FIG. 2.

Tax2 region is responsible for the activation of NFAT. (A) Structures of the chimeric genes and the position of the boundary between Tax1 and Tax2B are indicated. (B) Cell lysates were prepared from Jurkat cells transfected with the indicated plasmids (2 μg), and the amount of Tax in each lysate was measured by Western blot analysis using an anti-Tax1 antibody (left) or an anti-Tax2B antibody (right). Arrows indicate the Tax proteins recognized by the antibodies. (C) Jurkat cells were transfected with the indicated Tax expression plasmid (0.01 to 0.5 μg) together with the luciferase plasmid regulated by the NFAT element (pNFAT-Luc). Cell lysates were prepared from transfected cells, and luciferase activity was determined. Luciferase activity was normalized to that of β-galactosidase. The fold activation represents the luciferase activity of cells transfected with the tax plasmid relative to that with the control plasmid. Three independent experiments were carried out to confirm reproducibility.