A lox511 site, loxP site and FRT flanked neo cassette were inserted upstream of exon 11 and a loxP site, a splice acceptor site, IRES site, EGFP cassette, F3 flanked hygromycin cassette and lox2272 site were inserted downstream of exon 15. Flp mediated recombination removed the neo and hygromycin cassettes. (J:184012)