(A) Schematic representation of MT constructs used for the luciferase reporter assay. A and B1 represent region A and the region B1 of the promoter, respectively. , WT promoter; , MT1 promoter; and , MT2 promoter. (B–D) Effect of PMA on the H1R promoter activity. HeLa cells were cotransfected with the MT plasmid and pRL-MPK. After 5 h, cells were serum-starved for 24 h and then treated with 100 nM of PMA for 10 h. (E) Effect of histamine on the H1R promoter activity. Cells were treated with 100 μM histamine for 10 h. Data are presented as mean ± S.E.M. [n = 5 (B), 6 (C and D), and 8 (E)]. **, p < 0.05 vs p1137 (B) or p65 (C and D). In E, **, p < 0.05 vs. p1137; ##, p < 0.05 vs. p65.