Ribosomal protein L9 is the product of GRC5, a homolog of the putative tumor suppressor QM in S. cerevisiae.
Genes encoding members of the highly conserved QM family have been identified in eukaryotic organisms from yeast to man. Results of previous studies have suggested roles for QM in control of cell growth and proliferation, perhaps as a tumor suppressor, and in energy metabolism. We identified recessive lethal alleles of the Saccharomyces cerevisiae QM homolog GRC5 that increased GCN4 expression when present in multiple copies. These alleles encode truncated forms of the yeast QM protein Grc5p. Using a functional epitope-tagged GRC5 allele, we localized Grc5p to a 60S fraction that contained the large ribosomal subunit. Two-dimensional gel analysis of highly purified yeast ribosomes indicated that Grc5p corresponds to 60S ribosomal protein L9. This identification is consistent with the predicted physical characteristics of eukaryotic QM proteins, the highly biased codon usage of GRC5, and the presence of putative Rap1p-binding sites in the 5' sequences of the yeast GRC5 gene.
Nika
J
J
Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson 75083-0688, USA.
Erickson
F L
FL
Hannig
E M
EM
D000483:Alleles; D002352:Carrier Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic; D000080882:Ribosomal Protein L10; D012269:Ribosomal Proteins / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*
D002352:Carrier Proteins; D012269:Ribosomal Proteins; C049650:ribosomal protein L9