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A study of the DNA damage checkpoint in C andida albicans : uncoupling of the functions of Rad 53 in DNA repair, cell cycle regulation and genotoxic stress‐induced polarized growth
Author(s) -
LollKrippleber Raphaël,
d'Enfert Christophe,
Feri Adeline,
Diogo Dorothée,
Perin Aurélie,
MarcetHouben Marina,
Bougnoux MarieElisabeth,
Legrand Mélanie
Publication year - 2014
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12471
Subject(s) - biology , loss of heterozygosity , g2 m dna damage checkpoint , dna damage , candida albicans , cell cycle , microbiology and biotechnology , mutant , genetics , cell cycle checkpoint , chromosome , mutation , mitosis , dna repair , dna , gene , allele
Summary In response to genotoxic stress ( GS ), C andida albicans can undergo polarized growth and massive genome rearrangements including loss‐of‐heterozygosity ( LOH ) events. We evaluated the contribution of the Ca Rad 53p and Ca Dun 1p kinases of the DNA damage checkpoint ( DDCP ) in these processes. Characterization of C . albicans rad53 ΔΔ and dun1 ΔΔ mutants revealed that the two kinases were involved in the maintenance of heterozygosity. SNP ‐ RFLP typing and whole‐genome sequencing of rad53 ΔΔ isolates having undergone a LOH revealed that, according to the chromosome on which LOH had occurred, these were predominantly due to break‐induced replication/mitotic cross‐over or chromosome loss. Loss of CaRAD53 also resulted in frequent aneuploidies. Deletion of CaDUN1 led to an increase in recombination‐dependent LOH but did not trigger aneuploidies. It also increased GS sensitivity but did not impair GS ‐induced polarized growth contrary to CaRAD53 deletion. Characterization of Ca Rad 53p site‐directed mutants demonstrated that its kinase activity and N ‐terminal phosphorylation sites were crucial for its function in the resistance to GS , maintenance of heterozygosity, cell cycle regulation and polarized growth. Moreover, using phosphomimic mutants, we revealed an uncoupling of the functions of Ca Rad 53p in these different processes, thus providing a novel understanding of how the DDCP may regulate downstream events in response to GS .