The RSRT stop cassette present in TI{TI}Dscam1TM2.iso-KO has been excised, leaving a single RSRT site and a Tag:V5 epitope tag inserted in the endogenous Dscam1 locus, in the juxtamembrane domain in exon 17.2. Exons 17.1 and 17.2 of Dscam1 are mutually exclusive, encoding two different transmembrane and juxtamembrane domains (TM1 and TM2); exon 17.2 encodes the TM2 alternative form, thus TM2-containing isoforms of Dscam1 are tagged with Tag:V5.