Fig. 3. Centrin-RNAi cells contained additional, nonflagellate basal bodies. (A) Antibodies to centrin (a-c), polyglutamylated (e) and acetylated tubulin (f) were used to demonstrate the presence of nonflagellate bbs in A10 (a-c) and N41 (e,f). a'-c', corresponding anti--tubulin images. Arrowheads, bbs without attached flagella. GT335 also stained the cell nucleus because nucleosome assembly proteins are polyglutamylated in addition to bb tubulin (Regnard et al., 2000). Bar, 5 µm. (B) EM analysis of wild-type (a) or N41 bbs (b-e) in longitudinal section. (a) Wild-type bb with transition region (arrowhead) and dCF (arrow). (b-e) bbs of N41 showing extremely short (b) or no flagella (c-e). The transition region, in longitudinal section usually appearing as an H-like structure, was defective in N41 (arrowhead in b). Note that bbs in N41 are improperly docked to the plasma membrane (c,d) or reside within the cytoplasma (e), and sometimes contained electron-dense material in the lumen (arrowhead in c). Arrowhead in d, basal feet. Arrowhead in e, attached microtubules. Bar, 250 nm. (C) Wild-type (a) and N41 bbs in cross-section. The stellate structure (a) was absent in the centrin-RNAi strains (b), causing the central pair microtubules to penetrate the bb. Bar, 200 nm.