Abstract
The killer character of yeast is determined by a 1.4 x 106 molecular weight double-stranded RNA plasmid and at least 12 chromosomal genes. Wild-type strains of yeast that carry this plasmid (killers) secrete a toxin which is lethal only to strains not carrying this plasmid (sensitives). ——— We have isolated 28 independent recessive chromosomal mutants of a killer strain that have lost the ability to secrete an active toxin but remain resistant to the effects of the toxin and continue to carry the complete cytoplasmic killer genome. These mutants define two complementation groups, kex1 and kex2. Kex1 is located on chromosome VII between ade5 and lys5. Kex2 is located on chromosome XIV, but it does not show meiotic linkage to any gene previously located on this chromosome. ——— When the killer plasmid of kex1 or kex2 strains is eliminated by curing with heat or cycloheximide, the strains become sensitive to killing. The mutant phenotype reappears among the meiotic segregants in a cross with a normal killer. Thus, the kex phenotype does not require an alteration of the killer plasmid. ——— Kex1 and kex2 strains each contain near-normal levels of the 1.4 x 106 molecular weight double-stranded RNA, whose presence is correlated with the presence of the killer genome.
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Selected References
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- Bevan E. A., Somers J. M. Somatic segregation of the killer (k) and neutral (n) cytoplasmic genetic determinants in yeast. Genet Res. 1969 Aug;14(1):71–77. doi: 10.1017/s0016672300001865. [DOI] [PubMed] [Google Scholar]
- Hartwell L. H., Culotti J., Reid B. Genetic control of the cell-division cycle in yeast. I. Detection of mutants. Proc Natl Acad Sci U S A. 1970 Jun;66(2):352–359. doi: 10.1073/pnas.66.2.352. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lam S. T., Stahl M. M., McMilin K. D., Stahl F. W. Rec-mediated recombinational hot spot activity in bacteriophage lambda. II. A mutation which causes hot spot activity. Genetics. 1974 Jul;77(3):425–433. doi: 10.1093/genetics/77.3.425. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Perkins D. D. Biochemical Mutants in the Smut Fungus Ustilago Maydis. Genetics. 1949 Sep;34(5):607–626. doi: 10.1093/genetics/34.5.607. [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]