C/EBPalpha regulates SIRT1 expression during adipogenesis.
SIRT1 plays an important role in adipogenesis, but how SIRT1 is regulated in adipogenesis is largely unknown. In this study, we show that both SIRT1 protein and mRNA levels were increased along with CCAAT/enhancer-binding protein alpha (C/EBPalpha) during adipocyte differentiation. C/EBPalpha, but not C/EBPalphap30, activated SIRT1 promoter in both HeLa cells and 3T3-L1 preadipocytes. Furthermore, C/EBPalpha upregulated SIRT1 mRNA and protein levels in HeLa cells and increased SIRT1 expression in a p53-independent manner in Soas2 cells. In preadipocytes, ectopic expression of C/EBPalpha upregulated SIRT1 protein level and knockdown of C/EBPalpha led to the decrease of SIRT1 protein level. Moreover, by promoter deletion analysis, gel shift assay and chromatin immunoprecipitation, we found that C/EBPalpha bound to the SIRT1 promoter at a consensus C/EBPalpha binding site. These data demonstrate that C/EBPalpha regulates SIRT1 expression during adipogenesis by directly binding to the SIRT1 promoter.
Jin
Qihuang
Q
Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
Zhang
Fang
F
Yan
Tingting
T
Liu
Zhen
Z
Wang
Chunxi
C
Ge
Xinjian
X
Zhai
Qiwei
Q
D041721:3T3-L1 Cells; D050156:Adipogenesis; D000818:Animals; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D002460:Cell Line; D047369:Chromatin Immunoprecipitation; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D056564:Sirtuin 1 / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D022763:CCAAT-Enhancer-Binding Protein-alpha; D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53; C447939:SIRT1 protein, human; D056564:Sirtuin 1