Huang Baoying, Huffaker Tim C
Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
J Cell Biol. 2006 Oct 9;175(1):17-23. doi: 10.1083/jcb.200606021.
Attachment of chromosomes to the mitotic spindle has been proposed to require dynamic microtubules that randomly search three-dimensional space and become stabilized upon capture by kinetochores. In this study, we test this model by examining chromosome capture in Saccharomyces cerevisiae mutants with attenuated microtubule dynamics. Although viable, these cells are slow to progress through mitosis. Preanaphase cells contain a high proportion of chromosomes that are attached to only one spindle pole and missegregate in the absence of the spindle assembly checkpoint. Measurement of the rates of chromosome capture and biorientation demonstrate that both are severely decreased in the mutants. These results provide direct evidence that dynamic microtubules are critical for efficient chromosome capture and biorientation and support the hypothesis that microtubule search and capture plays a central role in assembly of the mitotic spindle.
染色体附着在有丝分裂纺锤体上被认为需要动态微管，这些微管随机搜索三维空间，并在被动粒捕获后变得稳定。在这项研究中，我们通过检查微管动力学减弱的酿酒酵母突变体中的染色体捕获来测试该模型。尽管这些细胞是有活力的，但它们在有丝分裂过程中进展缓慢。前期细胞中含有高比例仅附着于一个纺锤体极的染色体，并且在没有纺锤体组装检查点的情况下会发生错误分离。对染色体捕获和双定向速率的测量表明，在突变体中这两者都严重降低。这些结果提供了直接证据，表明动态微管对于有效的染色体捕获和双定向至关重要，并支持微管搜索和捕获在有丝分裂纺锤体组装中起核心作用的假设。
