Briefly, the cells were incubated with 1% formaldehyde for 10 min, and then incubated with 0.125 M glycine (final concentration) for 5 min. The nuclei of each sample was incubated with 0.6 μL micrococcal nuclease in MNase digestion buffer working solution for 5 min. The input DNA was prepared by treating aliquots of chromatin with NaCl, proteinase K and heat for de-crosslinking. The supernatants of experimental groups were incubated with 8 μL immunoprecipitation grade anti-human SOD1 primary antibody (Abcam; ab16831) overnight at 4 °C on a rocking platform. Following capturing the immune complex using Protein A/G Plus Agarose, the immune complexes were treated with NaCl, proteinase K and heated for de-crosslinking. Finally, DNAs were purified using Agencourt AMPure XP (Beckman Coulter; 15770600). Illumina sequencing libraries were prepared from ChIP and Input DNAs by the standard consecutive enzymatic steps of end-polishing, dA-addition, and adaptor ligation. After amplification by PCR, the resulting DNA libraries were quantified and sequenced on the Illumina HiSeq platform according to the manufacturer's instructions.