The Splicing Factor RNA-Binding Fox Protein 1 Mediates the Cellular Immune Response in Drosophila melanogaster

The uptake and destruction of bacteria by phagocytic cells is an essential defense mechanism in metazoans. To identify novel genes involved in the phagocytosis of , a major human pathogen, we assessed the phagocytic capacity of adult blood cells (hemocytes) of the fruit fly, by testing several lines of the Drosophila Genetic Reference Panel. Natural genetic variation in the gene ( ) correlated with low phagocytic capacity in hemocytes, pointing to Rbfox1 as a candidate regulator of phagocytosis. Loss of Rbfox1 resulted in increased expression of the Ig superfamily member ( ). Silencing of in Rbfox1-depleted blood cells rescued the fly's cellular immune response to , indicating that downregulation of by Rbfox1 is critical for phagocytosis in To our knowledge, this study is the first to demonstrate a link between and host defense against .