WWOX prevents Tax-induced NF-κB transcriptional activation. (A) WWOX prevention of Tax-induced NF-κB activation. 293 cells were transfected with plasmids expressing Tax, A κB-driven firefly luciferase reporter and a TK-driven Renilla luciferase reporter in the presence of an increasing amount of Myc-WWOX or Myc-WWOX Y33R, followed by measure of luciferase activity. The luciferase activity was presented as the percentile of that activated by Tax alone (set as 100). Protein expression levels of transfected Tax, Myc-WWOX, and its mutant were examined by IB. (B-C) WWOX prevention of NF-κB constitutive activation in HTLV-I–transformed T cells. The indicated HTLV-I–transformed T-cell lines were transfected with a κB-driven firefly luciferase reporter and a TK-driven Renilla luciferase reporter in the presence of an increasing amount of Myc-tagged WWOX or WWOX Y33R, followed by measure of luciferase activity as described in panel A. (D) Enhancement of Tax-induced NF-κB activation by WWOX knockdown. The 293 cells were transfected with Tax and κB-driven luciferase reporter in the presence or absence of different WWOX shRNA followed by measure of luciferase activity. The RNA and protein expression level of WWOX and Tax was examined by RT-PCR and IB assays, respectively.