Fig. 1
From: CRISPR/Cas9 technology: applications in oocytes and early embryos
Schematic of CRISPR system and early embryo development. a Schematic of the CRISPR system structure and gene repair mechanism. The crRNA (blue) and tracrRNA (orange) direct the Cas9 protein to target the gene of interest, and two nuclease domains (HNH and RuvC) cut the corresponding gene sites to generate DSB. HDR and NHEJ mechanisms repair DNA sequences, and the different outcome is shown in the diagram. b Schematic of early embryo development and a series of epigenetic events, including maternal RNA/protein elimination (red curve), zygotic genome activation (ZGA, green curve), and the changes of DNA methylation and chromatin structures, are also shown