Frequency of MTOC polarization to the cell-cell junction induced by wild-type or mutant HTLV-1 Tax protein. Jurkat cells were transfected with expression plasmids encoding either wild-type or mutant Tax protein. After 6 hours, the cells were allowed to form conjugates for 1 hour at 37°C. In 2-cell conjugates (n = 50-100 in each experiment) formed between Tax⁺ and Tax⁻ cells, we scored the frequency of polarization of MTOC in the Tax⁺ cell to the cell-cell junction. The bars represent the mean plus or minus SE of 3 to 5 independent experiments.