Transposase is the only nematode protein required for in vitro transposition of Tc1

The Tcl element of Caenorhabditis elegans is a member of the most widespread class of DNA transposons known in nature. Here, we describe efficient and precise transposition of Tcl in a cell-free system. Tcl appears to jump by a cut-and-paste mechanism of transposition. The terminal 26 bp of the Tcl terminal repeats together with the flanking TA sequence are sufficient for transposition. The target site choice in vitro is similar to that in vivo. Transposition is achieved with an extract prepared from nuclei of transgenic nematodes that overexpress Tcl transposase but also by recombinant transposase purified from Escherichia coli. The simple reaction requirements explain why horizontal spread of Tcl/mariner transposons can occur. They also suggest that Tcl may be a good vector for transgenesis of diverse animal species.