Mutated genomic Cirl sequence has been inserted into the attP site in TI{TI}CirlKO.attP.w-, reconstituting a Cirl locus that exclusively expresses the Cirl-1TM protein isoform (a silent mutation has been introduced at the splice donor of the exon 6/intron 6 boundary and the Cirl-7TM protein isoform-specific coding sequence following intron 6 has been removed). The expressed Cirl-1TM protein is tagged with 2xTag:V5 at the C-terminal end.