UAS regulatory sequences drive expression of an isolated polyglutamine (polyQ) repeat from Hsap\ATXN3. The polyQ repeat has an expanded length of 80 residues and is encoded by CAGCAA doublet repeats, rather than a pure CAG tract, to avoid the possibility of repeat-associated non-ATG (RAN) translation and mRNA toxicity. The open reading frame is tagged with Tag:HA.