Li X, Nicklas R B
Department of Zoology, Duke University, Durham, North Carolina 27708-1000.
Nature. 1995 Feb 16;373(6515):630-2. doi: 10.1038/373630a0.
Every time a cell divides, the chromosomes must be distributed accurately to the daughter cells. Errors in distribution arise if chromosomes are improperly attached to the mitotic spindle. Improper attachment is detected by a cell-cycle checkpoint in many cells and the completion of cell division is delayed, allowing time for error correction. How is an improperly attached chromosome detected? An absence of tension from mitotic forces is one possibility. Here we test this possibility directly by applying tension to an improperly attached chromosome with a micromanipulation needle. In the absence of tension, the entry into anaphase and the completion of mitosis was delayed by 5-6 hours. When the misattached chromosome was placed under tension, however, the cell entered anaphase in 56 minutes, on average. Tension from mitotic forces or from a micromanipulator's needle evidently signals to the checkpoint that all is in order and that cell division can proceed.
每次细胞分裂时，染色体都必须精确地分配到子细胞中。如果染色体与有丝分裂纺锤体的附着不当，就会出现分配错误。在许多细胞中，细胞周期检查点会检测到这种不当附着，细胞分裂的完成会延迟，从而留出纠错时间。那么，如何检测到附着不当的染色体呢？一种可能性是缺乏来自有丝分裂力的张力。在这里，我们通过用显微操作针向附着不当的染色体施加张力来直接测试这种可能性。在没有张力的情况下，进入后期和有丝分裂的完成延迟了5至6小时。然而，当将错误附着的染色体置于张力之下时，细胞平均在56分钟后进入后期。来自有丝分裂力或显微操作针的张力显然会向检查点发出信号，表明一切正常，细胞分裂可以继续进行。
