Figure 3.

(A) Fixed LLC-PK1 cells expressing chimeric GFP-p55CDC. In interphase cells, a pair of dots at the centrosome (arrow) is brightly labeled throughout the cell cycle. In mitotic cells, the p55CDC-GFP concentrates at the kinetochores from late prophase to late anaphase. A pool of the protein also remains diffusely distributed. In addition, the spindle poles (arrows) and the kinetochore microtubules show concentrations of the p55CDC-GFP. During prometaphase, the intensity of the kinetochore p55CDC-GFP signal is more intense at the kinetochores of unaligned chromosomes located near the spindle poles (black arrowheads) compared with the kinetochores of chromosomes aligned at metaphase plate (white arrowheads). No apparent difference is seen in intensity of the p55CDC-GFP signal between the leading and the trailing kinetochore of individual unaligned chromosome (small arrows in prometaphase row). In anaphase cells, the spindle poles (big arrows) remain p55CDC-GFP-positive while kinetochore labeling diminishes. (B) An interphase and a mitotic LLC-PK1 cell expressing the GFP alone show no specific fluorescent kinetochore, spindle microtubule, or spindle pole signals. Bars, 5 μm.