Dresden 2026 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 17: Poster I
CPP 17.4: Poster
Monday, March 9, 2026, 19:00–21:00, P5
Partial demixing of RNA Polymerase II condensates in transcription regulation — Arya Changiarath1, Rosa Herrera Rodriguez1, Jasper Michels3, Friederike Schmid1, Jan Padeken2, and •Lukas Stelzl1,2 — 1Johannes Gutenberg University Mainz — 2Institute of Molecular Biology (IMB) — 3Max Planck Insitute for Polymer Research
Phase-separated condensates may spatio-temporally regulate RNA polymerase II (Pol II) during the transcription of genes. Distinct condensates may underpin the two key stages of transcription, initiation and elongation. However, it remains unclear whether these condensates mix or maintain distinct chemical environments. To investigate this, we combined multi-scale molecular dynamics simulations with experiments in C. elegans. We identified a lower critical solution temperature (LCST) behavior for Pol II, where higher temperatures promote condensation. This behavior correlates with an incremental transcriptional response to temperature but is largely uncoupled from the classical heat stress response. Our simulations demonstrate that the phosphorylation state of the disordered CTD controls the demixing of CTD and pCTD, resulting in full or partial engulfment depending on composition. Remarkably, we observe such partially-demixed of RNA polymerase II condensates by super resolution microscopy of C. elegans embryos. Overall, our results suggest that partially demixed condensates provide distinct chemical environments and binding platforms to facilitate transcription initiation and elongation.
Keywords: Molecular dynamics; multi-scale; gene regulation; phase separation; coarse-grained molecular dynamics