Centromeres and Telomeres as Rheological Probes of the Human Nucleus

The nucleus of eukaryotic cells stores genetic information in chromatin, the functional form of DNA in cells. Chromatin loci have been observed to exhibit anomalous motion that is often ascribed to the viscoelastic nature of the chromatin, transient interactions of DNA-associated proteins and/or physical obstructions [1,2]. However, a direct link between a chromatin locus motion and the rheology of its local environment is missing. In this work, we investigate dynamics of specific genomic loci, centromeres and telomeres, the centers and ends of the linear interphase chromosomes, respectively, in the context of their local rheological environment. Using simultaneous two-color spinning disc confocal microscopy combined with recently developed machine-learning-assisted tracking algorithms [3], we monitor the motion of telomeres and centromeres in live human cells and extract the rheological properties of their surrounding environment, mapping the chromatin rheology across the cell nucleus.

[1] Levi et al, Biophys. J., 2005
[2] Bronstein et al, Phys. Rev. Lett., 2009
[3] Eaton and Zidovska, Biophys. J., 2020