Interplasmid transposition demonstrates piggyBac mobility in vertebrate species Neil F. Lobo, Tresa S. Fraser, John A. Adams & Malcolm J. Fraser Jr.* Department of Biological Sciences, Center for Tropical Diseases Research and TrainingUniversity of Notre Dame, P.O. Box 369, Notre Dame, IN 46556-0369, USA; *Author for correspondence: (Phone: +574-631- 6209, Fax: +574-631-7413, E-mail: fraser.1@nd.edu) Received 16 June 2005; Accepted 1 February 2006 Key words: piggyBac, transposon, transposition Abstract The piggyBac transposon is an extremely versatile helper-dependent vector for gene transfer and germ line transformation in a wide range of invertebrate species. Analyses of genome sequencing databases have identified piggyBac homologues among several sequenced animal genomes, including the human genome. In this report we demonstrate that this insect transposon is capable of transposition in primate cells and embryos of the zebrafish, Danio rerio. piggyBac mobility was demonstrated using an interplasmid trans- position assay that has consistently predicted the germ line transformation capabilities of this mobile element in several other species. Both transfected COS-7 primate cells and injected zebrafish embryos supported the helper-dependent movement of tagged piggyBac element between plasmids in the charac- teristic cut-and-paste, TTAA target-site specific manner. These results validate piggyBac as a valuable tool for genetic analysis of vertebrates. Introduction The Lepidopteran-derived piggyBac transposon is the type element for a unique group of TTAA- targeting Class II transposable elements originally isolated as mutation-inducing insertions in bacu- lovirus genomes (Fraser, Smith & Summers, 1983; Fraser et al., 1985; Cary et al., 1989; Wang, Fraser & Cary, 1989; see Fraser, 2001 for a review). Initial functional analyses confirmed its potential as a helper-dependent gene transfer vector (Fraser et al., 1995), and subsequent demonstrations of its effectiveness as a gene transfer vector have been performed in a number of invertebrate species including the important disease vectors Aedes aegypti (Kokoza et al., 2001; Lobo et al., 2002) and Anopheles gambiae (Grossman et al., 2001; Kim et al., 2004). Its range of utility has been expanded into non-arthropod invertebrates such as Planaria (Gonzalez-Estevez et al., 2003). As yet there has been no demonstrated mobilization of piggyBac in prokaryotic organisms. This unique transposon has also become established as a highly useful transgenic vector for the model genetic system, Drosophila melanogaster (Handler & Harrell, 1999; Hacker et al., 2003; Horn et al., 2003; Lorenzen et al., 2003; Ryder and Russell, 2003; Bonin & Mann, 2004; Parks et al., 2004; Thibault et al., 2004). By using piggyBac in conjunction with P-element as an insertional mutagenesis tool in Drosophila the number of genes tagged in mutational screens has been sig- nificantly expanded (Parks et al., 2004; Thibault et al., 2004). In applying this vector to this inver- tebrate species there has been a demonstrated po- tential for a wide variety of useful genetic manipulations (Parks et al., 2004; Thibault et al., 2004). While this report was under review, Ding Genetica (2006) 128:347–357 Ó Springer 2006 DOI 10.1007/s10709-006-7165-2