Abstract
Mutants of the killer plasmid of Saccharomyecs cerevisiae have been isolated that depend upon chromosomal diploidy for the expression of plasmid functions and for replication or maintenance of the plasmid itself. These mutants are not defective in any chromosomal gene needed for expression or replication of the killer plasmid.—Haploids carrying these mutant plasmids (called d for diploid-dependent) are either unable to kill or unable to resist being killed or both and show frequent loss of the plasmid. The wild-type phenotype (K+R+) is restored by mating the d plasmid-carrying strain with either (a) a wild-type sensitive strain which apparently has no killer plasmid; (b) a strain which has been cured of the killer plasmid by growth at elevated temperature; (c) a strain which has been cured of the plasmid by growth in the presence of cycloheximide; (d) a strain which has lost the plasmid because it carries a mutation in a chromosomal mak gene; or (e) a strain of the opposite mating type which carries the same d plasmid and has the same defective phenotype, indicating that the restoration of the normal phenotype is not due to recombination between plasmid genomes or complementation of plasmid or chromosomal genes.—Sporulation of the phenotypically K+R+ diploids formed in matings between d and wild-type nonkiller strains yields tetrads, all four of whose haploid spores are defective for killing or resistance or maintenance of the plasmid or a combination of these. Every defective phenotype may be found among the segregants of a single diploid clone carrying a d plasmid. These defective segregants resume the normal killer phenotype in the diploids formed when a second round of mating is performed, and the segregants from a second round of meiosis and sporulation are again defective.
Full Text
The Full Text of this article is available as a PDF (1.0 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Berry E. A., Bevan E. A. A new species of double-stranded RNA from yeast. Nature. 1972 Sep 29;239(5370):279–280. doi: 10.1038/239279a0. [DOI] [PubMed] [Google Scholar]
- Bevan E. A., Herring A. J., Mitchell D. J. Preliminary characterization of two species of dsRNA in yeast and their relationship to the "killer" character. Nature. 1973 Sep 14;245(5420):81–86. doi: 10.1038/245081b0. [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]
- Shaffer B., Brearley I., Littlewood R., Fink G. R. A stable aneuploid of Saccharomyces cerevisiae. Genetics. 1971 Apr;67(4):483–495. doi: 10.1093/genetics/67.4.483. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Somers J. M., Bevan E. A. The inheritance of the killer character in yeast. Genet Res. 1969 Feb;13(1):71–83. doi: 10.1017/s0016672300002743. [DOI] [PubMed] [Google Scholar]
- Somers J. M. Isolation of Suppressive Sensitive Mutants from Killer and Neutral Strains of SACCHAROMYCES CEREVISIAE. Genetics. 1973 Aug;74(4):571–579. doi: 10.1093/genetics/74.4.571. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vodkin M. H., Fink G. R. A nucleic acid associated with a killer strain of yeast. Proc Natl Acad Sci U S A. 1973 Apr;70(4):1069–1072. doi: 10.1073/pnas.70.4.1069. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vodkin M., Katterman F., Fink G. R. Yeast killer mutants with altered double-stranded ribonucleic acid. J Bacteriol. 1974 Feb;117(2):681–686. doi: 10.1128/jb.117.2.681-686.1974. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wickner R. B. Chromosomal and nonchromosomal mutations affecting the "killer character" of Saccharomyces cerevisiae. Genetics. 1974 Mar;76(3):423–432. doi: 10.1093/genetics/76.3.423. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Woods D. R., Bevan E. A. Studies on the nature of the killer factor produced by Saccharomyces cerevisiae. J Gen Microbiol. 1968 Apr;51(1):115–126. doi: 10.1099/00221287-51-1-115. [DOI] [PubMed] [Google Scholar]