Fig 2: SOD1 binds to BOP1 and WDR12, and regulates the assembly of PeBoW complex. a Flag-SOD1 is prominently localized in the nucleoli. Sod1Flox/Flox KP NSCLC cells stably expressing Flag-SOD1 were treated with 4OHT and doxycycline was added to the medium to induce expression of Flag-SOD1. Cells were fixed on day 5 post treatment and analyzed by immunofluorescence analysis using antibodies against Flag (red) and UBF (green, nucleoli). Dashed lines demarcate the nucleus. Scale bars represent 10 µm. Data are represented by three independent experiments. b Flag-SOD1 is colocalized with BOP1 and WDR12. Sod1Flox/Flox KP cells stably expressing Flag-SOD1 were treated with 4OHT and doxycycline to induce knockout of endogenous Sod1 and expression of ectopic Flag-SOD1, respectively. IF analysis was performed with antibodies against Flag (green) and BOP1 or WDR12 (red). Dashed lines indicate the nucleus. Scale bar represents 10 µm. Data are represented by three independent experiments. c SOD1 interacts with the PeBoW complex in intact cells as judged by Duolink. Sod1Flox/Flox KP cells stably expressing Flag-SOD1 were treated with 4OHT and doxycycline to induce knockout of endogenous Sod1 and expression of ectopic Flag-SOD1, respectively. Cells were fixed and analyzed by Duolink to detect the interaction of Flag-SOD1 and WDR12 or BOP1 (red dots). Shown is a representative image. Scale bars, 10 µm. Data are represented by three independent experiments. d Sod1 knockout or overexpression does not affect the protein level of CRM1, BOP1, and WDR12. Same as (c) except that samples were analyzed by immunoblot. Data are represented by three independent experiments. e Sod1 knockout disrupts the interaction between BOP1 and WDR12 in mouse KP NSCLC cells. Mouse Sod1Flox/Flox KP NSCLC cells were treated with or without 4OHT to knock out endogenous Sod1, and Dox to induced Flag-SOD1 expression. BOP1–WDR12 interaction was analyzed by Duolink. Scale bar represents 10 µm. Data are represented by three independent experiments. f–i SOD1 knockdown disrupts the interaction between BOP1 and WDR12 in human KP and KL NSCLC cells. Human KP and KL NSCLC cells were transfected with SOD1 human siRNA (si-hSOD1) or a control siRNA (siNC). BOP1–WDR12 interaction was analyzed by Duolink. Scale bar represents 10 µm. Data are represented by three independent experiments.