The researchers found the gene a few years ago through a database search for new genes of the PDI family. Following extensive research, they established that the gene made an important protein in the testes.
The PDILT gene, part of the PDI family, helps another gene product called ADAM3 to form and assemble correctly, and then to reach the surface of a sperm, thereby equipping it with the right tools and machinery to navigate and make contact with an egg.
The new findings show the importance of PDILT in the process of sperm-to-egg binding and in enabling sperm to swim past the uterus, ascend the oviduct and to get through the sticky outer layers of an egg.
The team honed in on the role of the protein by switching it off in mice and tracking the ability of sperm to bind to and fertilise eggs in Petri dishes and in mice. They noticed that sperm from mice with the gene switched off will not bind to a bare egg, but will bind to an egg surrounded by cumulous cells.
Dr Benham said: "We now hope to discover how the PDILT protein affects fertility in humans. Mutations in the gene may be responsible for unexplained male fertility problems and further research may aid more effective IVF treatment."