This mutant allele contains a loxP- and FRT-flanked neomycin resistance cassette, in reverse orientation, in intron 13 in addition to the EGFP coding sequence, followed by a third loxP site, inserted into the last exon. It encodes a fusion protein in which the C-terminal of TCIRG1 is joined to the N-terminal of EGFP by the linker sequence AALELVDPPGSIAT. (J:150327)