Abstract
During adipocyte differentiation, CCAAT/enhancer-binding protein α (C/EBPα) functions as a pleiotropic transcriptional activator of numerous adipocyte genes. The promoter of the C/EBPα gene has an E-box upstream of C/EBP binding site. Deletion or mutation of the E-box decreases promoter activity, suggesting that the E-box participates in the regulation of C/EBPα expression. Protein binding to the E-box during the adipocyte differentiation is increased as indicated by EMSA and UV cross-linking. Purification of the E-box binding proteins from differentiated 3T3-L1 adipocytes, showed that USF and AP-4 are associated with the E-box. Supershift analysis showed that USF1 and USF2 bind to this element as heterodimers, whereas the addition of anti-AP-4 antibody enhanced the binding complex, suggesting that AP-4 negatively regulates the promoter activity. The expression of AP-4 is reciprocally regulated with USF-1 during adipocyte differentiation. These findings suggest that USF-1 and 2 play roles in C/EBPα expression, whereas the AP-4 represses it.
Original language | English (US) |
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Pages (from-to) | 517-521 |
Number of pages | 5 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 354 |
Issue number | 2 |
DOIs | |
State | Published - Mar 9 2007 |
Keywords
- AP-4
- Adipocyte differentiation
- C/EBPα
- DNA binding activity
- E-box
- Promoter
- USF
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology
- Cell Biology