Methods of modifying eukaryotic cells

a technology of eukaryotic cells and vectors, applied in the field of methods of modifying eukaryotic cells, can solve the problems of reducing any potential benefit, vectors have not been generally useful for modifying endogenous genes or chromosomal changes,

Inactive Publication Date: 2005-06-30
REGENERON PHARM INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0011] 1. Bacterial homologous recombination to precisely engineer a desired genetic modification within a large cloned genomic fragment, thereby creating a large targeting vector for use in eukaryotic cells (LTVECs);

Problems solved by technology

In addition, the increased targeting frequency obtained using long homology arms could diminish any potential benefit that can be derived from using isogenic DNA in these targeting vectors.
However, once made, these vectors have not been generally useful for modifying endogenous genes or chromosomal loci via homologous recombination because of the difficulty in detecting rare correct targeting events when homology arms are larger than 10-20 kb (Joyner, The Practical Approach Series, 293, 1999).

Method used

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  • Methods of modifying eukaryotic cells
  • Methods of modifying eukaryotic cells
  • Methods of modifying eukaryotic cells

Examples

Experimental program
Comparison scheme
Effect test

example 1

Engineering Mouse ES Cells Bearing a Deletion of the OCR10 Gene

a. Selection of a Large Genomic DNA Clone Containing mOCR10.

[0121] A Bacterial Artificial Chromosome (BAC) clone carrying a large genomic DNA fragment that contained the coding sequence of the mouse OCR10 (mOCR10) gene was obtained by screening an arrayed mouse genomic DNA BAC library (Incyte Genomics) using PCR. The primers employed to screen this library were derived from the mOCR10 gene cDNA sequence.

[0122] Two primer pairs where used:

(a) OCR10.RAA(5′-AGCTACCAGCTGCAGATGCGGGCAG-3′)andOCR10.PVIrc(5′-CTCCCCAGCCTGGGTCTGAAAGATGACG-3′)which amplifies a 102 bp DNA; and(b) OCR10.TDY(5′-GACCTCACTTGCTACACTGACTAC-3′)andOCR10.QETrc(5′-ACTTGTGTAGGCTGCAGAAGGTCTCTTG-3′)which amplifies a 1500 bp DNA.

[0123] This mOCR10 BAC contained approximately 180 kb of genomic DNA including the complete mOCR10 coding sequence. This BAC clone was used to generate an LTVEC which was subsequently used to delete a portion of the coding region of...

example 2

Increased Targeting Frequency and Abrogation of the Need to Use Isogenic DNA when LTVECs are Used as the Targeting Vectors

[0136] As noted above, the increased targeting frequency obtained using long homology arms should diminish the benefit, if any, derived from using genomic DNA in constructing LTVECs that is isogenic with (i.e. identical in sequence to) the DNA of the eukaryotic cell being targeted. To test this hypothesis, Applicants have constructed several LTVECs using genomic DNA derived from the same mouse substrain as the eukaryotic cell to be targeted (presumably isogenic), and a large number of other LTVECs using genomic DNA derived from mouse substrains differing from that of the eukaryotic cell to be targeted (presumably non-isogenic). The non-isogenic LTVECs exhibited an average targeting frequency of 6% (ranging from 1-20%, Table 1), while the isogenic LTVECs exhibited as average targeting frequency of 3% (ranging from 2-5%), indicating that the rate of successful tar...

example 3

Detailed Description of the TagMan®-Based MOA for Identification of Targeted ES Clones

[0137] ES cell clones that have taken up the LTVEC and incorporated it into the genome at the targeted locus by homologous recombination are identified by a modification of allele (MOA) assay that uses real-time quantitative PCR to discern the difference between targeted ES cell clones, in which one of the two targeted alleles is modified, and non-targeted ES cell clones, in which both alleles remain unmodified. The MOA assay consists of a primary and a secondary screen. The primary screen contains the following steps: (1) growth of LTVEC-transfected ES cell clones on gelatin-coated 96-well plates; (2) isolation of genomic DNA from each ES cell clone; (3) use of each genomic DNA sample as a template in 8 separate quantitative PCRs on two 384-well plates in which 2 of the PCRs employ a target-locus-specific primer set that hybridyzes to DNA sequences at one end of the genomic fragment targeted for ...

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Abstract

A method for engineering and utilizing large DNA vectors to target, via homologous recombination, and modify, in any desirable fashion, endogenous genes and chromosomal loci in eukaryotic cells. These large DNA targeting vectors for eukaryotic cells, termed LTVECs, are derived from fragments of cloned genomic DNA larger than those typically used by other approaches intended to perform homologous targeting in eukaryotic cells. Also provided is a rapid and convenient method of detecting eukaryotic cells in which the LTVEC has correctly targeted and modified the desired endogenous genes(s) or chromosomal locus (loci) as well as the use of these cells to generate organisms bearing the genetic modification.

Description

[0001] This application claims priority to U.S. patent application Ser. No. 09 / 732,234, filed Dec. 7, 2000 and U.S. Provisional Application No. 60 / 244,665, filed Oct. 31, 2000. Throughout this application various publications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application.FIELD OF THE INVENTION [0002] The field of this invention is a method for engineering and utilizing large DNA vectors to target, via homologous recombination, and modify, in any desirable fashion, endogenous genes and chromosomal loci in eukaryotic cells. These large DNA targeting vectors for eukaryotic cells, termed LTVECs, are derived from fragments of cloned genomic DNA larger than those typically used by other approaches intended to perform homologous targeting in eukaryotic cells. The field of the invention further provides for a rapid and convenient method of detecting eukaryotic cells in which the LTVEC has correctly target...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): A01K67/027C12N5/10C12N15/09C12N15/79C12N15/00C12N15/90C12Q1/68
CPCA01K67/0275A01K2217/05C12Q1/6827C12N15/907C12N15/79A01K2227/105C12N5/0606C12N15/85C12N2510/00C12N2810/10
Inventor ECONOMIDES, ARISMURPHY, ANDREWVALENZUELA, DAVIDFRENDEWEY, DAVIDYANCOPOULOS, GEORGE
Owner REGENERON PHARM INC
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