title: A cluster region of AP-1 responsive elements is required for transcriptional activity of mouse ODC gene by hepatocyte growth factor.
abstract: Ornithine decarboxylase (ODC) activity is regulated by a variety of mechanisms including transcription, translation, and RNA and protein half-life. Since in mouse B16-F1 melanoma cells an early and remarkable (about 6-fold) increase in steady state mRNA levels was observed after hepatocyte growth factor (HGF) treatment, we investigated the transcriptional regulation of mouse ODC promoter. Transient transfection of various ODC-luciferase promoter constructs into the B16-Fl cells in combination with electrophoretic mobility shift assays identified the HGF-responsive element as a cluster of three AP-1 binding sites (-1660 to -1572). Even if each site differs from the canonical TPA responsive element for one nucleotide, only the first two AP-1 consensus sequences seemed to be functional since allowed DNA-binding activity of nuclear proteins after HGF treatment. Comparison of the results of transfection assays with the pOD2.5-luc (2.5 kb gene fragment) and with the construct deprived of the AP-1 cluster pOD-B-luc showed that this 50 bp region was required for ODC transactivating activity in response to HGF. Since in B16-F1 cells HGF increased AP-1 activity and the mRNA expression of various AP-1 subunits, we may conclude that HGF-induced transcription of mouse ODC was largely due to triggering of AP-1 pathway.
authors.affiliation: Institute of General Pathology and C.N.R. Center for Research on Cell Pathology, University of Milano, School of Medicine, via L. Mangiagalli, 31-20133 Milan, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Bianchi
authors.forename: Lorenza
authors.initials: L
authors.lastname: Tacchini
authors.forename: Emanuela
authors.initials: E
authors.lastname: Matteucci
authors.forename: Maria Alfonsina
authors.initials: MA
authors.lastname: Desiderio
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D016384:Consensus Sequence; D004273:DNA, Neoplasm / Q000378:metabolism; D015870:Gene Expression; D017228:Hepatocyte Growth Factor / Q000494:pharmacology*; D007700:Kinetics; D008546:Melanoma, Experimental / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009955:Ornithine Decarboxylase / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects; D014407:Tumor Cells, Cultured
chemical_list: D004273:DNA, Neoplasm; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D018808:Transcription Factor AP-1; D017228:Hepatocyte Growth Factor; D009955:Ornithine Decarboxylase