title: Zinc sparks are triggered by fertilization and facilitate cell cycle resumption in mammalian eggs.
abstract: In last few hours of maturation, the mouse oocyte takes up over twenty billion zinc atoms and arrests after the first meiotic division, until fertilization or pharmacological intervention stimulates cell cycle progression toward a new embryo. Using chemical and physical probes, we show that fertilization of the mature, zinc-enriched egg triggers the ejection of zinc into the extracellular milieu in a series of coordinated events termed zinc sparks. These events immediately follow the well-established series of calcium oscillations within the activated egg and are evolutionarily conserved in several mammalian species, including rodents and nonhuman primates. Functionally, the zinc sparks mediate a decrease in intracellular zinc content that is necessary for continued cell cycle progression, as increasing zinc levels within the activated egg results in the reestablishment of cell cycle arrest at metaphase. 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.
authors.affiliation: Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, 250 E. Superior St., Suite 3-2303, Chicago, Illinois 60611, United States.
authors.forename: Alison M
authors.initials: AM
authors.lastname: Kim
authors.forename: Miranda L
authors.initials: ML
authors.lastname: Bernhardt
authors.forename: Betty Y
authors.initials: BY
authors.lastname: Kong
authors.forename: Richard W
authors.initials: RW
authors.lastname: Ahn
authors.forename: Stefan
authors.initials: S
authors.lastname: Vogt
authors.forename: Teresa K
authors.initials: TK
authors.lastname: Woodruff
authors.forename: Thomas V
authors.initials: TV
authors.lastname: O'Halloran
mesh_terms: D000818:Animals; D020013:Calcium Signaling; D002453:Cell Cycle / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D008252:Macaca fascicularis; D008253:Macaca mulatta; D008297:Male; D008322:Mammals / Q000378:metabolism; D008540:Meiosis; D008677:Metaphase / Q000502:physiology; D051379:Mice; D008815:Mice, Inbred Strains; D009865:Oocytes / Q000166:cytology / Q000502:physiology; D010063:Ovum / Q000166:cytology* / Q000502:physiology; D010312:Parthenogenesis; D015032:Zinc / Q000378:metabolism*
chemical_list: D015032:Zinc