Transposons Tn10 and Tn5

Tn 10 and Tn5 are composite bacterial transposons (Fig. 1). Both these transposons, as well as their respective IS elements (IS10 and IS50), transpose by a nonreplicative cut-and-paste mechanism. Tn10/IS10was the first bacterial transposon shown to transpose by the cut-and-paste mechanism and as such provided an early model for this mode of transposition (1,2). In cut-and-paste transposition the transposon is first excised from flanking donor DNA by a pair of transposase-catalyzed double-strand breaks at each transposon end after which the excised transposon is inserted into a target site. Host repair of the transposon-target DNA junction completes the transposition process and leaves a characteristic target-site duplication.