FIG 5.

FAM92A is required for primary cilium formation. RPE1 cells were either mock transfected or transfected with FAM92A siRNA-1 or FAM92A siRNA-2 and serum starved for 48 h to induce ciliogenesis. (A) Western blot analysis verified the efficient depletion of FAM92A by siRNA. Interestingly, the levels of the FAM92B protein were decreased, while those of the Cby1 protein were unchanged. GAPDH was used a loading control. (B) Quantification of the number of cells with primary cilia after siRNA treatment. RPE1 cells were immunostained for FAM92A and A-tub. FAM92A-positive cells for mock-treated controls and FAM92A-negative cells for siRNA-treated samples were counted in 4 (siRNA-1) or 12 (siRNA-2) independent experiments (a total of over 1,000 cells per siRNA). Data are presented as means ± standard deviations. *, P < 0.05. (C) Representative image of FAM92A siRNA-1-treated cells that were immunostained for FAM92A and A-tub. The red arrowhead indicates a FAM92A-positive cell with a primary cilium, whereas the white arrowhead indicates a FAM92A-depleted cell with no primary cilium. Nuclei were visualized by DAPI staining. Bar, 5 μm.