engleski

Bridging the gap between sister kinetochores

The main task of the mitotic spindle is to generate forces that position the chromosomes at the metaphase plate and subsequently pull them apart toward the opposite spindle poles. These forces in living cells are, unfortunately, not easily accessible by current experimental techniques. However, much about the forces can be inferred from the shape of the spindle because the shape is an outcome of forces. K-fibers, which are bundles of microtubules ending at the kinetochore, are typically curved, suggesting that they are under compression. By severing a k-fiber with a laser we have shown that the bridging fiber moves together with sister k-fibers, revealing that these 3 fibers are strongly linked and thus able to survive large physical perturbations such as cutting of k-fibers. Severing of a k-fiber at different locations also revealed that the bridging fiber is linked laterally to the k-fibers in the region away from the kinetochore, while these fibers separate from each other close to the kinetochore.

compression ; forces ; kinetochores ; k-fibers ; mitotic spindle ; microtubules ; mitosis ; metaphase ; PRC1 ; tension

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