A lox66 site was inserted upstream of exon 33. The following vector was inserted into intron 34 (5' through 3'): eGFP, exon 33 splice acceptor site, lox77 site, and FRT flanked neo cassette. Flp mediated recombination removed the neo cassette. Cre-mediated recombination will invert the region between lox66 and lox77, bringing eGFP into frame after exon 32. (J:165897)