title: Rad6p represses yeast-hypha morphogenesis in the human fungal pathogen Candida albicans.
abstract: 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.
authors.affiliation: Department of Molecular and Cell Biology, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK.
authors.forename: P
authors.initials: P
authors.lastname: Leng
authors.forename: P E
authors.initials: PE
authors.lastname: Sudbery
authors.forename: A J
authors.initials: AJ
authors.lastname: Brown
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002176:Candida albicans / Q000254:growth & development*; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000528:radiation effects; D005800:Genes, Fungal; D006801:Humans; D008025:Ligases / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D011487:Protein Conformation; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014157:Transcription Factors; D044763:Ubiquitin-Conjugating Enzymes; D014466:Ultraviolet Rays
chemical_list: D004268:DNA-Binding Proteins; C121438:EFG1 protein, Candida albicans; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C471606:RAD6 protein, S cerevisiae; D044763:Ubiquitin-Conjugating Enzymes; D008025:Ligases