Micromechanics regulating the dynamics of chromosome segregation

在减数分裂/有丝分裂过程中，准确的染色体分离需要一个形状和大小合适的两极纺锤体的组装。我们计划用定量的力测量来研究染色体分离机制的潜在机制，重点是脊椎动物减数分裂纺锤体在非洲爪哇卵提取物中自组装的结构调控机制。本项目的主要成果如下：(1)开发了一种基于测力的新技术来探测体外组装主轴的机械结构，该技术使得利用纳牛力和微米级扰动来检测主轴的变形和刚度等力学特性成为可能。(2)利用测力技术，我们发现减数分裂中期的纺锤体表现为粘弹性或塑性结构，这取决于外加载荷的大小。(3)不同大小的中期纺锤体在外加控制外力的作用下可发生相互转换，表明尺寸控制机构对机械扰动具有响应和调节作用。

Accurate chromosome segregation during meiosis/mitosis critically requires the assembly of a bipolar spindle of proper shape and size. We planned to investigate the underlying mechanisms of chromosome segregation machinery with quantitative force measurements, focusing on the architectural regulatory mechanism of the vertebrate meiotic spindle self-assembled in Xenopus egg extracts. The main results of this project are summarized as follows: (1) We developed a new technique based on the force measurements to probe the mechanical framework of the in vitro assembled spindle.This technique makes it possible to examine the mechanical features of the spindle, such as its deformability and stiffness, with the application of nanonewton forces and micron-size perturbations. (2) Using the force measuring techniques, we found that the meiotic spindle at metaphase behaves like either a viscoelastic or a plastic structure depending on the extent of applied load. (3) Transformations between the metaphase spindles of different sizes can be induced by the applying controlled external force, which indicates that the size-control mechanisms respond to and can be modulated by mechanical perturbation.