Cohesin regulates promoter-proximal pausing of RNA Polymerase II by limiting recruitment of super elongation complex

Abstract

Cohesin is a ring-shaped complex, responsible for establishing sister chromatid cohesion and forming topologically associating domains (TADs) and chromatin loops. Loss-of-function mutations in cohesin subunits and its regulatory factors can cause Cornelia de Lange syndrome (CdLS). Because dysregulated gene expression was observed in CdLS, it has long been thought that cohesin plays a regulatory role in transcription. Here, we investigated the effect of acute cohesin depletion on transcription and observed that a small number of genes exhibited differential expression. Analysis of RNA polymerase II (Pol II) distribution revealed that the depletion reduced Pol II promoter binding and pausing simultaneously at the majority of genes. This implies that at most genes, the two decreases counterbalance each other, resulting in unchanged gene expression. Additionally, we find that cohesin loss increased promoter binding of super elongation complex (SEC), which mediates the release of Pol II from paused state. Moreover, the reduction in pausing caused by cohesin depletion was no longer observed when SEC was inhibited. These observations suggest that cohesin regulates Pol II pausing by restricting SEC recruitment to promoters. Together, our study demonstrates the involvement of cohesin in transcriptional regulation, particularly in Pol II pause and release.