Mysterious Mediator multiprotein

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Science  04 Aug 2017:
Vol. 357, Issue 6350, pp. 468-469
DOI: 10.1126/science.357.6350.468-e

Mediator is a multiprotein complex that physically connects transcription activators bound at enhancers and RNA polymerase II bound at promoters to initiate transcription. Petrenko et al. measured transcriptional activity after depleting Mediator in yeast. Instead of eliminating activity as expected, the depletion of individual subunits caused a modest decrease in transcription. Only when all three (head, middle, and tail) modules of Mediator were simultaneously inactivated was transcription abrogated. Furthermore, different Mediator modules promoted RNA polymerase II in different ways, and Mediator was not found in the preinitiation complex. This result questions the classic model of Mediator bridging enhancers and promoters and begs for answers about how Mediator activates transcription.

eLife 10.7554/eLife.28447 (2017).

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