Regensburg 2022 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 8: Focus Session: Phase Separation in Biochemical Systems
BP 8.3: Vortrag
Dienstag, 6. September 2022, 10:15–10:30, H15
Lattice based model and continuum theory of active microemulsion — •Rakesh Chatterjee1,2, Hui-Shun Kuan1,2, and Vasily Zaburdaev1,2 — 1Friedrich-Alexander University, Erlangen-Nuremberg, Erlangen, Germany — 2Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
During transcription, RNA polymerase II (Pol II) attaches and moves along the DNA strand to produce messenger-RNA (mRNA) transcript. It has been recently shown that in the nucleus, DNA and RNA are spatially organised in agreement with a microphase separation process [1], where the full phase separation of the RNA-rich phase from DNA is prevented by the transcribing Pol II playing the role of an amphiphile. To gain the comprehensive understanding of physical mechanisms behind this process we propose a phenomenological lattice model where DNA, mRNA and Pol II serve as the three basic components similar to the equilibrium oil-water-amphiphile system, which exhibits two and three phase coexistence. Here however, Pol II undergoes chemical transitions reflecting different stages of the transcription process. In the model, it is realised by assuming transient dynamics of the amphiphiles which switches between active and inactive states. Numerical simulations of the lattice model show that amphiphile activity significantly modifies phase behaviour of the system compared to the equilibrium scenario. Furthermore, by rigorous coarse-graining of the lattice model we could derive the continuum theory and predict the relaxation dynamics of the dynamic structure factor of active microemulsion.
[1] Hilbert et.al, Nature Comm. 12, (1) 2021.