Birth of Normal Offspring from Mouse Eggs Activated by a Phospholipase Cζ Protein Lacking Three EF-hand Domains

Abstract

Sperm-specific phospholipase C, PLCζ, is a candidate for the Ca²⁺ oscillation-inducing factor that is introduced into the ooplasm upon sperm-egg fusion. In addition to the 647-residue full-length PLCζ, s-PLCζ lacking the N-terminal 110 amino acids is known to be present in the mouse testis. In this study, we attempted to obtain full-term offspring from s-PLCζ-activated eggs by round spermatid injection. Metaphase II-arrested eggs injected with a high RNA concentration of s-PLCζ RNA normally developed to blastocysts. When the round spermatid nucleus was injected into telophase II-stage eggs previously activated by s-PLCζ RNA, three live offspring were successfully obtained by transfer of the developed 4-cell embryos to pseudopregnant mice. These three offspring all grew to be normal adults and reproduced healthy second-generation mice.