FIG. 9.

Spi-1/PU.1-regulated promoter activity of the −270/−41 region of the mouse Fli-1 gene in 745-A cells. 745-A cells (10⁶) were transfected with equal amounts (2 μg) of either pGL2-basic, tk-luc, or −270/−41 Fli-1 luc reporter construct together with the indicated amount of either Spi-1 expression vector pHOOK-Spi-1 or empty vector pHOOK in the presence (hatched boxes) or absence (empty boxes) of 5 mM HMBA as indicated. Luciferase activities were determined on lysates prepared from equal numbers of cells from each lot of transfected cells 24 h following the addition of DNA. The experiment was repeated three times, and the results are given as means of relative luciferase activities standardized for each repetition by the activity (taken as 100%) obtained for cells transfected with the −270/−41 Fli-1 luc construct in the absence of both pHOOK-Spi-1 and HMBA (lane 2).