Zac1 significantly enhances the S100A7 promoter activity driven by heterodimeric AP-1 complexes.

The schematic presentation of the luciferase reporter driven by S100A7 promoter containing two putative AP-1 binding sites is shown at the upper panel. Although previously we have demonstrated that Zac1 can physically interact with each of c-Jun, c-Fos and Fra-1, the S100A7 promoter activity can only be mildly enhanced by over-expressed Zac1 itself (lane 1; compare open to closed bar) or together with co-expressed c-Jun, c-Fos, or Fra-1 (compare lanes 2–4 to lane 1; open bars to closed bars), respectively. However, the S100A7 promoter activity driven by heterodimeric AP-1 complexes formed by c-Jun/c-Fos or c-Jun-Fra-1 paring is significantly enhanced by co-expressed Zac1 (lanes 5 and 6; compare open to closed bars). These data are the average of three experiments (mean ± SD; n = 3). All p values less than 0.05 were considered statistically significant.