FIG. 3.

Wg and dMyc protein expression in late third-instar wing imaginal discs. (A) Subdivision of the Drosophila late third-instar wing imaginal disc relative to the Wg expression pattern (red). Two rings of Wg expression mark the presumptive hinge territory; the wing pouch primordium lies within the inner ring, while the notum is formed from tissue outside of the outer ring. Furthermore, Wg is expressed in a thin stripe of cells straddling the boundary between dorsal (D) and ventral (V) compartments, subdividing the prospective wing pouch into dorsal and ventral halves. (B) Late third-instar wing imaginal disc stained for dMyc protein (red). A white circle roughly outlines the boundary between prospective wing pouch and hinge, while a larger white circle distinguishes the prospective hinge area from the prospective notal area. dMyc protein is highly expressed within all cells of the presumptive notum and wing pouch domains except for a stripe of cells extending along the dorsal-ventral boundary. This area of reduced dMyc protein expression corresponds to the ZNC, where dmyc has been showed to be transcriptionally repressed by peak Wg activity associated with the dorsal-ventral boundary. Discs are oriented ventral up and anterior to the left.