5'TG3' interacting factor interacts with Sin3A and represses AR-mediated transcription.
Like other nuclear receptors, the AR exerts its transcriptional function by binding to cis elements upstream of promoters and interacting with other transcriptional factors (e.g. activators, repressors, and modulators). Among them, histone acetyltransferases (HATs) and histone deacetylases (HDACs) play critical roles in altering the acetylation state of core histones, thereby regulating nuclear hormone receptor-mediated transcription. The nuclear receptor corepressor can repress the TR and RAR in the absence of ligand through either a Sin3A-dependent or -independent manner by recruiting HDACs. AR and some other steroid hormone receptors cannot silence transcription through a similar mechanism in that they are located in the cytoplasm as complexes with heat-shock proteins before exposure to ligand. It has been shown that AR can bind to p160/SRC, cAMP response element-binding protein-binding protein (CBP)/P300 and other coactivators to increase the AR-mediated transcription. However, the molecular mechanism for turning AR from transcriptionally active into silent states is unknown. In this study, we demonstrated that the transcription repressor, 5'TG3' interacting factor (TGIF), selectively represses AR-mediated transcription from several AR-responsive promoters. The repression is mediated through binding of TGIF to the DNA binding domain of AR and is trichostatin sensitive. We also identified a direct protein-protein interaction between TGIF and a transcription corepressor, Sin3A, which suggests a novel pathway for TGIF recruiting HDAC1 to the repression complex. These results provide fresh insight into understanding the mechanism for repressing AR-, and perhaps other steroid hormone receptor-, mediated transcriptions.
Sharma
M
M
Department of Surgery, Stanford University School of Medicine, Stanford, California 94305, USA.
Sun
Z
Z
D000818:Animals; D001665:Binding Sites; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D056284:Histone Deacetylase 1; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D008297:Male; D025941:Protein Interaction Mapping; D011944:Receptors, Androgen / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D056264:Sin3 Histone Deacetylase and Corepressor Complex; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D018398:Homeodomain Proteins; D006877:Hydroxamic Acids; D011944:Receptors, Androgen; D012097:Repressor Proteins; C099683:SIN3A transcription factor; C097504:TGIF1 protein, human; D014157:Transcription Factors; C012589:trichostatin A; C110550:HDAC1 protein, human; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases; D056264:Sin3 Histone Deacetylase and Corepressor Complex