Fant Xavier, Merdes Andreas, Haren Laurence
Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Edinburgh EH9 3JR, United Kingdom.
Int Rev Cytol. 2004;238:1-57. doi: 10.1016/S0074-7696(04)38001-0.
Mitotic and meiotic cells contain a bipolar spindle apparatus of microtubules and associated proteins. To arrange microtubules into focused spindle poles, different mechanisms are used by various organisms. Principally, two major pathways have been characterized: nucleation and anchorage of microtubules at preexisting centers such as centrosomes or spindle pole bodies, or microtubule growth off the surface of chromosomes, followed by sorting and focusing into spindle poles. These two mechanisms can even be found in cells of the same organism: whereas most somatic animal cells utilize the centrosome as an organizing center for spindle microtubules, female meiotic cells build an acentriolar spindle apparatus. Most interestingly, the molecular components that drive acentriolar spindle pole formation are also present in cells containing centrosomes. They include microtubule-dependent motor proteins and a variety of structural proteins that regulate microtubule orientation, anchoring, and stability. The first of these spindle pole proteins, NuMA, had already been identified more than 20 years ago. In addition, several new proteins have been characterized more recently. This review discusses their role during spindle formation and their regulation in the cell cycle.
有丝分裂和减数分裂细胞含有由微管和相关蛋白组成的双极纺锤体装置。为了将微管排列成聚焦的纺锤体极，不同的生物体采用了不同的机制。主要有两种主要途径已得到表征：微管在诸如中心体或纺锤体极体等预先存在的中心处的成核和锚定，或者微管从染色体表面生长，随后分类并聚焦成纺锤体极。这两种机制甚至可以在同一生物体的细胞中找到：大多数体细胞动物细胞利用中心体作为纺锤体微管的组织中心，而雌性减数分裂细胞则构建无中心粒的纺锤体装置。最有趣的是，驱动无中心粒纺锤体极形成的分子成分在含有中心体的细胞中也存在。它们包括微管依赖性运动蛋白和多种调节微管方向、锚定和稳定性的结构蛋白。这些纺锤体极蛋白中的第一种，核仁磷酸化蛋白（NuMA），早在20多年前就已被鉴定出来。此外，最近又有几种新蛋白得到了表征。本综述讨论了它们在纺锤体形成过程中的作用及其在细胞周期中的调节。
