FXR1 interacts with MRE11. Extracts from C3ABR (A and B: upper panel), or MRC5SV (B: lower panel) and NBS1-defective NBS cells (B: lower panel) without (−) or with 10 Gy of IR were immunoprecipitated with anti-MRE11 antibody (Novus), anti-NBS1 antibody (Novus) or normal IgG, and then the immuno-complexes were detected by western blot analysis using the indicated antibodies. WCE = Whole cell extract. (C and D) Cytoplasmic distribution of FXR1. U2OS cells (C) or NBS cells (D) were irradiated with 5 Gy of IR. After 0.5 h, the cells were fixed and immuno-staining was performed using anti-FXR1 (Bethyl) and anti-MRE11 antibody (GeneTex).