Regensburg 2022 – scientific programme

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BP: Fachverband Biologische Physik

BP 8: Focus Session: Phase Separation in Biochemical Systems

BP 8.1: Invited Talk

Tuesday, September 6, 2022, 09:30–10:00, H15

Phase separation in cells: gene localization and noise buffering — •Samuel Safran — Weizmann Institute of Science, Rehovot, Israel

Biomolecular condensates formed by phase separation allow the cell to organize itself in space and can promote or inhibit biochemical reactions. I will focus upon recent observations of phase separation of chromatin (chains of DNA and proteins) in the nucleus that suggests a new paradigm in which the genetic material is separated into domains, which in some cases, have a complex, marshland, mesoscale structure. How this mesoscale structure affects gene expression noise is a topic of current research. While many of the equilibrium properties of biomolecular condensates can be understood by extensions of statistical physics, biological molecules often do not maintain constant overall compositions, in contrast to equilibrium phase separation; over time, the cell stochastically produces and degrades many proteins, resulting in a noise-induced concentration distribution. Our theory shows how in the limit of slow production/degradation relative to molecular diffusion, one can incorporate the effects of such noise into the equilibrium phase diagram to predict the extent of noise reduction (buffering) by the phase separation in multicomponent systems.