Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam, Germany.
Department of Physics, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain.
Proc Natl Acad Sci U S A. 2020 Mar 24;117(12):6330-6338. doi: 10.1073/pnas.1912428117. Epub 2020 Mar 11.
Cytokinesis-the division of a cell into two daughter cells-is a key step in cell growth and proliferation. It typically occurs in synchrony with the cell cycle to ensure that a complete copy of the genetic information is passed on to the next generation of daughter cells. In animal cells, cytokinesis commonly relies on an actomyosin contractile ring that drives equatorial furrowing and separation into the two daughter cells. However, also contractile ring-independent forms of cell division are known that depend on substrate-mediated traction forces. Here, we report evidence of an as yet unknown type of contractile ring-independent cytokinesis that we termed wave-mediated cytofission. It is driven by self-organized cortical actin waves that travel across the ventral membrane of oversized, multinucleated cells. Upon collision with the cell border, waves may initiate the formation of protrusions that elongate and eventually pinch off to form separate daughter cells. They are composed of a stable elongated wave segment that is enclosed by a cell membrane and moves in a highly persistent fashion. We rationalize our observations based on a noisy excitable reaction-diffusion model in combination with a dynamic phase field to account for the cell shape and demonstrate that daughter cells emerging from wave-mediated cytofission exhibit a well-controlled size.
细胞分裂(将一个细胞分裂成两个子细胞)是细胞生长和增殖的关键步骤。它通常与细胞周期同步发生,以确保遗传信息的完整副本传递给下一代子细胞。在动物细胞中,胞质分裂通常依赖于肌动球蛋白收缩环,该收缩环驱动赤道皱缩和两个子细胞的分离。然而,也已知存在不依赖收缩环的细胞分裂形式,这些形式依赖于基质介导的牵引力。在这里,我们报告了一种未知的、不依赖收缩环的细胞分裂形式,我们称之为波介导的细胞分裂。它由跨越过大、多核细胞的腹侧膜的自我组织皮层肌动蛋白波驱动。当波与细胞膜边界碰撞时,可能会引发突起的形成,这些突起会伸长并最终缢裂形成独立的子细胞。它们由一个稳定的伸长波段组成,该波段被细胞膜包围,并以高度持久的方式移动。我们基于噪声激发反应扩散模型结合动态相场来解释细胞形状,从而合理化我们的观察结果,并证明从波介导的细胞分裂中出现的子细胞具有良好的尺寸控制。