title: Defect in the GTPase activating protein (GAP) function of eIF5 causes repression of GCN4 translation.
abstract: In eukaryotes, the eIF5 protein plays an important role in translation start site selection by providing the GAP (GTPase activating protein) function. However, in yeast translation initiation fidelity defective eIF5G31Rmutant causes preferential utilization of UUG as initiation codon and is termed as Suppressor of initiation codon (Sui-) phenotype due to its hyper GTPase activity. The eIF5G31Rmutant dominantly represses GCN4 expression and confers sensitivity to 3-Amino-1,2,4-Trizole (3AT) induced starvation. The down-regulation of the GCN4 expression (Gcn-phenotype) in the eIF5G31Rmutant was not because of leaky scanning defects; rather was due to the utilization of upUUG initiation codons at the 5' regulatory region present between uORF1 and the main GCN4 ORF.
authors.affiliation: School of Biological Sciences, National Institute of Science Education and Research Bhubaneswar, Constituent Institutes of Homi Bhabha National Institute (HBNI), P.O Jatni, Khurda 752050 India.
authors.forename: Charles
authors.initials: C
authors.lastname: Antony A
authors.affiliation: School of Biological Sciences, National Institute of Science Education and Research Bhubaneswar, Constituent Institutes of Homi Bhabha National Institute (HBNI), P.O Jatni, Khurda 752050 India. Electronic address: pankaj@niser.ac.in.
authors.forename: Pankaj V
authors.initials: PV
authors.lastname: Alone
mesh_terms: D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics*; D003062:Codon / Q000235:genetics; D063185:Epigenetic Repression / Q000235:genetics*; D020690:GTPase-Activating Proteins / Q000235:genetics*; D005786:Gene Expression Regulation / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D010448:Peptide Initiation Factors / Q000235:genetics*; D014176:Protein Biosynthesis / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D013329:Structure-Activity Relationship; D000097574:Eukaryotic Translation Initiation Factor 5A
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D003062:Codon; D020690:GTPase-Activating Proteins; D010448:Peptide Initiation Factors; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D000097574:Eukaryotic Translation Initiation Factor 5A; C501391:GCN4 protein, S cerevisiae
keywords: GCN4 expression; Gcn(–) phenotype; Sui(–) phenotype; Translation initiation; eIF5