Base composition reflects RNA polymerase II displacement.

Genes with GC-rich regions surrounding Pol II displacement sites show increased chromatin accessibility and higher phospho-threonine 4 levels on Pol II CTD.

• Why it matters: Understanding Pol II displacement mechanisms is essential for insights into RNA transcription termination and RNA processing, with disruptions linked to cellular stress and disease.
• What they did: Using a probabilistic mixture model on nascent RNA sequencing data, the study analyzed Pol II dynamics across gene bodies in multiple cell types and species, identifying two classes based on base composition patterns near displacement sites.
• The result: Genes with only upstream T-rich regions are more susceptible to perturbations like heat shock and viral infection, indicating that base composition influences Pol II displacement stability under stress conditions.