Figure 3.

Adult wing phenotypes associated with PS⁻ clones that express transmembrane or nuclear forms of Notch. Clones are marked by expression of Yellow under UAS/Gal4 control, which darkens cuticular structures, including wing hairs and margin bristles (not visible in the figure). (A) PS⁻ clones that express N^ECN display phenotypes associated with the absence of Notch signal transduction. One clone (*) crosses the wing margin (which coincides with the dorsoventral compartment boundary) and displays extensive wing notching. A second clone (arrowhead) within the dorsal compartment of the blade forms an abnormally thick vein. (B) A clone of PS⁻ cells that express N^ECN in the presence of the rescuing Tub-PS⁺ transgene displays constitutive Notch activity (arrow). The clone is associated with a double dorsal wing outgrowth which is flanked by adjacent rows of dorsal wing margin bristles (here, as in C, an arrow points down the plane of mirror symmetry). Note that in this experiment, the presence of the clone could not be scored on the margin bristles because the Tub-PS⁺ transgene used in this experiment includes a yellow⁺ gene which rescues normal (dark) pigmentation in the bristles. However, the contribution of the clone to the rest of the wing blade could still be scored because this yellow⁺ gene does not rescue pigmentation of the wing hairs. (C) A clone of N^intra-expressing PS⁻ cells (arrow) associated with a double dorsal wing outgrowth which coincides with a thin strip of mutant cells flanked by adjacent rows of dorsal wing margin bristles formed by neighboring wild-type cells.