Figure 6. Systemic injection of insulin rescues (G4C2)36 toxicity in Drosophila.

Injection of 0.03 mg/ml insulin (INS) significantly extended lifespan of flies (n = 120) expressing (G4C2)36 when compared with flies injected with PBS (**p=0.00034, log-rank test), while it slightly shortened lifespan in non-induced flies (*p=0.043). Genotype: w; UAS-(G4C2)36 /+; ElavGS/+.

Figure 6—figure supplement 1. Systemic injection of insulin reduces (G4C2)36 toxicity in Drosophila.

(A) Injection of different concentrations of insulin 0.03, 0.3, and 3 mg/ml into (G4C2)36 flies haemolymph (n = 120). Injection of 3 mg/ml insulin into (G4C2)36-induced flies greatly shortened their lifespan (p<0.0001, log-rank test), while 0.3 mg/ml had no significant effect (p=0.083), and 0.03 mg/ml modestly increased lifespan (p=0.038, log-rank test, PBS induced vs. 0.03 mg/ml INS induced). In uninduced (G4C2)36 flies, injection of insulin at 0.3 or 0.03 mg/ml shortened lifespan (p<0.0001, log-rank test, PBS uninduced flies vs. 0.3 mg/ml INS uninduced; p=0.039, log-rank test, PBS uninduced flies vs 0.03 mg/ml INS uninduced). (B) Injection of insulin (INS) at 0.03 mg/ml significantly extended lifespan of flies (n = 80) expressing (G4C2)36 when compared with flies injected with PBS (*p=0.037, log-rank test) in induced flies, while it shortened lifespan in non-induced flies (*p=0.007). Genotype (A, B) w; UAS-(G4C2)36/+; ElavGS/+.