title: eIF5A Functions Globally in Translation Elongation and Termination.
abstract: The eukaryotic translation factor eIF5A, originally identified as an initiation factor, was later shown to promote translation elongation of iterated proline sequences. Using a combination of ribosome profiling and in vitro biochemistry, we report a much broader role for eIF5A in elongation and uncover a critical function for eIF5A in termination. Ribosome profiling of an eIF5A-depleted strain reveals a global elongation defect, with abundant ribosomes stalling at many sequences, not limited to proline stretches. Our data also show ribosome accumulation at stop codons and in the 3' UTR, suggesting a global defect in termination in the absence of eIF5A. Using an in vitro reconstituted translation system, we find that eIF5A strongly promotes the translation of the stalling sequences identified by profiling and increases the rate of peptidyl-tRNA hydrolysis more than 17-fold. We conclude that eIF5A functions broadly in elongation and termination, rationalizing its high cellular abundance and essential nature.
authors.affiliation: Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Schuller
authors.affiliation: Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Colin Chih-Chien
authors.initials: CC
authors.lastname: Wu
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Dever
authors.affiliation: Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Allen R
authors.initials: AR
authors.lastname: Buskirk
authors.affiliation: Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Electronic address: ragreen@jhmi.edu.
authors.forename: Rachel
authors.initials: R
authors.lastname: Green
mesh_terms: D020413:3' Untranslated Regions; D020816:Amino Acid Motifs; D018388:Codon, Terminator; D020869:Gene Expression Profiling / Q000379:methods; D006868:Hydrolysis; D007700:Kinetics; D010441:Peptide Chain Elongation, Translational; D010443:Peptide Chain Termination, Translational; D010448:Peptide Initiation Factors / Q000235:genetics / Q000378:metabolism*; D010454:Peptide Termination Factors / Q000235:genetics / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D010458:Peptidyl Transferases / Q000235:genetics / Q000378:metabolism; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D012346:RNA, Transfer, Amino Acyl / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D000097574:Eukaryotic Translation Initiation Factor 5A
chemical_list: D020413:3' Untranslated Regions; D018388:Codon, Terminator; D010448:Peptide Initiation Factors; D010454:Peptide Termination Factors; D010455:Peptides; D010458:Peptidyl Transferases; D012331:RNA, Fungal; D012346:RNA, Transfer, Amino Acyl; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D000097574:Eukaryotic Translation Initiation Factor 5A; C080775:SUP45 protein, S cerevisiae; C019037:tRNA, peptidyl-; C011083:polyproline
keywords: biochemistry; eIF5A; ribosome profiling; translation elongation; translation termination