Expression pattern for OPT-2, a proton-coupled oligopeptide transporter, using promoter::GFP transgenic reporter strains. GFP reporter expression in transgenic nematodes was driven by genomic DNA fragments containing either 4 kb of promoter alone (panels C-F) or 4 kb of promoter along with the entire open reading frame of the cognate protein, fused in-frame with GFP (panels I-L). The
opt-2 gene promoter (panels C and D) drove GFP expression in the gut of the worm. The OPT-2 (panels I-L) fusion protein was targeted to the apical membrane of the intestine, which expands prior to contacting the pharynx, as demonstrated in panel L.