Fig. 4.

Insulin protects against viral infection of the gut. (A) Drosophila cells were either mock insulin-treated (3.4 µM), infected with SINV (MOI = 20) or DCV (MOI = 6), and monitored by microscopy (virus, green; nuclei, blue). Quantification with mean ± SD of three independent experiments; *P < 0.05. (B) Mosquito Aag2 cells were either mock or insulin-treated (3.4 µM), infected with SINV (MOI = 2), and monitored by microscopy (virus, green; nuclei, blue). Quantification with mean ± SD of three independent experiments; *P < 0.05. (C) Immunoblot analysis of intestines from wild-type flies fed PBS or insulin (83.5 µM) for 30 min. (D and E) Flies were fed either PBS or insulin (83.5 µM) and orally challenged with DCV (2 µL of 1 × 10¹³ IU/mL) for 7 d. DCV infection of intestines were analyzed by microscopy (virus, green; nuclei, blue) (D) or qRT-PCR normalized to Rp49 (E) and shown relative to the control. Mean ± SD of five independent experiments; *P < 0.05.