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

C. Bernecky, D. Taatjes, Journal of Molecular Biology 417 (2012) 387–394.


Journal Article | Published | English
Author
Bernecky, CarrieIST Austria ; Taatjes, Dylan
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-EM analysis of this assembly, coupled with pol II crystal structure docking, revealed that pol II binds Mediator at the same general location; however, in contrast to VP16-bound Mediator, pol II does not appear to stably orient in the absence of an activator. Variability in pol II orientation might be important mechanistically, perhaps to enable sense and antisense transcription at human promoters. Because Mediator interacts extensively with pol II, these results suggest that Mediator structural shifts induced by activator binding help stably orient pol II prior to transcription initiation.
Publishing Year
Date Published
2012-04-13
Journal Title
Journal of Molecular Biology
Volume
417
Issue
5
Page
387 - 394
IST-REx-ID
596

Cite this

Bernecky C, Taatjes D. Activator-mediator binding stabilizes RNA polymerase II orientation within the human mediator-RNA polymerase II-TFIIF assembly. Journal of Molecular Biology. 2012;417(5):387-394. doi:10.1016/j.jmb.2012.02.014
Bernecky, C., & Taatjes, D. (2012). Activator-mediator binding stabilizes RNA polymerase II orientation within the human mediator-RNA polymerase II-TFIIF assembly. Journal of Molecular Biology, 417(5), 387–394. https://doi.org/10.1016/j.jmb.2012.02.014
Bernecky, Carrie, and Dylan Taatjes. “Activator-Mediator Binding Stabilizes RNA Polymerase II Orientation within the Human Mediator-RNA Polymerase II-TFIIF Assembly.” Journal of Molecular Biology 417, no. 5 (2012): 387–94. https://doi.org/10.1016/j.jmb.2012.02.014.
C. Bernecky and D. Taatjes, “Activator-mediator binding stabilizes RNA polymerase II orientation within the human mediator-RNA polymerase II-TFIIF assembly,” Journal of Molecular Biology, vol. 417, no. 5, pp. 387–394, 2012.
Bernecky C, Taatjes D. 2012. Activator-mediator binding stabilizes RNA polymerase II orientation within the human mediator-RNA polymerase II-TFIIF assembly. Journal of Molecular Biology. 417(5), 387–394.
Bernecky, Carrie, and Dylan Taatjes. “Activator-Mediator Binding Stabilizes RNA Polymerase II Orientation within the Human Mediator-RNA Polymerase II-TFIIF Assembly.” Journal of Molecular Biology, vol. 417, no. 5, Elsevier, 2012, pp. 387–94, doi:10.1016/j.jmb.2012.02.014.
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