FIG. 8.

Comparison of four VP16 fusion activators in three different assay systems. Shown are activities of various VP16 fusion activators on three different reporters: integrated lacZ reporters in yeast cells, CAT reporters in Schneider cells, and lacZ reporters carried on replicating 2μm plasmids in yeast cells. For each class of reporters, four different enhancer elements were tested: the natural hb and kni enhancer elements and their modified derivatives. The comparison shows a general good agreement of the activator behaviors in different assays; see the text for discussions of major exceptions. The activity of Bcd-VP16 for each reporter was assigned a value of 100. β-Galactosidase units for this activator in yeast assays were 278, 65, 380, and 243 on integrated hb-lacZ, kni-lacZ, hb(6A)-lacZ, and kni(6A)-lacZ reporters, respectively; on the replicating reporters, they were 361, 127, 578, and 370.