Cby localization at different stages of ciliated cell differentiation. (A) MTECs were colabeled at the indicated ciliogenesis stages with antibodies against Cby and the centriole/basal body/ciliary axoneme marker acetylated (ac) α-tubulin or the centriole/basal body marker γ-tubulin. Essentially, immunostaining of CbyKO MTECs with the Cby antibody produced no signals (not depicted) confirming the antibody specificity. Bars: (main images) 2 µm; (high magnification images for stage II) 0.5 µm. See also Fig. S2 A. (B) Stage II MTECs were costained with Cby and IFT20 antibodies (a–c) or with the IFT20 antibody and the cis-medial Golgi marker lectin HPA (d–f). Nuclei in the merged image were visualized by DAPI (blue). (a–c) Arrowheads indicate areas of diffuse Cby staining that prominently overlap with IFT20. (d–f) In ciliated cells, IFT20 also showed Golgi localization. Dashed lines demarcate cell boundaries. Bars, 5 µm. See also Fig. S2 B.