Fig. 1

The correlation of CCP5 expression with ciliogenesis. A The time course of endogenous CCP5 mRNA levels (black line) and the percentage of ciliated cells (blue line) in hTERT-RPE1 cells after serum starvation. The expression level of CCP5 is dramatically reduced in 30 min after serum starvation and remains low after 4 h when ciliogenesis initiates, but gradually recovered to a level comparable to that before serum starvation at 48 h when cell ciliation is completed. The bars represent the mean ± s.d. from 3 independent experiments (Additional file 2). For the percentage of ciliated cells, at least 55 cells were analyzed per experimental condition (Additional file 2). B Representative immunoblot showed that in a HEK293T cell line stably expressing myc-CCP5, the exogenous CCP5 protein is reduced upon serum starvation and remains low 12 h later when cilia are rapidly formed (A). β-actin was used as a loading control. C Representative immunofluorescence images showed that in hTERT-RPE1 cells transfected with CCP5-GFP, CCP5 (green) is co-localized with and γ-tubulin (red). The nucleus is visualized by DAPI (blue) staining. The inserts are higher magnification views of the boxed regions. D After 24 h serum starvation, hTERT-RPE1 cells transfected with GFP or CCP5-GFP were stained with GFP (green), ARL13B (red), and the nucleus is visualized by DAPI (blue) staining. While the majority of GFP-transfected can form cilia, the CCP5-GFP-transfected cells rarely form cilia. E The quantification of the ciliated cells from 3 independent experiments with at least 30 cells analyzed per experimental condition in each experiment is shown in (D, Additional file 2). Error bars represent s.d. ∗  ∗ , P < 0.01, Student’s t test. Scale bars: 10 µm