HEK293T embryonic kidney cells (CRL‐3216), and 143B osteosarcoma cells (CRL‐8303) were obtained from ATCC. HEK293 Flp-In T-REx 293 cells were obtained from Invitrogen. The 143B.TK rho0 derivative (143B206), obtained from Dr Carlos Moraes, was generated by Dr M.P. King (24 (link)). The details of the cell lines are listed in Supplementary Table S4. HEK293T cells KO for MTG1, GTPBP10, or DDX28 were previously generated and reported by our group (4 ,9 (link),11 (link)). All cell lines were cultured at 37°C under 5% CO2 in high-glucose, sodium pyruvate, l-glutamine DMEM medium supplemented with 10% FBS and 100 μg/ml uridine (complete DMEM medium). Analysis of mycoplasma contamination was routinely performed. The chemicals and reagents used in this study are listed in the Supplementary Table S8.