Juno is the egg Izumo receptor and is essential for mammalian fertilization / Juno é o receptor Izumo do ovo e é essencial para a fertilização de mamíferos

Juno is the egg Izumo receptor and is essential for mammalian fertilization
Juno é o receptor Izumo do ovo e é essencial para a fertilização de mamíferos

Authors: Enrica Bianchi, Brendan Doe, David Goulding & Gavin J. Wright

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Fertilization occurs when sperm and egg recognize each other and fuse to form a new, genetically distinct organism. The molecular basis of sperm–egg recognition is unknown, but is likely to require interactions between receptor proteins displayed on their surface. Izumo1 is an essential sperm cell-surface protein, but its receptor on the egg has not been described. Here we identify folate receptor 4 (Folr4) as the receptor for Izumo1 on the mouse egg, and propose to rename it Juno. We show that the Izumo1–Juno interaction is conserved within several mammalian species, including humans. Female mice lacking Juno are infertile and Juno-deficient eggs do not fuse with normal sperm. Rapid shedding of Juno fromthe oolemmaafter fertilization suggests amechanismfor themembrane block to polyspermy, ensuring eggs normally fuse with just a single sperm. Our discovery of an essential receptor pair at the nexus of conception provides opportunities
for the rational development of new fertility treatments and contraceptives.