Wickner R B, Leibowitz M J
Genetics. 1976 Mar 25;82(3):429-42. doi: 10.1093/genetics/82.3.429.
The killer character of yeast is determined by a 1.4 X 10(6) molecular weight double-stranded RNA plasmid and at least 12 chromosomal genes. Wild-type strains of yeast that carry this plasmid (killers) secret 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 10(6) molecular weight double-stranded RNA, whose presence is correlated with the presence of the killer genome.
酵母的杀伤特性由一个分子量为1.4×10⁶的双链RNA质粒和至少12个染色体基因决定。携带该质粒的酵母野生型菌株（杀伤型）分泌一种毒素，该毒素仅对不携带此质粒的菌株（敏感型）具有致死性。——我们从一个杀伤型菌株中分离出28个独立的隐性染色体突变体，这些突变体失去了分泌活性毒素的能力，但仍对毒素的作用具有抗性，并继续携带完整的细胞质杀伤基因组。这些突变体定义了两个互补群，即kex1和kex2。Kex1位于第VII号染色体上ade5和lys5之间。Kex2位于第XIV号染色体上，但它与该染色体上先前定位的任何基因均未表现出减数分裂连锁关系。——当通过加热或用环己酰亚胺处理消除kex1或kex2菌株的杀伤质粒时，这些菌株对杀伤变得敏感。在与正常杀伤型菌株的杂交中，减数分裂分离物中会再次出现突变体表型。因此，kex表型不需要杀伤质粒发生改变。——Kex1和kex2菌株各自含有接近正常水平的分子量为1.4×10⁶的双链RNA，其存在与杀伤基因组的存在相关。
