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Résumé |
Chromatin is intricately organized within the cell nucleus so that the essential
processes governing genetic material can occur in a coordinated and orderly way.
At the same time, chromatin is a polymer operating at submicroscopic scales, where
its behavior is strongly shaped by physical forces, including the constant
stochastic fluctuations produced by thermal motion. In this talk, I will present
recent work aimed at understanding how out of equilibrium processes are
fundamental to understand the emergence of chromatin structure. First, I will
discuss how macromolecular crowding influences DNA conformation. I will then
examine the factors shaping telomere organization in yeast along the growth cycle,
focusing on phase separation. I will show how the out-of-equilibrium processes of
surface wetting, ripening, coalescence and nucleation are key to understand the
observations. This work led me to speculate that the lens of physiology, rather
than the more traditional molecular biology perspective, might be the key
framework to understand the principles of chromosome organization. Finally, I will
present our current work on loop extrusion, an active processes that is
predominant in the structuring of eukaryotic chromosomes, and show how the energy
spent for this process results in the emergence of osmoelastic tensions and
increased ordering in chromosomes. |
