An FRT cassette containing y+t7.7 and Rnor\Cd2 sequences separates UAS regulatory sequences from 'Nrt-wg' (a membrane-tethered form of wg in which Tag:M(Nrt) acts as the membrane tethering sequence) that is tagged with 3 copies of Tag:HA at the junction between the Tag:M(Nrt) and wg sequences.