Fig. 2. Effect of loss-of-function USP on the expression of proneural and neurogenic genes in the wing margin [usp² clones in a Minute (RpS5²) background]. Absence of GFP (green) marks usp² tissue. (A,A') Wing disc from a late feeding larva. Expression of the ac-lacZ reporter is not affected by loss of USP function. (B,B') The neur reporter A101 in a disc from an early wandering larva is precociously expressed in the absence of USP function. (C,C') Senseless (SENS) is expressed precociously in the mutant clone in a disc from an early wandering larva. Note the accumulation of SENS in the mutant SOPs. In wild-type tissue low levels are detected anteriorly. (D) Diagram gives the orientation of the disc with the area depicted in A-C. Arrowheads indicate estimated intersection of the A/P boundary with the margin. A'-C' show the expression of the different markers.