A loxP site was inserted into intron 2 and an frt-neo-frt-loxP cassette was inserted into intron 4, floxing exons 3 and 4 of the Slc1a2 gene from the bacterial artificial chromosome clone RP24-315H4. The neomycin cassette was removed via FLP-mediated recombination, leaving exons 3 and 4 floxed by loxP sites. Cre-mediated recombination can be used to remove exons 3 and 4 which results in a frameshift deletion.