Starr D A, Williams B C, Hays T S, Goldberg M L
Section of Genetics and Development, Cornell University, Ithaca, New York 14853-2703, USA.
J Cell Biol. 1998 Aug 10;142(3):763-74. doi: 10.1083/jcb.142.3.763.
Mutations in the Drosophila melanogaster zw10 gene, which encodes a conserved, essential kinetochore component, abolish the ability of dynein to localize to kinetochores. Several similarities between the behavior of ZW10 protein and dynein further support a role for ZW10 in the recruitment of dynein to the kinetochore: (a) in response to bipolar tension across the chromosomes, both proteins mostly leave the kinetochore at metaphase, when their association with the spindle becomes apparent; (b) ZW10 and dynein both bind to functional neocentromeres of structurally acentric minichromosomes; and (c) the localization of both ZW10 and dynein to the kinetochore is abolished in cells mutant for the gene rough deal. ZW10's role in the recruitment of dynein to the kinetochore is likely to be reasonably direct, because dynamitin, the p50 subunit of the dynactin complex, interacts with ZW10 in a yeast two-hybrid screen. Since in zw10 mutants no defects in chromosome behavior are observed before anaphase onset, our results suggest that dynein at the kinetochore is essential for neither microtubule capture nor congression to the metaphase plate. Instead, dynein's role at the kinetochore is more likely to be involved in the coordination of chromosome separation and/or poleward movement at anaphase onset.
果蝇黑腹果蝇zw10基因发生突变，该基因编码一种保守的、必不可少的动粒成分，会消除动力蛋白定位于动粒的能力。ZW10蛋白与动力蛋白行为之间的几个相似之处进一步支持了ZW10在将动力蛋白招募到动粒中的作用：(a) 响应染色体上的双极张力，在中期时，当它们与纺锤体的结合变得明显时，这两种蛋白质大多会离开动粒；(b) ZW10和动力蛋白都与结构上无着丝粒的微型染色体的功能性新着丝粒结合；(c) 在rough deal基因的突变细胞中，ZW10和动力蛋白定位于动粒的现象都消失了。ZW10在将动力蛋白招募到动粒中的作用可能相当直接，因为动力蛋白激活蛋白复合物的p50亚基动力素在酵母双杂交筛选中与ZW10相互作用。由于在zw10突变体中，在后期开始之前未观察到染色体行为的缺陷，我们的结果表明，动粒处的动力蛋白对于微管捕获和向中期板的汇聚都不是必需的。相反，动力蛋白在动粒处的作用更可能涉及后期开始时染色体分离和/或向极移动的协调。
