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A single Ho-induced double-strand break at the MAT locus is lethal in Candida glabrata.
PLoS Genet. 2020 10; 16(10):e1008627.PG

Abstract

Mating-type switching is a complex mechanism that promotes sexual reproduction in Saccharomycotina. In the model species Saccharomyces cerevisiae, mating-type switching is initiated by the Ho endonuclease that performs a site-specific double-strand break (DSB) at MAT, repaired by homologous recombination (HR) using one of the two silent mating-type loci, HMLalpha and HMRa. The reasons why all the elements of the mating-type switching system have been conserved in some Saccharomycotina, that do not show a sexual cycle nor mating-type switching, remain unknown. To gain insight on this phenomenon, we used the yeast Candida glabrata, phylogenetically close to S. cerevisiae, and for which no spontaneous and efficient mating-type switching has been observed. We have previously shown that expression of S. cerevisiae's Ho (ScHo) gene triggers mating-type switching in C. glabrata, but this leads to massive cell death. In addition, we unexpectedly found, that not only MAT but also HML was cut in this species, suggesting the formation of multiple chromosomal DSBs upon HO induction. We now report that HMR is also cut by ScHo in wild-type strains of C. glabrata. To understand the link between mating-type switching and cell death in C. glabrata, we constructed strains mutated precisely at the Ho recognition sites. We find that even when HML and HMR are protected from the Ho-cut, introducing a DSB at MAT is sufficient to induce cell death, whereas one DSB at HML or HMR is not. We demonstrate that mating-type switching in C. glabrata can be triggered using CRISPR-Cas9, without high lethality. We also show that switching is Rad51-dependent, as in S. cerevisiae, but that donor preference is not conserved in C. glabrata. Altogether, these results suggest that a DSB at MAT can be repaired by HR in C. glabrata, but that repair is prevented by ScHo.

Authors+Show Affiliations

Université Paris-Saclay, INRAE, CNRS, AgroParisTech, GQE-Le Moulon, Gif-sur-Yvette, France.Université Paris-Saclay, INRAE, CNRS, AgroParisTech, GQE-Le Moulon, Gif-sur-Yvette, France.Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France.Université Paris-Saclay, INRAE, CNRS, AgroParisTech, GQE-Le Moulon, Gif-sur-Yvette, France.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

33057400

Citation

Maroc, Laetitia, et al. "A Single Ho-induced Double-strand Break at the MAT Locus Is Lethal in Candida Glabrata." PLoS Genetics, vol. 16, no. 10, 2020, pp. e1008627.
Maroc L, Zhou-Li Y, Boisnard S, et al. A single Ho-induced double-strand break at the MAT locus is lethal in Candida glabrata. PLoS Genet. 2020;16(10):e1008627.
Maroc, L., Zhou-Li, Y., Boisnard, S., & Fairhead, C. (2020). A single Ho-induced double-strand break at the MAT locus is lethal in Candida glabrata. PLoS Genetics, 16(10), e1008627. https://doi.org/10.1371/journal.pgen.1008627
Maroc L, et al. A Single Ho-induced Double-strand Break at the MAT Locus Is Lethal in Candida Glabrata. PLoS Genet. 2020;16(10):e1008627. PubMed PMID: 33057400.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A single Ho-induced double-strand break at the MAT locus is lethal in Candida glabrata. AU - Maroc,Laetitia, AU - Zhou-Li,Youfang, AU - Boisnard,Stéphanie, AU - Fairhead,Cécile, Y1 - 2020/10/15/ PY - 2020/01/22/received PY - 2020/09/12/accepted PY - 2020/10/27/revised PY - 2020/10/16/pubmed PY - 2020/12/31/medline PY - 2020/10/15/entrez SP - e1008627 EP - e1008627 JF - PLoS genetics JO - PLoS Genet VL - 16 IS - 10 N2 - Mating-type switching is a complex mechanism that promotes sexual reproduction in Saccharomycotina. In the model species Saccharomyces cerevisiae, mating-type switching is initiated by the Ho endonuclease that performs a site-specific double-strand break (DSB) at MAT, repaired by homologous recombination (HR) using one of the two silent mating-type loci, HMLalpha and HMRa. The reasons why all the elements of the mating-type switching system have been conserved in some Saccharomycotina, that do not show a sexual cycle nor mating-type switching, remain unknown. To gain insight on this phenomenon, we used the yeast Candida glabrata, phylogenetically close to S. cerevisiae, and for which no spontaneous and efficient mating-type switching has been observed. We have previously shown that expression of S. cerevisiae's Ho (ScHo) gene triggers mating-type switching in C. glabrata, but this leads to massive cell death. In addition, we unexpectedly found, that not only MAT but also HML was cut in this species, suggesting the formation of multiple chromosomal DSBs upon HO induction. We now report that HMR is also cut by ScHo in wild-type strains of C. glabrata. To understand the link between mating-type switching and cell death in C. glabrata, we constructed strains mutated precisely at the Ho recognition sites. We find that even when HML and HMR are protected from the Ho-cut, introducing a DSB at MAT is sufficient to induce cell death, whereas one DSB at HML or HMR is not. We demonstrate that mating-type switching in C. glabrata can be triggered using CRISPR-Cas9, without high lethality. We also show that switching is Rad51-dependent, as in S. cerevisiae, but that donor preference is not conserved in C. glabrata. Altogether, these results suggest that a DSB at MAT can be repaired by HR in C. glabrata, but that repair is prevented by ScHo. SN - 1553-7404 UR - https://www.unboundmedicine.com/medline/citation/33057400/A_single_Ho_induced_double_strand_break_at_the_MAT_locus_is_lethal_in_Candida_glabrata_ DB - PRIME DP - Unbound Medicine ER -