Rad6p Represses Yeast-Hypha Morphogenesis in the Human Fungal Pathogen Candida Albicans

Mol Microbiol. 2000 Mar;35(5):1264-75. doi: 10.1046/j.1365-2958.2000.01801.x.


Rad6p plays important roles in post-replication DNA repair, chromatin organization, gene silencing and meiosis. In this study, we show that Rad6p also regulates yeast-hypha morphogenesis in the human pathogen Candida albicans. CaRAD6 gene and cDNAs were isolated and characterized revealing that the gene carries two 5'-proximal introns. CaRad6p shows a high degree of sequence similarity to Rad6 proteins from fungi to man (60-83% identity), and it suppresses the UV sensitivity and lack of induced mutagenesis displayed by a Saccharomyces cerevisiae rad6 mutant. In C. albicans, CaRAD6 expression is induced in response to UV, and CaRad6p depletion confers UV sensitivity, confirming that Rad6p serves a role in protecting this fungus against UV damage. CaRAD6 overexpression inhibits hyphal development, whereas CaRad6p depletion enhances hyphal growth. Also, CaRAD6 mRNA levels decrease during the yeast-hypha transition. These effects are dependent on Efg1p, but not Cph1p, indicating that CaRad6p acts specifically through the Efg1p morphogenetic signalling pathway to repress yeast-hypha morphogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Candida albicans / growth & development*
  • DNA-Binding Proteins*
  • Fungal Proteins / metabolism
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / radiation effects
  • Genes, Fungal
  • Humans
  • Ligases / chemistry
  • Ligases / genetics
  • Ligases / physiology*
  • Molecular Sequence Data
  • Protein Conformation
  • Saccharomyces cerevisiae Proteins*
  • Sequence Homology, Amino Acid
  • Signal Transduction
  • Transcription Factors*
  • Ubiquitin-Conjugating Enzymes
  • Ultraviolet Rays


  • DNA-Binding Proteins
  • EFG1 protein, Candida albicans
  • Fungal Proteins
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • RAD6 protein, S cerevisiae
  • Ubiquitin-Conjugating Enzymes
  • Ligases

Associated data

  • GENBANK/AF036707
  • GENBANK/AF118145