Normal yeast tRNACAGGln can suppress amber codons and is encoded by an essential gene

William A. Weiss, Errol C. Friedberg

Research output: Contribution to journalArticlepeer-review

58 Scopus citations


We have isolated a gene that can encode yeast tRNACAGGln. When present on a multicopy plasmid, this gene suppresses the phenotype of a number of amber mutants, but has no effect on the ocher mutants tested. We therefore conclude that the anticodon CUG in tRNACAGGln decode the amber codon UAG by G · U mispairing, possibly by wobble base-pairing in the first codon position. This represents the second example we have observed in this laboratory of nonsense suppression in yeast by natural tRNAGln, involving G · U mispairing in the first codon position. Replacing the genomic copy of the cloned gene with a disrupted tRNA gene results in recessive lethality in heterozygous diploids and is lethal to haploid cells. This lethality can be rescued by transformation of cells with a single copy plasmid containing the tRNACAGGln gene. Thus, the gene encoding tRNACAGGln is apparently essential for viability in yeast, suggesting that it is normally present as a single copy gene.

Original languageEnglish (US)
Pages (from-to)725-735
Number of pages11
JournalJournal of Molecular Biology
Issue number4
StatePublished - Dec 20 1986

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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