Polymers 2017, 9(8), 317; doi:10.3390/polym9080317
Are There Knots in Chromosomes?
Jonathan T. Siebert 1, Alexey N. Kivel 1, Liam P. Atkinson 2, Tim J. Stevens 3, Ernest D. Laue 2 and Peter Virnau 1,*
1 Department of Physics, Johannes Gutenberg University Mainz, Staudinger Weg 9, 55128 Mainz, Germany
2 Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
3 MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
* Author to whom correspondence should be addressed.
Received: 30 June 2017 / Revised: 24 July 2017 / Accepted: 25 July 2017 / Published: 2 August 2017
(This article belongs to the Special Issue Knotted and Catenated Polymers)
Researchers at Mainz University found two knots in chromosome 14, here indicated by the solid lines. The blue and red dots mark the beginning and end of the chromosome. The coloring used in the image is designed to help with orientation only.
Credit: Ill. / ©: Jonathan Siebert, JGU
Abstract
Recent developments have for the first time allowed the determination of three-dimensional structures of individual chromosomes and genomes in nuclei of single haploid mouse embryonic stem (ES) cells based on Hi–C chromosome conformation contact data. Although these first structures have a relatively low resolution, they provide the first experimental data that can be used to study chromosome and intact genome folding. Here we further analyze these structures and provide the first evidence that G1 phase chromosomes are knotted, consistent with the fact that plots of contact probability vs sequence separation show a power law dependence that is intermediate between that of a fractal globule and an equilibrium structure. View Full-Text
Keywords: knots; chromosomes; chromosome territories; DNA; fractal globule
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).
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