Fig. 2

Dhx38 deletion leads to p53-dependent apoptosis and abnormal mitosis in zebrafish retinas (A) Whole embryo TUNEL staining showed many apoptotic cells in the retina, brain and spinal cord of dhx38 mutants at 36 and 48 hpf. White arrows, apoptotic signals. Scale bar, 100 μm. (B) Retinal sections showed many apoptotic signals at 30, 36 and 48 hpf in dhx38 mutant zebrafish retinas White arrows, apoptotic RPCs. n = 9 per panel; Scale bar, 50 μm. (C) qPCR showed activation of the p53 pathway in the dhx38 mutant at 36 hpf. Data was shown as mean ± SD. n.s., no significance; ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001 as indicated. (D) p53 deletion in dhx38 mutants significantly reduces apoptosis of RPCs, but could not rescue retinal differentiation defects. 36 hpf for TUNEL; 48 hpf for Sox2 and Islet1. Scale bar, 50 μm. (E‒G) The quantitative analysis of TUNEL-positive cells, Sox2-positive cells and Islet1-positive cells is shown in D. n ≥ 5 per panel. Data was shown as mean ± SD. n.s., no significance; ∗∗p < 0.01, ∗∗∗∗p < 0.0001 as indicated. (H) The spindle and nuclei of RPCs in siblings, dhx38−/− and dhx38−/−/p53−/− zebrafish were stained using anti-α-tubulin (red) and γ-tubulin (green) antibodies and DAPI (blue), respectively. The different types of spindle abnormalities are shown in the panels (abnormal 1–4). Hexagon, mitotic karyotype. Scale bar, 10 μm. (I) Quantitative analysis of the number of RPCs at each stage of mitosis in siblings and dhx38 mutant embryos shown in (H).