Fig. 1.

Asymmetric spindle poles in CPAP-depleted mitotic cells. (A) HeLa cells were transfected with the control (siCTL) or CPAP (siCPAP) siRNAs and cultured for 48 h. The cells were subjected to immunoblot analysis with the CPAP and β-tubulin antibodies. (B) HeLa cells were transfected with control (siCTL) or CPAP (siCPAP) siRNAs. Forty-eight hours later, the cells were observed with a phase-contrast microscope. The scale bar represents 100 μm. The mitotic index was determined with more than 3000 cells per experimental group from three independent experiments. The results were presented as means and standard errors *P < 0.05. (C) The CPAP-depleted HeLa cells were coimmunostained with the CPAP (green) and γ-tubulin (red) antibodies. The scale bar represents 10 μm. The relative γ-tubulin intensity between a pair of spindle poles was determined. A difference in intensity greater than 1.5 was defined as an asymmetric distribution. Over 300 cells per group were analyzed from three independent experiments, and the results are presented as means and standard errors. (D) The CPAP-depleted mitotic cells were immunostained with the centrin-2 antibody along with the pericentrin or CEP215 antibody. The scale bar represents 10 μm. Relative intensities of pericentrin and CEP215 were measured in spindle pole pairs with an intact number of centrioles. A difference in intensity greater than 1.5 was defined as an asymmetric distribution. For statistical analysis, over 180 mitotic cells per group were analyzed from two independent experiments. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)