The process of egg fertilization seems like a simple mechanism. However, a number of molecular steps are necessary for efficient fertilization by sperm to occur.
Researchers at Durham University, UK and Osaka University, Japan recently identified a key player in this process, a protein made by the PDILT gene.
Using a mouse model in which the PDILT gene was knocked out, scientists found that the PDILT gene seems to allow sperm to bind to an egg and enable fertilization.
In normal mice, fertilization will occur in 80% of the female eggs. However, in the PDILT knock-out mice, less than 3% of the eggs were fertilized, showing a dramatic decrease in fertility.
The presence of cumulus cells surrounding the egg also aids fertilization by allowing the sperm to bind to the egg.
Dr Adam Benham, a coauthor of the study from Durham University, describes the role of PDIL, “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 fertilisation process.”
These experiments were performed in a mouse model. The researchers are now working to test the role of the PDILT gene in human cells.
These data are significant for the field of reproductive medicine because they could help diagnose unexplained male infertility.