Physiology of Killer Factor in Yeast

Abstract

Publisher Summary his chapter explores that killer yeasts have appealed to a wider audience than that enjoyed by most esoteric problems of yeast genetics. The sinister name helps of course, but so does the venomous nature of the organism; poisons and their machinations have always attracted attention, in science as in other human endeavors. It discusses that killer yeast secrete a plasmid-coded protein toxin and they are immune to it, but most strains of Saccharomyces cerevisiae without the plasmid are killed. The plasmid is a linear dsRNA molecule, encapsidated in a virus-like particle. Killing by killer yeast is an easily scored, well defined phenotype and its presence in this simple eukaryotic microbe offers a fine model system for studying the molecular biology of the interaction of the plasmid with its host. In this interaction, the plasmid makes use of many cellular processes, some of which are currently of great interest to cell biologists, because they are considered to be problems amenable to solution. It also focuses on the problems of toxin synthesis and action. The synthesis of extracellular killer toxin affords a good system for studying the events involved in secretion of a non-glycosylated protein from a eukaryotic cell. The chapter also highlights that if the specific toxin-recognition sites are used for other essential metabolic purposes, then analogs retaining site-recognition specificity would competitively inhibit the essential function.