The human Mediator complex controls RNA polymerase II (pol II) function in ways that remain incompletely understood.
Wu, S.-Y., Zhou, T. & Chiang, C.-M. Human Mediator Enhances Activator-Facilitated Recruitment of RNA Polymerase II and Promoter Recognition by TATA-Binding Protein (TBP) Independently of TBP-Associated Factors.
The human Mediator complex was also found to be extremely dynamic.
First, the experimentally most studied yeast and human Mediator will be discussed.
It was show that human Mediator containing cdk8 subcomplex is stably associated with the acetyltransferase GCN5L.
The human Mediator is an assembly of 26 subunits, but the number of subunits varies between species.
General transcription factors could further contribute to alterations of the human Mediator RNAPII structure, as it was observed for TFIIF.
Both yeast and human Mediator are enriched in motifs (43 and 79, respectively), which are biased for α-helical conformation.
In the presence of VP16 activator, conformational heterogeneity was observed in low-resolution cryo-EM data of the human Mediator RNAPII complex.
Although EM analysis of both yeast and human Mediator revealed significant conformational flexibility, no long-range correlations were observed between different parts of the structure.
