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BP: Fachverband Biologische Physik
BP 9: Poster Session Ib
BP 9.16: Poster
Montag, 18. März 2024, 18:00–20:30, Poster D
A Pump-Leak model can reproduce the biophysical properties of eukaryotic cell nuclei — •Omar Muñoz1,2, Abin Biswas1,3,4, Kyoohyun Kim1,4, Johen Guck1,2,4, Vasily Zaburdaev1,2, and Simone Reber3,5 — 1Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany. — 2Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany — 3Max Planck Institute for Infection Biology, Berlin, Germany — 4Max Planck Institute for the Science of Light, Erlangen, Germany — 5University of Applied Sciences Berlin, Berlin, Germany
Biophysical properties of the cell nucleus are important for various cellular processes from migration to stress responses, but largely are still not well understood. One fundamental example is the mass density: we observed that the nuclear mass density consistently displays a lower value than its cytoplasmic counterpart for a wide range of species, which is surprising given that it contains the highly compacted genetic material. To understand the mechanisms behind this, we measured volume and mass density in two systems: growing nuclei reconstituted in Xenopus egg extracts and interphase HeLa cells. We propose a minimal theoretical description using the Pump and Leak model (PLM), which relies on a pressure balance. Based on our experimental results, we incorporate the most relevant contributions to the pressure balance, which we find to be the osmotic pressure and entropic polymer pressure exerted by chromatin. By taking into account relevant biological processes such as nucleocytoplasmic transport and its apparent coupling to chromatin, we are able to reproduce the experimental results.
Keywords: Cell Nucleus; Nuclear Transport; Osmotic Pressure