Lampson Michael A, Renduchitala Kishore, Khodjakov Alexey, Kapoor Tarun M
Laboratory of Chemistry and Cell Biology, Rockefeller University, New York, NY 10021, USA.
Nat Cell Biol. 2004 Mar;6(3):232-7. doi: 10.1038/ncb1102. Epub 2004 Feb 8.
For accurate segregation of chromosomes during cell division, microtubule fibres must attach sister kinetochores to opposite poles of the mitotic spindle (bi-orientation). Aurora kinases are linked to oncogenesis and have been implicated in the regulation of chromosome-microtubule attachments. Although loss of Aurora kinase activity causes an accumulation of mal-orientated chromosomes in dividing cells, it is not known how the active kinase corrects improper chromosome attachments. The use of reversible small-molecule inhibitors allows activation of protein function in living vertebrate cells with temporal control. Here we show that by removal of small-molecule inhibitors, controlled activation of Aurora kinase during mitosis can correct chromosome attachment errors by selective disassembly of kinetochore-microtubule fibres, rather than by alternative mechanisms involving initial release of microtubules from either kinetochores or spindle poles. Observation of chromosomes and microtubule dynamics with real-time high-resolution microscopy showed that mal-orientated, but not bi-orientated, chromosomes move to the spindle pole as both kinetochore-microtubule fibres shorten, followed by alignment at the metaphase plate. Our results provide direct evidence for a mechanism required for the maintenance of genome integrity during cell division.
为了在细胞分裂过程中实现染色体的精确分离，微管纤维必须将姐妹动粒连接到有丝分裂纺锤体的相对两极（双定向）。极光激酶与肿瘤发生有关，并参与染色体 - 微管附着的调节。虽然极光激酶活性的丧失会导致分裂细胞中错误定向染色体的积累，但尚不清楚活性激酶如何纠正不正确的染色体附着。使用可逆小分子抑制剂可在时间控制下激活活体内脊椎动物细胞中的蛋白质功能。在此，我们表明，通过去除小分子抑制剂，在有丝分裂期间对极光激酶进行可控激活可以通过选择性拆卸动粒 - 微管纤维来纠正染色体附着错误，而不是通过涉及微管从动粒或纺锤体极最初释放的其他机制。用实时高分辨率显微镜观察染色体和微管动力学表明，错误定向而非双定向的染色体在动粒 - 微管纤维缩短时移向纺锤体极，随后在中期板处对齐。我们的结果为细胞分裂过程中维持基因组完整性所需的机制提供了直接证据。
