Scientists in the UK have successfully used genome editing on a human embryo, uncovering a gene that may play a key role in fertility.
The research was conducted by the Francis Crick Institute, who applied for permission to begin gene editing back in September 2015. The study, published in Nature, identified what appears to be a fertility “master gene”.
The team successfully used CRISPR-Cas9, a popular gene-editing technique that can accurately target and modify DNA, to edit an embryo. They were able to stop a key gene from producing a protein called OCT4.
OCT4 normally becomes active in the first few days of embryo development. When inhibited, it prevented the formation of a “blastocyst”, which is basically the outer shell of the embryo. This suggests that OCT4 plays a previously unknown key role in embryo development.
"We were surprised to see just how crucial this gene is for human embryo development, but we need to continue our work to confirm its role," said Dr Norah Fogarty, the study’s first author, in a statement.
"Other research methods, including studies in mice, suggested a later and more focused role for OCT4, so our results highlight the need for human embryo research."
Using CRISPR-Cas9, the team were able to change the DNA of 41 human embryos. The development of the embryos then stopped after seven days, allowing them to be analyzed. The initially frozen embryos were donated by couples who had undergone IVF treatment.
OCT4 may not just be useful in embryo development. It’s thought it may also play a role in stem cell biology too. Lower than normal OCT4 activity may explain why embryos sometimes fail and lead to miscarriages.
"One way to find out what a gene does in the developing embryo is to see what happens when it isn't working,” said Dr Kathy Niakan, who led the research and submitted the application for permission to edit genes back in 2015.
“Now we have demonstrated an efficient way of doing this, we hope that other scientists will use it to find out the roles of other genes.”