FIGURE 2.

Expression of the adipocyte phenotype in MEF-3T3 cells transduced with expression constructs for wild type C/EBPβ and mutants that no longer bind HuR. MEF-3T3 cells were transduced with pRevTRE expression vector containing either the C/EBPβ cDNA or constructs altered at the HuR binding site (Fig. 1A). Expression of the constructs was up-regulated by removal of doxycycline from the culture medium, and the cells were induced to differentiate as described under “Experimental Procedures.” Cultures maintained in doxycycline resulted in suppression of construct expression and served as the negative controls. At day 8 post-induction of differentiation, the accumulated triacylglycerol in the cells was stained with oil red O. The data presented are representative of an experiment performed independently at least four times.