Spinal cord homogenates were taken from three different mouse strains: (1) tgSOD1G93A transgenic mice carrying the pathogenic SOD1 G93A mutation; (2) tgSOD1wtSOD1 transgenic mice overexpressing wildtype human SOD1 at a similar level to the tgSOD1G93A mice; these mice do not succumb to motor neuron disease; (3) wildtype control non-transgenic littermates from the tgSOD1G93A colony. Here, SOD1 is linked to motor neuron disorder.