Fig. 1. Expression of hth/exd in the Drosophila notum. (A) Single staining for hth expression in a middle third instar disc. hth expression (red) covers most of the notum but some modulation is already visible. (B-D) Notum region of a mature disc doubly stained for hth (red) and exd (green). The two regions of high hth expression are the and the ß subdomains. The image in C shows only exd staining and in D the red and green channels are merged. The hth and exd expression patterns are almost identical. (E) Third instar disc doubly stained for hth (red) and en (green). Part of the ß subdomain is included in the postnotum. (F) Notum part of a mature disc stained for hth (red) and eyg (green). The ß subdomain and the eyg expression domain abut and form a sharp border, but the subdomain is included within the eyg domain. (G) Double staining with anti-Hth (red) and anti-pMad (green). The ß subdomain contains high levels of Dpp signalling. (H) A schematic of hth expression in the adult thorax. (I) Thorax of an hth-Gal4 > UAS-lacZ stained with X-gal to reveal hth expression in adult structures.