.forename: S
authors.initials: S
authors.lastname: Bartkowski
authors.forename: B
authors.initials: B
authors.lastname: Holewa
authors.forename: C
authors.initials: C
authors.lastname: Zoidl
authors.forename: L
authors.initials: L
authors.lastname: Klein-Hitpass
authors.forename: G U
authors.initials: GU
authors.lastname: Ryffel
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D001665:Binding Sites; D003001:Cloning, Molecular; D004247:DNA; D004268:DNA-Binding Proteins; D004625:Embryo, Nonmammalian / Q000378:metabolism; D051537:Hepatocyte Nuclear Factor 1; D051538:Hepatocyte Nuclear Factor 1-alpha; D051539:Hepatocyte Nuclear Factor 1-beta; D051557:Hepatocyte Nuclear Factor 4; D008099:Liver / Q000196:embryology / Q000378:metabolism*; D008322:Mammals; D051379:Mice; D008845:Microinjections; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D009928:Organ Specificity / Q000235:genetics; D010750:Phosphoproteins; D011401:Promoter Regions, Genetic; D051381:Rats; D017385:Sequence Homology; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation; D029867:Xenopus Proteins; D014982:Xenopus laevis
chemical_list: D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D051538:Hepatocyte Nuclear Factor 1-alpha; D051557:Hepatocyte Nuclear Factor 4; C496488:Hnf1a protein, mouse; C496489:Hnf1a protein, rat; C000627649:Hnf1b protein, Xenopus; C496496:Hnf1b protein, mouse; D009687:Nuclear Proteins; D010750:Phosphoproteins; C501970:Tcfl4 protein, mouse; D014157:Transcription Factors; D029867:Xenopus Proteins; C496490:hnf1a protein, Xenopus; D051537:Hepatocyte Nuclear Factor 1; D051539:Hepatocyte Nuclear Factor 1-beta; D004247:DNA