FIGURE 4.

ChIP analysis of LXR binding to the apoE gene in response to the treatment with PPARγ ligands. 3T3-L1 cells were treated with 10 μg 22-OHch or ciglitazone (Cig)(A) or rosiglitazone (Rosi)(B) for 48 h and then harvested for ChIP analysis as described under “Experimental Procedures.” After immunoprecipitation, a 152-bp amplicon of the apoE enhancer containing the LXRE was amplified by PCR. The amount of LXR bound to the LXR enhancer was assessed using real-time PCR to quantitate immunoisolated DNA. Representative images of agarose gels show RNA polymerase II binding to the GAPDH promoter (as an internal control) and LXR binding to apoE. The real-time PCR results are mean ± S.D. from three different ChIP analyses, each done in triplicate. *, p < 0.05 compared with untreated control.