The cDNA encoding a N-terminal-truncated form (lacking 286 amino-acid residues) of human ATAXIN-3 with 69 glutamine repeats is driven by a Purkinje-cell specific L7 promoter (Pcp2). The ATG start codon in exon 2 of Pcp2 was mutated to inhibit the expression of exons 1-3. In addition an N-terminal hemagglutinin epitope was added. Three lines were generated, a, b, and c.