Fig. 4. Melanization defects in egr mutants. (A,B) an egr¹/def mutant crystal cell is shown 10 minutes (A) and 60 minutes (B) after bleeding. Crystals are still visible in A (arrows) and not in B without leading to visible melanization. Bar, 10 µm. (C,D) Melanization in egr mutants was measured photometrically. (C) Melanization is reduced in egr¹/def mutants compared to wild-type (wt) activity (n=3, ^*P=0.014). When Egr is overexpressed using he-Gal4 in an egr¹ homozygous background melanization is restored to levels above wild-type activity (n=3, ^**P=0.007 for comparison with the wild type). (D) Melanization in UAS-egr control larvae and in larvae overexpressing Eiger in the fat body (lsp2-Gal4>UAS-egr) or in hemocytes (he-Gal4>UAS-egr). Only expression in hemocytes leads to significant induction (n=3, ^**P=0.006). Note that the crosses were kept at 25°C. Data are mean ± s.d.