Transactivation of the HIAP-1 promoter by the HTLV-1 Tax protein. (A) Overview of the HIAP-1 promoter and deletion variants. The potential NF-κB binding sites are indicated in black, deletions in gray. (B) Tax transactivation of the HIAP-1 promoter. Jurkat T lymphocytes were cotransfected with the HIAP-1 promoter (HIAP1P) or the mutant (HIAP1PD-147/136D-196/187D-209/200), in which 3 NF-κB sites were deleted, together with Tax_WT, Tax mutants (M7, M22, and M47), or empty expression vector (pcDNA3.1). Luciferase activity was determined and normalized to the negative control (HIAP1P + pcDNA3.1). The columns represent the mean of 3 independent experiments and standard deviation. (C) Tax transactivation of the NF-κB site deletion variants of the HIAP-1 promoter. Indicated promoter constructs were transfected in the presence and absence of Tax, luciferase activity was analyzed, and the fold activation of each construct by Tax was determined. The bars represent the mean of 2 independent experiments; error bars indicate the mean error.