A multi-protein complex, termed mediator, has been isolated from yeast, based on its requirement for transcriptional activation in a system reconstituted from pure RNA polymerase II and general transcription factors. Mediator polypeptides include the products of many genes previously recovered from screens for mutations affecting transcription. This connection between biochemical and genetic studies reveals that mediator is important for both activation and repression of transcription, and that mediator plays a role in transcriptional regulation in vivo as well as in vitro. Mediator binds the carboxy-terminal domain of RNA polymerase II, forming a polymerase holoenzyme, whose possible association with additional proteins is a subject of some controversy.
Bibliographical noteFunding Information:
The authors apologize for omitting several related contributions and references owing to space limitations. S. B. is supported by grants from the Swedish Natural Science Research Council, the Magn. Bergvalls Stiftelse, and Sven and Ebba-Christina Hagbergs Stiftelse.
All Science Journal Classification (ASJC) codes
- Molecular Biology