Roles of proteasomal 19S regulatory particles in promoter loading of thyroid hormone receptor.
19S regulatory particles (19SRP) of 26S proteasome participate in multiple steps of gene transcription in yeast. We previously showed that Tat-binding protein-1 (TBP-1), an ATPase of 19SRP, interacts with thyroid hormone receptor (TR) and enhances TR-mediated transcription synergistically with steroid receptor coactivator-1 (SRC-1). To further elucidate the roles of ATPases and a non-ATPase component of 19SRP in gene regulation by TR, we investigated whether knockdown (KO) of TBP-1, TRIP1 or Rpn10 using small interfering RNA affects TR-mediated transactivation in HeLa cells. KO of individual subunits attenuated TR-mediated transactivation through the thyroid hormone response element (TRE) in the absence or presence of cotransfected SRC-1 without altering TR and SRC-1 protein levels. KO of TBP-1 disrupted ligand-induced loading of TR, SRC-1, and RNA polymerase II in chromatin immunoprecipitation assays. Collectively, both ATPase and non-ATPase components of 19SRP play critical roles in TR-mediated transactivation by coordinating the proper loading of liganded TR to TRE.
Satoh
Tetsurou
T
Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, 3-39-15 Showa-machi, Maebashi 371-8511, Japan. tsato@showa.gunma-u.ac.jp
Ishizuka
Takahiro
T
Yoshino
Satoshi
S
Tomaru
Takuya
T
Nakajima
Yasuyo
Y
Shibusawa
Nobuyuki
N
Hashimoto
Koshi
K
Yamada
Masanobu
M
Mori
Masatomo
M
D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D039621:Eukaryotic Initiation Factor-3 / Q000378:metabolism; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D011401:Promoter Regions, Genetic; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins; D011988:Receptors, Thyroid Hormone / Q000378:metabolism*; D015533:Transcriptional Activation
D039621:Eukaryotic Initiation Factor-3; C498506:PSMD4 protein, human; D016601:RNA-Binding Proteins; D011988:Receptors, Thyroid Hormone; C096013:EIF3I protein, human; D046988:Proteasome Endopeptidase Complex; D000251:Adenosine Triphosphatases; D000074183:ATPases Associated with Diverse Cellular Activities; C064757:PSMC3 protein, human