FIG 4.

A TLR9 promoter region containing the three NF-B-responsive elements A, B, and C is required for UV-induced TLR9 transcriptional activation. (A) Schematic diagram of the three TLR9 promoter luciferase (Luc) constructs: the full-length (−3227/−1) construct containing four NF-κB REs (A, B, C, and D) and the two deleted (−1017/−1 and −290/-1) constructs. (B) NIKS cells were transfected with these TLR9 promoter constructs cloned in front of a luciferase reporter gene. After 40 h, the cells were either UVB irradiated at a dose of 25 mJ/cm² (UVB+) or mock irradiated (UVB−), and then cultured in a humidified chamber for 8 h at 37°C. The cells were then harvested; their luciferase activities were measured and are expressed as percent relative luminescence units (% RLU). The data shown are the means from three independent experiments performed in triplicate. **, P < 0.01; ns, not significant.