Healthcare (Commonwealth Union) – Since Gregor Mendel an Austrian scientist discovered the inheritance of traits in the 1800s, the role of the gene has continued to enhance into wide variety of fields from gene therapy, to forensic science.
As genetics continues to advance a more recent study led by the University of Cambridge, Loke Centre for Trophoblast Research has demonstrated that a genome editing method can be used to modify a single gene in human embryonic cells. This permits scientists to evaluate the earliest stages of human development in exceptional detail. This approach, called base editing, is a more precise version of CRISPR/Cas9 gene editing.
It allows for the precise alteration of a single nucleotide base pair, the basic unit of DNA, within the approximately 3 billion base pairs that constitute the human genome.
Even without NANOG, cells that become the placenta and yolk sac, important tissues that support early embryonic development, still can develop.
Previous studies have reported base editing in human embryos, but this is the first study to use this method specifically to study gene function in human embryos. Results indicate that the high specificity of base editing could reduce the likelihood of unwanted chromosomal damage, a complication that can occur with the more commonly used CRISPR/Cas9 approach.
Improved knowledge of the genes that are essential for early development, including NANOG, may ultimately lead to improved success rates of IVF treatments and help explain causes of early pregnancy loss.
Professor Kathy Niakan from the University of Cambridge Loke Centre for Trophoblast Research, who led the research indicated that base editing marks a major improvement over traditional CRISPR/Cas9, as it significantly reduces the chance of unintended chromosomal changes. She pointed out that it is capable of accurately switching a single nucleotide base pair within the roughly 3 billion base pairs that make up the human genome – an extraordinary achievement.
Professor Niakan also pointed out that their results suggest that the NANOG gene plays a vital role in the formation of pluripotent cells, which are the fundamental building blocks of human development.
Pluripotent cells have the ability to transform into virtually any cell type in the body and are essential tools in biomedical science, including areas such as drug discovery and disease modelling. Human embryonic stem cells, which are pluripotent, originate in regions of the developing embryo where NANOG activity is particularly high, leading scientists to believe the gene is crucial to their formation.
Dr Oliver Bower, a researcher at the University of Cambridge’s Loke Centre for Trophoblast Research and first author of the study indicated that the high precision of base editing represents a significant leap beyond earlier genome editing methods and it enables them to investigate the earliest stages of human development with much greater accuracy and confidence.
“By pinpointing how genes like NANOG control the development of pluripotent cells, we can make stem-cell systems for biomedical research more predictable and reliable” he said.
Researchers of the study indicated that in mouse studies on prior occasions, loss of NANOG caused disruption in the epiblast and the yolk sac – a tissue that backs the forming embryo. In this particular human embryo research, loss of NANOG mainly had an impact on the epiblast, which is the future body-forming line of cells.
Since the present researchers were unable to directly explore the function of NANOG in human embryos due to the fact that the genome editing methods that are available, such as conventional CRISPR/Cas9, cause a lot of damage to the DNA, that is not desired. This study underscores the significance of a direct evaluation of human development.
