Figure 3.

Cell identity changes associated with Iro-C⁻ clones in the presumptive notum. Clones are revealed by the absence of Myc expression (red, C,D,I,J). (A,B) l(2)09261/CyO disc showing caup (red) and lacZ (green) expression. Within the presumptive notum, these expressions overlap only at the NP region (arrowhead). The arrow in A points to the notum/wing hinge fold and at the plane of the z-axis confocal section shown in B. In late third instar discs, cells expressing Caup can form up to approximately half of the fold (B). The arrowhead marks the bottom of the fold. (C–E) l(2)09261/+; Df(3L)iro^DFM1 clone (*) with ectopic expression of lacZ (green channel, cf. with A). lacZ is also expressed in cells adjacent to the clone (arrow) and closest to the NP region (arrowhead). (F,G) Notum region of a wild-type disc and a disc bearing a Df(3L)iro^DFM3 clone (*) stained with anti-Tsh antibody. Note the strong Tsh accumulation in the lateral notum (arrowhead) and the derepression of tsh in wild-type cells adjacent to the clone (arrow). (H) Notum region of a wg–lacZ/CyO disc stained with anti β-galactosidase (green) and anti-Caup (red) antibodies. (I,J) wg–lacZ/+;Df(3L)iro^DFM1 clones (*) in discs stained with anti-β-galactosidase (green) and anti-Myc (red) antibodies. wg–lacZ is not expressed within the clones (I) and in part of the surrounding cells (J, arrowhead, cf. with H).