The enigmatic DUP240 yeast gene family plays a role in defense against K28 killer toxin

Killer yeast are yeast strains that secrete a proteinaceous killer toxin which inhibits growth of susceptible cells through various mechanisms (e.g. pore formation, induced apoptosis, cell cycle arrest [1]) There is considerable natural variation in resistance to killer toxins among yeast strains, in particular to the K28 toxin [2, this study]. However, little is known about evolutionary strategies employed by uninfected yeast as a defense against killer toxins in the wild.

Using quantitative trait locus (QTL) mapping in Saccharomyces cerevisiae, we pinpointed an uncharacterized gene, YAR028W, which supports resistance to K28 and is the primary gene responsible for the difference in K28 sensitivity between BY and RM strains. Our hypothesis is that DUP240 genes have evolved as a defense mechanism against killer toxins.