Egg Zinc Sparks: Triggered by Fertilization and Facilitate Cell Cycle Resumption

Using probes, we show that fertilization of mature, zinc-enriched eggs trigger the ejection of zinc into the extracellular milieu as zinc sparks. The sparks mediate a decrease in intracellular zinc content that is necessary for continued cell cycle progression. The mammalian egg thus uses a zinc-dependent switch mechanism to toggle between metaphase arrest and resumption of the meiotic cell cycle at the initiation of embryonic development. Read Article.