A fob null allele is hypersensitive to infections with E. coli. (A) Schematic representation of the Drosophila fob gene and its neighbors. The targeting fragment generated in vivo (Gong and Golic, 2003) contains portions of neighboring genes around the mini-white gene (red box). (B) Southern hybridization with the entire fob gene yielded a signal with Ore-R (wt) but with any fob allele. Reprobing the same membrane with dVps33b confirmed the presence of DNA in all lanes. (C) qRT-PCR showed no expression of fob but similar levels of expression for neighboring genes in fob¹ compared with wild type. Gene expression levels were normalized with rp49 as an internal control and are shown relative to wild type. (D and E) Survival after infection was measured for wt, fob¹, and rescued fob¹ flies after injection with E. coli (D) or E. faecalis (E). (F) Induction of AMP genes 6 h after injection with E. coli (Drosocin, Diptericin, Cecropin, and Attacin) or 12 h after injection with E. faecalis (Defensin). (G) Bacterial load in injected flies at the indicated day after injection with E. coli. Error bars indicate standard deviation.