Fig. 3.

Adding back wild-type, but not kinase-dead form of Aur-A, to Aur-A-depleted cycling extracts corrects the timing of G₂/M transition and rescues the bipolar spindle formation. (A) Mock or Aur-A-depleted extracts were supplemented with nuclei (500 per μl) and rhodamine-labeled tubulin. Wild-type Aur-A, kinase-dead D281A Aur-A, or buffer control was added to Aur-A-depleted cycling extracts at 30 min. Samples were analyzed as in Fig. 2. (B) Samples were taken during mitosis and stained with Hoechst dye 33342. The percentage of distinct spindle structures in mitosis was averaged from four independent experiments. At each time point, >100 spindle structures were counted. (C) Representative spindle structures are shown. (D) Sixty minutes after mitosis, samples were again taken and examined as above.