Worm Breeder's Gazette 15(1): 30 (October 1, 1997)
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
|1||The Netherlands Cancer Institute, Division of Molecular Biology, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands|
|2||Massachusetts General Hospital, Harvard Medical School 149, 13th street, Charlestown, MA 02129, USA|
Members of the Tc1/mariner transposon family are present in many species from different phyla. Interestingly, distantly related species have been shown to carry closely related Tc1- like sequences, while different Tc1-like elements can be found in the same species. These findings strongly suggest horizontal transmission of Tc1-like elements during evolution. We have sown previously that the requirements for Tc1 transposition are limited to the transposase protein and the terminal part of the inverted repeats of the transposon (Vos et. al. (1996) Genes & Development 10:755-761). In vitro transposition is observed when purified transposase is incubated with an artificial transposon that carries only the last 26 basepairs of the inverted repeats. These limited requirements might explain why the family of Tc1/mariner elements has so successfully spread through the animal kingdom and might make it possible to use Tc1 for the transgenesis of different species. We coinjected plasmids containing a modified Tc3 transposon together with Tc3 transposase mRNA into one cell stage zebrafish embryos. The progeny of the injected fish were screened for the presence of the transposon and absence of the plasmid that carried the transposon. Three founder fish were isolated which transmitted the transposon sequence through their germ line. These fish also express the GFP gene, which was cloned into the Tc3 element. The insertion site of one of the Tc3 elements was sequenced. The element had correctly integrated into a TA sequences. Upon injection of Tc3 mRNA into progeny embryos of this founder fish the integrated element was correctly excised, resulting in a characteristic footprint at the site of excision. These results show that Tc3, and most likely all Tc1-like elements, can transpose in a wide range of hosts as long as the minimal requirements for transposition are met. Preliminary results show that Tc1 can also transpose in human cell lines. We will continue to develop this new tool for transgenesis.