Controlling gene activity in human development
In the developing embryo and during the specialisation of stem cells , the activity of genes must be tightly controlled (by a process called epigenetics) so that the correct genes are switched on and off at the right time and in the right cells. One of the main ways that this process is regulated is by a protein complex called Polycomb Repressive Complex 2 (PRC2), which keeps genes switched off until they are needed. We know from previous studies that PRC2 is necessary for controlling gene activity during the development of the fruit fly and the mouse, but we know very little about its role in human development or in the specialisation of stem cells. As described in the journal Cell Reports, the researchers used the CRISPR gene editing technique to delete PRC2 from human embryonic stem cells . Loss of PRC2 caused the cells to switch on many genes that are not normally active in these cells. Interestingly, the set of genes that were switched on have important roles in the formatio...