Figure 5. PyST expression triggers spindle assembly checkpoint activation.
To determine the status of the spindle checkpoint, the phosphorylation patterns of Bub1 and BubR1 were analyzed by Western blotting (A). PyST expressing cells had increased levels of slowly migrating phosphorylated Bub1 and BubR1, indicating that the SAC is active. Cells were also stained with anti-Bub1 (Bi) or anti-BubR1 (Bii) followed by FITC/Alexa 488 secondary antibodies for epifluorescence micrographs. PyST expressing cells had Bub1/BubR1 staining associated with their kinetochores. Representative micrographs from one of two such experiments are shown.
