Fig. 5. Asymmetric Bub1 staining is microtubule dependent. (A) Enlarged images of kinetochore pairs taken from Fig. 3A showing Bub1 (red), BubR1 (green) and the merged image (right column). Although the BubR1 signal at sister kinetochores is roughly equivalent, the Bub1 signal is often asymmetric, giving rise to a green and yellow spots in the merged image. (B) 3D plots of a kinetochore pair confirming BubR1 symmetry and Bub1 asymmetry. (C) A bar graph plotting the fluorescence ratio (K1/K2) for Bub1 (red) and BubR1 (green) where K1 is the kinetochore within a pair exhibiting stronger Bub1 fluorescence. The cells were either untreated (U) or treated with nocodazole (N) or taxol (T) for one hour. (D) A histogram plotting the percentage of kinetochore pairs exhibiting a given K1/K2 Bub1 fluorescence ratio. (E) A bar graph plotting the average ratio of BubR1/Bub1 signal at kinetochores K1 (green) and K2 (red). Values represent the mean and the standard error of the mean (s.e.m.).