Gβ2 subunit inhibits Tax-1 transactivation activity. (A-B) Ten micrograms reporter plasmids pLTR1-Luc, pκB-Luc, or pHIV1-Luc and different amounts of effector vectors (1 μg pCMVTax-1 or pREP9Tat1 and 10, 100, or 1000 ng pcDNAFlag-Gβ2) were transfected into 107 Jurkat cells according to the DEAE dextran method. Forty-eight hours after transfection, cells were lysed and luciferase activities were determined. Luciferase data were normalized to protein content, and the data are reported as mean ± SD of 3 independent experiments in triplicate. (C-D) HeLa cells (3 × 105) were cotransfected with 3 μg reporter construct pLTR1-Luc, increasing amounts of pcDNAFlag-Gβ2 (10, 100, 500, and 1000 ng) and with or without HTLV-1 Tax–expressing construct (300 ng). Twenty-four hours after transfection, cells were lysed and luciferase activities were determined. An aliquot from each lysate was separated by SDS-PAGE, and Western blot was performed using anti–Tax-1, anti-Flag, and antiactin antibodies.
