Fig. 1. Basal body replication takes place in the absence of a flagellum. (A-C) Merged images of double immunofluorescence staining with mAb22 (marker of the proximal end of the mature and the pro-basal body, green) and the anti-TBBC antibody (marker of the mature basal body, red) of detergent-extracted cytoskeleton from non-induced (A, –TET) or 48-hour-induced IFT140^RNAi (B, +TET) cells stained with DAPI (blue). Insets show magnification of the basal body region. BB, basal body. (C) Non-flagellated cells can duplicate their basal body (a) but fail to divide, hence becoming multinucleated cells (b) that accumulate several pairs of basal bodies. a' and b' show magnification of the boxed basal body regions in a and b. (D) Transmission electron micrograph of a section through an IFT172^RNAi cell induced for 72 hours, which has four basal bodies (arrows). TET, tetracycline.