Fig. 2. Widerborst activates the catalytic subunit of PP2A, which promotes hair formation. (A) The multiple wing hair phenotype caused by Widerborst overexpression is suppressed by removing one copy of mts. Each bar represents the average number of wing hair duplications in the region between veins 4 and 5, distal to the posterior crossvein. At least 12 wings were averaged. (B) Wing from a fly that expressed the wild-type catalytic subunit of PP2A along the AP compartment boundary under the control of PatchedGAL4. Each overexpressing cell makes prodigious numbers of hairs that point in all directions. (C) Wing from a fly that expressed a dominant negative catalytic subunit along the AP compartment boundary. Wing hairs are stunted or fail to form. (D) Dominant-negative catalytic subunit expression wing showing a milder phenotype than in C; hairs display stunting and polarity defects.