title: How tRNAs dictate nuclear codon reassignments: Only a few can capture non-cognate codons.
abstract: mRNA decoding by tRNAs and tRNA charging by aminoacyl-tRNA synthetases are biochemically separated processes that nevertheless in general involve the same nucleotides. The combination of charging and decoding determines the genetic code. Codon reassignment happens when a differently charged tRNA replaces a former cognate tRNA. The recent discovery of the polyphyly of the yeast CUG sense codon reassignment challenged previous mechanistic considerations and led to the proposal of the so-called tRNA loss driven codon reassignment hypothesis. Accordingly, codon capture is caused by loss of a tRNA or by mutations in the translation termination factor, subsequent reduction of the codon frequency through reduced translation fidelity and final appearance of a new cognate tRNA. Critical for codon capture are sequence and structure of the new tRNA, which must be compatible with recognition regions of aminoacyl-tRNA synthetases. The proposed hypothesis applies to all reported nuclear and organellar codon reassignments.
authors.affiliation: a Group Systems Biology of Motor Proteins , Department of NMR-based Structural Biology, Max-Planck-Institute for Biophysical Chemistry , Göttingen , Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Kollmar
authors.affiliation: b Milner Centre for Evolution, Department of Biology and Biochemistry , University of Bath, Milner Centre for Evolution , Bath , UK.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Mühlhausen
mesh_terms: D000818:Animals; D000926:Anticodon; D003062:Codon / Q000235:genetics*; D018388:Codon, Terminator; D005815:Genetic Code; D006801:Humans; D014176:Protein Biosynthesis; D012343:RNA, Transfer / Q000235:genetics*; D015003:Yeasts / Q000235:genetics / Q000378:metabolism
chemical_list: D000926:Anticodon; D003062:Codon; D018388:Codon, Terminator; D012343:RNA, Transfer
keywords: Anticodon; Pachysolen tannophilus; codon reassignment; genetic code; tRNA; yeasts