B. Similar assay as described in supplementary figure 2D was carried out in the presence of a small molecule inhibitor against Aurora-B (ZM447439) in combination with the proteasome inhibitor MG-132 to keep cells arrested in mitosis and in B. with an inhibitor against Plk1 (BI2536). Drugs were added at the same timing as Hoechst, 30 minutes prior to imaging. 