Regensburg 2016 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 12: Single Molecule Biophysics
BP 12.2: Vortrag
Montag, 7. März 2016, 15:30–15:45, H45
How RNA Polymerase II elongates through di-nucleosomal DNA? — Veronika Fitz1,2, •Jaeoh Shin3, Vasily Zaburdaev3, and Stephan Grill1,2,3 — 1Max-Planck-Institute of Molecular Cell Biology and Genetics, D-01307 Dresden — 2Technical University Dresden, BIOTEC, D-01307 Dresden — 3Max-Planck-Institute for the Physics of Complex Systems, D-01187 Dresden
RNA polymerase II (Pol II), an enzyme which catalyzes messenger RNA from DNA template, plays a fundamental role in gene regulation. In eukaryotic cells, a large fraction of the DNA molecules are wrapped around nucleosomes, which interfere with the transcription process. Here we study Pol II elongation in di-nucleosomal template by using the optical tweezer setup. Our goal is to understand the role of the neighboring nucleosome on the Pol II elongation, which is relevant in the context of in vivo situation. We found that the Pol II elongation through the first nucleosome depends on the separation between the nucleosomes in a non-monotonous way. We suggest that this effect results from the relative angle between the nucleosomes. To better understand the experimental results, we develop a 2-dimensional random walk model accounting the nucleosomal barrier, backtracking, and the assisting force acting on Pol II. The model reproduces the dynamics of Pol II elongation in agreement with the experimental data without any fitting parameter. Out model shows that the relative strength of the nuclesomal barrier and the assisting force dramatically change the elongation dynamics. We also discuss how the second nucleosome affects the stability of the first nucleosome.