Figure 2
Targeted hFOXO3a and dFOXO expression in the developing Drosophila eye induces organ-size reduction and cell death, and the phenotypes are sensitive to insulin signaling and nutrient levels. (a) GMR-Gal4- expressing control fly. (b) No discernible phenotype results from hFOXO3a expression. (c) Expression of hFOXO3a-TM in the eye disc leads to pupal lethality; escapers at 18°C show a necrotic phenotype and severely disrupted cell specification. (d) Expression in w--marked clones of cells induces a similar phenotype at 25°C. (e) Dp110DN expression slightly reduces eye size, and (f) co-expression of wild-type hFOXO3a partially mimicks the hFOXO3a-TM escaper phenotype. (g) The same enhancement of hFOXO3a activity was observed in a dPKB-/- background. (h,i) Expression of transgenic or endogenous dFOXO results in a small-eye phenotype, which is also dramatically enhanced by (j) Dp110DN. (k-o) hFOXO3a and dFOXO phenotypes are progressively exacerbated by protein deprivation ('sugar') and complete starvation ('PBS'). Flies like the one shown in (m) die within one day, and complete starvation of dFOXO-expressing flies resulted in pupal lethality (not shown). Genotypes are: (a) y w; GMR-Gal4/+; (b) y w; GMR-Gal4/+; UAS-hFOXO3a/+; (c) y w; GMR-Gal4/+; UAS-hFOXO3a-TM/+; (d) y w hs-flp/y w; GMR >FRT-w+ STOP - FRT >Gal-4/+; UAS-hFOXO3a-TM/+; (e) y w; GMR-Gal4 UAS-Dp110DN/+; (f) y w; GMR-Gal4 UAS-Dp110DN/+; UAS-hFOXO3a/+; (g) y w; UAS-hFOXO3a/GMR-Gal4; dPKB3/dPKB1; (h) y w; UAS-dFOXO/GMR-Gal4; (i) y w; GMR-Gal4/+; EP-dFOXO/+; (j) y w; GMR-Gal4 UAS-Dp110DN/+; EP-dFOXO/+; (k-m) y w; GMR-Gal4/+; UAS-hFOXO3a/+; (n,o) y w; GMR-Gal4/+; EP-dFOXO/+.