Krüppel-like factor 5 (Klf5) regulates expression of mouse T1R1 amino acid receptor gene (<i>Tas1r1</i>) in C2C12 myoblast cells

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Author(s)

    • HIRATA Yuki
    • Division of Oral Reconstruction and Rehabilitation, Department of Oral Functions, Kyushu Dental University
    • TOYONO Takashi
    • Division of Anatomy, Department of Health Promotion, Kyushu Dental University
    • KOKABU Shoichiro
    • Division of Molecular Signaling and Biochemistry, Department of Health Promotion, Kyushu Dental University
    • OBIKANE Yui
    • Division of Oral Reconstruction and Rehabilitation, Department of Oral Functions, Kyushu Dental University
    • KATAOKA Shinji
    • Division of Anatomy, Department of Health Promotion, Kyushu Dental University
    • MASAKI Chihiro
    • Division of Oral Reconstruction and Rehabilitation, Department of Oral Functions, Kyushu Dental University
    • HOSOKAWA Ryuji
    • Division of Oral Reconstruction and Rehabilitation, Department of Oral Functions, Kyushu Dental University
    • SETA Yuji
    • Division of Anatomy, Department of Health Promotion, Kyushu Dental University

Abstract

<p>T1R1 and T1R3 are receptors expressed in taste buds that detect L-amino acids. These receptors are also expressed throughout diverse organ systems, such as the digestive system and muscle tissue, and are thought to function as amino acid sensors. The mechanism of transcriptional regulation of the mouse T1R1 gene (<i>Tas1r1)</i> has not been determined; therefore, in this study, we examined the function of <i>Tas1r1</i> promoter in the mouse myoblast cell line, C2C12. Luciferase reporter assays showed that a 148-bp region upstream of the ATG start codon of <i>Tas1r1</i> had a promoter activity. The GT box in the <i>Tas1r1</i> promoter was conserved in the dog, human, mouse, and pig. Site-directed mutagenesis of this GT box significantly reduced the promoter activation. The GT box in promoters is a recurring motif for Sp/KLF family members. RNAi-mediated depletion of Sp4 and Klf5 decreased <i>Tas1r1</i> expression, while overexpression of Klf5, but not Sp4, significantly increased <i>Tas1r1</i> expression. The ENCODE data of chromatin immunoprecipitation and sequencing (ChIP-seq) showed that Klf5 bound to the GT box during the myogenic differentiation. Furthermore, the <i>Klf5</i> knockout cell lines led to a considerable decrease in the levels of<i> Tas1r1</i> expression. Collectively, these results showed that Klf5 binds to the GT box in the <i>Tas1r1</i> promoter and regulates <i>Tas1r1</i> expression in C2C12 cells.</p>

Journal

  • Biomedical Research

    Biomedical Research 40(2), 67-78, 2019

    Biomedical Research Press

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