FIGURE 3.

The activation of transcription of the natural tinman, brinker, and twist promoters in Drosophila S2R+ cells by Dorsal and the dependence of their activation on the DPE motif. Drosophila S2R+ cells were co-transfected with firefly luciferase reporter constructs containing wt or mDPE promoter, as well as varying amounts of a Dorsal expression plasmid, as indicated. To normalize for transfection efficiency, cells were co-transfected with a Pol III-Renilla luciferase control plasmid and assayed for dual luciferase activity. The activities are reported relative to the wild-type promoter in the absence of co-transfected Dorsal expression plasmid, which was defined to be 1. A schematic diagram of the genomic fragments is shown on top of panels A–C. A, transcriptional activation of the natural tinman promoter by Dorsal (n = 3). B, transcription activation of the natural brinker promoter by Dorsal (n = 3). C, transcription activation of the natural twist promoter by Dorsal (n = 4). D, basal transcription levels of twi. To enable the visualization of the basal transcription levels of wt and mDPE twist reporters, these data are presented in a separate panel. In all panels, error bars represent S.E.