Cells with one centrosome can organize bipolar spindles in mitosis by forming a PCM-positive acentriolar spindle pole (PCM pole). (A) Schematic illustration of centrinone-induced removal of centriole. (B) DMSO-treated control mitotic spindles (two centrosomes) and centrinone B–treated centrosome-depleted spindles (one or zero centrosomes). Green, red, and blue represent GT335 (polyglutamylated centriole microtubules), α-tubulin, and DNA, respectively. Z-projections: 12 planes, each 0.13 µm apart. Scale bar, 5 µm. (C–E) Mitotic duration, the time required from NEBD to cytokinesis, in DMSO-treated two-centrosome (C), centrinone-treated one-centrosome (D) and zero-centrosome (E) cells in Fig. S1, G–I. Line and error bars represent the mean and SD (n ≥ 20 cells from two independent experiments). Kruskal–Wallis test was used to determine the significance of the difference. *, P < 0.05; **, P < 0.005; *** P < 0.0001; n.s., not significant. (F) Distribution of centrosomal factors in centriolar and acentriolar spindle poles. DMSO-treated control mitotic spindles (two centrosomes) and centrinone-treated mitotic spindles (one or zero centrosomes) in HeLa cells. Green, red, and blue represent GT335, the protein of interest (pericentrin, CDK5RAP2, or CEP192), and DNA, respectively. Z-projections: 21 sections, every 1 µm. Scale bar, 10 µm. Arrowheads indicate the PCM at the acentriolar spindle pole. (G) Quantification of pole patterns in F and Fig. S2 A. Values are presented as mean percentages from two independent experiments (n = 25 for each experiment). (H) Schematic illustration of PCM localization at spindle poles in two-, one-, or zero-centrosome cells.