Issue 2, 2023

Direct observation of surface charge and stiffness of human metaphase chromosomes

Abstract

Metaphase chromosomes in which both polynucleotides and proteins are condensed with hierarchies are closely related to life phenomena such as cell division, cancer development, and cellular senescence. Nevertheless, their nature is rarely revealed, owing to their structural complexity and technical limitations in analytical methods. In this study, we used surface potential and nanomechanics mapping technology based on atomic force microscopy to measure the surface charge and intrinsic stiffness of metaphase chromosomes. We found that extra materials covering the chromosomes after the extraction process were positively charged. With the covering materials, the chromosomes were positively charged (ca. 44.9 ± 16.48 mV) and showed uniform stiffness (ca. 6.23 ± 1.98 MPa). In contrast, after getting rid of the extra materials through treatment with RNase and protease, the chromosomes were strongly negatively charged (ca. −197.4 ± 77.87 mV) and showed relatively non-uniform and augmented stiffness (ca. 36.87 ± 17.56 MPa). The results suggested undulating but compact coordination of condensed chromosomes. Additionally, excessive treatment with RNase and protease could destroy the chromosomal structure, providing an exceptional opportunity for multiscale stiffness mapping of polynucleotides, nucleosomes, chromatin fibers, and chromosomes in a single image. Our approach offers a new horizon in terms of an analytical technique for studying chromosome-related diseases.

Graphical abstract: Direct observation of surface charge and stiffness of human metaphase chromosomes

Supplementary files

Article information

Article type
Communication
Submitted
13 Sept. 2022
Accepted
17 Dec. 2022
First published
20 Dec. 2022
This article is Open Access
Creative Commons BY license

Nanoscale Adv., 2023,5, 368-377

Direct observation of surface charge and stiffness of human metaphase chromosomes

S. Roh, T. Lee, D. Y. Cheong, Y. Kim, S. Oh and G. Lee, Nanoscale Adv., 2023, 5, 368 DOI: 10.1039/D2NA00620K

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