The targeting vector is designed to insert a loxP site upstream of exon 5, and an FRT-flanked and loxP-flanked neomycin resistance (neo) cassette downstream of exon 7 of the gene. An internal ribosome entry site (IRES) fused to an enhanced green fluorescent protein sequence was inserted into the 3 prime UTR. Flp-mediated recombination removed the FRT-flanked neo cassette leaving exons 5 through 7 floxed. (J:101977)