COUNCIL CHRONICLE – More than 17 years after the end of the human genomics project, scientists have come to understand a lot about how genes function, how they are structured, and crucially, how they are controlled.
Gene Editing Used to Look at the Human Embryo
CRISPR/Cas9 was found naturally in the immune system of certain bacteria. There, it destroys the DNA of invading viruses. Because it potentially opens up the door for gene editing in humans, this gene editing technology is shrouded in some controversy. But in this new study, it was used to understand the nature of human development.
The researchers injected CRISPR/Cas9 into 58 single-celled embryos. These were no longer needed for in-vitro fertilization and had been donated for research. The Cas9 enzyme then disrupted the production of a protein called OCT4 that is essential for embryonic development.
Half of the control group that had not been injected with CRISPR continued to develop normally, compared to only 19 percent of the experimental group. The study reveals that OCT4 seems to play a role in the development of certain cell types, including placental cells.
Although parts of OCT4 still remain a mystery, researchers plan further studies using the CRISPR sequence. They hope to understand why the development process can go awry in some embryos and not others. This might lead to the elaboration of a treatment that boosts the success rate of in-vitro fertilization.
The study also helps researchers understand embryo evolution. After all, what separates one species from another is not merely the precise sequence of genes or proteins. Instead, it is the regulation of gene expression during different stages of development.
“This paper opens up a new era of human functional genetics,” according to Amy Ralston, a developmental biologist at Michigan State University.