FIGURE 5.

DNA-PKcs and its kinase activity affect microtubule dynamics in vivo. HeLa cells expressing the EGFP-α-tubulin fusion protein were transfected with control siRNA (A) or DNA-PKcs siRNA (B) for 48 h and were subjected to live cell image recording at 10-min intervals for the indicated time (hr:min). C, EGFP-α-tubulin cells with a visible spindle apparatus were pulsed with nocodazole (100 ng/ml) for 15 min to monitor mitotic spindle disassembly and reassembly. Dimethyl sulfoxide was used as a mock control treatment. D, the same experiment was carried out in the presence of Nu7441 (10uM). E, the average time of spindle recovery after nocodazole withdrawal. Ten mitotic cells were analyzed for each treatment.