A targeting vector was designed to insert a loxP site and frt-flanked neomycin (neo) resistance cassette upstream of exon 2, and a second loxP site downstream of exon 3 of the solute carrier family 17, member 9 (Slc17a9) gene. Flp-mediated recombination removed the neo cassette leaving exon 2 floxed. (J:167972)