YOU CAN FORGET about the birds and the bees. If you really want to learn how babies are made, you need to know about Juno and Izumo.
Fertilization takes place when an egg cell and a sperm cell recognize one another and fuse to form an embryo. But how they recognize each other in order to hook up had remained a mystery.
Researchers said yesterday that they have identified a protein on the egg cell's surface that interacts with another protein on the surface of a sperm cell, allowing the two cells to join.
This protein, dubbed Juno in honor of the ancient Roman goddess of fertility and marriage, and its counterpart in sperm, named Izumo after a Japanese marriage shrine, are essential for reproduction in mammals including people, they said.
This new understanding of the role of these two proteins could help improve the treatment of infertility and guide the development of new contraceptives, the researchers said.
"By identifying this interaction between Juno and Izumo, we now know the identity of the receptor proteins found on the surface of our father's sperm and our mother's egg that must interact at the moment at which we were conceived," said Gavin Wright of the Wellcome Trust Sanger Institute in Britain, one of the researchers in the study published in the journal Nature.
The researchers are now screening infertile women to try to determine whether problems with the Juno receptor are to blame.