Full Aurora B kinase activity on chromosome arms requires intact and dynamic microtubules. (Top) Immunofluorescence of histone H3 pS10 levels in HeLa cells treated with DMSO, nocodazole (Noc), or taxol for 2 h. Images represent maximum-intensity projections. Histone H3 pS10 levels are scaled equivalently. Bars, 10 µm. (Bottom) Fluorescence intensity quantification of chromosome-bound histone H3 pS10 immunofluorescence in mitotic HeLa cells treated as above. Prometaphase (Prometa) and metaphase (Meta) cells were quantified separately to determine whether histone H3 pS10 levels change during mitosis. Treatment with either nocodazole or taxol for 2 h to depolymerize or stabilize microtubules, respectively, greatly reduced the levels of histone H3 pS10 on chromosomes. SD is plotted for the mean from each condition. n = 15 cells from two independent experiments. Asterisks indicate statistical significance of mean value difference when compared with prometaphase as assessed by the Kruskal-Wallis test. **, P < 0.01; ****, P < 0.0001. FI, fluorescence intensity.