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. 2009 Aug 3;284(40):27042–27053. doi: 10.1074/jbc.M109.047340

FIGURE 5.

FIGURE 5.

IsoNAM enhances binding of AP-1 to the PEPCK-C gene promoter. Panel A, an EMSA of the purified AP-1 components bound to the overlapping HNF4α site-2/AP-1 region in the PEPCK-C gene promoter. Panel B, purified AP-1 and HNF4α compete for the overlapping HNF4α site-2/AP-1 region in the PEPCK-C gene promoter. Panel C, IsoNAM enhanced the interaction of AP-1, but decreased the binding of HNF4α, to the PEPCK-C gene promoter. HepG2 cells were treated 5 mm IsoNAM for 10 h. A ChIP assay was used to monitor the binding of AP-1, HNF4α, and C/EBPβ to the overlapping HNF4α site-2/AP-1 region (target region). Panel D, AP-1 and HNF4α competitively regulated the CRE-mutated PEPCK-C gene promoter. HepG2 cells were co-transfected with a CRE-mutated p2000-Luc plasmid and with 0.05 and 0.1 μg of plasmids expressing HNF4α or AP-1 and luciferase activity was measured. The values are expressed as the mean ± S.E. of triplicate measurements. *, p < 0.05 and **, p < 0.01. BSA, bovine serum albumin.