The targeting construct inserted between the Jalpha and C alpha exons four polyadenylation sequences, a 1.8 kb of upstream regulatory sequence, the Valpha14 promoter, a leader sequence, a floxed stop cassette, the sequence for the Valpha14 and Jalpha18 invariant (Valpha14i) arrangement expressed in most NKT cells and a 0.2 kb intronic sequence. This insertion abolishes TCRalpha expression. (J:201417)