Loss of Blm function does not increase sensitivity to DNA damage, however severely reduces lifespan in zebrafish.A, A′ Anti-γ-H2AX labeling in the head and trunk of 3 dpf untreated wild-type (A) and blm−/− embryos (A′) (Scale bar: 500 μm). B, B′ Anti-γ-H2AX labeling in the head and trunk of 3 dpf wild-type (B) and blm−/− (B′) animals after treatment with the DNA interstrand cross-linking agent diepoxybutane (DEB) (Scale bar: 500 μm). C, D γ-H2AX-positive foci in the head and trunk of different blm genotypes under control circumstances (C) and after DEB treatment (D) (ns not significant). E Phenotypes observed after gamma irradiation: Class 1—wild-type; Class 2—mild necrosis in the tectum and smaller eyes; Class 3—heavy necrosis all over the body, heart edema. Untreated controls were all Class 1. F, G The distribution of phenotype severity following gamma irradiation (F) and DEB treatment (G) (ns not significant). H Survival probability graphs of different blm genotypes. (Pairwise p values were calculated with the log-rank test, using Benjamini & Hochberg adjustment. dpf days post-fertilization).
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