title: Involvement of CREM in CYP1A1 induction through ligand-independent activation pathway of aryl hydrocarbon receptor in HepG2 cells.
abstract: Using a radiation-hybrid cell, E11, produced by the fusion of Hepa-1c1c7 and X-ray irradiated HepG2 cells, we located the omeprazole (OP) responsive region on chromosome 10p. The cDNA of 12 genes expressed in E11 cells were cloned from HepG2 mRNA by RT-PCR. The cDNA was transfected into Hepa-1c1c7 cells to check the increased expression of Cyp1a1 by reporter gene (luciferase) assay. Finally, one gene (tauCREM: cAMP responsive element modulator, tau-isoform) was identified as a candidate gene for the gene responsive to OP. The regulatory sequence of Cyp1a1 in response to tauCREM transfection was identified in one region (-60 to -52bp relative to the transcription start site), which was the basic transcription element (BTE). Electromobility shift assay with the BTE sequence showed an increase in the band intensity when the cells were treated with OP. Decreased level of endogenous CREM by siRNA transfection inhibited the induction of CYP1A1-mRNA in HepG2 cells by OP.
authors.affiliation: Division of Cell Technology, Department of Biochemistry and Biotechnology, Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Aomori Prefecture, Hirosaki 036-8561, Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Sasamori
authors.forename: Shuji
authors.initials: S
authors.lastname: Shimoyama
authors.forename: Shinichi
authors.initials: S
authors.lastname: Fukushige
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kikuchi
mesh_terms: D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D051786:Cyclic AMP Response Element Modulator / Q000378:metabolism*; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D006657:Histones / Q000737:chemistry; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008024:Ligands; D010957:Plasmids / Q000378:metabolism; D020033:Protein Isoforms; D034741:RNA, Small Interfering / Q000378:metabolism; D018336:Receptors, Aryl Hydrocarbon / Q000737:chemistry*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
chemical_list: C497410:CREM protein, human; D018076:DNA, Complementary; D006657:Histones; D008024:Ligands; D020033:Protein Isoforms; D034741:RNA, Small Interfering; D018336:Receptors, Aryl Hydrocarbon; D051786:Cyclic AMP Response Element Modulator; D019363:Cytochrome P-450 CYP1A1