Rpb4/Rpb7 subcomplex of yeast RNA polymerase II has counterparts in all multi-subunit RNA polymerases from archaebacteria to higher eukaryotes. The Rpb4/7 subcomplex in S. cerevisiae is unique in that it easily dissociates from the core, unlike in other organisms. The relative levels of Rpb4 and Rpb7 in yeasts affect differential gene expression and stress response. Rpb4 is nonessential in S. cerevisiae and affects expression of a small number of genes under normal growth conditions. Here, using ChIP on chip technique, we compared genome wide binding of Rpb4 to that of a core Pol II subunit, Rpb3. Our results showed that in spite of being nonessential for survival, Rpb4 was recruited on coding regions of most transcriptionally active genes similar to the core Pol II subunit, Rpb3, albeit to a lesser extent. The extent of Rpb4 recruitment increased with increasing gene length. We also observed Pol II lacking Rpb4 to be defective in transcribing long, GC rich transcription units suggesting a role for Rpb4 in transcription elongation. This role in transcription elongation was supported by the observed 6-azauracil sensitivity of rpb4Delta mutant. Unlike most phenotypes of rpb4Delta, the 6AU sensitivity of rpb4Delta strain was not rescued by over expression of RPB7. This report provides the first instance of a distinct role for Rpb4 in transcription, which is independent of its interacting partner, Rpb7.
|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|