Fig. 4. Centriole splitting requires microtubule integrity. Centrosomal abnormalities [i.e. overduplication (hatched columns) and splitting (black columns)] were recorded in cultures transfected with vector, wild-type RanBP1 or RanBP1^L186A/V188A mutant (indicated as NES) during mitosis following thymidine release, or after treatment with nocodazole (NOC), or released after NOC arrest. For each condition, three to five experiments were carried out with wild-type RanBP1 and at least two with the RanBP1^L186A/V188A mutant. Data were pooled and analysed using the ² test. *, P<0.05; **, P<0.001.