Activator-mediator binding stabilizes RNA polymerase II orientation within the human mediator-RNA polymerase II-TFIIF assembly.

ABSTRACT: The human Mediator complex controls RNA polymerase II (pol II) function in ways that remain incompletely understood. Activator-Mediator binding alters Mediator structure, and these activator-induced structural shifts appear to play key roles in regulating transcription. A recent cryo-electron microscopy (EM) analysis revealed that pol II adopted a stable orientation within a Mediator-pol II-TFIIF assembly in which Mediator was bound to the activation domain of viral protein 16 (VP16). Whereas TFIIF was shown to be important for orienting pol II within this assembly, the potential role of the activator was not assessed. To determine how activator binding might affect pol II orientation, we isolated human Mediator-pol II-TFIIF complexes in which Mediator was not bound to an activator. Cryo-E

SUBMITTER: Bernecky C 

PROVIDER: S-EPMC4582759 | biostudies-literature | 2012 Apr

REPOSITORIES: biostudies-literature