Metal Ion Fluxes Controlling Amphibian Fertilization

Journal Article · Thu Jul 01 00:00:00 EDT 2021 · Nature Chemistry

DOI:https://doi.org/10.1038/s41557-021-00705-2· OSTI ID:1841769

Seeler, John F.; Sharma, Ajay; Zaluzec, Nestor J.; Bleher, Reiner; Lai, Barry; Schultz, Emma G.; Hoffman, Brian M.; LaBonne, Carole; Woodruff, Teresa K.; O’Halloran, Thomas V.

Mammalian oocytes undergo major changes in zinc content and localization to be fertilized, the most striking being the rapid exocytosis of over 10 billion zinc ions in what are known as zinc sparks. Here, we report that fertilization of amphibian Xenopus laevis eggs also initiates a zinc spark that progresses across the cell surface in coordination with dynamic calcium waves. This zinc exocytosis is accompanied by a newly recognized loss of intracellular manganese. Synchrotron-based X-ray fluorescence and analytical electron microscopy reveal that zinc and manganese are sequestered in a system of cortical granules that are abundant at the animal pole. Through electron-nuclear double-resonance studies, we rule out Mn2+ complexation with phosphate or nitrogenous ligands in intact eggs, but the data are consistent with a carboxylate coordination environment. Our observations suggest that zinc and manganese fluxes are a conserved feature of fertilization in vertebrates and that they function as part of a physiological block to polyspermy.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: National Institutes of Health (NIH); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1841769
• Journal Information: Nature Chemistry, Vol. 13, Issue 7
• Country of Publication: United States
• Language: English