The mito-G93ASOD1 fusion protein contains a mouse mitofilin (Immt) cDNA sequence encoding the first 187 amino acids (including the mitochondrial targeting presequence, MMP cleavage site and transmembrane domain) fused in-frame to the N-terminus of a human Cu,Zn superoxide dismutase cDNA sequence harboring the G93A mutation (SOD1) associated with amyotrophic lateral sclerosis (ALS). The SOD1 start codon was removed and substituted with an in-frame 6 nt DNA linker. This mito-G93ASOD1 sequence was inserted between exon 2 and exon 3 of mouse prion protein (PrP or Prnp) gene at a unique XhoI site in the MoPrP.Xho plasmid vector. The founder line with the highest expression level (founder line 7) was characterized.