Failure of repression of Tax-dependent transcription from the hiNOS promoter by the dominant-negative mutants of IκB and IκBβ. Jurkat cells were transfected with 5 μg of a p65 or Tax expression vector, 5 μg of IκB▵N or IκBβ▵N effector plasmid, and 5 μg of a luciferase reporter construct under transcriptional control of either the κB-LUC, WT-LUC, or pGLNOSa. Input DNA for all transfections was normalized by addition of a blank pCMV4 expression vector. The resulting activities were plotted as fold induction relative to that with the corresponding reporter in the absence of p65 or Tax. Data represent the mean ± SEM of three experiments.