Null dFOXO mutants are viable, have no overgrowth phenotype and are hypersensitive to oxidative stress. (a) Dp110DN expressing control fly. (b) EP-driven coexpression of dFOXO elicits a necrotic eye phenotype. (c,d) EMS-induced mutations in dFOXO lead to a reversion of the overexpression phenotype. (e,f) Selective removal of dFOXO from the head (right) does not lead to an organ-size alteration compared to a control fly (left). (g) w--marked dFOXO-deficient photoreceptor cells are the same size as wild-type cells. (h) In contrast to dPTEN, dFOXO null mutants have no organismal growth phenotype. For each genotype, the left bar indicates the body weight of females and the right bar the weight of males. Values are shown ± standard deviation (SD). (i) dFOXO mutants are hypersensitive to oxidative stress. The graph shows a survival curve of male adult flies on PBS/sucrose gel containing 5% hydrogen peroxide. The observed hypersensitivity is more pronounced in males, but is also observed in females (not shown). The increased resistance of homozygous EP-dFOXO flies might be caused by low basal dFOXO overexpression from the EP element, which occurs due to leakiness of UAS enhancers in the absence of Gal4. Control flies placed on PBS/sucrose without oxidant survived during the time window shown. Genotypes are: (a) y w; GMR-Gal4 UAS-Dp110DN/+; (b) y w; GMR-Gal4 UAS-Dp110DN/+; EP-dFOXO/+; (c) y w; GMR-Gal4 UAS-Dp110DN/+; EP-dFOXO21/+; (d) y w; GMR-Gal4 UAS-Dp110DN/+; EP-dFOXO25/+; (e,f) y w ey-flp/y w; FRT82/FRT82 cl3R3 w+ (left); y w ey-flp/y w; FRT82 EP-dFOXO21/FRT82 cl3R3 w+ (right); (g) y w hs-flp/y w; FRT82 EP-dFOXO21/FRT82 w+.
Jünger et al. Journal of Biology 2003 2:20 doi:10.1186/1475-4924-2-20