Figure 6.

Maintenance of centromere-associated DRad21 in Mad2-depleted cells. All cells were collected, fixed, and stained to reveal DNA (blue), Polo (green), and the cohesin subunit DRad21 (red). Cells from control and cells treated with dsRNA against Mad2 or BubR1 were analyzed without colchicine (A), after colchicine treatment (B), and in cells transiently arrested with MG132 (C) and then released into media containing colchicine (180 min). Note that Mad2-depleted cells released into this media are unable to degrade cohesion, whereas BubR1-depleted cells fail to maintain sister chromatid cohesion in the presence of colchicine, suggesting an inactive SAC response (see also higher magnification inserts). Bar, 5 μm.