Saturday, May 12, 2012
Japan – UK - Scientists Find Gene For Male Fertility In Mice
Researchers from Japan and the U.K. have identified a new male fertility gene that may help with the development of future fertility treatments in humans.
Experts from Durham University in the U.K. and Osaka University in Japan have identified a new gene that may help with the development of future fertility treatments.
In a study published in the journal, Proceedings of the National Academy of Sciences, they discovered that this gene, which makes a protein called PDILT, enables sperm to bind to an egg, a process essential to fertilization.
When the gene was ‘switched off’ in male mice, the team found that less than three percent of females’ eggs were fertilized compared to more than 80 percent in mice when the gene was left switched on.
The researchers also found that the cumulus cells, a cluster of cells surrounding and protecting an egg, play an important role in fertility – their presence enables sperm to bind properly to an egg.
“The protein is an essential part of the navigation system of sperm. It helps sperm swim through the oviduct to the egg and without it sperm get stuck. Our results show that navigating the oviduct is an important part of the fertilization process,” said Dr. Adam Benham from Durham University in the U.K.
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. ADAM3 then helps the sperm swim past the uterus, ascend the oviduct, and get through the sticky outer layers of an egg.
The team honed in on the role of the PDILT protein by switching it off in mice and tracking the ability of sperm to bind to and fertilize eggs in petri dishes and in mice. They noticed that sperm from mice with the PDILT gene switched off will not bind to a bare egg, but will bind to an egg surrounded by cumulus cells.
“This protein is essential for sperm to migrate successfully and is required for fertility. The next step is to see how this protein works with other proteins to control the sperm binding and fusion process,” said Dr. Masahito Ikawa from Osaka University.
Although the research and findings are at an early stage, the researchers now hope to look at how the gene affects sperm-to-egg binding in humans. They also hope that their research may lead to new in vitro fertility treaments. Similarly, new contraceptive techniques could be developed that deactivate the PDILT gene and prevent sperm from fertilizing the egg.
The article can be found at: Tokuhiro K et al. (2012) Protein disulfide isomerase homolog PDILT is required for quality control of sperm membrane protein ADAM3 and male fertility.
Source: Durham University.