An enhancer activates the pig lactase phlorizin hydrolase promoter in intestinal cells.
Lactase phlorizin hydrolase is a small intestinal-specific brush border protein commonly used as a specific marker of differentiated enterocytes. A number of transcription factors involved in the enterocyte-specific expression of lactase phlorizin hydrolase have been identified. An upstream regulatory region, which we have named the "LPH enhancer", located at position -894 to -798 in the porcine lactase phlorizin hydrolase gene, is necessary for high differentiation-dependent LPH expression in intestinal cells. The LPH enhancer was studied by mutation analysis, transfection experiments and electrophoretical mobility shift assays. The LPH enhancer is active in intestinal cells (Caco-2) and not in non-intestinal cells (HeLa). The LPH enhancer is only able to enhance expression when it is located in front of an intestinal-specific promoter such as the lactase phlorizin hydrolase promoter or the sucrase-isomaltase promoter. In front of an SV40-derived promoter the LPH enhancer has no stimulatory effect. In addition to the lack of promoter-promiscuity, the LPH enhancer is not a classical enhancer in the sense that it is not orientation-independent and it cannot function when located 3' of a reporter gene. The LPH enhancer contains at least three cis-elements (at -894 to -880, -880 to -875 and -833 to -814) with functional importance for the LPH enhancer activity.
Troelsen
Jesper T
JT
Department of Medical Biochemistry and Genetics, Biochemical Laboratory C, The Panum Institute, University of Copenhagen, Blegdamsvej 3, DK-2200 N Copenhagen, Denmark. troelsen@imbg.ku.dk
Mitchelmore
Cathy
C
Olsen
Jørgen
J
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001665:Binding Sites / Q000235:genetics; D018938:Caco-2 Cells / Q000378:metabolism*; D004268:DNA-Binding Proteins; D024202:Electrophoretic Mobility Shift Assay; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D006367:HeLa Cells / Q000378:metabolism; D051537:Hepatocyte Nuclear Factor 1; D051538:Hepatocyte Nuclear Factor 1-alpha; D051539:Hepatocyte Nuclear Factor 1-beta; D006801:Humans; D010694:Lactase-Phlorizin Hydrolase / Q000235:genetics*; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013552:Swine; D014157:Transcription Factors / Q000235:genetics / Q000276:immunology / Q000502:physiology
D000906:Antibodies; D004268:DNA-Binding Proteins; C496487:HNF1A protein, human; C496495:HNF1B protein, human; D051538:Hepatocyte Nuclear Factor 1-alpha; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D051537:Hepatocyte Nuclear Factor 1; D051539:Hepatocyte Nuclear Factor 1-beta; D008156:Luciferases; D010694:Lactase-Phlorizin Hydrolase