A truncated form of Hsap\ATXN3, consisting of the normal length glutamine tract (27 repeats) flanked upstream by 12 amino acids and downstream by the carboxy terminal 43 amino acids of Hsap\ATXN3, is expressed under the control of UASt regulatory sequences. The Hsap\ATXN3 protein is tagged at the N-terminal end with Tag:HA.