Fig 1: RPLP0 promotes NHEJ-mediated DSB repair.A Knockdown of RPLP0 extends the recovery time of IR-induced DNA damage. Forty-eight hours after siRNA transfection, HCT116 and U2OS cells were irradiated (10 Gy), and cultured for indicated time before western blotting analysis. B Knockdown of RPLP0 increases ?-H2A.X foci in tumor cells after IR. Thirty-six hours after transfection, HCT116 cells were irradiated (2 Gy) and cultured for indicated time. Cells were fixed and subjected to immunofluorescence analysis. n = 120, 85, 59, 96, 73, 58, 62, 75, 96, 62, 68, 93, 71, 81, 64, and 68 (from left to right column). Scale bars, 10 µm. C 4-OHT induces the nuclear import of ER-RPLP0. Cells were treated with 300 nM 4-OHT for 4 h before IF assay. Scale bars, 10 µm. D Nuclear RPLP0 enhances DNA repair. Thirty minutes before irradiation (2 Gy), 300 nM 4-OHT was added to medium. Cells were cultured for 20 h after irradiation. n = 203 (DMSO), n = 170 (4-OHT). Scale bars, 10 µm. E Depletion of RPLP0 suppresses the ligation of linearized DNA in vitro. pCSCMV-tdTomato plasmid was linearized with BamHI and incubated with nuclear protein of U2OS cells. The ligation product was separated using 0.8% agarose gels. F RPLP0 silencing suppresses translation. Forty-eight hours after siRNA transfection, cells were subjected to polysome profile assay. The impact of translation inhibitor cycloheximide (CHX) on DNA repair capacity was examined using western blotting (G) or IF assay (H). HCT116 cells, treated with 100 µg/ml CHX for 12 h, were irradiated and cultured for indicated time before western blotting (G) or IF assay (H). n = 148 (Ctrl), n = 183 (CHX). ***, P < 0.001; ns no significance.