Topo II CTD SUMOylation promotes Aurora B recruitment and metaphase checkpoint activation. (A) Western blot showing endogenous Topo II depletion achieved after RNAi in HeLa EM2-11ht cell lines and induction (Dox) of exogenous mCherry-Topo II and mCherry-TopoII-3KR. (B) Classification of Aurora B localization in cells treated as in A, with endogenous Topo II depleted and exogenous Topo II expressed. (C) Representative examples of Aurora B localization categories as in B. (D and E) Analysis of metaphase duration in live HeLa cell lines in A, after depletion of endogenous Topo II and expression of exogenous alleles. (D) Quantification of the mCherry-Topo II signal at the first time point captured for each of the cells analyzed in E. a.u., arbitrary unit. Bars, 10 µm. Error bars, standard deviation. Data collected from three independent experiments.