title: The role of Candida albicans homologous recombination factors Rad54 and Rdh54 in DNA damage sensitivity.
abstract: BACKGROUND
  The fungal pathogen Candida albicans is frequently seen in immune suppressed patients, and resistance to one of the most widely used antifungals, fluconazole (FLC), can evolve rapidly. In recent years it has become clear that plasticity of the Candida albicans genome contributes to drug resistance through loss of heterozygosity (LOH) at resistance genes and gross chromosomal rearrangements that amplify gene copy number of resistance associated genes. This study addresses the role of the homologous recombination factors Rad54 and Rdh54 in cell growth, DNA damage and FLC resistance in Candida albicans.
  
  
  RESULTS
  The data presented here support a role for homologous recombination in cell growth and DNA damage sensitivity, as Candida albicans rad54Δ/rad54Δ mutants were hypersensitive to MMS and menadione, and had an aberrant cell and nuclear morphology. The Candida albicans rad54Δ/rad54Δ mutant was defective in invasion of Spider agar, presumably due to the altered cellular morphology. In contrast, mutation of the related gene RDH54 did not contribute significantly to DNA damage resistance and cell growth, and deletion of either Candida albicans RAD54 or Candida albicans RDH54 did not alter FLC susceptibility.
  
  
  CONCLUSIONS
  Together, these results support a role for homologous recombination in genome stability under nondamaging conditions. The nuclear morphology defects in the rad54Δ/rad54Δ mutants show that Rad54 performs an essential role during mitotic growth and that in its absence, cells arrest in G2. The viability of the single mutant rad54Δ/rad54Δ and the inability to construct the double mutant rad54Δ/rad54Δ rdh54Δ/rdh54Δ suggests that Rdh54 can partially compensate for Rad54 during mitotic growth.
authors.affiliation: Department of Biochemistry, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA.
authors.forename: Samantha J
authors.initials: SJ
authors.lastname: Hoot
authors.forename: Xiuzhong
authors.initials: X
authors.lastname: Zheng
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Potenski
authors.forename: Theodore C
authors.initials: TC
authors.lastname: White
authors.forename: Hannah L
authors.initials: HL
authors.lastname: Klein
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology; D002176:Candida albicans / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D004249:DNA Damage / Q000187:drug effects; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair / Q000187:drug effects; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D059765:Homologous Recombination / Q000187:drug effects; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D009153:Mutagens / Q000494:pharmacology
chemical_list: D000935:Antifungal Agents; D005656:Fungal Proteins; D009153:Mutagens; D008741:Methyl Methanesulfonate; D004265:DNA Helicases