UAS drives expression of the entire mRNA sequence of the transcription factor "α1ACT" (with its native start and stop codons), which is one product of the bicistronic Hsap\CACNA1A gene. The CAG repeat/polyQ region that is linked to spinocerebellar ataxia type 6 occurs within α1ACT, and this construct contains a pathogenic, polyQ-expanded version with a repeat of 70Q. (The wild type CAG repeat is between 4 and 18, whereas the SCA6-causing allele shows an expansion between 19 and 33 repeats.)