UAS regulatory sequences drive expression of two coding regions separated by a 2A peptide sequence that are designed to be used to report neuromodulator release in vivo using the 'Tango' system (PMID:18165312). The upstream coding region encodes a tethered transcription factor which is composed of the Dop1R1 receptor fused via a Tag:CS(TEVp) cleavage site to a lexA::UnkAD driver (the driver is tagged with the Tag:HA epitope) (this coding region is represented in FlyBase by the Dop1R1UAS.Tango allele). The downstream coding region consists of Arr1 fused to the TEV\NIa protease (this coding region is represented in FlyBase by the Arr1::TEV\NIaUAS.Tango allele). Upon activation of the Dop1R1 receptor by its ligand, the Arr1::TEV\NIa protein is recruited, resulting in cleavage at the Tag:CS(TEVp) site. This allows the Tag:HA-tagged lexA::UnkAD driver to translocate to the nucleus, where it can drive expression of a reporter that is controlled by lexAop regulatory sequences.