Activation of an HIV-1 κB-TATA-luciferase reporter plasmid after overexpression of Bcl-3 in TF-1 cells. A total of 0.5 μg of plasmids expressing Bcl-3, p50, or p52 was cotransfected with 0.5 μg of the HIV-1 κB-TATA-luciferase reporter plasmid into TF-1 cells separately or in combination. The pGL2 basic vector (0.5 μg) was used as negative control. Where noted, 1.0 μg of Bcl-3 was cotransfected. The total amount of transfected DNA was kept constant by adding appropriate amounts of expression vector without insert. At 48 hours after transfection, cells were collected for luciferase assay. Results are expressed as the mean ± SEM (×10³ cpm). Five experiments were performed. *A significant increase above the κB-TATA reporter plasmid (P ≤ .05).