Activation of Nrf2 protects embryonic macrophages from excessive ROS accumulation. (A) Representative images of macrophages from uninjected embryos or embryos injected with fluorescent ROS dyes. (B) Macrophage ARE-GFP activation increased with embryonic stage, using a synthetic ARE-GFP reporter for Nrf2 activity. (C) Relative Nrf2, GstD1, and gclM mRNA levels from stage 15 control and srp > Nrf2^RNAi macrophages isolated by FACS; data representative of three technical replicates of one biological replicate. (D and E) Stage 15 macrophage Nrf2^RNAi increased the percentage of DHE-positive phagosomes per cell (D) and DHE-positive macrophage per embryo (E). (F–H) Nrf2^RNAi increased the levels of ROS at the cell body (F and G) and increased oxidative damage (H). (I) Macrophage expression of bacterial LexA^RNAi did not increase DNA oxidative damage (8-oxodG) above control levels. (J) Macrophage expression of Nrf2^RNAi increases DNA oxidative damage (8-oxodG) above Luciferase^RNAi and control levels. Data (C–E, G, and J) generated using Nrf2^RNAi Flybase ID FBtp0069370 and data (F and H) generated using Nrf2^RNAi TRiP HMS02021. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 via Mann–Whitney test (B, F′, G′, H′, I′) and unpaired t test (C, D, and E), Dunn’s multiple comparison (J′). Images collected from 17 control and 8 ARE-GFP embryos (B); 8 control, 9 srp > Nrf2^RNAi embryos (D); 21 control, 30 srp > Nrf2^RNAi embryos (F); 10 control, 24 srp > Nrf2^RNAi embryos (G); 7 control, 8 srp > Nrf2^RNAi embryos (H); 5 control, 5 srp > LexA^RNAi embryos (I); 5 control, 5 Luciferase^RNAi, 7 srp > Nrf2^RNAi embryos (J). Also see Fig. 1.