Fig 1: Bex1 localizes to the ciliary base and promotes ciliogenesis. a Immunofluorescence analysis of BEX1 and primary cilia in human ARPE19 cells. The primary cilia were stained with the ARL13B antibody. Bex1 localized to the base of primary cilia. Nuclei were stained with DAPI. Scale bar = 10 µm. b Immunofluorescence analysis of BEX1, PCNT and ARL13B in human ARPE19 cells. BEX1 and PCNT colocalize at the ciliary base. Scale bar = 5 µm. c Immunofluorescence analysis for the primary cilia in ARPE19 cells transfected with control siRNA or BEX1 siRNA. Cilia formation was abrogated by the BEX1 depletion. Nuclei were stained with DAPI. Scale bar = 25 µm. d Frequency of ciliated cells after transfection with control siRNA or BEX1 siRNA. The number of ciliated cells was counted in the experiment (c). e Immunofluorescence analysis for the primary cilia in mouse NIH3T3 cells transfected with control siRNA or Bex1 siRNA. Primary cilia were visualized with the acetylated tubulin (Ac-tubulin) antibody. Nuclei were stained with DAPI. Scale bar = 25 µm. f qPCR analysis for the expression of Bex1 in NIH3T3 cells transfected with control siRNA or Bex1 siRNA. Data were normalized to Tubb5. g Supernumerary cilia observed in Bex1-depleted cells. The primary cilia were stained with antibodies against Ac-tubulin and IFT88. Nuclei were stained with DAPI. Scale bar = 10 µm. h Distribution of the number of primary cilia in a cell after transfection with control siRNA or Bex1 siRNA. A total of 9.1% of Bex1-depleted cells exhibited supernumerary cilia (denoted as “2 or more”). i Length (µm) distribution of the cilia in NIH3T3 cells transfected with control siRNA or Bex1 siRNA. j Average length (µm) of the primary cilia in NIH3T3 cells after transfection of control siRNA or Bex1 siRNA. *** p < 0.001; Student’s t test. The data are presented as the means ± standard deviations