XPO1 and lung carcinoma: Fig 5A shows that most of the tRNAs tested co-immunoprecipitated with NXF1 but not XPO1. To further verify that NXF1 is involved in the nuclear export of tRNAs, NXF1 was knocked down by specific siRNAs in lung cancer cell lines (Fig 5B). RT-qPCR showed that decreased expression of NXF1 caused nuclear accumulation of the various tRNA species examined (Figs 5C and S7A).