Biology Department, University of Massachusetts Amherst, 221 Morrill South, 611 North Pleasant Street, Amherst, MA 01003, USA.
Exp Cell Res. 2012 Jul 15;318(12):1400-6. doi: 10.1016/j.yexcr.2012.04.006. Epub 2012 Apr 19.
Cortical force generators play a central role in the orientation and positioning of the mitotic spindle. In higher eukaryotes, asymmetrically localized cortical polarity determinants recruit or activate such force generators, which, through interactions with astral microtubules, position the mitotic spindle at the future site of cytokinesis. Recent studies in budding yeast have shown that, rather than the cell cortex, the astral microtubules themselves may provide polarity cues that are needed for asymmetric pulling on the mitotic spindle. Such asymmetry has been shown to be required for proper spindle positioning, and consequently faithful and accurate chromosome segregation. In this review, we highlight results that have shed light on spindle orientation in this classical model of asymmetric cell division, and review findings that may shed light on similar processes in higher eukaryotes.
皮层力发生器在有丝分裂纺锤体的定向和定位中起着核心作用。在高等真核生物中，不对称定位的皮层极性决定因素招募或激活这种力发生器，通过与星体微管相互作用，将有丝分裂纺锤体定位在未来的胞质分裂部位。芽殖酵母的最新研究表明，可能不是细胞皮层，而是星体微管本身提供了有丝分裂纺锤体不对称牵拉所需的极性线索。这种不对称性对于正确的纺锤体定位是必需的，从而保证了染色体的正确分离。在这篇综述中，我们强调了阐明经典不对称细胞分裂模型中纺锤体定向的结果，并回顾了可能阐明高等真核生物中类似过程的发现。
