Yeast aspartyl-tRNA synthetase binds specifically its own mRNA.
Dimeric class II aspartyl-tRNA synthetase (AspRS) from yeast has a modular architecture and includes an N-terminal appendix of 70 amino acid residues that protrudes from the anticodon-binding module. This extension, of predicted helical structure, is not essential for aminoacylation but contains an RNA-binding motif that promotes non-specific interactions with tRNAs. As shown here, this protein extension can also interact with the 5' end of the AspRS mRNA. In vitro, optimal binding occurs on an mRNA domain comprising part of the 87 nucleotide long 5'UTR and the sequence encoding the N-terminal appendix. At the protein side, only the appendix and the anticodon-binding module participate in the interaction between AspRS and the mRNA domain. Binding is specific, since only tRNA(Asp) can dissociate the complex. In vivo, AspRS also binds specifically this mRNA domain and in doing so triggers a reduced translation of a fused GFP mRNA. From that, a mechanism for the regulation of this eukaryotic aminoacyl-tRNA synthetase is proposed. Implications for aspartylation accuracy in yeast are given.
Frugier
Magali
M
Département "Mécanismes et Macromolécules de la Synthèse Protéique et Cristallogenèse", UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, 15 rue René Descartes, F-67084 Strasbourg Cedex, France.
Giegé
Richard
R
D020121:5' Untranslated Regions; D020816:Amino Acid Motifs; D001226:Aspartate-tRNA Ligase / Q000737:chemistry* / Q000378:metabolism; D001667:Binding, Competitive; D015153:Blotting, Western; D004305:Dose-Response Relationship, Drug; D015971:Gene Expression Regulation, Enzymologic; D005800:Genes, Fungal; D049452:Green Fluorescent Proteins; D007700:Kinetics; D008164:Luminescent Proteins / Q000378:metabolism; D010957:Plasmids; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism
D020121:5' Untranslated Regions; D008164:Luminescent Proteins; D012333:RNA, Messenger; D049452:Green Fluorescent Proteins; D012313:RNA; D012343:RNA, Transfer; D001226:Aspartate-tRNA Ligase