Figure 6.

Lin and Wg similarly control ve gene expression. (A) Wild type, Ve RNA in situ. ve is expressed in one epidermal stripe extending from the dorsal edge (arrowheads) to the ventral midline (broken line). ve is expressed posteriorly adjacent to the En domain (Gritzan et al. 1999). Also note ve expression in some mesodermal and nerve cells underlying the epidermis. (B) Blockage of Wg signaling activity by expression of dominant-negative Pan with the Ptc–GAL4 driver leads to an ectopic stripe of ve that extends from the dorsal edge (arrowheads) to the ventral midline (arrows). The ectopic ve stripe is anteriorly adjacent to the En domain (Gritzan et al. 1999). (C) Reciprocally, activation of the Wg pathway by expression of activated Arm with the Ptc–GAL4 driver leads to repression of ve expression. (D) In lin mutants, an ectopic stripe of ve is found dorsally (arrowheads), but not ventrally. (E) Activation of Wg signaling by expression of activated Arm, with the Ptc–GAL4, in lin mutants represses ve expression ventrally but not dorsally. Bar, 20 μm in all panels.