CA2304642C

Expression of endogenous genes by non-homologous recombination of a vector construct with cellular dna

Abstract

The present invention relates generally to activating gene expression or causing over-expression of a gene by recombination methods in situ. The invention also relates generally to methods for expressing an endogenous gene in a cell at levels higher than those normally found in the cell. In one embodiment of the invention, expression of an endogenous gene is activated or increased following integration into the cell, by non-homologous or illegitimate recombination, of a regulatory sequence that activates expression of the gene. In another embodiment, the expression of the endogenous gene may be further increased by co-integration of one or more amplifiable markers, and selecting for increased copies of the one or more amplifiable markers located on the integrated vector. The invention also provides methods for the identification and expression of genes undiscoverable by current methods since no target sequence is necessary for integration. The invention also provides methods for isolation of nucleic acid molecules (particularly cDNA molecules) encoding transmembrane proteins, and for isolation of cells expressing such transmembrane proteins which may be heterologous transmembrane proteins. The invention also relates to isolated genes, gene products, nucleic acid molecules, and compositions comprising such genes, gene products and nucleic acid molecules, that may be used in a variety of therapeutic and diagnostic applications. Thus, by the present invention, endogenous genes, including those associated with human disease and development, may be activated and isolated without prior knowledge of the sequence, structure, function, or expression profile of the genes.

CA2304642C, drawing sheet 1
Sheet 1 of 19

Term

No projected expiry on record.

