KINETOCHORES, MICROTUBULES AND THE METAPHASE CHECKPOINT

A decade ago, kinetochores were generally regarded as rather uninterst ing structures that served only to attach mitotic chromosomes to micro tubules. In the past few years, however, a number of experiments have belied this view and demonstrated that kinetochores are actively invol ved in moving chromosomes along the microtubules of the mitotic spindl e. Now it appears that in addition to their function in motility, kine tochores act as dynamic and adaptable centres for regulating cell cycl e progression through mitosis.