Involvement of activator protein 1 complexes in the epithelium-specific activation of the laminin gamma2-chain gene promoter by hepatocyte growth factor (scatter factor).
Laminin-5 is a trimer of laminin alpha3, beta3 and gamma2 chains that is found in the intestinal basement membrane. Deposition of the laminin gamma2 chain at the basement membrane is of great interest because it undergoes a developmental shift in its cellular expression. Here we study the regulatory elements that control basal and cytokine-activated transcriptional expression of the LAMC2 gene, which encodes the laminin gamma2 chain. By using transient transfection experiments we demonstrated the presence of constitutive and cytokine-responsive cis-elements. Comparison of the transcriptional activity of the LAMC2 promoter in the epithelial HT29mtx cells with that in small-intestinal fibroblastic cells (C20 cells) led us to conclude that two regions with constitutive epithelium-specific activity are present between positions -1.2 and -0.12 kb. This was further validated by transfections of primary foetal intestinal endoderm and mesenchyme. A 2.5 kb portion of the LAMC2 5' flanking region was equally responsive to PMA and hepatocyte growth factor (HGF), whereas it was less responsive to transforming growth factor beta1. A minimal promoter limited to the initial 120 bp upstream of the transcriptional start site maintained inducibility by PMA and HGF. This short promoter fragment contains two activator protein 1 (AP-1) elements and the 5'-most of these is a composite AP-1/Sp1 element. The 5'AP-1 element is crucial to the HGF-mediated activity of the promoter; analysis of interacting nuclear proteins demonstrated that AP-1 proteins containing JunD mediate the response to HGF.
Olsen
J
J
INSERM U.381, 3 avenue Molière, 67200 Strasbourg, France. jolsen@biobase.dk
Lefebvre
O
O
Fritsch
C
C
Troelsen
J T
JT
Orian-Rousseau
V
V
Kedinger
M
M
Simon-Assmann
P
P
D001483:Base Sequence; D002460:Cell Line; D004247:DNA / Q000235:genetics / Q000378:metabolism; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D019281:Dimerization; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D017228:Hepatocyte Growth Factor / Q000494:pharmacology*; D006801:Humans; D007797:Laminin / Q000235:genetics*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009154:Mutation; D009928:Organ Specificity; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D020218:Response Elements / Q000235:genetics; D016329:Sp1 Transcription Factor / Q000378:metabolism; D051705:Sp3 Transcription Factor; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D015533:Transcriptional Activation / Q000187:drug effects*; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D053773:Transforming Growth Factor beta1
D004268:DNA-Binding Proteins; C400567:LAMC2 protein, human; D007797:Laminin; D046911:Macromolecular Substances; D016755:Proto-Oncogene Proteins c-jun; D016329:Sp1 Transcription Factor; C508960:TGFB1 protein, human; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D051705:Sp3 Transcription Factor; D017228:Hepatocyte Growth Factor; D004247:DNA; D003850:Deoxyribonuclease I; D013755:Tetradecanoylphorbol Acetate