AP-2-mediated regulation of human NAD(P)H: quinone oxidoreductase 1 (NQO1) gene expression.
NAD(P)H:quinone oxidoreductase 1 (NQO1) is a flavoprotein that catalyzes two-electron reduction and detoxification of quinones. We have shown previously that twenty-four base pairs of the human Antioxidant Response Element (hARE) mediate basal and xenobiotic-induced expression of the NQO1 gene [Li and Jaiswal, J Biol Chem 267: 15097-15104, 1992]. In the present report, we have characterized a second cis-element, AP-2, at nucleotide position -157 of the human NQO1 gene promotor that regulates basal and cAMP-induced transcription of the NQO1 gene. The NQO1 gene AP-2 mediated expression of the chloramphenicol acetyl transferase (CAT) gene and the binding of nuclear proteins to the AP-2 element were observed in HeLa (AP-2 positive) cells but not in human hepatoblastoma Hep-G2 (AP-2 deficient) cells, indicating the involvement of transcription factors AP-2 in the regulation of NQO1 gene expression. Affinity purification of nuclear protein that binds to the NQO1 gene AP-2 DNA element and western analysis revealed that AP-2 indeed binds to the NQO1 gene AP-2 element and regulates its expression HeLa cells. The involvement of AP-2 in the regulation of NQO1 gene expression was confirmed by the observation that cDNA-derived AP-2 protein in Hep-G2 cells increased in NQO1 gene AP-2 but not mutant AP-2 mediated expression of CAT gene in Hep-G2 cells.
Xie
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Department of Pharmacology, Fox Chase Cancer Center, Philadelphia, PA. 19111, USA.
Jaiswal
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AK
D001483:Base Sequence; D001665:Binding Sites; D002454:Cell Differentiation / Q000502:physiology; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D000242:Cyclic AMP / Q000502:physiology; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D006367:HeLa Cells; D018197:Hepatoblastoma / Q000235:genetics; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000502:physiology*; D014162:Transfection
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D000242:Cyclic AMP; D016660:NAD(P)H Dehydrogenase (Quinone); D015500:Chloramphenicol O-Acetyltransferase