Fig. 1. Response of hh-lacZ (A-C) and en-lacZ (D-E) to gro loss of function in the wing. Df(3R)Espl22 clones are shown, marked by increased GFP expression (bright green) in A-C and by absence of GFP expression (absence of green) in D-E. The gro^+/+ twin spots (clones arising from the sister cell bearing the reciprocal recombination product) lack GFP and hh-lacZ (A-C, see Materials and Methods) or have twice the level of GFP (D-E). Anti-ß-galactosidase staining is shown in red. (A) A large anterior clone abutting the boundary (blue line) expresses hh-lacZ strongly (type I) – note comparable expression levels in a posterior clone, where hh-lacZ copy number is also 2 (arrow). (B) Large anterior clones further away from the AP boundary also express hh-lacZ strongly, but the intensity drops away from the DV boundary (type II/III). (C) Examples of small type II (short arrows) and III clones (long arrows) that express hh-lacZ only when located within an anterior domain close to the AP boundary. Several non-expressing clones (type IV-arrowheads) are seen in C, away from the AP boundary. (D,E) These large type I/II clones shown should express hh strongly throughout the clone (compare with A,B); however, en-lacZ derepression is more restricted. (A'-E') Red channel only. (A''-E'') Green channel only. The blue line in A,D E marks the AP boundary. Anterior is towards the left and dorsal is upwards.