PCIF1 deficiency induces a cilia-dependent cell cycle arrest. RPE-1 cells cultured in normal conditions were treated with the indicated siRNAs for 48 h and then processed to the following analyses. (A) Graphical representations of the cell cycle distribution. (B) The percentages of cell populations in G0/G1, S, and G2/M phases. (C) Western blotting analysis of the Cyclin A2, IFT20, and PCIF1. Actin served as a loading control. (D) Immunofluorescence images of RPE-1 cells stained with EdU (red) and DNA (blue). Scale bar, 30 μm. (E) The percentages of EdU-positive cells were quantified. (F) Immunofluorescence images of RPE-1 cells with anti-ARL13B (green) and γ-tubulin (red) antibodies. DNA was stained with DAPI (blue). Cilia were indicated by white arrows. Scale bar, 10 μm. (G) Quantification analysis of the percentage of ciliated cells. Each color in SuperPlots represents an independent biological replicate. Smaller symbols are the percentages of EdU-positive cells (E) or the percentage of ciliated cells under each field of view (G), and larger symbols are the mean of each replicate. All error bars represent means ± SD. Student’s t test, *P < 0.05, **P < 0.01, ***P < 0.001, ns, not significant. Source data are available for this figure: SourceData F6.