Germ-line transmission of transgenes in Xenopus laevis

Adult Xenopus laevis frogs made transgenic by restriction enzyme-mediated i ntegration were bred to test the feasibility of establishing lines of frogs that express transgenes. All of the 19 animals raised to sexual maturity g enerated progeny that expressed the transgene(s). The patterns and levels o f expression of green fluorescent protein transgenes driven by a viral prom oter, rat promoter, and four X. laevis promoters were all unaffected by pas sage through the germ line. These results demonstrate the ease of establish ing transgenic lines in X. laevis.