Figure 4.

Ush antagonizes Pnr transcriptional synergy with Tin in the regulation of the D-mef2 cardiac enhancer. Drosophila S2 cells were cotransfected with a D-mef2-CAT reporter plasmid along with Tin, Pnr, and Ush expression plasmids, as indicated. The normalized CAT activity obtained from the transfections of a test effector(s) with the reporter plasmid was divided by the corresponding value obtained with an empty vector (pIZ/V5-His) and reporter, with the value shown as fold activation. The data show that Pnr collaborates with Tin to activate the D-mef2 enhancer, and this effect is diminished by the inclusion of Ush.