Centrosomes direct cell polarity independently of microtubule assembly in C-elegans embryos
Centrosomes direct cell polarity independently of microtubule assembly in C-elegans embryos
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DOI：
10.1038/nature02825
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发表时间：
2004-09-02
期刊：
影响因子：
64.8
通讯作者：
Hyman, AA
中科院分区：
文献类型：
--
作者：
Cowan, CR;Hyman, AA
极性的建立需要一个破环事件，从而产生一个决定子被隔离的沿着轴。在秀丽隐杆线虫中，卵母细胞是非极性的，并且在受精后被触发沿沿着一个轴快速地分裂。这第一个极性轴的建立揭示了PAR蛋白和皮质活性的不对称分布在单细胞胚胎。目前的证据表明，由精子贡献的中心体原核复合体参与定义极化轴（1-6）。在这里，我们直接评估的贡献，中心体的极性建立激光消融中心体之前和期间的极化。我们发现，中心体是启动极性而不是维持极性所必需的，极性的启动与中心体靠近皮质和中心粒周围物质在未成熟精子中心体上的组装相一致。微管或微管成核剂γ-微管蛋白的耗竭不影响极性的建立。这些结果表明，中心体提供了一个启动信号，极化C。elegans胚胎，并表明这一信号事件可能是独立的中心体作为微管成核剂的作用。
Polarity establishment requires a symmetry-breaking event, resulting in an axis along which determinants are segregated. In Caenorhabditis elegans, oocytes are apolar and are triggered to polarize rapidly along one axis after fertilization. The establishment of this first polarity axis is revealed by the asymmetric distribution of PAR proteins and cortical activity in the one-celled embryo. Current evidence suggests that the centrosome pronucleus complex contributed by the sperm is involved in defining the polarization axis(1-6). Here we directly assess the contribution of the centrosome to polarity establishment by laser ablating the centrosome before and during polarization. We find that the centrosome is required to initiate polarity but not to maintain it. Initiation of polarity coincides with the proximity of the centrosome to the cortex and the assembly of pericentriolar material on the immature sperm centrosome. Depletion of microtubules or the microtubule nucleator gamma-tubulin did not affect polarity establishment. These results demonstrate that the centrosome provides an initiating signal that polarizes C. elegans embryos and indicate that this signalling event might be independent of the role of the centrosome as a microtubule nucleator.