Pseudouridine 35 (psi35) in the branch site recognition region of yeast U2 snRNA is absolutely conserved in all eukaryotes examined. Pus7p catalyzes pseudouridylation at position 35 in S. cerevisiae U2. The pus7-deletion strain, although viable in rich medium, is growth-disadvantaged under certain conditions. To clarify the function of U2 psi35 in yeast, we used this pus7-deletion strain to screen a collection of mutant U2 snRNAs, each containing a point mutation near the branch site recognition sequence, for a synthetic growth defect phenotype. The screen identified two U2 mutants, one containing a U40 to G40 substitution (U40G) and another having a U40 deletion (U40D). Yeast strains carrying either of these U2 mutations grew as well as the wild-type strain in the selection medium, but they exhibited a temperature-sensitive growth defect phenotype when coupled with the pus7-deletion (pus7D). A subsequent temperature-shift assay and a conditional pus7-depletion (via GAL promoter shutoff) in the U2-U40 mutant genetic background caused pre-mRNA accumulation, suggesting that psi35 is required for pre-mRNA splicing under certain conditions.
|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|