Cavazza Tommaso, Malgaretti Paolo, Vernos Isabelle
Cell and Developmental Biology Programme, Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08003 Barcelona, Spain Universitat Pompeu Fabra, 08003 Barcelona, Spain.
Departament de Fisica Fonamental, Universitat de Barcelona, 08028 Barcelona, Spain Max-Planck-Institut für Intelligente Systeme and IV. Institut für Theoretische Physik, Universität Stuttgart, D-70569 Stuttgart, Germany.
Mol Biol Cell. 2016 Oct 1;27(19):2935-45. doi: 10.1091/mbc.E16-05-0322. Epub 2016 Aug 3.
Centrosome maturation is the process by which the duplicated centrosomes recruit pericentriolar components and increase their microtubule nucleation activity before mitosis. The role of this process in cells entering mitosis has been mostly related to the separation of the duplicated centrosomes and thereby to the assembly of a bipolar spindle. However, spindles can form without centrosomes. In fact, all cells, whether they have centrosomes or not, rely on chromatin-driven microtubule assembly to form a spindle. To test whether the sequential activation of these microtubule assembly pathways, defined by centrosome maturation and nuclear envelope breakdown, plays any role in spindle assembly, we combined experiments in tissue culture cells and Xenopus laevis egg extracts with a mathematical model. We found that interfering with the sequential activation of the microtubule assembly pathways compromises bipolar spindle assembly in tissue culture cells but not in X. laevis egg extracts. Our data suggest a novel function for centrosome maturation that determines the contribution of the chromosomal microtubule assembly pathway and favors bipolar spindle formation in most animal cells in which tubulin is in limiting amounts.
中心体成熟是一个过程，通过该过程，复制后的中心体在有丝分裂前招募中心粒周围成分并增强其微管成核活性。这一过程在进入有丝分裂的细胞中的作用主要与复制后的中心体分离相关，进而与双极纺锤体的组装有关。然而，纺锤体可以在没有中心体的情况下形成。事实上，所有细胞，无论有无中心体，都依赖染色质驱动的微管组装来形成纺锤体。为了测试由中心体成熟和核膜破裂所定义的这些微管组装途径的顺序激活在纺锤体组装中是否起作用，我们将组织培养细胞和非洲爪蟾卵提取物中的实验与一个数学模型相结合。我们发现，干扰微管组装途径的顺序激活会损害组织培养细胞中的双极纺锤体组装，但在非洲爪蟾卵提取物中则不会。我们的数据表明中心体成熟具有一种新功能，即决定染色体微管组装途径的贡献，并有利于大多数微管蛋白数量有限的动物细胞中的双极纺锤体形成。
