Zebrafish Intestinal Fatty Acid Binding Protein (I-FABP) Gene Promoter Drives Gut-Specific Expression in Stable Transgenic Fish

Mammalian intestinal fatty acid-binding protein (I-FABP) is a small cytosolic protein and is thought to play a crucial role of intracellular fatty acid trafficking and metabolism in gut. To establish an in vivo system for investigating its tissue-specific regulation during zebrafish intestinal development, we isolated 5′-flanking sequences of the zebrafish L-FABP gene and used a transgenic strategy to generate gut-specific transgenic zebrafish with green/red fluorescent intestine. The 4.5-kb 5′-flanking sequence of zebrafish I-FABP gene was sufficient to direct fluorescent expression in intestinal tube, first observed in 3 dpf embryos and then continuously to the adult stage. This pattern of transgenic expression is consistent with the expression pattern of the endogenous gene. In all five transgenic lines 45-52% of the F2 inheritance rates were consistent with the ratio of Mendelian segregation. These fish can also provide a valuable resource of labeled adult intestinal cells for in vivo or in vitro studies. Finally, it is possible to establish an in vivo system using these fish for screening genes required for gut development.