A Novel Selection Marker for Efficient DNA Cloning and Recombineering in E. coli

Production of recombinant DNA in bacterial cells is an essential technique in molecular biology. Plasmids are usually maintained in an E. coli host by antibiotic selection. However, there are only a few antibiotic-resistance markers available in common use. Here we report the adoption of a novel selection marker, mfabl (mutant fabl) for plasmid propagation in E. coli. mfabl expands the limited repertoire of selection markers and allows for more efficient molecular manipulation and plasmid propagation in E. coli. We show that mfabl is not only an efficient plasmid selection marker, but it also possesses unique activity that may facilitate molecular manipulation of unstable sequences. Furthermore, we have incorporated mfabl in the recombineering tool kit for generating mouse gene targeting vectors and demonstrate the advantage of using mfabl-containing recombineering vectors.