Figure 1

EGFR signalling leads to the formation of wing veins by overriding Groucho-mediated repression. (A) Shown are abbreviated presentations of the EGFR and Notch signalling pathways. (B) A photograph of a Drosophila wing, with the veins numbered (L1–L5). Below, a schematic illustration of adjacent vein and intervein regions, depicting how MAPK phosphorylation of Gro may relieve transcriptional silencing by multiple antivein Gro-dependent repressors, promoting the formation of wing veins.