A targeting vector introduced point mutations (GCTCAACCT to CGGCCGCGG) in exon 3 resulting in a leucine to glycine substitution at amino acid 160 (L160G), an asparagine to arginine change at amino acid 161 (N161R), and a leucine to glycine change at amino acid 162 (L162G), creating the delta JBD mutation. In addition, a floxed neomycin resistance cassette was introduced in intron 3. Cre-mediated recombination excised the selection cassette. The delta JBD mutation results in a defective JNK-binding domain. (J:261382)