BPCPPDYSOE21 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 11: Poster A: Single Molecule, Multicellular, Bioimaging, Focus Sessions, etc.
BP 11.12: Poster
Montag, 22. März 2021, 16:30–19:00, BPp
Cohesin and condensin extrude DNA loops in a cell cycle-dependent manner — •Stefan Golfier1,2, Thomas Quail1,2, and Jan Brugues1,2 — 1Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany — 2MPI-PKS, Nöthnitzer Straße 38, Dresden, Germany
How cells spatially organise long DNA polymers inside the confinements of the cell nucleus without creating knots and tangles has been a central question in cell biology. Recent observations have unveiled the physical architecture of the genome as a hierarchy of higher-order structures that deeply impact biological function. Despite their role for gene regulation, DNA repair and genome propagation, the underlying mechanisms shaping the 3D genome remained elusive. The active formation of vast DNA loops by the molecular motors cohesin and condensins has been proposed as a general mechanism to spatially organize the genome across the cell cycle. However, the requirements for genome organisation change dramatically during the cell cycle. To date it remained unclear, if DNA loops shape the drastically different chromatin architectures in inter- and metaphase. Using Xenopus laevis egg extracts, we reconstitute and directly observe DNA loop formation for the first time in a native environment and dependence of the cell cycle. We show that DNA loops are actively formed in both meta- and interphase, but with distinct biophysical properties and responsible factors. Our findings provide fundamental evidence that DNA loops are the physical building blocks of genome architecture, that are molecularly regulated during the cell cycle.