FIGURE 6:

Reduced DNA damage–induced centrosome amplification in the absence of C-NAP1. (A) Immunofluorescence microscopy showing γ-tubulin (green) and CEP135 (red) in cells of the indicated C-NAP1 genotype at 48 h after 5-Gy IR treatment. Scale bar, 5 μm. (B) Centrosome quantitation in cells of the indicated genotype and treatment 48 h after 5-Gy IR. Centrosomes were quantitated using antibodies for CEP135, and bar graph indicates mean ± SD of three separate experiments in which at least 100 cells were counted. (C) Immunoblot of CHK1 activation in wild-type and C-NAP1–knockout cells in untreated cells and in cells at the indicated times after exposure to 5-Gy IR. Ponceau S staining of the membrane after protein transfer was used as a loading control. Size markers at left are in kilodaltons. (D) Cells of the indicated genotype were treated with 4 mM HU for 48 h before fixation. Centrosomes were quantitated by staining with antibodies to glutamylated tubulin and γ-tubulin. Bar graph indicates mean ± SD of three separate experiments in which at least 200 cells were counted. ***p < 0.001; *p < 0.05; ns, not significant by unpaired t test.