FIG. 6.

Effect of distamycin on the late A10L promoter. (A) A β-galactosidase reporter gene plasmid (5 μg), driven by the vaccinia virus A10L promoter, was transfected into HeLa cells (previously infected with vaccinia virus strain vTF7-3, which expresses the T7 RNA polymerase. Where indicated, 100 μM distamycin and/or 5 mM HU was included at the time of infection. Also, where indicated, 5 μg each of plasmids encoding the late transcription factors (LTFs) A1L, A2L, and G8R driven by a T7 promoter was cotransfected with the reporter gene plasmid. After 18 h, cells were harvested and β-galactosidase activity was determined. Activity was normalized to protein content. Activities are expressed as that relative to the activity of the reporter gene in the absence of inhibitors. (B) Activity of a T7 promoter β-galactosidase reporter construct in the absence (open bar) and presence (filled bar) of distamycin.