Yeast suppressors of UAA and UAG nonsense codons work efficiently in vitro via tRNA

R. F. Gesteland, M. Wolfner, P. Grisafi, G. Fink, D. Botstein, J. R. Roth

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


A cell-free protein-synthesizing system, containing an S-100 fraction from yeast, ribosomal subunits from Krebs ascites cells, and ribosome initiation factors from rabbit reticulocytes, translates yeast, adenovirus, and rabbit globin messenger RNAs and the RNA from bacteriophage Qβ. An amber mutation in the Qβ synthetase gene is suppressed in vitro if the S-100 fraction is from yeast strains carrying amber suppressor mutations. Suppressor SUP6-2 gives 16% suppression, and the recessive lethal suppressor RL-1 gives 50% suppression. Extracts from strain FM6, which has the ochre suppressor SUP4-1, give a longer protein product from the normal synthetase gene of Qβ with an efficiency of 63%. This implies that UAA is the terminator for the synthetase gene, and that synthesis of this read through protein can be used as an assay for ochre suppression. Suppression in each of these cases is mediated by tRNA, since purified tRNA is the only fraction from suppressing strains that is required in an otherwise nonsuppressing cell-free system.

Original languageEnglish (US)
Pages (from-to)381-390
Number of pages10
Issue number3
StatePublished - 1976
Externally publishedYes

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology
  • Medicine(all)


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