The evolutionarily conserved eukaryotic arginine attenuator peptide regulates the movement of ribosomes that have translated it.
Translation of the upstream open reading frame (uORF) in the 5' leader segment of the Neurospora crassa arg-2 mRNA causes reduced initiation at a downstream start codon when arginine is plentiful. Previous examination of this translational attenuation mechanism using a primer-extension inhibition (toeprint) assay in a homologous N. crassa cell-free translation system showed that arginine causes ribosomes to stall at the uORF termination codon. This stalling apparently regulates translation by preventing trailing scanning ribosomes from reaching the downstream start codon. Here we provide evidence that neither the distance between the uORF stop codon and the downstream initiation codon nor the nature of the stop codon used to terminate translation of the uORF-encoded arginine attenuator peptide (AAP) is important for regulation. Furthermore, translation of the AAP coding region regulates synthesis of the firefly luciferase polypeptide when it is fused directly at the N terminus of that polypeptide. In this case, the elongating ribosome stalls in response to Arg soon after it translates the AAP coding region. Regulation by this eukaryotic leader peptide thus appears to be exerted through a novel mechanism of cis-acting translational control.
Wang
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Department of Biochemistry and Molecular Biology, Oregon Graduate Institute of Science & Technology, Portland, Oregon 97291-1000, USA.
Fang
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Sachs
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D000595:Amino Acid Sequence; D001120:Arginine / Q000378:metabolism*; D001483:Base Sequence; D019733:Carbon-Nitrogen Ligases with Glutamine as Amide-N-Donor / Q000378:metabolism*; D003062:Codon / Q000235:genetics; D017124:Conserved Sequence / Q000235:genetics*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics; D017930:Genes, Reporter; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009492:Neurospora crassa / Q000235:genetics*; D016366:Open Reading Frames / Q000235:genetics; D010441:Peptide Chain Elongation, Translational / Q000235:genetics; D010446:Peptide Fragments / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000235:genetics*; D021382:Protein Sorting Signals / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D012270:Ribosomes / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D014764:Viral Proteins
D003062:Codon; D005656:Fungal Proteins; D010446:Peptide Fragments; D010455:Peptides; D021382:Protein Sorting Signals; D012333:RNA, Messenger; D014764:Viral Proteins; C116079:arginine attenuator peptide; D001120:Arginine; C062210:bacteriophage T7 RNA polymerase; D012321:DNA-Directed RNA Polymerases; D019733:Carbon-Nitrogen Ligases with Glutamine as Amide-N-Donor