title: Effect of a negative regulatory element (NRE) on the human CYP1A1 gene expression in breast carcinoma MCF-7 and hepatoma HepG2 cells.
abstract: The expression of the cytochrome P4501A1 gene, CYP1A1, is induced by e.g. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) mainly by transcriptional mechanisms. The inducers mediate their effect upon binding and activation of the aryl hydrocarbon receptor (AHR) transcription-factor complex. Utilizing chimeric CYP1A1/CAT constructs transient gene expression experiments indicate that the putative negative regulatory element (NRE) of CYP1A1 influence the relative TCDD induced CAT activity in HepG2 cells, whereas this effect was not observed in MCF-7 cells. Differences in the formation of cell-specific protein-DNA complexes were demonstrated by gel retardation assays suggesting a functional difference of NRE in these two cell lines.
authors.affiliation: Department of Environmental and Occupational Medicine, University of Aarhus, Denmark.
authors.forename: E C
authors.initials: EC
authors.lastname: Jørgensen
authors.forename: H
authors.initials: H
authors.lastname: Autrup
mesh_terms: D001483:Base Sequence; D001943:Breast Neoplasms; D006528:Carcinoma, Hepatocellular; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000235:genetics*; D004273:DNA, Neoplasm / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D008113:Liver Neoplasms; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D014158:Transcription, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D004273:DNA, Neoplasm; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D003577:Cytochrome P-450 Enzyme System; D015500:Chloramphenicol O-Acetyltransferase