FIGURE 4.

CREMα binding reduces IL17F promoter activity. A, alignment of the CRE consensus sequence with the CRE site (−127/−123) of the proximal human IL17F promoter. The schematic on the right displays IL17F reporter plasmids used for luciferase assays (636 and 166 bp). IL17F_p(−166mut)_luc indicates a reporter plasmid containing a site-directed mutation at the CRE site (−127/−123). B, human Jurkat T cells were transfected with the empty pGL3-Basic reporter (black bar) or the IL17F promoter-driven reporter plasmids (gray bars). Cells were collected 5 h after transfection, and firefly luciferase activity was measured and normalized by Renilla luciferase activity. n = 3 independent experiments. C, human Jurkat T cells were co-transfected with the indicated reporter constructs and either pcDNA3 empty vector (EV; black bars) or CREMα expression plasmid (gray bars). For each reporter, pcDNA3 empty vector (EV) co-transfection was set to 1.0, and the relative effect mediated by CREMα was calculated. Each experiment was performed three times, and values are given as mean ± S.D. D, mutation of the CRE site (−127/−123) results in a significantly increased spontaneous promoter activity. n = 3 independent experiments.