FIGURE 6.

The adipocyte-specific Retn enhancer is not directly involved in the suppression of Retn mRNA by synthetic ligand for PPARγ. A, luciferase activity of empty or Retn enhancer (–8872 to –8676 bp) reporter constructs treated with or without 1 μm rosiglitazone (rosi) for 48 h in 3T3-L1 adipocytes. B, luciferase activity of empty or Retn enhancer (–8872 to –8676 bp) reporter constructs cotransfected with C/EBPα and PPARγ/RXRα expression vectors into HEK 293T cells with or without 1 μm rosi for 24 h. C, 3T3-L1 adipocytes were treated with DMSO or 1 μm rosi for 48 h, and 5 μg/ml of actionomycin D were added. RNA was extracted at the indicated time points. Retn mRNA levels were corrected by Arbp expression and plotted as log₂. D, 3T3-L1 adipocytes were treated with DMSO or 1 μm rosi for 48 h, and the Retn pre-mRNA levels were measured as described under “Materials and Methods.” Each value represents the mean ± S.E. (n = 3 per condition).