Fig. 5.

Improved ablation efficiency with epNTR. A: optimization of nitroreductase for ablation using embryo injections. Embryos were injected with mRNA (50 pg) and treated with 10 mM metronidazole (Met) overnight. At 24 hpf, the dead, severely deformed, slightly deformed, and normal embryos were counted (total n for each injection is indicated above the columns). nfsBz is codon optimized for zebrafish with a custom algorithm. Variants with the amino acid changes were also tested. The triple mutant is significantly better than the next best double mutant (χ² = 11.7, P < 0.001). B: Met dose response curve for nfsB, nfsBz, and epNTR (nfsBz with T41L, N71S, and F124W). For each data point, the fraction of dead or deformed embryos is normalized to a matched population of injected embryos not treated with Met. C: confocal image stacks in y269;UAS:nfsB-mCherry (top) or y269;UAS:epNTR-RFP (bottom) larvae comparing RFP expression in control larvae (left) to larvae after ablation (right). Arrows indicate cells remaining after ablation with the original nsfB. A, Anterior.