Transgenesis in Zebrafish with the Tol2 Transposon System

The zebrafish (Danio rerio ) is a useful model for genetic studies of vertebrate development. Its embryos are transparent and develop rapidly outside the mother, making it feasible to visualize and manipulate specific cell types in the living animal. Zebrafish is well suited for transgenic manipulation since it is relatively easy to collect large numbers of embryos from adult fish. Several approaches have been developed for introducing transgenes into the zebrafish germline, from the injection of naked DNA to transposon-mediated integration. In particular, the Tol2 transposable element has been shown to create insertions in the zebrafish genome very efficiently. By using Tol2 , gene trap and enhancer trap vectors containing the GFP reporter gene or yeast transcription activator Gal4 gene have been developed. Here we outline methodology for creating transgenic zebrafish using Tol2 vectors, and their applications to visualization and manipulation of specific tissues or cells in vivo and for functional studies of vertebrate neural circuits.