ATF3 and amyotrophic lateral sclerosis: Cultured DRG neurons from ALS mice express ATF332,33; therefore, we evaluated the levels of ATF3 in DRGs by immunohistochemistry, because ATF3 is a stress-responsive transcription factor and a well-known marker for nerve injury and pathological damage.34 As shown in Fig. 1F, DRGs in SOD1G93A mice express ATF3 at the symptomatic stage, and the number of DRGs expressing ATF3 was increased at the end-stage (Fig. 1F and H).