Abstract
Transgenesis is an essential, powerful tool for investigating gene function and the activities of enhancers, promoters, and transcription factors in the chromatin environment. In Xenopus, current methods generate germ-line transgenics by random insertion, often resulting in mosaicism, position-dependent variations in expression, and lab-to-lab differences in efficiency. We have developed and tested a Xenopus FLP-FRT recombinase-mediated transgenesis (X-FRMT) method. We demonstrate transgenesis of Xenopus laevis by FLP-catalyzed recombination of donor plasmid cassettes into F(1) tadpoles with host cassette transgenes. X-FRMT provides a new method for generating transgenic Xenopus. Once Xenopus lines harboring single host cassettes are generated, X-FRMT should allow for the targeting of transgenes to well-characterized integration site(s), requiring no more special reagents or training than that already common to most Xenopus labs.