By: Gunter Schutz
From: Forschungszentrum Julich, Germany
At: Online - Zoom (https://videoconf-colibri.zoom.us/j/89644383253)
We show that non-steric molecular interactions between RNA polymerase (RNAP) motors that move simultaneously on the same DNA track determine strongly the kinetics of transcription elongation. With a focus on the role of collisions and cooperation, we introduce a stochastic model that allows for the exact analytical computation of the stationary properties of transcription elongation as a function of RNAP density, their interaction strength, nucleoside triphosphate concentration, and rate of pyrophosphate release. We show that cooperative pushing, i.e., an enhancement of the average RNAP velocity and elongation rate, requires a molecular repulsion beyond steric hindrance and in excess of a critical strength. It disappears beyond a critical RNAP density, above which jamming due to collisions takes over. However, for strong repulsion and at the same time strong stochastic blocking, cooperative pushing at low RNAP densities is suppressed and a reentrance regime at higher densities appears. For a simpler model we report density anticorrelations along the track that arise from slow transcription sites.