Fig. 7. Notum-to-wing transformation observed in Ubx-GAL4/UAS-Dras1^N17 or Ubx-GAL4/UAS-Aos was due to their expression in the PM and not in the DP. All wing discs shown in this figure stained for Wg expression. Top panel shows the expression patterns of different GAL4 drivers (visualized with UAS-nuclear lacZ) used in this study. Middle panel shows the effect of overexpression of DN-Ras using those GAL4 drivers and the lower panel shows the effect of overexpression of DN-Aos. 426-GAL4 is expressed only in the presumptive hinge (A), whereas pnr-GAL4 in the presumptive lateral notum (D). Overexpression of DN-Ras (B,E) and Aos (C,F) using these two GAL4 drivers does not affect wing development, reflecting late (early to mid-third instar larval stages) activation of 426- and pnr-GAL4 expression. ap-GAL4 is expressed in the dorsal pouch and in the entire notum (G). Overexpression of DN-Ras (H) or Aos (I) using this GAL4 driver causes severe reduction in notum tissue; however, no transformation is observed. (J-M) tsh-(J) and AgiR-GAL4 (M) drivers are expressed in both DP and PM cells. In the DP, tsh-GAL4 is expressed in the hinge and in the presumptive lateral notum (J), whereas AgiR-GAL4 is expressed in the posterior mesonotum (asterisk in M). Overexpression of DN-Ras (K) and Aos (L) using tsh-GAL4 caused severe loss of notum tissue, and no pattern duplication is observed. DN-Ras overexpression using AgiR-GAL4 resulted in loss of notum tissue (N), whereas no phenotype was observed with Aos (O). (P-R) Ubx-GAL4 expression pattern (P) and the effect of overexpression of DN-Ras (Q) and Aos (R) using this GAL4 driver is shown again (for details, see Fig. 6) for comparison.