Sequence analysis and functional characterization of the 5'-flanking region of the rat multidrug resistance protein 2 (mrp2) gene.
Gene expression of the canalicular conjugate transporter mrp2 is inducible by treatment with the DNA-damaging agents 2-acetylaminofluorene (50 and 100 microM), and cisplatin (20 microM) in primary rat hepatocytes as well as in the rat hepatoma cell line H4IIE. Furthermore, phenobarbital (1 and 2 mM) induces mrp2 gene expression, probably explaining the increase in bile-salt-independent bile flow caused by phenobarbital, while the cholestatic drug ethinyl estradiol (10(-6) M) leads to an increase in mrp2 mRNA but decreases Mrp2 protein level probably via a posttranscriptional mechanism. The 5'-flanking region of the rat mrp2 gene was sequenced and cloned into a luciferase reporter vector. Transient transfection assays with reporter vectors containing unidirectionally deleted 5'-flanking regions using H4IIE cells indicate that two different sequences of 17 and 37 bases comprising a Y-Box and a GC-Box are required for mrp2 gene basal expression. Sequences mediating 2-AAF induction are located within a region 250 bases upstream of the translation start site while the inducing effect of phenobarbital seems to be mediated by another domain located further upstream.
Kauffmann
H M
HM
Institute of Food Chemistry and Environmental Toxicology, University of Kaiserslautern, Germany.
Schrenk
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D015073:2-Acetylaminofluorene / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D006528:Carcinoma, Hepatocellular / Q000737:chemistry*; D002945:Cisplatin / Q000494:pharmacology; D002994:Clofibrate / Q000494:pharmacology; D003001:Cloning, Molecular; D004997:Ethinyl Estradiol / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D019450:Genes, MDR / Q000235:genetics*; D017930:Genes, Reporter / Q000235:genetics; D010634:Phenobarbital / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017422:Sequence Analysis, DNA; D014162:Transfection / Q000235:genetics; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger; D004997:Ethinyl Estradiol; D015073:2-Acetylaminofluorene; D002994:Clofibrate; D002945:Cisplatin; D010634:Phenobarbital