Figure 4. Refractoriness to Wg is conferred by the Notch target gene cut.

(A) Mature cut⁶ mutant wing disc showing co-expression of the proteins Senseless, Sens, (in blue) and Wg (in red) in boundary cells. (B) Clones of cells lacking cut activity marked by the absence of GFP (red). Sens (in blue) starts to be expressed in boundary cells. (C) Mature cut⁶ mutant wing disc that expresses the intracellular domain of Notch (N^intra) under dpp^Gal4 control. Wg protein expression is shown in red and Sens protein expression in blue. (D) Mature wing disc that expresses Cut and GFP (green) under dpp^Gal4 control. Note the loss of Sens expression (blue) and ectopic expression of Wg (red) in non-boundary cells. (A'–D') In silico counterparts of the results shown in (A–D).