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The zinc spark is an inorganic signature of human egg activation

2016; Nature Portfolio; Volume: 6; Issue: 1 Linguagem: Inglês

10.1038/srep24737

2045-2322

Francesca E. Duncan, Emily L. Que, Nan Zhang, Eve C. Feinberg, Thomas V. O’Halloran, Teresa K. Woodruff,

Sperm and Testicular Function

Abstract Egg activation refers to events required for transition of a gamete into an embryo, including establishment of the polyspermy block, completion of meiosis, entry into mitosis, selective recruitment and degradation of maternal mRNA and pronuclear development. Here we show that zinc fluxes accompany human egg activation. We monitored calcium and zinc dynamics in individual human eggs using selective fluorophores following activation with calcium-ionomycin, ionomycin, or hPLCζ cRNA microinjection. These egg activation methods, as expected, induced rises in intracellular calcium levels and also triggered the coordinated release of zinc into the extracellular space in a prominent “zinc spark.” The ability of the gamete to mount a zinc spark response was meiotic-stage dependent. Moreover, chelation of intracellular zinc alone was sufficient to induce cell cycle resumption and transition of a meiotic cell into a mitotic one. Together, these results demonstrate critical functions for zinc dynamics and establish the zinc spark as an extracellular marker of early human development.