Human sperm devoid of PLC, zeta 1 fail to induce Ca²⁺ release and are unable to initiate the first step of embryo development
J. Clin. Invest. 118:11 doi:10.1172/JCI36942 [Go to this article.]

Figure 6
Injection of mouse Plcz1 mRNA rescues egg activation failure after ICSI in mouse eggs.

(A) Injection of a sperm from patient W, with normal [Ca²⁺]_i oscillatory activity (left panel), induces resumption of meiosis after 2 hours (arrows denote anaphase II) and PN formation (broken arrows) by 6 hours after injection. (B) Injection of sperm from patient K, which is unable to initiate [Ca²⁺]_i oscillations (left panel), fails to induce egg activation by either 2 hours or 6 hours (arrowhead denotes MII chromatin). (C) Injection of mouse Plcz1 mRNA (0.1 μg/μl) 2 hours after injection of sperm initiates fertilization-like oscillations and rescues egg activation, as shown by the resumption of meiosis (2 hours) and PN formation (6 hours; 8 hours after injection of patient K’s sperm). 1^st PB, first polar body; 2PB, second polar body. TO-PRO-3 staining (blue) was used to stain the chromatin. Asterisk in inset points to the persistence of the human sperm tail in mouse eggs. Scale bar: 10 μm.