Genomic sequence has been inserted into the attP site in TI{TI}CirlKO.attP.w-, reconstituting a Cirl locus in which a H>A mutation has been introduced into the GPCR proteolysis site (GPS) to abolish autoproteolytic cleavage. The coding sequence is tagged in 3 different locations. A mRFP(Unk) tag is inserted within the N-terminal fragment of the extracellular region and tags both the Cirl-1TM and Cirl-7TM protein isoforms. In addition, the Cirl-1TM protein isoform is tagged with 2xTag:V5 at the C-terminal end of the coding sequence and the Cirl-7TM protein isoform is tagged with 3xTag:FLAG in the third intracellular loop.