SOD1 and amyotrophic lateral sclerosis: To generate motor neuron models of ALS in which misfolded and aggregated SOD1 accumulates inside cells, expression vectors containing human wild-type SOD1 (hSOD1WT) or four ALS-causing hSOD1 mutants (G93A, G37R, D90A, and G85R) tagged with green fluorescent protein (GFP) were used to transiently transfect NSC-34 cells, a motor neuron-like cell line.