For the first time, a pig model of a new conditional expression Cas9 gene tool was constructed and a model of primary lung cancer in large animals was established.

On November 16th, the latest research results of the Lai Liang Studies Group of the Guangzhou Institute of Biomedicine and Health of the Chinese Academy of Sciences were published online in Genome Research under the title Cre-dependent Cas9-expressing energy efficient in vivo genome editing.
the first study to build a new conditional expression Cas9 gene tool pig model, using this model, the first to achieve direct inviviable large animals for inviviable gene editing, and for the first time to establish a large animal primary lung cancer model.
pigs are closer to humans in organ structure, size, physiological metabolism, immune system, etc., and are generally considered to be ideal models of large animal diseases, xenotransplant donor models and heterogeneous organ re-engineering receptor models.
obtain these models requires genome editing of pigs.
at present, it is not technically feasible to make genetic mutations directly in the body of large animals such as pigs.
pig's genome editing relies on fertilized egg injections or somatic cell nuclear transplantation techniques.
fertilized egg injection method to establish gene editing animals easy to produce chimines, need to reproduce to the second generation, even the third generation, 2-3 years time to obtain a real-world gene editing pig; Using gene targeting techniques,
researchers were able to insert the Cas9 protein gene that cut the gene into a specific site in the pig genome (ROSA26), the equivalent of adding a gene scissors to the pig's body, and adding a loxp site that binds to Crererereenzyme near the Cas9 gene, which is equivalent to a switch that controls the opening of its shear function.
the researchers used this tool model, eliminating the need to rely on fertilized egg injections or somatic nuclei transplanttechnology, to transfer in animals gRNAs and recombinant enzymes that identify specific genes, and to edit the pig's genome directly to quickly obtain the corresponding gene-edited pig model.
researchers packaged gRNAs slow viruses containing Crerereenzyme and targeting six tumor-related genes by ticking the nose to infect the lungs of the tool pigs, which undergo cancerous mutations in the genome of the pig's lung cells.
three months later, the pig showed typical lung cancer symptoms and pathological changes, thus establishing a large animal model of primary lung tumor.
using the conditional expression Cas9 gene pig model, can efficiently achieve the editing of single-, multi-gene, super-large fragment genes in large animals.
the results of this research will advance the research on the function of the pig gene and accelerate the establishment of gene-modified pig models with important applications in biomedicine and agriculture.
research work has been supported by the National Natural Science Foundation of China, the key projects of international cooperation in science and technology, the Guangdong Science and Technology Program and the Guangzhou Science (Technology) Research Project.
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