Fig. 4: Removal of histone H1 or HPL-1 alleviates lethality inherited from sperm.

a, Gene Ontology term analysis for biological processes among significantly regulated proteins from a SILAC assay for wild-type worms with or without parental exposure to ionizing radiation. The top four enriched processes are highlighted in grey. FDR, false discovery rate. Values of log₁₀FDR larger than 1.3 correspond to FDR < 0.05. b, Relative expression of proteins involved in chromosome- or DNA-binding processes upon parental exposure to ionizing radiation. The floating bar shows the range of values, and the centre line represents the median. n = 4 biological replicates. c, Progeny lethality characterization of the his-24; fog-2 mutant with or without paternal ionizing radiation irradiation. n indicates the number of biological replicates. Data are median ± 95% confidence interval. P values are shown. d, Left, H3K9me2 (green) and DAPI (blue) staining in the germline of indicated strains. Scale bars, 20 μm. Right, three representative nuclei co-stained with the X chromosome marker HIM-8 (red). Scale bar, 3 μm. e, H3K9me2 (green) and DAPI (blue) staining in the germline of indicated RNAi strains with or without paternal ionizing radiation exposure. Scale bar, 10 μm. Bottom, quantification of H3K9me2 signal intensity. n indicates cell numbers. Data are median ± 95% confidence interval. P values are shown; one-way ANOVA with Bonferroni’s multiple comparisons test. Experiments in d,e were repeated three times with similar observations. EV, empty vector. f, Progeny lethality of fog-2 and hpl-1; fog-2 with or without paternal ionizing radiation irradiation. n indicates the number of biological replicates. Data are median ± 95% confidence interval. P values are shown; GLM with logit link function was used for proportional data (c,f), and two-tailed t-test with arcsine transformation was used to confirm the statistical results. Full statistical analysis is shown in Supplementary Table 1.