A 452bp fragment from the tup upstream region (coordinates 2L:18900307..18899855 , release 6 genome) is fused upstream of a membrane-targeted fusion protein containing the Tag:SS(Akh) signal peptide, the Hsap\CD4 transmembrane domain, a tandem fluorescent dimer composed of EGFP and GFP and an endoplasmic reticulum export signal from the Hsap\KCNJ2 gene (generated using vector pDEST-HemmarG, Addgene:31221 ).