The gut-enriched Kruppel-like factor suppresses the activity of the CYP1a1 promoter in an Sp1-dependent fashion

Weiqing Zhang, Janiel M. Shields, Kazuhiro Sogawa, Yoshiaki Fujii-Kuriyama, Vincent W. Yang

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    112 Citations (Scopus)

    Abstract

    The gut-enriched Kruppel-like factor (GKLF) is a newly identified zinc finger-containing transcription factor. Recent studies indicate that GKLF binds to a core DNA sequence of 5'-(G/A)(G/A)GG(C/T)G(C/T)-3', which is found in an endogenous cis element, the basic transcription element (BTE) of the cytochrome P-450IA1 (CYP1A1) promoter. The present study characterizes the ability of GKLF to regulate CYP1A1 expression. By electrophoretic mobility gel shift assay (EMSA) and methylation interference assay, GKLF was found to bind BTE in a manner similar to several other transcription factors known to interact with BTE including Sp1 and BTEB. Cotransfection studies in Chinese hamster ovary cells showed that GKLF inhibited the CYP1A1 promoter in a dose- and BTE-dependent manner. The same experiments also revealed that BTE was responsible for a significant portion of the CYP1A1 promoter activity. EMSA of nuclear extracts from Chinese hamster ovary cells showed that Sp1 and Sp3 were two major proteins that interacted with BTE. Additional cotransfection studies showed that GKLF inhibited Sp1-mediated activation of the CYP1A1 promoter. In contrast, GKLF enhanced Sp3-dependent suppression of the same promoter. Moreover, the ability of GKLF to inhibit Sp1-dependent transactivation was in part due to physical interaction of the two proteins. These findings indicate that GKLF is a negative regulator of the CYP1A1 promoter in a BTE-dependent fashion and that this inhibitory effect is in part mediated by physical interaction with Sp1.

    Original languageEnglish
    Pages (from-to)17917-17925
    Number of pages9
    JournalJournal of Biological Chemistry
    Volume273
    Issue number28
    DOIs
    Publication statusPublished - 1998 Jul 10

    ASJC Scopus subject areas

    • Biochemistry
    • Molecular Biology
    • Cell Biology

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