A cos-mini-Mu vector for in vivo DNA cloning

Construction of a mini-Mu plasmid vector containing a cosmid replicon is described. Upon derepression of mini-Mu transposition, bacterial DNA sequences can be flanked by the integrated mini-Mu. These sequences can then be packaged into λ heads by superinfection with a λ helper phage. Cosmid clones carrying particular bacterial genes can be recovered by selection after infection of appropriate strains with the cosmid transducing λ lysate. We report here the successful in vivo cloning of several Escherichia coli genes using the transposoncosmid vector.