site - directed mutagenesis using positive antibiotic selection

The basis for site-directed mutagenesis by positive antibiotic selection is that a selection oligonucleotide or oligonucleotides are simultaneously annealed, with the mutagenic oligonucleotide, to repair an antibiotic resistance gene. Selection for the mutant strand is enabled by antibiotic resistance of the mutated DNA and sensitivity of the nonmutated strand. This approach offers a very efficient means to generate an indefinite number of the desired mutations with little hands-on time. Transformation following mutagenesis is performed in a mismatch repair-deficient strain of E. coli (such as ES1301 mutS) followed by transformation into a final host.