Interkinetochore distance and delta can be experimentally uncoupled. (A) Selected frames from time-lapse imaging of GFP-tubulin cells after ZW10 RNAi treatment. Cells progress through mitosis in 36 ± 13 min (n = 141 cells) in the absence of ZW10, which is faster than control cells (51 ± 17 min). (B and C) Reduced levels of ZW10 cause interkinetochore distances and delta (n = 777 kinetochore pairs) to be reduced relative to controls. Western blot analysis (inset) reveals efficient knockdown of ZW10 by RNAi (96 h). (D) Frames from time-lapse imaging of GFP-tubulin cells after SMC1 RNAi. Similar to control cells (51 ± 17 min), SMC1 dsRNA–treated cells progress through mitosis in 48 ± 15 min (n = 222 cells). (E and F) SMC1 RNAi increases the interkinetochore distance without affecting delta (n = 451 kinetochore pairs). SMC1 is nearly undetectable by Western blotting (inset) after dsRNA treatments (96 h). The mean values ± standard deviations and the two-tailed p-values for all conditions are shown in each graph. AO, anaphase onset. Bars, 10 µm.