UAS regulatory sequences drive expression of a single mRNA that can give rise to three distinct proteins, due to the presence of a self cleaving T2A element between each of the three open reading frames. The three encoded proteins are lexA(DBD)::CIBN, mCherry and p65(AD)::CRY2 respectively. The lexA(DBD)::CIBN and p65(AD)::CRY2 proteins form the two halves of a light-regulated split transcriptional activation system.