Researchers have broken new ground in the field of reproductive health. Scientists have identified the key protein that helps facilitate the fusion of sperm and egg cells during fertilization.
A study conducted by scientists from the Wellcome Trust Sanger Institute in the UK has resulted in the discovery of a protein that is active on the surface egg cells in mammals. This important protein serves a key function in allowing female gametes to identify male gametes during the process of conception. The researchers published their findings in the online journal Nature.
"We have solved a long-standing mystery in biology by identifying the molecules displayed on the sperm and egg which must bind each other at the moment we were conceived," said Wellcome Trust Sanger Institute researcher Dr. Gavin Wright. "Without this essential interaction, fertilisation just cannot happen. We may be able to use this discovery to improve fertility treatments and develop new contraceptives." Wright is also the senior author of the study.
The fusion of the sperm and egg is one of the most important processes in reproduction. This is considered as the exact moment when fertilization occurs and a zygote is produced.
Back in 2005, Japanese scientists successfully identified the protein present in sperm cells that allowed the sperm cell to recognize an egg cell. The protein was named the Izumo protein, after the Japanese word for a marriage shrine. While the male protein has been studied extensively since then, researchers struggled to find the protein's female counterpart.
The team from Wellcome Trust Sanger Institute has successfully identified the egg cell protein. The researchers named the newly discovered protein as the Juno protein, after the Roman goddess of fertility.
"The Izumo-Juno pairing is the first known essential interaction for sperm-egg recognition in any organism," said Dr. Enrica Bianchi, another researcher from the Wellcome Trust Sanger Institute and one of the study's co-authors. "The binding of the two proteins is very weak, which probably explains why this has remained a mystery until now. Previous work in the laboratory led us to expect the interaction to be weak, and this then guided the design of our experiments, and, after a lot of effort, it finally worked."
To find the Juno protein, the scientists developed a synthetic Izumo protein that was then used to find the corresponding binding protein on a mouse egg cell's surface. To gain a deeper understanding of the Izumo-Juno pairing, the scientists also developed a group of mice that could not produce the Juno protein. The team found that these female mice were rendered infertile, further emphasizing the importance of the Juno protein in reproduction.
Experts believe that the new discovery could have important applications in reproductive health. Possible applications range from the development of more effective contraceptives and even improved treatment protocols to help couples suffering from reproductive difficulties.