PCIF1 knockdown promotes the stability and translation of BICD2 mRNA. (A) Western blotting analysis of BICD2 and PCIF1 protein of RPE-1 cells transfected with the indicated siRNAs for 48 h under normal culture conditions. Actin is the internal control. (B) Western blotting of BICD2 and PCIF1 proteins of RPE-1 cells treated with the indicated siRNAs for 24 h and transfected with the indicated plasmids for another 36 h under normal culture conditions. Actin is the internal control. (C and D) RT-qPCR (real-time quantitative PCR) analysis of PCIF1 and BICD2 mRNA of PCIF1 depleted RPE-1 cells. GAPDH is the internal control. (E) Western blot analysis of BICD2 and PCIF1 protein of RPE-1 cells transfected with the indicated siRNAs for 48 h under normal culture conditions. Actin is the internal control. (F) RT-qPCR of BICD2 mRNA in PCIF1-depleted cells and control cells treated with actinomycin D (5 μg/ml). (G) Polysome profile of BICD2 mRNA in cells transfected with the indicated siRNA after sucrose gradient centrifugation. Data are presented as the means ± SD from at least three independent experiments (C, D, and F). Student’s t test, *P < 0.05, **P < 0.01, ***P < 0.001. Source data are available for this figure: SourceData F4.