Human mediator subunit MED15 promotes transcriptional activation

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Author(s)

    • Nakatsubo Takuya
    • Laboratory of Gene Regulation, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
    • Nishitani Saori
    • Laboratory of Gene Regulation, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
    • Kikuchi Yuko
    • Laboratory of Gene Regulation, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
    • Iida Satoshi
    • Laboratory of Gene Regulation, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
    • Yamada Kana
    • Laboratory of Gene Regulation, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
    • Tanaka Aki
    • Laboratory of Gene Regulation, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
    • Ohkuma Yoshiaki
    • Laboratory of Gene Regulation, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama

Abstract

In eukaryotes, the Mediator complex is an essential transcriptional cofactor of RNA polymerase II (Pol II). In humans, it contains up to 30 subunits and consists of four modules: head, middle, tail, and CDK/Cyclin. One of the subunits, MED15, is located in the tail module, and was initially identified as Gal11 in budding yeast, where it plays an essential role in the transcriptional regulation of galactose metabolism with the potent transcriptional activator Gal4. For this reason, we investigated the function of the human MED15 subunit (hMED15) in transcriptional activation. First, we measured the effect of hMED15 knockdown on cell growth in HeLa cells. The growth rate was greatly reduced. By immunostaining, we observed the colocalization of hMED15 with the general transcription factors TFIIE and TFIIH in the nucleus. We measured the effects of siRNA-mediated knockdown of hMED15 on transcriptional activation using two different transcriptional activators, VP16 and SREBP1a. Treatment with siRNAs reduced transcriptional activation, and this reduction could be rescued by overexpression of HA/Flag-tagged, wild-type hMED15. To investigate hMED15 localization, we treated human MCF-7 cells with the MDM2 inhibitor Nutlin-3, thus inducing p21 transcription. We found that hMED15 localized to both the p53 binding site and the p21 promoter region, along with TFIIE and TFIIH. These results indicate that hMED15 promotes transcriptional activation.

Journal

  • Drug Discoveries & Therapeutics

    Drug Discoveries & Therapeutics 8(5), 212-217, 2014

    International Research and Cooperation Association for Bio & Socio-Sciences Advancement

Codes

  • NII Article ID (NAID)
    130004714671
  • Text Lang
    ENG
  • ISSN
    1881-7831
  • Data Source
    J-STAGE 
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