Base Composition Influences the Position and Precision of RNA Polymerase II Disassociation in Basal and Perturbed Conditions.

Pol II transcription termination is crucial for mRNA maturation and, when disrupted, can lead to altered mRNA processing and mRNA export. Termination involves two intertwined processes: pre-mRNA cleavage, and Pol II release from the DNA (disassociation).

Despite its importance, the exact mechanisms underlying Pol II disassociation from the DNA remain poorly understood. Moreover, under certain cellular stress conditions, there is a partial failure of cleavage, leading to a shift of the position of disassociation further downstream, a phenomenon known as run-on transcription. We performed the first-ever systematic analysis of Pol II termination across cell types and species and provide novel insights into the mechanism of disassociation.