Gene editing methods for establishing animal models mainly include transgene and gene targeting. Gene targeting technology refers to site-specific recombination of endogenous DNA to change a specific gene in the genome to study the function of the gene in vivo, including gene knockout and knock-in. Due to the lack of embryonic stem cell lines of large animals, traditional gene targeting techniques are difficult to establish primate disease models. The recently developed targeted genome editing method CRISPR/Cas9 technology can directly target in embryonic cells and has been widely used in different species for genome modification and genetic modification.
CRISPR/Cas9 is a new technology derived from bacterial acquired immunity that uses RNA to guide Cas protein to edit and modify genes. Non-human primates (such as macaques, cynomolgus monkeys, etc.) are biologically highly similar to humans. In 2011, Chinese scientists completed a comparative analysis of the genomes of cynomolgus monkey and rhesus monkey. The homology between macaque and human genome is as high as 93%, and the macaque brain is anatomically similar to humans.
But at present, the use of primates to study the gene modification function of CRISPR/Cas9 is limited to the detection of genomic DNA mutations. Therefore, the use of primates to establish genetically modified animal models still faces huge challenges. First of all, the target rate of positive embryos and the success rate of transplantation need to be improved, especially considering the long reproductive cycle and reproductive period of primates, and high animal costs. Secondly, currently reported genetically modified monkeys have the deficiencies of chimeric polymorphism and non-single-point genetic mutations. Whether all cells in the animal body have the same genetic modification remains to be confirmed. Optimizing the target rate of positive embryos and the success rate of transplantation is the key to establishing primate models.
The rapid development of the new gene editing technology CRISPR/Cas9 system makes the establishment of animal disease models no longer limited to a few model organisms, making it possible to realize genome editing in all species. Primates have a high degree of similarity with humans in the nervous system, metabolic system and immune system. In addition, my country is rich in primate resources, and the advanced gene editing technology CRISPR/Cas9 system is used to construct a major human nervous system degeneration The primate model of disease will be the trend of future biomedical research development.