Figure 3.

Recombinant human phospholipase Cζ (PLCζ) protein induces Ca²⁺ oscillations in mouse and human eggs and initiates early embryo development. (A) Representative fluorescence (au: arbitrary units) recordings reporting the Ca²⁺ concentration changes in a mouse and human egg after microinjection of human PLCζ recombinant protein (top and bottom trace, respectively). Microinjection of NusA alone does not induce Ca²⁺ release in mouse eggs (middle trace). (B) Micrographs illustrating mouse embryos at the various early developmental stages (pronuclear formation [PN], two-cell and eight-cell stages, and blastocyst stage) achieved after egg microinjection with ∼80 fg of purified, wild-type human PLCζ recombinant protein (0.0167 mg/mL). The optimal efficiency of blastocyst formation achieved by microinjection of hPLCζ into mouse eggs was 50% to 60%.