Patent ID: 11505792

Abstract:
Provided is a method for knocking in a gene of interest to a cell. The genome of the cell contains a negative selectable marker, e.g., a thymidine kinase gene flanked by a pair of recombinase recognition sites (RRS), e.g., attP. The method involves introducing into the cell a targeting construct that contains a gene of interest flanked by a second pair of RRS, e.g., attB. The targeting construct also contains in the vector backbone a negative selectable marker, e.g., thymidine kinase gene. When a recombinase recognizing the RRS is expressed, the recombination events between the two pairs of RRS result in the site-specific integration of the gene of interest in the genome of the cell. Upon selection based on the negative selectable marker, the parental cells, cells with undesired integration, e.g., random integration, or the integration of the vector backbone are removed.