The targeting vector deletes 136 bp in the 3 UTR of the gene. The vector contains a loxP site, a wild type exon 2, an FRT-flanked neomycin cassette, a second loxP site and a mutant exon 2 containing the 136 bp deletion. Cre-mediated recombination removed the wild-type exon 2 and the neomycin cassette. (J:229078)