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.

Abstract: A substantially enriched mammalian hepatic liver engrafting cell population is provided. Methods are provided for the isolation and culture of this liver engrafting cell, for example, a cell population containing human liver engrafting cells wherein at least one cell in the population is HLAlow/neg; and expresses at least one marker selected from the group consisting of albumin; 5E12; Ep-Cam; CD49f; and E-Cadherin. The progenitor cells are obtained from a variety of sources, including fetal and adult tissues. The cells are useful in transplantation, for experimental evaluation, and as a source of lineage and cell specific products, including mRNA species useful in identifying genes specifically expressed in these cells, and as targets for the discovery of factors or molecules that can affect them.

Abstract: A substantially enriched mammalian hepatic liver engrafting cell population is provided. Methods are provided for the isolation and culture of this liver engrafting cell. The progenitor cells are obtained from a variety of sources, including fetal and adult tissues. The cells are useful in transplantation, for experimental evaluation, and as a source of lineage and cell specific products, including mRNA species useful in identifying genes specifically expressed in these cells, and as targets for the discovery of factors or molecules that can affect them.

Abstract: Enriched neural stem and progenitor cell populations, and methods for identifying, isolating and enriching for neural stem cells using reagent that bind to cell surface markers, are provided.

Abstract: The invention provides a method for using collagenase to dissociate neural stem cells in neural stem cell cultures when passaging aggregated neural stem cells. The collagenase treatment results in an increased cell viability and an increased number of proliferated neural stem cells over time.