  1. Priority
  2. Filed
  3. Granted
  4. Today

3 claims: 3 independent, 0 dependent

  1. 1
    CA 02304642 2013-10-25 -75CLAIMS:1. An in vitro method for over-expressing an endogenous gene in a cell comprising: (a) introducing a vector construct into a cell, said vector construct comprising a promoter which up-regulates gene expression operably linked to an unpaired splice donor sequence and one or more amplifîable markers;(b) the cell integrating said construct into the genome of said cell by non-homologous recombination;and (c) the cell over-expressing said endogenous gene in said cell. 2. An in vitro method for over-expression an endogenous gene in a cell comprising: (a) introducing a vector construct into a cell, said vector construct comprising a promoter which up-regulates gene expression operably linked to a translational start codon, a secretion signal sequence and an unpaired splice donor site, (b) the cell integrating said construct into the genome of said cell by non-homologous recombination;and (c) the cell over-expressing said endogenous gene in said cell, wherein said secretion signal sequence is operably linked to said endogenous gene. 3. An in vitro method for over-expressing an endogenous gene in a cell comprising: (a) introducing a vector construct into a cell, said vector construct comprising a promoter which up-regulates gene expression operably linked to a translational start codon, epitope tag and an unpaired splice donor site;(b) the cell integrating said construct into the genome of said cell by non-homologous recombination;and (c) the cell over-expressing said endogenous gene in said cell. 4. An in vitro method for over-expressing an endogenous gene in a cell comprising: CA 02304642 2013-10-25 (a) introducing a vector construct into a cell, said vector construct comprising a promoter which up-regulates gene expression operably linked to a translational start codon, a secretion signal sequence, epitope tag and an unpaired splice donor site;(b) the cell integrating said construct into the genome of said cell by non-homologous recombination;and (c) the cell over-expressing said endogenous gene in said cell. 5. An in vitro method for over-expressing an endogenous gene in a cell comprising: (a) introducing a vector construct into a cell, said vector construct comprising a promoter which up-regulates gene expression, operably linked to an unpaired splice donor sequence, an amplifîable marker, and a viral origin of replication;(b) the cell integrating said construct into the genome of said cell by non-homologous recombination;and (c) the cell over-expressing said endogenous gene in said cell. 6. An in vitro method for producing an isolated expression product of an endogenous gene, comprising: (a) over-expressing an endogenous gene in a cell according to the method of any of claims 3 to 5, wherein an expression product of said endogenous gene is produced by said cell;and (b) isolating said expression product from said cell. 7. An in vitro method for producing an isolated protein product of an endogenous gene, comprising: (a) introducing a vector comprising a promoter which up-regulates gene expression, operably linked to an unpaired splice donor sequence, into a cell;(b) the cell integrating said vector into the genome of said cell by non-homologous recombination;CA 02304642 2013-10-25 (c) the cell over-expressing an endogenous gene in said cell by upregulation of said gene by said promoter;(d) screening said cell for over-expression of said endogenous gene;(e) culturing said cell under conditions favoring the production of the protein product of said endogenous gene by said cell;and (f) isolating said protein. 8. An in vitro method for producing a protein product of an endogenous gene comprising: (a) introducing a vector comprising a non-retrovirus constitutive promoter which up-regulates gene expression, operably linked to an unpaired splice donor sequence, into a cell;(b) the cell integrating said vector into the genome of said cell by non-homologous recombination;(c) the cell over-expressing an endogenous gene in said cell by upregulation of said gene by said promoter;(d) screening said cell for over-expression of said endogenous gene;and (e) culturing said cell under conditions favoring the production of the protein product of said endogenous gene by said cell. 9. An in vitro method for producing an expression product of an endogenous gene comprising: (a) introducing a vector construct comprising a promoter which upregulates gene expression operably linked to a secretion signal sequence, operably linked to an unpaired splice donor sequence into a cell;(b) the cell integrating said vector into the genome of said cell by non-homologous recombination;(c) the cell over-expressing an endogenous gene in said cell by upregulation of said gene by said promoter;CA 02304642 2013-10-25 (d) screening said cell for over-expression of said endogenous gene;and (e) culturing said cell under conditions favoring the production of the expression product of said endogenous gene by said cell, wherein said secretion signal sequence is operably linked to said endogenous gene. 10. An in vitro method for producing an expression product of an endogenous gene comprising: (a) introducing a vector comprising a non-retrovirus promoter which up-regulates gene expression operably linked to a secretion signal sequence, operably linked to an unpaired splice donor sequence, into a cell;(b) the cell integrating said vector into the genome of said cell by non-homologous recombination;(c) the cell over-expressing an endogenous gene in said cell by upregulation of said gene by said promoter;(d) screening said cell for over-expression of said endogenous gene;and (e) culturing said cell under conditions favoring the production of the expression product of said endogenous gene by said cell. 11. The method of any one of claims 1 to 5 and 8 to 10, further comprising isolating said expression product. 12. An in vitro method for producing an expression product of an endogenous gene, comprising: (a) introducing a vector comprising a promoter which up-regulates gene expression, operably linked to an unpaired splice donor sequence, and one or more amplifîable markers into a cell;(b) the cell integrating said vector into the genome of said cell by non-homologous recombination;CA 02304642 2013-10-25 (c) the cell over-expressing an endogenous gene in said cell by upregulation of said gene by said promoter;(d) screening said cell for over-expression of said endogenous gene;(e) culturing said cell under conditions in which said vector and said endogenous gene are amplified in said cell;and (f) culturing said cell under conditions favoring the production of the expression product of said endogenous gene by said cell. 13. The method of claim 12, further comprising isolating said expression product. 