Validation of nitroreductase, a prodrug-activating enzyme, mediated cell death in embryonic zebrafish (Danio rerio).

1Escherichia coli gene nfsB encodes a nitroreductase (NTR) enzyme that converts prodrugs like metronidazole (Met) and CB 1954 to cytotoxic metabolites. My coworkers and I have validated this prodrug-enzyme system in zebrafish (Danio rerio) by ubiquitously expressing NTR-EGFP fusion protein and exposing these embyos to CB 1954 and Met. These embryos showed extensive gross pathologic changes and death by 24 h of incubation in the prodrugs. They also exhibited widespread and marked apoptotic changes by 8 h of incubation in Met. Neither the prodrugs themselves nor the NTR-EGFP fusion protein were toxic to the developing zebrafish embryos. Thus the NTR-CB 1954 and NTR-Met systems can be used to ablate a wide variety of cells and tissues in zebrafish embryos.