Rpa34 and Rpa49 are non-essential subunits of RNA polymerase I, conserved from yeast to man. Rpa34 binds an N-terminal region of Rpa49 in a two-hybrid assay and is lost from RNA polymerase in an rpa49 mutant lacking this Rpa34-binding domain, whereas rpa34Delta weakens the binding of Rpa49 to RNA polymerase. rpa34Delta is caffeine-sensitive and is lethal in top1Delta and in rpa14Delta, rpa135-L656P and rpa135-D398N RNA polymerase mutants. These defects are shared with rpa49Delta and suppressed by over-expressing Rpa49, and are thus presumably mediated by Rpa49 itself. rpa49 mutants lacking the Rpa34-binding domain essentially behave like rpa34Delta, but rpa49Delta and rpa49-338::HIS3 (lacking the conserved C-end of Rpa49) reduce polymerase occupancy at 30 degrees C, fail to grow at 25 degrees C and are sensitive to 6-azauracil and mycophenolate. Mycophenolate almost fully dissociates the mutant polymerase from its rDNA template. These mutants have a dual effect on the Rrn3/TIF-IA factor. They partly impair its recruitment to the rDNA promoter, which is bypassed by rpa43-35,326, an N-terminal deletion of the Rpa43 subunit, and strongly reduce the release of the Rrn3 initiation factor during elongation. These data suggest a dual role of the Rpa49-Rpa34 dimer during the recruitment of Rrn3 and its subsequent dissociation from the elongating polymerase.
|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|