ABSTRACT
Rrs1 has an essential role in 60S ribosomal subunit assembly in Saccharomyces cerevisiae. We isolated a temperature-sensitive kcs1 mutant that suppresses the cold sensitivity of rrs1-1. The kcs1 allele, resulting in truncation of inositol 6 phosphate kinase domain, and kcs1 disruption suppress a defect of rrs1-1 in 60S ribosomal subunit assembly. These results suggest that inositol polyphosphate metabolism affects ribosome biogenesis in yeast.
Subject(s)
Phytic Acid/metabolism , Ribosomes/metabolism , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Alleles , Cold Temperature , Genes, Fungal , Mutation , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Phosphotransferases (Phosphate Group Acceptor)/genetics , Phosphotransferases (Phosphate Group Acceptor)/metabolism , Saccharomyces cerevisiae/cytology , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae Proteins/metabolismABSTRACT
Rrs1p is a ribosomal protein L11-binding protein in Saccharomyces cerevisiae. We have obtained temperature-sensitive rrs1 mutants by random PCR mutagenesis. [(3)H]Methionine pulse-chase analysis reveals that the rrs1 mutations cause a defect in maturation of 25S rRNA. Ribosomal protein L25-enhanced green fluorescent protein, a reporter of the 60S ribosomal subunit, concentrates in the nucleus with enrichment in the nucleolus when the rrs1 mutants are shifted to the restrictive temperature. These results suggest that Rrs1p stays on the pre-60S particle from the early stage to very late stage of the large-subunit maturation and is required for export of 60S subunits from the nucleolus to the cytoplasm.
