title: Mating-type locus control of killer toxins from Kluyveromyces lactis and Pichia acaciae.
abstract: Killer-toxin complexes produced by Kluyveromyces lactis and Pichia acaciae inhibit cell proliferation of Saccharomyces cerevisiae. Analysis of their actions in haploid MATalpha cells revealed that introduction of the opposite mating-type locus (MATa) significantly suppressed antizymosis. Together with resistance expressed by MATa/MATalpha diploids, the reciprocal action of MATa or MATalpha in haploids of opposite mating types suggests that these killer toxins may be subject to MAT locus control. Congruently, derepressing the silent mating-type loci, HMR and HML, by removing individual components of the histone deacetylase complex Sir1-4, either by transposon-tagging or by chemically inactivating the histone deacetylase catalytic subunit Sir2, yields toxin resistance. Consistent with MAT control of toxin action, killer-toxin-insensitive S. cerevisiae mutants (kti) become mating-compromised despite resisting the toxins' cell-cycle effects. Mating inhibition largely depends on the time point of toxin application to the mating mixtures and is less pronounced in Elongator mutants, whose resistance to the toxins' cell-cycle effects is the result of toxin-target process deficiencies. In striking contrast, non-Elongator mutants defective in early-response events such as toxin import/activation hardly recover from toxin-induced mating inhibition. This study reveals a novel effect of yeast killer toxins on mating and sexual reproduction that is independent of their impact on cellular proliferation and cell-cycle progression.
authors.affiliation: Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Münster, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Klassen
authors.forename: Daniel
authors.initials: D
authors.lastname: Jablonowski
authors.forename: Michael J R
authors.initials: MJ
authors.lastname: Stark
authors.forename: Raffael
authors.initials: R
authors.lastname: Schaffrath
authors.forename: Friedhelm
authors.initials: F
authors.lastname: Meinhardt
mesh_terms: D049770:Genes, Mating Type, Fungal; D006579:Heterozygote; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000235:genetics / Q000502:physiology; D055646:Killer Factors, Yeast; D000072235:Mating Factor; D016254:Mutagenesis, Insertional; D009154:Mutation; D009183:Mycotoxins / Q000633:toxicity*; D010455:Peptides / Q000235:genetics / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology; D056565:Sirtuin 2; D037761:Sirtuins / Q000235:genetics / Q000502:physiology
chemical_list: D056572:Histone Deacetylase Inhibitors; D055646:Killer Factors, Yeast; D009183:Mycotoxins; D010455:Peptides; C084121:SIR1 protein, S cerevisiae; C084122:SIR3 protein, S cerevisiae; C061573:SIR4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; C058975:zymocin; C087906:killer toxin, Pichia; D000072235:Mating Factor; C087778:SIR2 protein, S cerevisiae; D056565:Sirtuin 2; D037761:Sirtuins; D006655:Histone Deacetylases