Using a highly pure transcription system derived from Saccharomyces cerevisiae, we have purified an activity in yeast whole-cell extracts that represses RNA polymerase II transcription. Mechanistic studies suggest that this repressor specifically targets transcriptional reinitiation. The two polypeptides that constitute the repressor have been identified as Ceg1p and Cet1p, the two subunits of the yeast pre-mRNA capping enzyme. A purified recombinant capping enzyme is able to reconstitute repressor activity. Cet1p is necessary for and capable of this repression. Transcriptional run-on experiments indicate that the capping enzyme also serves as a repressor in vivo. Efficient pre-mRNA capping relies on interactions between the capping enzyme and transcription apparatus. Repression by the capping enzyme suggests a bidirectional flow of information between capping and transcription.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|