Fig 4

Increasing intracellular Ca²⁺ either by Ionomycin or IP₃ rescues egg activation defects in par2a mutants.

A–D: Images of WT (A, B) or severe par2a mutants (C, D) embryos derived from natural spawning and treated with 0.1% DMSO (A, C) or 2 µM Ionomycin (B, D). E: Proportion of WT and severe par2a^−/− embryos showing egg activation and blastomere division phenotypes at 1.5 hpf following treatment with 0.1% DMSO or 2 µM Ionomycin. Key: CL: Chorion Lift, BD: Blastodisc, CD: Cell Division, +: Present, −: absent. ^†: Abnormal. Chi-squared analyses; *** = p < 0.001. F–K: Images of naturally fertilized severe par2a mutant embryos injected with KCl alone (F, G, H) or with IP₃ in KCl (I, J, K) at 2 hpf (F, I), 4 hpf (G, J) and 18 hpf (H, K). L: Proportion of egg activation and blastomere division phenotypes in fertilized severe par2a mutant eggs injected with IP₃ in KCl or KCl alone. Key: CL: Chorion Lift, BD: Blastodisc, CD: Cell Division, +: Present, −: absent. Chi-squared analyses; *** = p < 0.001. Scale bars: D, J, K = 200 µm. See file S1 Data for underlying data. IP₃ is necessary for zebrafish egg activation.