Fig. 3. Expression of wing-hinge markers in tup clones located in the notum region. tup clones are identified by the absence of GFP (green) expression. (A) First instar-induced tup^isl-1 clone (asterisk). The lacZ insertion line l(2)09261 is derepressed. (B-B'') tup² clones (arrowheads) derepressing zfh2 (B') and/or msh⁸⁹-lacZ (msh, B''). Asterisk, endogenous msh expression in the notum. (C) Optical z-axis section through tup^ex4 clones. Red, msh⁸⁹-lacZ; blue, Twist, a marker for adepithelial cells; arrowheads, nuclei of tup^ex4 cells; arrow, peripodial membrane. (D) Extruding tup^ex4 clone stained with phalloidin (red). Arrowhead, apical actin accumulation. (E) tup² clone inducing msh-lacZ expression autonomously and non-autonomously (arrowhead). (F) First instar-induced tup² clone with enhanced expression of msh-lacZ. Compare (arrowheads) with the wild-type disc (G). (H) Derepression of sal (purple) within a tup^ex4 clone (asterisk) and in cells surrounding it. Compare with wild-type sal expression (I).