A targeting vector from the International Mouse Knockout Consortium (IKMC) containing an FRT site, IRES-LacZ, loxP site, neo cassette, FRT site, LoxP site, sequence encoding exon 2, and a loxP site was inserted via homologous recombination. Flp-mediated recombination removed the LacZ and neo cassettes leaving exon 2 floxed. (J:229094)