FIG. 1.

(A) Schematic representation of pBLV-IF encoding wild-type and mutant Tax. Positions of nucleotide substitutions are indicated by arrowheads. Number in parentheses correspond to positions in the sequence determined by Sagata et al. (22). (B) Transactivation activities of wild-type and mutant Tax proteins encoded by infectious clones of BLV. 293T cells were transfected with the reporter plasmid pGV-BLTR, the reference plasmid pRL-SV40, and individual BLV molecular clones or the control plasmid pBluescript II SK+. At 48 h after transfection, cells were recovered, and the activities of firefly and Renilla luciferases were measured in cell lysates. For each sample, the firefly luciferase activity (pGV-BLTR) was normalized by reference to the Renilla luciferase activity (pRL-SV40). The values are means and standard deviations (error bars) of results from three independent experiments.