Mendonca Tania, Urban Roman, Lucken Kellie, Coney George, Kad Neil M, Tassieri Manlio, Wright Amanda J, Booth Daniel G
Biodiscovery Institute, School of Medicine, University of Nottingham, Nottingham, NG7 2RD, UK.
Optics and Photonics Research Group, Faculty of Engineering, University of Nottingham, Nottingham, NG7 2RD, UK.
Nat Commun. 2025 Jul 10;16(1):6399. doi: 10.1038/s41467-025-61755-5.
In dividing cells, chromosomes are coated in a sheath of proteins and RNA called the mitotic chromosome periphery. This sheath is thought to confer biophysical properties to chromosomes, critical for successful cell division. However, the details of chromosome mechanics, and specifically, if and how the chromosome periphery contributes to them, remain poorly understood. In this study, we present a comprehensive characterisation of single-chromosome mechanics using optical tweezers and an improved broadband microrheology analysis. We extend this analysis to direct measurements of the chromosome periphery by manipulating levels of Ki-67, its chief organiser, and apply a rheological model to isolate its contribution to chromosome mechanics. We report that the chromosome periphery governs dynamic self-reorganisation of chromosomes and acts as a structural constraint, providing force-damping properties. This work provides significant insight into chromosome mechanics and will inform our understanding of the mitotic chromosome periphery's role in cell division.
在正在分裂的细胞中，染色体被一层由蛋白质和RNA组成的鞘所包裹，这层鞘被称为有丝分裂染色体外周。人们认为这层鞘赋予了染色体生物物理特性，而这些特性对于细胞成功分裂至关重要。然而，染色体力学的细节，尤其是染色体外周是否以及如何对其产生影响，仍然知之甚少。在这项研究中，我们使用光镊和改进的宽带微流变学分析对单染色体力学进行了全面表征。我们通过操纵其主要组织者Ki-67的水平，将这种分析扩展到对染色体外周的直接测量，并应用流变学模型来分离其对染色体力学的贡献。我们报告称，染色体外周控制着染色体的动态自我重组，并作为一种结构约束，提供力阻尼特性。这项工作为染色体力学提供了重要的见解，并将有助于我们理解有丝分裂染色体外周在细胞分裂中的作用。
