Figure 1. Knock down of eater mRNA in Drosophila S2 cells leads to reduced bacterial phagocytosis in the absence of major transcriptional changes. (A) S2 cells were analyzed for bacterial phagocytosis using a mixture of heat-inactivated, fluorescently labeled Gram-positive and Gram-negative bacteria (Staphylococcus aureus and Serratia marcescens, respectively). Error bars indicate SD (B and C) Gene expression microarray analysis of S2 cells after RNAi-mediated knock down and exposure to bacteria. Black dots indicate significant expression changes of > 3-fold (FDR ≤ 0.05; mean of three independent repeat experiments). (B) Genome-wide transcriptional changes after 90 min of exposure to bacteria. One transcript (eater) was reduced significantly by > 3-fold. Similar results were obtained at 30 and 180 min. (C) Genes significantly upregulated by > 3-fold after 90 min of exposure to bacteria were strongly enriched for immune response functions (DAVID enrichment scores of 7.92 and 7.66). Overlap between eater knock down and control samples: 93%.