TY - JOUR
T1 - Peroxisome Proliferator-Activated Receptor γ and C/EBPα Synergistically Activate Key Metabolic Adipocyte Genes by Assisted Loading
AU - Madsen, Maria Stahl
AU - Siersbæk, Rasmus
AU - Boergesen, Michael
AU - Nielsen, Ronni
AU - Mandrup, Susanne
PY - 2014
Y1 - 2014
N2 - Peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBPα) are key activators of adipogenesis. They mutually induce the expression of each other and have been reported to cooperate in activation of a few adipocyte genes. Recently, genome-wide profiling revealed a high degree of overlap between PPARγ and C/EBPα binding in adipocytes, suggesting that cooperativeness could be mediated through common binding sites. To directly investigate the interplay between PPARγ and C/EBPα at shared binding sites, we established a fibroblastic model system in which PPARγ and C/EBPα can be independently expressed. Using RNA sequencing, we demonstrate that coexpression of PPARγ and C/EBPα leads to synergistic activation of many key metabolic adipocyte genes. This is associated with extensive C/EBPα-mediated reprogramming of PPARγ binding and vice versa in the vicinity of these genes, as determined by chromatin immunoprecipitation combined with deep sequencing. Our results indicate that this is at least partly mediated by assisted loading involving chromatin remodeling directed by the leading factor. In conclusion, we report a novel mechanism by which the key adipogenic transcription factors, PPARγ and C/EBPα, cooperate in activation of the adipocyte gene program.
AB - Peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBPα) are key activators of adipogenesis. They mutually induce the expression of each other and have been reported to cooperate in activation of a few adipocyte genes. Recently, genome-wide profiling revealed a high degree of overlap between PPARγ and C/EBPα binding in adipocytes, suggesting that cooperativeness could be mediated through common binding sites. To directly investigate the interplay between PPARγ and C/EBPα at shared binding sites, we established a fibroblastic model system in which PPARγ and C/EBPα can be independently expressed. Using RNA sequencing, we demonstrate that coexpression of PPARγ and C/EBPα leads to synergistic activation of many key metabolic adipocyte genes. This is associated with extensive C/EBPα-mediated reprogramming of PPARγ binding and vice versa in the vicinity of these genes, as determined by chromatin immunoprecipitation combined with deep sequencing. Our results indicate that this is at least partly mediated by assisted loading involving chromatin remodeling directed by the leading factor. In conclusion, we report a novel mechanism by which the key adipogenic transcription factors, PPARγ and C/EBPα, cooperate in activation of the adipocyte gene program.
U2 - 10.1128/MCB.01344-13
DO - 10.1128/MCB.01344-13
M3 - Journal article
C2 - 24379442
VL - 34
SP - 939
EP - 954
JO - Molecular and Cellular Biology
JF - Molecular and Cellular Biology
SN - 0270-7306
IS - 6
ER -