DNA Topology: from single molecules to chromosomes

DNA Topology: from single molecules to chromosomes - Featured

Title: DNA Topology: from single molecules to chromosomes
When: Tuesday, February 06, 2024, 12:00
Place: Department of Theoretical Condensed Matter Physics, Faculty of Sciences, Module 5, Seminar Room (5th Floor)
Speaker: Enrico Carlon, Soft Matter and Biophysics, KU Leuven, Belgium.

While performing its function in cells, DNA is subject to considerable mechanical deformations due to the interactions with other biomolecules and to thermal fluctuations. Torques and forces applied to very long DNA molecules lead to the formation of complex topological structures, as intertwined loops called plectonemes. Proteins interacting with DNA in the cell nucleus also contribute to the structural organization of long chromosomes. In this talk we will discuss two different topics linked to topological properties of DNA. The first part will be focused on equilibrium fluctuations of DNA plectonemes as generated by Magnetic Tweezers (MT), which can apply controlled torques and forces to a single DNA molecule. We will show, using analytical models and simulations, how from the analysis of fluctuations of MT data one can detect DNA binding protein events. The second part will be dedicated to the analysis of high-resolution microscopy data of human chromosome 21, which unveil the complex topological organization of DNA in cell nuclei captured by scaling laws, and which indicate an underling phase separation process.

References

  1. W. Vanderlinden, E. Skoruppa, P. Kolbeck, E. Carlon, J. Lipfert, DNA fluctuations reveal the size and dynamics of topological domains, PNAS Nexus 1, pgac268 (2022)
  2. E. Skoruppa, E. Carlon, Equilibrium Fluctuations of DNA Plectonemes Phys. Rev. E 106, 024412 (2022)
  3. L. Remini, M. Segers, J. Palmeri, J.-C. Walter, A. Parmeggiani, E. Carlon, Chromatin structure from high resolution microscopy: scaling laws and microphase separation bioRxiv 2023.08.01.551471
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