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.

Tc1 as a tool for transgenesis of vertebrates

Henri G.A.M. van Luenen1, Erez Raz2, Barbara Shaerringer2, Wolfgang Driever2, Ronald H.A. Plasterk1

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.