Science Daily October 17, 2019
Researchers at Cornell University have unraveled the mystery of how DNA’s double helix manage to replicate without being tangled up from a topological perspective. Using eukaryotes as their model system, they found that the intrinsic mechanical properties of the chromatin (a complex of DNA and proteins) determine how the chromatin fibers will entwine. This topology is crucial to the successful separation of newly replicated DNA: If the fibers twist too tightly too early, then the molecules are unable to properly segregate during cell division. They found that twisting a single chromatin fiber is much easier than twisting a double fiber. This means that the extra twist, caused by a great deal of torsional stress on the DNA when replisome splits two DNA strands and moves forward, will preferentially go to the front, thus minimizing the intertwining of the two daughter DNA molecules. This research highlights the importance of physical principles in fundamental biological processes…read more. Open Access TECHNICAL ARTICLE
Graphical abstract. Credit: Cell, VOLUME 179, ISSUE 3, P619-631.E15, OCTOBER 17, 2019Â