Impact of the six nucleotides downstream of the stop codon on translation termination.
The efficiency of translation termination is influenced by local contexts surrounding stop codons. In Saccharomyces cerevisiae, upstream and downstream sequences act synergistically to influence the translation termination efficiency. By analysing derivatives of a leaky stop codon context, we initially demonstrated that at least six nucleotides after the stop codon are a key determinant of readthrough efficiency in S. cerevisiae. We then developed a combinatorial-based strategy to identify poor 3' termination contexts. By screening a degenerate oligonucleotide library, we identified a consensus sequence -CA(A/G)N(U/C/G)A-, which promotes >5% readthrough efficiency when located downstream of a UAG stop codon. Potential base pairing between this stimulatory motif and regions close to helix 18 and 44 of the 18S rRNA provides a model for the effect of the 3' stop codon context on translation termination.
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Laboratoire de génétique moléculaire de la traduction, Institut de Génétique et Microbiologie, Université Paris-Sud, 91405 Orsay Cedex, France.
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Rousset
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D000483:Alleles; D020816:Amino Acid Motifs; D001483:Base Sequence; D003001:Cloning, Molecular; D003062:Codon; D018388:Codon, Terminator; D015723:Gene Library; D005998:Glycine / Q000737:chemistry; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010957:Plasmids / Q000378:metabolism; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D012337:RNA, Ribosomal, 18S / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
D003062:Codon; D018388:Codon, Terminator; D012333:RNA, Messenger; D012337:RNA, Ribosomal, 18S; D012343:RNA, Transfer; D005998:Glycine