14. The method of any one of claims 1 to 7, 9 and 13 wherein said promoter is a viral promoter. 15. The method of claim 14 wherein said viral promoter is the cytomegalovirus immediate early promoter. 16. The method of any one of claims 1 to 7, 9 and 13 wherein said promoter is inducible. 17. An in vitro method for activating expression from an endogenous gene comprising: (a) introducing into a chromosome-containing host cell a vector suitable for activating an endogenous gene, said vector comprising an unpaired splice donor sequence operably linked to a transcriptional regulatory sequence;(b) treating said cell with an agent capable of introducing DNA breaks in the chromosome of said host cell prior to or following introduction of said vector;and (c) integrating said vector into said DNA breaks so as to result in the formation of an operable linkage between said vector and said endogenous gene, CA 02304642 2013-10-25 -80whereby said endogenous gene is activated by one or more vector-encoded nucleotide sequences;wherein said vector contains a promoter wherein said promoter when inserted into a cellular genome increases expression of the endogenous gene. 18. An in vitro method for drug discovery comprising: (a) integrating a vector, into the genome of a eukaryotic host cell, said vector comprising an unpaired splice donor sequence operably linked to a transcriptional regulatory sequence, wherein said vector integration activates expression of an endogenous gene in said host cell;(b) culturing said cell under conditions favoring expression of said activated gene, thereby producing a gene product of said activated gene;(c) treating said cell with one or more test compounds to be screened for drug activity;and (d) determining the ability of said one or more test compounds to interact with, or affect a cellular phenotype induced by, said gene product;wherein said vector contains a promoter wherein said promoter when inserted into a cellular genome increases expression of the endogenous gene. 19. A method for drug discovery comprising: (a) integrating a vector into the genome of a eukaryotic host cell, said vector comprising an unpaired splice donor sequence operably linked to a transcriptional regulatory sequence, wherein said vector integration activates expression of an endogenous gene in said host cell;(b) culturing said cell in reduced serum medium under conditions favoring production of a gene product of said activated gene, thereby producing cellconditioned media comprising said gene product;and (c) screening one or more test compounds for drug activity by determining the ability of said test compounds to interact with said gene product in said cell-conditioned media;CA 02304642 2013-10-25 -81wherein said vector contains a promoter wherein said promoter when inserted into a cellular genome increases expression of the endogenous gene. 20. The method of any one of claims 1 to 16, wherein said over-expressing non-homologously recombinant cell is isolated and cloned. 21. A method for producing a protein from an endogenous gene in a cell comprising: (1) introducing a genetically engineered vector comprising a transcriptional regulatory sequence operably linked to an unpaired splice donor sequence into a purified eukaryotic cell;
  2. 2
    (2) maintaining said cell under conditions appropriate for integrating said vector into the genome of said cell by non-homologous recombination whereby said transcriptional regulatory sequence and unpaired splice donor sequence are operably linked to said endogenous gene, said splice donor sequence being spliced to a splice acceptor sequence in said gene;
  3. 3
    (3) maintaining said cell under conditions appropriate for expressing said endogenous gene in said cell by means of said transcriptional regulatory sequence; and (4) maintaining said cell so as to produce amounts of the protein encoded by said endogenous gene. 22. The method of claim 20, wherein said transcriptional regulatory sequence is non-retro viral. CA 02304642 2013-10-25 23. A method to express and screen for expression of an endogenous gene in a cell comprising:(1) introducing a genetically engineered vector into a purified eukaryotic cell and maintaining said cell under conditions appropriate for integrating said vector into the genome of a cell, said vector lacking targeting sequences and containing a transcriptional regulatory sequence and unpaired splice donor sequence, so that the coding region of a gene in the genome is operably linked to the transcriptional regulatory sequence and splice donor sequence on the vector, said splice donor sequence being spliced to a splice acceptor sequence in said gene;and (2) screening said cell for expression of a protein that is encoded by said gene. 24. The method of claim 23 wherein said transcriptional regulatory sequence is non-retro viral. 25. The method of claim 23 with the additional step of isolating the cell producing the protein encoded by said gene. 26. A method to express and screen for expression of an endogenous gene in a cell comprising: (1) introducing a genetically engineered vector into a purified eukaryotic cell and maintaining said cell under conditions appropriate for integrating said vector into the genome of a cell by non-homologous recombination, said vector containing a transcriptional regulatory sequence and unpaired splice donor sequence, so that the coding region of a gene in the genome is operably linked to the transcriptional regulatory sequence and splice donor sequence on the vector, said splice donor sequence being spliced to a splice acceptor sequence in said gene;and (2) screening said cell for expression of a protein encoded by the gene, said gene and said upstream region of said gene lacking homology to the vector that would CA 02304642 2013-10-25 -835 facilitate homologous recombination of the vector with the genome to cause expression of said gene. 27. A method to express and screen for expression of an endogenous gene in a cell encoding a protein comprising: (1) constructing a vector comprising a transcriptional regulatory sequence and an unpaired splice donor sequence;(2) introducing said 10 vector into a purified eukaryotic cell;(3) maintaining the cell under conditions permitting non-homologous recombination events between the inserted vector and the genome of the cell whereby said transcriptional regulatory sequence and splice donor sequence are operably linked to said gene, said splice donor sequence being spliced to a splice acceptor sequence in said gene;and (4) screening the recombinant cell by 15 assay for expression of the protein encoded by said gene, said gene and upstream region of said gene having no homology to the vector that would facilitate homologous recombination of the vector with the genome to cause expression of said gene.