The transgene insert contains a 22.5-kb human TCRD gene minilocus consisting of germline Vdelta1, Vdelta2, Ddelta3, Jdelta1, Jdelta3, and Cdelta gene segments and all "intronic" sequence between, including enhancer sequence between Jdelta3 and Cdelta where TCF/LEF-binding site CTTTGAA was mutated to CATAGAA. (J:330514)