Figure 1.

Merotelic kinetochores can produce lagging chromosomes near the spindle equator in anaphase. (a) Live-cell imaging of a PtK1 cell expressing GFP-H2B. A lagging chromosome remains near the spindle equator as the rest of the chromosomes segregate to their poles. Time on each frame given in minutes. From Cimini et al. (2002). (b) Spinning disk confocal fluorescence microscopy of PtK1 cell showing how microtubule attachments to the opposite poles stretch a merotelic kinetochore laterally from its normal width of about 0.4 to 2 μm or more. The kinetochores (green) were labelled by immunofluorescence with CREST antibodies to inner kinetochore proteins while microtubules (red) were labelled with tubulin antibodies. From Cimini et al. (2001). (c) 3D reconstruction from electron micrographs of a merotelic kinetochore of an anaphase lagging chromosome done by Alexey Khodjakov. From Cimini et al. 2001.