A multiprotein mediator of transcriptional activation and its interaction with the C-terminal repeat domain of RNA polymerase II.
A mediator was isolated from yeast that enabled a response to the activator proteins GAL4-VP16 and GCN4 in a transcription system reconstituted with essentially homogeneous basal factors and RNA polymerase II. The mediator comprised some 20 polypeptides, including the three subunits of TFIIF and other polypeptides cross-reactive with antisera against ... GAL11, SUG1, SRB2, SRB4, SRB5, and SRB6 proteins. Mediator not only enabled activated transcription but also conferred 8-fold greater activity in basal transcription and 12-fold greater efficiency of phosphorylation of RNA polymerase II by the TFIIH-associated C-terminal repeat domain (CTD) kinase, indicative of mediator-CTD interaction. A holoenzyme form of RNA polymerase II was independently isolated that supported a response to activator proteins with purified basal factors. The holoenzyme proved to consist of mediator associated with core 12-subunit RNA polymerase II.
Mesh Terms:
DNA-Binding Proteins, Fungal Proteins, Peptides, Phosphorylation, Protein Binding, Protein Kinases, Protein Structure, Tertiary, RNA Polymerase II, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Trans-Activators, Transcription Factors, Transcription, Genetic, Transcriptional Activation
DNA-Binding Proteins, Fungal Proteins, Peptides, Phosphorylation, Protein Binding, Protein Kinases, Protein Structure, Tertiary, RNA Polymerase II, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Trans-Activators, Transcription Factors, Transcription, Genetic, Transcriptional Activation
Cell
Date: May. 20, 1994
PubMed ID: 8187178
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