title: Paralog-Specific Functions ofRPL7AandRPL7BMediated by Ribosomal Protein or snoRNA Dosage inSaccharomyces cerevisiae.
abstract: Most ribosomal proteins inSaccharomyces cerevisiaeare encoded by two paralogs that additively produce the optimal protein level for cell growth. Nonetheless, deleting one paralog of most ribosomal protein gene pairs results in a variety of phenotypes not observed when the other paralog is deleted. To determine whether paralog-specific phenotypes associated with deletingRPL7AorRPL7Bstem from distinct functions or different levels of the encoded isoforms, the coding region and introns of one paralog, including an intron-embedded snoRNA (small nucleolar RNA) gene, were exchanged with that of the other paralog. Among mutants harboring a single native or chimericRPL7allele, expression from theRPL7Alocus exceeded that from theRPL7Blocus, and more Rpl7a was expressed from either locus than Rpl7b Phenotypic differences in tunicamycin sensitivity,ASH1mRNA localization, and mobility of the Ty1 retrotransposon were strongly correlated with Rpl7 and ribosome levels, but not with the Rpl7 or snoRNA isoform expressed. Although Ty1 RNA is cotranslationally localized, depletion of Rpl7 minimally affected synthesis of Ty1 Gag protein, but strongly influenced Ty1 RNA localization. Unlike the other processes studied, Ty1 cDNA accumulation was influenced by both the level and isoform of Rpl7 or snoRNA expressed. These cellular processes had different minimal threshold values for Rpl7 and ribosome levels, but all were functional when isoforms of either paralog were expressed from theRPL7Alocus or bothRPL7loci. This study illustrates the broad range of phenotypes that can result from depleting ribosomes to different levels.
authors.affiliation: Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201.|Department of Biomedical Sciences, School of Public Health, University at Albany, New York 12201.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Palumbo
authors.affiliation: Department of Biological Sciences, The RNA Institute, University at Albany-State University of New York, New York 12222.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Fuchs
authors.affiliation: Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201.
authors.forename: Sheila
authors.initials: S
authors.lastname: Lutz
authors.affiliation: Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201 joan.curcio@health.ny.gov.|Department of Biomedical Sciences, School of Public Health, University at Albany, New York 12201.
authors.forename: M Joan
authors.identifier: 0000-0001-5361-3909
authors.initials: MJ
authors.lastname: Curcio
mesh_terms: D017124:Conserved Sequence / Q000235:genetics; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D010641:Phenotype; D020033:Protein Isoforms / Q000235:genetics; D020537:RNA, Small Nucleolar / Q000235:genetics; D018626:Retroelements / Q000235:genetics*; D012269:Ribosomal Proteins / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: D020033:Protein Isoforms; C084787:RLP7 protein, S cerevisiae; D020537:RNA, Small Nucleolar; D018626:Retroelements; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; D014415:Tunicamycin; C073617:RPL7A protein, S cerevisiae
keywords: RNA localization; isoform; paralog; retrotransposon; ribosomal protein