Figure 1. Abnormal cleavage divisions of Wdr8^−/− zygotes are rescued by EYFP–huWdr8 expression.

(a) Phenotypes of paternal and maternal Wdr8^−/− zygotes before and after midblastula transition. The maternal Wdr8^−/− zygotes, but not the paternal, showed disordered cleavage divisions and failure of gastrulation. Dotted lines represent developing zygotes onto the yolk. (b) Timing of cleavage cycles in zygotes produced from the individual mating combinations in a. In the first cleavage cycle, there was no apparent delay between WT and the zygote from WT mother/Wdr8^−/− father, indicating that there are no paternal contributions causing one-cycle delay¹⁷. On the other hand, zygotes from Wdr8^−/− mother (crosses; Wdr8^−/− ♀ × WT♂ and Wdr8^−/− ♀ × Wdr8^−/− ♂) accumulated delay and variance of the cleavage timing due to cytokinesis failure and abnormal spindle assemblies (Fig. 3b, Supplementary Fig. 4). Boxes and whiskers represent median with 25th and 75th percentile and maximum/minimum, respectively. Total zygotes and biological replicates are denoted in Supplementary Table 1. (c,d) Full rescue of m/zWdr8^−/− zygotes (from Wdr8^−/− ♀ × Wdr8^−/− ♂) by exogenous expression of EYFP–huWdr8 (c) and its efficiency at 1.5 dpf (d). N, total embryos from three independent experiments. Data represent mean ± s.e.m. Scale bars, 200 μm. Stages are denoted as minutes/days post fertilisation (mpf, dpf) and the corresponding stages of WT are denoted in parentheses.