title: Interplay between GCN2 and GCN4 expression, translation elongation factor 1 mutations and translational fidelity in yeast.
abstract: Genetic screens in Saccharomyces cerevisiae have identified the roles of ribosome components, tRNAs and translation factors in translational fidelity. These screens rely on the suppression of altered start codons, nonsense codons or frameshift mutations in genes involved in amino acid or nucleotide metabolism. Many of these genes are regulated by the General Amino Acid Control (GAAC) pathway. Upon amino acid starvation, the kinase GCN2 induces the GAAC cascade via increased translation of the transcriptional activator GCN4 controlled by upstream open reading frames (uORFs). Overexpression of the GCN2 or GCN4 genes enhances the sensitivity of translation fidelity assays that utilize genes regulated by GCN4, such as the suppression of a +1 insertion by S.cerevisiae translation elongation factor 1A (eEF1A) mutants. Paromomycin and the prion [PSI+], which reduce translational fidelity, do not increase GCN4 expression to induce the suppression phenotype and in fact reduce derepression. eEF1A mutations that reduce translation, however, reduce expression of GCN4 under non-starvation conditions. These eEF1A mutants also reduce HIS4 mRNA expression. Taken together, this system improves in vivo strategies for the analysis of translational fidelity and further provides new information on the interplay among translation fidelity, altered elongation and translational control via uORFs.
authors.affiliation: Department of Molecular Genetics, Microbiology and Immunology, UMDNJ Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
authors.forename: Tanya
authors.initials: T
authors.lastname: Magazinnik
authors.forename: Monika
authors.initials: M
authors.lastname: Anand
authors.forename: Evelyn
authors.initials: E
authors.lastname: Sattlegger
authors.forename: Alan G
authors.initials: AG
authors.lastname: Hinnebusch
authors.forename: Terri Goss
authors.initials: TG
authors.lastname: Kinzy
mesh_terms: D000429:Alcohol Oxidoreductases / Q000096:biosynthesis / Q000235:genetics; D000483:Alleles; D000619:Aminohydrolases / Q000096:biosynthesis / Q000235:genetics; D048708:Cell Growth Processes; D004268:DNA-Binding Proteins / Q000378:metabolism*; D016368:Frameshift Mutation; D017930:Genes, Reporter; D009154:Mutation; D010303:Paromomycin / Q000494:pharmacology; D010441:Peptide Chain Elongation, Translational; D020648:Peptide Elongation Factor 1 / Q000235:genetics*; D010641:Phenotype; D014176:Protein Biosynthesis; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D011755:Pyrophosphatases / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D013489:Suppression, Genetic
chemical_list: D004268:DNA-Binding Proteins; D020648:Peptide Elongation Factor 1; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D010303:Paromomycin; D000429:Alcohol Oxidoreductases; C092116:HIS4 protein, S cerevisiae; D011494:Protein Kinases; C512912:GCN2 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; D000619:Aminohydrolases; D011755:Pyrophosphatases