Regensburg 2022 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 7: Poster 1
BP 7.14: Poster
Montag, 5. September 2022, 18:00–20:00, P1
Liquid-liquid phase separation of promoter and gene-body condensates in multi-scale simulations — •Arya Changiarath Sivadasan1,2 and Lukas stelzl1,2 — 1Institute of Physics, JGU Mainz — 2Faculty of Biology JGU Mainz and institute of Molecular Biology (IMB), Mainz
Liquid-Liquid phase separation plays an important role in the formation of localized nuclear hubs of RNAPII during the transcription process. Our research is focused on understanding the molecular basis of phase separation of CTD, the largest subunit of RNAPII, using molecular dynamics (MD) simulation methods. We investigated how the CTD phase separation is affected by differences in CTD sequences using coarse-grained MD simulations and the results indicate that deviation from the ideal heptapeptide sequence has less tendency to phase separate, which suggests that these deviations from the ideal heptapeptide repeats are important for responsive regulation of transcription. Moreover, we are looking at how phosphorylation of CTD and the presence of other biomolecules that can influence CTD phase behavior. Hyper-phosphorylation prevents phase separation as the negatively charged phosphate groups repel each other. We show how hyperphosphorylated CTD might co-phase separate in elongation with HRD of Cylin-T1 in accordance with the experiment. To explore more on this, we studied the phase behavior of CTD and phosphorylated CTD in the presence of HRD and the results show that they co phase separate into a large cluster, but do not mix, which may help to physically distinguish between the initiation and elongation stages of transcription.