Abstract: The present disclosure provides compositions and methods for targeted insertion of a gene of interest in the genome of a cell using single-stranded DNA or double-stranded DNA with 3 overhang. Also provided are methods of generating single-stranded DNA or double-stranded DNA with 3? over-hang that can be used for targeted insertion.

Abstract: The present disclosure provides compositions and methods for enhanced expression of exogenous genes in eukaryotic cells. The method involves introducing into a mammalian cell an exogenous nucleic acid. wherein the exogenous nucleic acid intearates into a locus of the genome that comprises an extended methylation-free CpG island. Also provided are chromosomal loci, sequences for enhanced and stable expression of exogenous genes.

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.

Abstract: Provided are methods for screening a desired variant of a target gene in a eukaryotic system. Compositions for screening a desired variant of a target gene are also provided.

Abstract: The present disclosure provides a composition comprising a site-specific nuclease domain capable of cleaving a target DNA sequence; and a sequence-specific DNA binding domain capable of specifically binding to a recognition DNA sequence, wherein the site-specific nuclease domain operably links to the sequence-specific DNA binding domain.

Abstract: The present disclosure is directed to a novel, unexpected approach of expressing exogenous gene(s) at increased levels by predictably, optionally irreversibly, incorporating the gene(s) into a region of increased gene expression (RIDGE) on a chromosome of a host cell. This approach is accomplished by identification of RIDGE(s) and further by integration of integrase-specific sites (e.g., attP or attB) in the presence of or mediated by integrase. The approach renders a high level of gene expression; predictability of the location of the exogenous genes, elimination of genetic instability or unwanted phenotype; and reduction of time and cost in optimizing protein production in host cells, which will be every useful in the production of therapeutic, prophylactic, and diagnostic proteins.

Abstract: The present disclosure is directed to a novel, unexpected approach of expressing exogenous gene(s) at increased levels by predictably, optionally irreversibly, incorporating the gene(s) into a region of increased gene expression (RIDGE) on a chromosome of a host cell. This approach is accomplished by identification of RIDGE(s) and further by integration of integrase-specific sites (e.g., attP or attB) in the presence of or mediated by integrase. The approach renders a high level of gene expression; predictability of the location of the exogenous genes, elimination of genetic instability or unwanted phenotype; and reduction of time and cost in optimizing protein production in host cells, which will be every useful in the production of therapeutic, prophylactic, and diagnostic proteins.