Abstract
Strains of the yeast Saccharomyces cerevisiae that contain highly efficient amber (UAG) suppressors grow poorly on nutrient medium, while normal or nearly normal growth rates are observed when these strains lose the suppressors or when the suppressors are mutated to lower efficiencies. The different growth rates account for the accumulation of mutants with lowered efficiencies in cultures of strains with highly efficient amber suppressors. Genetic analyses indicate that one of the mutations with a lowered efficiency of suppression is caused by an intragenic mutation of the amber suppressor. The inhibition of growth caused by excessive suppression is expected to be exacerbated when appropriate suppressors are combined together in haploid cells if two suppressors act with a greater efficiency than a single suppressor. Such retardation of growth is observed with combinations of two UAA (ochre) suppressors (Gilmore 1967) and with combinations of two UAG suppressors when the efficiencies of each of the suppressors are within a critical range. In contrast, combinations of a UAA suppressor and a UAG suppressor do not affect growth rate. Apparently while either excessive UAA or excessive UAG suppression is deleterious to yeast, a moderate level of simultaneous UAA and UAG suppression is not.
Full Text
The Full Text of this article is available as a PDF (1.4 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Contreras R., Ysebaert M., Jou W. M., Fiers W. Bacteriophage Ms2 RNA: nucleotide sequence of the end of the a protein gene and the intercistronic region. Nat New Biol. 1973 Jan 24;241(108):99–101. doi: 10.1038/newbio241099a0. [DOI] [PubMed] [Google Scholar]
- Gilmore R. A. Super-suppressors in Saccharomyces cerevisiae. Genetics. 1967 Aug;56(4):641–658. doi: 10.1093/genetics/56.4.641. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McCready S. J., Cox B. S. Antisuppressors in yeast. Mol Gen Genet. 1973 Aug 28;124(4):305–320. doi: 10.1007/BF00267660. [DOI] [PubMed] [Google Scholar]
- Mortimer R. K., Hawthorne D. C. Genetic Mapping in Saccharomyces IV. Mapping of Temperature-Sensitive Genes and Use of Disomic Strains in Localizing Genes. Genetics. 1973 May;74(1):33–54. doi: 10.1093/genetics/74.1.33. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ohlsson B. M., Strigini P. F., Beckwith J. R. Allelic amber and ochre suppressors. J Mol Biol. 1968 Sep 14;36(2):209–218. doi: 10.1016/0022-2836(68)90376-8. [DOI] [PubMed] [Google Scholar]
- Person S., Osborn M. The conversion of amber suppressors to ochre suppressors. Proc Natl Acad Sci U S A. 1968 Jul;60(3):1030–1037. doi: 10.1073/pnas.60.3.1030. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sherman F., Stewart J. W., Parker J. H., Inhaber E., Shipman N. A., Putterman G. J., Gardisky R. L., Margoliash E. The mutational alteration of the primary structure of yeast iso-1-cytochrome c. J Biol Chem. 1968 Oct 25;243(20):5446–5456. [PubMed] [Google Scholar]
- Weiner A. M., Weber K. Natural read-through at the UGA termination signal of Q-beta coat protein cistron. Nat New Biol. 1971 Sep 15;234(50):206–209. doi: 10.1038/newbio234206a0. [DOI] [PubMed] [Google Scholar]