Fig. 3

wars1 messenger RNA (mRNA) is predominantly expressed in the zebrafish eye, brain, and muscle in the embryo and wars1 F0 mutants display gross morphological defects. (a) The wars1 mRNA expression in the 1 dpf embryo. Dorsal view, anterior to the left. (b) wars1 knockouts are generated by CRISPR/Cas9. Uninjected control, wars1 F0 mutant and wars1 F0 mutant rescued with wild-type WARS1 mRNA (rescue) embryo at 3 dpf. Blue line indicates the brain size. Red line indicates the eye size. Black arrow indicates heart edema. Lateral view, anterior to the left. (c) Quantification of eye and head size from uninjected controls, wars1 F0, wars1 F0 + 150 or 200 picogram (pg) of zebrafish wild-type wars1 mRNA (+wars1), and wars1 F0 + 150 or 200 pg of human wild-type WARS1 mRNA (+WARS1). Each group contains 30 embryos, and each dot represents one embryo. Error bar = mean ± SD. One-way analysis of variance (ANOVA) with Tukey's multiple comparisons test: ns, not significant p ≥ 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.0001. All marked groups were compared to wars1 F0 mutant embryos. (d, e) Histological analysis of uninjected control, wars1 F0 mutant, and wars1 F0 mutant rescued with human wild-type WARS1 mRNA (rescue) larva at 5 dpf by cross-section (d) and sagittal section (e). Red asterisk indicates loss of cell density. Red arrow indicates the shorter lower jaw. Forebrain (fb), midbrain (mb), midbrain and hindbrain boundary (MHB), hindbrain (hb), optic tectum (TeO), otic vesicle (ov), retinal pigment epithelium (RPE), outer nuclear layer (ONL), inner nuclear layer (INL), inner plexiform layer (IPL), ganglion cell layer (GCL), tectum (tc), telencephalon (Tel), and cerebellum (ce).