基因编辑技术 z-bo 2020-11-17 296

　　Scientists edit the genome of pigs to deactivate a family of retroviruses. These results have important implications for human transplantation medicine. The shortage of human organs and tissues for transplantation represents one of the most important unmet medical needs. One promising prospect is the use of animal organs in humans, where pig organs are particularly suitable for this type of transplant.

　　However, the pig genome contains porcine endogenous retroviruses (PERVs). When cells containing the virus are co-cultured with other cells, these viruses will be transmitted to other cells. Gene editing technology has proven to be used to remove viral genes from pig genomes in preparation for organ transplantation from pigs to humans. However, so far, these efforts have only been successfully achieved in cell lines (not live animals). prove.

　　Here, George Church, Dong Niu and colleagues demonstrated this feat in live animals. The research team first confirmed that PERVs in pig cells can be transmitted to the latter when co-cultured with human cells. Contacting PERV-infected human cells with uninfected human cells can also lead to the spread of the virus. This highlights the need to inactivate PERVs in pigs if organs of pigs need to be transplanted into humans one day.

　　Next, the researchers mapped and characterized the PERVs present in the porcine fibroblast genome, and they discovered a total of 25 PERVs. They used the gene editing tool CRISPR to inactivate all 25 genomic loci. Although there are highly modified cells in the cell population, when PERV editing efficiency is greater than 90%, these cloned cells cannot grow.

　　However, by adding a mixture of factors that are more related to DNA repair, the research team was able to inactivate PERVs up to 100% of viable cell growth. When they implanted the embryos into the sows, they found that the piglets produced did not show signs of PERV, and some piglets were still alive up to 4 months after birth.