Mutant and normal SOD1 from brainstem of 45- and 130-day-old G93A mice (G93A D45, “presymptomatic,” and G93A D130, “symptomatic,” respectively), 130-day-old NS mice (NS D130, normal SOD1), and control, nontransgenic littermates. Both mouse (mSOD1) and human (hSOD1) were detected by using a polyclonal antibody cross-reacting with the human and mouse protein. All SOD1 transgenic mice (G93A D45, G93A D130, and NS D130) produced high levels of human SOD1.