Abstract
Rosiglitazone (rosi) is a powerful insulin sensitizer, but serious toxicities have curtailed its widespread clinical use. Rosi functions as a high-affinity ligand for peroxisome proliferator-activated receptor γ (PPARγ), the adipocyte-predominant nuclear receptor (NR). The classic model, involving binding of ligand to the NR on DNA, explains positive regulation of gene expression, but ligand-dependent repression is not well understood. We addressed this issue by studying the direct effects of rosi on gene transcription using global run-on sequencing (GRO-seq). Rosi-induced changes in gene body transcription were pronounced after 10 min and correlated with steady-state mRNA levels as well as with transcription at nearby enhancers (enhancer RNAs [eRNAs]). Up-regulated eRNAs occurred almost exclusively at PPARγ-binding sites, to which rosi treatment recruited coactivators, including MED1, p300, and CBP. In contrast, transcriptional repression by rosi involved a loss of coactivators from eRNA sites devoid of PPARγ and enriched for other transcription factors, including AP-1 factors and C/EBPs. Thus, rosi activates and represses transcription by fundamentally different mechanisms that could inform the future development of anti-diabetic drugs.
Original language | English |
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Journal | Genes & Development |
Volume | 28 |
Issue number | 9 |
Pages (from-to) | 1018-28 |
Number of pages | 11 |
ISSN | 0890-9369 |
DOIs | |
Publication status | Published - 1 May 2014 |
Externally published | Yes |
Keywords
- 3T3-L1 Cells
- Adipocytes/drug effects
- Animals
- Gene Expression Regulation/drug effects
- Humans
- Hypoglycemic Agents/pharmacology
- Mediator Complex Subunit 1/metabolism
- Mice
- PPAR gamma/metabolism
- Protein Binding
- Thiazolidinediones/pharmacology
- Transcriptome