UAS regulates expression of the Rga intron (containing the sisRNA:1 stable intronic sequence RNA), cloned in between DsRed(Unk) and Tag:MYC. The 3' end of sisRNA:1 has been replaced with a 76bp antisense element against the endogenous long ncRNA lncRNA:roX1. In addition, compensatory mutations have been introduced to the regions of sisRNA:1 that base pair with this new 76bp sequence to preserve the secondary structure as much as possible.