发表机构
Xiamen University; Peking University（厦门大学; 北京大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究提出细胞大小与机械束缚可通过皮质曲率依赖的主动应力，在无分子极性线索时自发驱动不对称细胞分裂，其预测与秀丽隐杆线虫胚胎发生的实验数据相符。
AI 中文摘要
不对称细胞分裂（母细胞分裂为两个大小不等的子细胞）是生物学中的基础问题，此前认为不对称性源于母细胞预先的极化。本研究表明，即使在未极化的母细胞中，分裂不对称性也可自发产生：若母细胞被限制在狭小空间内，细胞皮质中依赖曲率的主动应力无需任何分子极性线索即可引发这种对称性破缺。减小细胞尺寸或增强机械束缚都会触发相同的自发对称性破缺不稳定性，此时收缩环会滑离赤道，产生体积不等的子细胞；若存在极性线索，该不稳定性会与线索协同调控分裂不对称性。将模型预测与秀丽隐杆线虫（C. elegans）胚胎发生的成像数据对比，该过程中被束缚在卵壳内的连续细胞分裂会使细胞尺寸不断缩小，实测的分裂不对称性随细胞缩小而增加，且当胚胎受机械压缩时会进一步放大，均与模型预测一致。
英文摘要
Asymmetric cell division -- in which a mother cell divides into two daughter cells of unequal size -- is a fundamental problem in biology. It is believed that the asymmetry originates from the prior polarization of the mother cell. Here we show that division asymmetry can occur spontaneously even in unpolarized mother cells. Specifically, curvature-dependent active stresses in the cell cortex can lead to this symmetry breaking without any molecular polarity cue if the mother cell is confined within a restricted space. Either reducing the cell size or tightening mechanical confinement triggers the same spontaneous symmetry-breaking instability, in which the contractile ring slips off the equator to yield daughters of unequal volume. In the presence of a polarity cue, this instability cooperates with the cue to program the division asymmetry. The model prediction is compared with the imaging data of C. elegans embryogenesis, in which successive cell divisions in a confined eggshell lead to smaller and smaller cell sizes. The measured division asymmetry indeed increases as the cells shrink, and is further amplified when the embryo is mechanically compressed, both in agreement with the model prediction.
Comments33 pages, 6 figures; includes Supplementary Information (5 supplementary figures, 3 supplementary tables). D.G. and G.G. contributed equally. Corresponding authors: R.M. (ruima@xmu.edu.cn), G.G. (guanguoye@gmail.com)
