Fig. 1.
Activation of UPR transcription factors and apoptosis-associated ER factors in transgenic SOD1G93A mice. (A) ATF6 immunoblot in spinal cords from transgenic SOD1G93A mice (G93A) at asymptomatic stage (AS, 1 month old), beginning of symptoms (BS, 3–4 months old), end stage (ES, 5 months old), and from their age-matched nontransgenic littermates (NTG) or from the cerebellum (Cb) of ES-G93A mice. Thapsigargin-treated PC12-cells were used as a positive control (Cont.). Full-length ATF6 is p90, and cleaved ATF6 is p50. (B) Immunolocalization of ATF6 in spinal cord sections: ATF6 (green), neurofilament (red), and DAPI (blue). (Scale bar, 20 μm.) (C) Ratios of IRE1-mediated splicing form of XBP1 (spliced -XBP1) over total XBP1 mRNA. ∗, P < 0.05; Student's t test. (D) Immunoblot for phosphorylated IRE1α (p-IRE1α) and nonphosphorylated IRE1α (IRE1α). (E) ATF4 immunoblot. ∗, P < 0.05; one-way ANOVA, Student–Newman–Keuls test. (F) Immunoblot of procaspase-12 (≈55 kDa) and its cleaved fragment (≈42 kDa). All values are means ± SEM (n = three to six per group). Analyses were performed in ES-G93A and age-matched NTG mouse spinal cords unless indicated otherwise.