Figure 8

Loss of ahr2 disrupts neural network formation without affecting brain size. Dorsal views of control (A) and homozygous ahr2 mutant embryos (B) at 48 hpf stained with Hoechst (DNA, blue) to visualize the parenchyma and immunolabeled with an anti-acetylated α-tubulin antibody to mark axon tracts (white and inverted to black). (C) Area measurements of the forebrain, optic tectum, cerebellum, hindbrain, and whole brain at 48 hpf in wild-type ahr2, heterozygous ahr2, and homozygous ahr2 mutant embryos. (D) Fold change of acetylated α-tubulin in the forebrain, optic tectum, cerebellum, hindbrain, and whole brain of heterozygous ahr2, and homozygous ahr2 mutant embryos zebrafish relative to the mean acetylated α-tubulin area coverage of wild-type embryos. There were no apparent differences in the size of the forebrain, optic tectum, cerebellum, hindbrain, and whole brain in mutants when compared to controls (C); however, acetylated α-tubulin coverage was significantly reduced in the optic tectum (purple arrowheads) and the whole brain of homozygous and heterozygous ahr2 mutant embryos embryos relative to controls (D). Acetylated α-tubulin coverage in the cerebellum (black arrowheads) and hindbrain (pink arrowheads) was also reduced, but this was not a statistically significant finding with the analysis pipeline used for quantification (D). Statistical significance determined by Welch’s t-test, *p < 0.05, **p < 0.01, ***p < 0.001. n = 14–21 fish/group across 3 replicates. Anterior is left in all confocal micrographs. Scale bar = 100 μm. Magnification = 10x with varying zoom.