Efficient Mating-Type Switching in Candida glabrata Induces Cell Death.
Candida glabrata is an apparently asexual haploid yeast that is phylogenetically closer to Saccharomyces cerevisiae than to Candida albicans. Its genome contains three MAT-like cassettes, MAT, which encodes either MATa or MATalpha information in different strains, and the additional loci, HML and HMR. The genome also contains an HO gene homolog, but this yeast has never been shown to switch mating-types spontaneously, as S. cerevisiae does. We have recently sequenced the genomes of the five species that, together with C. glabrata, make up the Nakaseomyces clade. All contain MAT-like cassettes and an HO gene homolog. In this work, we express the HO gene of all Nakaseomyces and of S. cerevisiae in C. glabrata. All can induce mating-type switching, but, despite the larger phylogenetic distance, the most efficient endonuclease is the one from S. cerevisiae. Efficient mating-type switching in C. glabrata is accompanied by a high cell mortality, and sometimes results in conversion of the additional cassette HML. Mortality probably results from the cutting of the HO recognition sites that are present, in HML and possibly HMR, contrary to what happens naturally in S. cerevisiae. This has implications in the life-cycle of C. glabrata, as we show that efficient MAT switching is lethal for most cells, induces chromosomal rearrangements in survivors, and that the endogenous HO is probably rarely active indeed.
Institut de Génétique et Microbiologie, Université Paris-Sud, UMR8621 CNRS, F-91405, Orsay, CEDEX, France; Génétique Quantitative et Évolution-Le Moulon, INRA-Université Paris-Sud-CNRS-AgroParisTech, Batiment 400, UFR des Sciences, F 91405, Orsay, CEDEX, France.
Stéphanie
S
Boisnard
Institut de Génétique et Microbiologie, Université Paris-Sud, UMR8621 CNRS, F-91405, Orsay, CEDEX, France; Génétique Quantitative et Évolution-Le Moulon, INRA-Université Paris-Sud-CNRS-AgroParisTech, Batiment 400, UFR des Sciences, F 91405, Orsay, CEDEX, France.
Youfang
Y
Zhou Li
Institut de Génétique et Microbiologie, Université Paris-Sud, UMR8621 CNRS, F-91405, Orsay, CEDEX, France.
Sylvie
S
Arnaise
Institut de Génétique et Microbiologie, Université Paris-Sud, UMR8621 CNRS, F-91405, Orsay, CEDEX, France.
Gregory
G
Sequeira
Génétique Quantitative et Évolution-Le Moulon, INRA-Université Paris-Sud-CNRS-AgroParisTech, Batiment 400, UFR des Sciences, F 91405, Orsay, CEDEX, France.
Xavier
X
Raffoux
Institut de Génétique et Microbiologie, Université Paris-Sud, UMR8621 CNRS, F-91405, Orsay, CEDEX, France; Hôpital de Bicêtre, Le Kremlin Bicêtre, APHP, France.
Adela
A
Enache-Angoulvant
Institut de Génétique et Microbiologie, Université Paris-Sud, UMR8621 CNRS, F-91405, Orsay, CEDEX, France; Génétique Quantitative et Évolution-Le Moulon, INRA-Université Paris-Sud-CNRS-AgroParisTech, Batiment 400, UFR des Sciences, F 91405, Orsay, CEDEX, France.
Monique
M
Bolotin-Fukuhara
Institut de Génétique et Microbiologie, Université Paris-Sud, UMR8621 CNRS, F-91405, Orsay, CEDEX, France; Génétique Quantitative et Évolution-Le Moulon, INRA-Université Paris-Sud-CNRS-AgroParisTech, Batiment 400, UFR des Sciences, F 91405, Orsay, CEDEX, France.
Cécile
C
Fairhead
D041221:Candida glabrata / Q000166:cytology* / Q000235:genetics* / Q000502:physiology; D016923:Cell Death / Q000235:genetics / Q000502:physiology*; D049770:Genes, Mating Type, Fungal / Q000235:genetics / Q000502:physiology*