Bipolar spindle formation in U2OS cell treated with 100 nM Nuf2 siRNA, monastrol and MG132. Example of a cell that forms a bipolar spindle. The cell expresses photoactivatable GFP-Tubulin and mCherry-Tubulin and is labeled with Sir-DNA. For each time point, DNA and mCherry-Tubulin images were acquired. Total time is 42 min. Bar, 10 μm.