Single-molecule studies reveal branched pathways for activator-dependent assembly of RNA polymerase II pre-initiation complexes.

ABSTRACT: RNA polymerase II (RNA Pol II) transcription reconstituted from purified factors suggests pre-initiation complexes (PICs) can assemble by sequential incorporation of factors at the TATA box. However, these basal transcription reactions are generally independent of activators and co-activators. To study PIC assembly under more realistic conditions, we used single-molecule microscopy to visualize factor dynamics during activator-dependent reactions in nuclear extracts. Surprisingly, RNA Pol II, TFIIF, and TFIIE can pre-assemble on enhancer-bound activators before loading into PICs, and multiple RNA Pol II complexes can bind simultaneously to create a localized cluster. Unlike TFIIF and TFIIE, TFIIH binding is singular and dependent on the basal promoter. Activator-tethered factors exhibit dw

SUBMITTER: Baek I 

PROVIDER: S-EPMC8416790 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature