Cells resistant to toxic genes and uses thereof
First Claim
1. A mutant host cell containing a gyrA gene, an endA gene, and a recA gene, wherein said gyrA and endA genes contain one or more mutations that render said host cell resistant to the expression of one or more toxic genes.
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Abstract
The present invention relates to cells and cell strains that are resistant to the killing effects of one or more toxic genes, particularly those that kill hosts in the absence of a suppressing function, e.g., kicB or ccdB. The host cells may comprise one or more suppression mutations, such as deletional or insertional mutations in gyrA, endA, or recA, or combinations thereof (particularly gyrA/endA or gyrA/recA), which allow cell strains carrying the one or more suppression mutations to survive the presence and/or expression of one or more toxic genes within their genome or in extrachromosomal genetic elements within the host cell. Preferred host cell strains include prokaryotic host cells, particularly specified strains of E. coli containing the gyrA462 mutation and/or one or more additional mutations, such as DB3, DB3.1, DB4 and DB5. The host cells of the invention are useful in producing recombinant genetic constructs, particularly cDNAs and cDNA libraries, via traditional genetic engineering techniques or via recombinational cloning using engineered recombination sites. The host cells are also useful in cloning and propagation of toxic genes that act upon DNA gyrase, such as ccdB.
58 Citations
22 Claims
- 1. A mutant host cell containing a gyrA gene, an endA gene, and a recA gene, wherein said gyrA and endA genes contain one or more mutations that render said host cell resistant to the expression of one or more toxic genes.
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12. Mutant host cell strain DB3 (deposit number NRRL B-30097).
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13. Mutant host cell strain DB3.1 (deposit number NRRL B-30098).
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14. Mutant host cell strain DB4 (deposit number NRRL B-30106).
- 15. Mutant host cell strain DB5 (deposit number NRRL B-30107).
Specification