UASt regulatory sequences drive expression of the full-length ACOX1 open reading frame (ORF) (from the GH07485 cDNA clone), mutated to carry a N250S amino acid substitution. This change is equivalent to a N237S change in the human ACOX1 gene, a variant identified in patients with progressive ataxia and hearing loss. The endogenous stop codon is present, thus even though three copies of the Tag:HA tag are present downstream of the ORF, they are not expected to form part of the translated protein. The ORF is flanked by a pair of incompatible FRT sites (FRT5 and FRT2), which allows for future in vivo exchange of either the promoter or tag sequence.