PLCζ1 is the essential SOAF in ICSI. (a) Oocytes at 2, 8, and 20 h after ICSI. Nuclei/pronuclei (PN) were visualized with H2B-mCherry (red). Oocytes with PN (WT 69/69 vs. KO 1/62), and 2cell embryos (WT 53/69 vs. KO 0/62) were counted at 8 h and 20 h after ICSI, respectively. Representative images are shown. Arrows, arrowheads, and asterisk indicate maternal, paternal, and fragmented chromosomes, respectively. Scale bar = 20 μm. (b) Intracellular Ca2+ changes in oocytes after ICSI. Ratio of GEM-GECO fluorescence was recorded.