Figure 3.

Forced mesodermal expression of the ush gene affects heart development. (A, C, and E) WT, wild-type embryos. (B, D, and F) UAS-Ush, embryos expressing ush in the mesoderm under the control of a twi-Gal4 driver. (A–D) Expression of ush results in a reduced number of cardial cells in the forming dorsal vessel. Stage 14 (A and B) and 16 (C and D) embryos stained for D-MEF2 protein. (E and F) Expression of ush results in a decreased activity of the D-mef2 cardial cell enhancer. Stage 16 embryos were stained for β-galactosidase protein in cardial cells of the dorsal vessel. Arrows point to missing cardial cells or cardioblasts that fail to express the lacZ reporter gene.