Real-time RT-PCR quantitation of p13 expression in Jurkat T cells transduced with lentiviral vectors expressing p13. Values on the y-axis represent the copy number of the p13 mRNA divided by the copy number of GAPDH (normalized copy number). The graph shows a comparison of the expression levels detected in HTLV-1–infected cell lines (MT2, C91PL) and Jurkat T-cell lines transduced with a lentiviral vector expressing wild-type p13, mutant p13, or with the empty vector (Δ).