Figure 5.

The PU.1/Spi-B and E-box4 motifs located in the BLV 5′-LTR are important for its PMA/ionomycin-stimulated transcriptional activity. DG75 cells were transiently transfected by electroporation with 8 µg of pLTR*-luc-derived constructs and 50 ng of pRL-TK (Promega). Cells were mock treated or treated with PMA/ionomycin 24 h after transfection. Luciferase activities (firefly and Renilla) were measured in cell lysates 48 h after transfection. Results are presented as histograms indicating PMA/ionomycin-mediated induction (n-fold) of pLTR*-luc-derivative constructs with respect to their respective basal activities and compared to the pLTR*wt-luc, which was assigned a value of 100%. Each value is the mean ± SEM of three separate experiments performed in triplicate. *P < 0.05, **P < 0.1 and ***P < 0.5 compared to the wild-type construct pLTR*-luc, as assessed by one-way ANOVA.