Abstract
Diacylglycerol acyltransferase 2 (DGAT2) catalyzes the final step of triacylglycerol (TG) synthesis. Despite the existence of an alternative acyltransferase (DGAT1), mice lacking DGAT2 have a severe deficiency of TG in adipose tissue, indicating a nonredundant role for this enzyme in adipocyte TG synthesis. We have studied the regulation of DGAT2 expression during adipogenesis. In both isolated murine preadipocytes and 3T3-L1 cells the temporal pattern of DGAT2 expression closely mimicked that of genes whose expression is regulated by CAAT/enhancer-binding protein beta (C/EBP beta). Inhibition of C/EBP beta expression in differentiating preadipocytes reduced DGAT2 expression, and electrophoretic mobility shift assay and chromatin immunoprecipitation experiments identified a promoter element in the DGAT2 gene that is likely to mediate this effect. The importance of C/EBP beta in adipocyte expression of DGAT2 was confirmed by the finding of reduced DGAT2 expression in the adipose tissue of C/EBP beta-null animals. However, DGAT2 expression is maintained at high levels during the later stages of adipogenesis, when C/EBP beta levels decline. We show that, at these later stages of differentiation, C/EBP alpha is capable of substituting for C/EBP beta at the same promoter element. These observations provide novel insight into the transcriptional regulation of DGAT2 expression. Moreover, they further refine the complex and serial roles of the C/EBP family of transcription factors in inducing and maintaining the metabolic properties of mature adipocytes.
Original language | English |
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Pages (from-to) | 21005-21014 |
Number of pages | 10 |
Journal | The Journal of Biological Chemistry |
Volume | 282 |
Issue number | 29 |
Early online date | 14 May 2007 |
DOIs | |
Publication status | Published - 20 Jul 2007 |
Keywords
- adipocyte differentiation
- mice lacking
- 3T3-L1 preadipocytes
- hepatic steaosis
- gene-expression
- adipose-tissue
- ppar-gamma
- in-vitro
- beta
- activation