Polarity controls forces governing asymmetric spindle positioning in the Caenorhabditis elegans embryo
Polarity controls forces governing asymmetric spindle positioning in the Caenorhabditis elegans embryo
复制标题
DOI：
10.1038/35054572
复制
发表时间：
2001-02-01
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：
Grill, SW;Gönczy, P;Hyman, AA
产生不同大小的子细胞的细胞分裂对于动物发育过程中细胞多样性的产生至关重要（1）。在这种不对称分裂中，有丝分裂纺锤体必须不对称地定位在后期结束时（2，3）。细胞极性转化为不对称纺锤体定位的机制尚不清楚。在这里，我们研究的性质的力量管理不对称纺锤体定位在单细胞阶段秀丽隐杆线虫胚胎。为了揭示作用在每个纺锤体极点上的力，我们用紫外激光微束物理地去除了活胚胎中的中央纺锤体，或者通过RNA介导的驱动蛋白干扰遗传地去除了中央纺锤体（4）。我们表明，在两个主轴极点上的主轴外部的拉力的作用。更强的净力作用于后极，从而解释了在野生型胚胎中观察到的整体后部位移。我们还表明，净力作用于每个纺锤体极是控制的PAR基因所需的细胞极性沿着的前-后胚胎轴。最后，我们讨论简单的数学模型，描述主轴极行为的主要特点。我们的工作提出了一种机制，通过改变作用在每个纺锤体极上的净拉力来产生纺锤体定位的不对称性，从而允许产生具有不同大小的子细胞。
Cell divisions that create daughter cells of different sizes are crucial for the generation of cell diversity during animal development(1). In such asymmetric divisions, the mitotic spindle must be asymmetrically positioned at the end of anaphase(2,3). The mechanisms by which cell polarity translates to asymmetric spindle positioning remain unclear. Here we examine the nature of the forces governing asymmetric spindle positioning in the single-cell-stage Caenorhabditis elegans embryo. To reveal the forces that act on each spindle pole, we removed the central spindle in living embryos either physically with an ultraviolet laser microbeam, or genetically by RNA-mediated interference of a kinesin(4). We show that pulling forces external to the spindle act on the two spindle poles. A stronger net force acts on the posterior pole, thereby explaining the overall posterior displacement seen in wild-type embryos. We also show that the net force acting on each spindle pole is under control of the par genes that are required for cell polarity along the anterior-posterior embryonic axis. Finally, we discuss simple mathematical models that describe the main features of spindle pole behaviour. Our work suggests a mechanism for generating asymmetry in spindle positioning by varying the net pulling force that acts on each spindle pole, thus allowing for the generation of daughter cells with different sizes.