Figure 2.

A PPARγ ligand rescues the inhibition of adipogenesis by dominant-negative ADD1/SREBP1. 3T3-L1 preadipocytes were infected with retroviruses containing either empty vector, ADD1, or dominant-negative ADD1 (ADD1-DN) as previously described (23). 3T3-L1-vector, -ADD1, and -ADD1-DN cell lines were treated with differentiation inducers in the absence (DMI/-TZD) or presence (DMI/+TZD) of the TZD ligand pioglitazone (5 μM) for 48 hr at confluence and subsequently cultured for 5 days. Cells were fixed and stained with Oil Red O. (A) Macroscopic view of dishes. (B) Microscopic views of dishes shown in A at ×25 original magnification. (C) Total RNA (10 μg per lane) was isolated from each cell lines at confluence (−) and after 5 days of postconfluent culture with treatment of either DMI/-TZD or DMI/+TZD. RNA was separated by electrophoresis, blotted to nylon membrane, and hybridized with the indicated ³²P-labeled cDNAs.