Fig. 4.

K263R mutation abolishes the centrosome duplication-suppressing activity of NPM/B23. (A) p53^−/− MEFs were transfected with FLAG-wild-type NPM/B23, FLAG-K263R, FLAG-T199A, or FLAG-T199A/K263R. The plasmid vector was transfected as a negative control. The GFP plasmid was also cotransfected as a transfection marker at 1:15 molar ratio. At 72 h posttransfection, cells were fixed with 10% formalin, immunostained with anti-γ-tubulin antibody, and counterstained with DAPI. The centrosome profiles of the GFP-positive transfectants were determined and are shown here. The results are shown as average ± SE from three experiments. In each experiment, >200 cells were examined. (B) Representative immunostaining images are shown. The arrows point to the positions of centrosomes. (Scale bar: 10 μm.)