The large subunit rRNA in eukaryotes contains an unusually dense cluster of 8-10 pseudouridine () modifications located in a three-helix structure (H37-39) implicated in several functions. This region is dominated by a long flexible helix (H38) known as the 'A-site finger' (ASF). The ASF protrudes from the large subunit just above the A-site of tRNA binding, interacts with 5S rRNA and tRNA, and through the terminal loop, forms a bridge (B1a) with the small subunit. In yeast, the three-helix domain contains 10 s and six are concentrated in the ASF helix (three of the ASF s are conserved among eukaryotes). Here, we show by genetic depletion analysis that the s in the ASF helix and adjoining helices are not crucial for cell viability; however their presence notably enhances ribosome fitness. Depleting different combinations of s suggest that the modification pattern is important and revealed that loss of multiple s negatively influences ribosome performance. The effects observed include slower cell growth (reduced rates up to 23% at 30 degrees C, and 40-50% at 37 degrees C and 11 degrees C), reduced level of the large subunit (up to 17%), impaired polysome formation (appearance of half-mers), reduced translation activity (up to 20% at 30 degrees C, and 25% at 11 degrees C), and increased sensitivity to ribosome-based drugs. The results indicate that the s in the three-helix region improve fitness of a eukaryotic ribosome.
|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|