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Figure S2. Aurora B function is required at the time of microtubule attachment to kinetochores. (A and B) HeLa cells were arrested in nocodazole. Hesperadin (B) or the solvent DMSO (A) were added shortly before release from nocodazole (outlined in Fig. 5 A). Chromosome spreads were performed with the arrested cells after addition of Hesperadin or DMSO (noc-arrest), directly after washing out nocodazole (0'), and at different time points after re-lease from nocodazole (15-150'). Cells in different mitotic stages were quantified. Different stages were defined as follows: interphase, normal, normal interphase nuclei; scattered, chromosomes not showing any sign of alignment to a metaphase plate (Fig. 5, C and D, noc-arrest); alignment/metaphase, chromosomes showing incomplete or complete alignment to the metaphase plate (Fig. 5 D, 0', 15', and 30'); sister separation/anaphase, chromosomes with separated sister chromatids (Fig. 5 C, bottom, 15'; Fig. 5 D, 45' and 60'); decondensation, decondensing chro-matin or abnormal interphase nucleus (Fig. 5 C, bottom, 30-150'; Fig. 5 D, 90'). (C and D) HeLa cells were arrested in nocodazole in the presence of Hesperadin (D) or the solvent DMSO (C). Hesperadin and DMSO were washed out before releasing cells from nocodazole (outlined in Fig. 5 B). Chromosome spreads were performed with the ar-rested cells after Hesperadin or DMSO washout (noc-arrest), directly after washing out nocodazole (0'), and at dif-ferent time points after release from nocodazole (15-150'). Cells in different mitotic stages were quantified as in A and B.