This allele contains a single Frt site and a single loxP site in intron 13 and the EGFP coding sequence, followed by another loxP site, inserted into the last exon. The modified gene encodes a fusion protein in which the C-terminal of TCIRG1 is joined to the N-terminal of EGFP by the linker sequence AALELVDPPGSIAT. EGFP fluorescence and the immunofluorescence signal for the a3 subunit of vacuolar-type ATPase (V-ATPase), which is encoded by the endogenous gene, are colocalized in the late endocytic compartments of mutant peritoneal macrophages. Cre recombinase excision of the loxP-flanked DNA segment generates a null allele. (J:150327)