Fig. 6: Disruption of IHO1-HORMAD1 interface prevents DSB top-up in late synapsing axes.
From: Seeding the meiotic DNA break machinery and initiating recombination on chromosome axes
A Immunostaining in nuclear spread late zygotene spermatocytes of adult mice. In wild type, dotted line separates a zygotene (top) from a diplotene (bottom) cell. In enlarged insets, dashed lines mark borders between unsynapsed (arrow) and synapsed (triangle) axes. Bars, 10 and 5 µm in low and high magnification panels, respectively. B Unsynapsed-to-synapsed DMC1 + RPA2 focus density ratios in late zygotene cells where SC formed on >70% of total axis length. C–G DSB focus densities on unsynapsed axes in late zygotene cells grouped (C, SC formed on <70% or >70% of total axis length) or ordered (D–G) according to the extent of synapsis nucleus-wide. B–G Each dot represents a single cell. n=numbers of spermatocytes. B, C Bars, medians, two-tailed Mann Whitney U-Test, ns=P > 0.05, *=P < 0.05, ****=P < 0.0001. Exact P values: (B), wild type vs. Iho1C7Δ/C7Δ P = 1.27e-10, wild type vs. Spo11−/− P = 0.1198, wild type vs. Ankrd31−/− P = 5.99e-10, Iho1C7Δ/C7Δ vs. Spo11−/− P < 2.2e-16, (C), comparison of >70% and <70% synapsed spermatocytes in wild type P = 0.06574, Iho1C7Δ/C7Δ P = 0.7645, Spo11−/− P = 0.01217, Ankrd31−/− P = 0.04398; comparison of spermatocytes with >70% synapsis, wild type vs. Iho1C7Δ/C7Δ P < 2.2e-16, Iho1C7Δ/C7Δ vs. Spo11−/− P < 2.2e-16, Iho1C7Δ/C7Δ vs. Ankrd31−/− P < 2.2e-16. D–G Linear regression (lines), the best-fit slope +/− standard error and the significance of slope deviation from zero (two-tailed F test, P) are shown. Source data are provided as a Source Data file.
