The targeting vector contains an FRT-flanked neomycin (neo) resistance cassette inserted downstream of exon 3. Exon 4 is modified to harbor alanine substitutions at amino acids 92 and 93 (S92A-L93A). These mutations are located in the hinge domain and are associated with the differentiation of TH17 cells. Flp-mediated recombination removed the FRT-flanked neo cassette. (J:248565)