title: HWP1 functions in the morphological development of Candida albicans downstream of EFG1, TUP1, and RBF1.
abstract: The morphological plasticity of Candida albicans is an important determinant of pathogenicity, and nonfilamentous mutants are avirulent. HWP1, a hypha-specific gene, was identified in a genetic screen for developmentally regulated genes and encodes a cell surface protein of unknown function. Heterozygous and homozygous deletions of HWP1 resulted in a medium-conditional defect in hyphal development. HWP1 expression was blocked in a Deltaefg1 mutant, reduced in an Deltarbf1 mutant, and derepressed in a Deltatup1 mutant. Therefore, HWP1 functions downstream of the developmental regulators EFG1, TUP1, and RBF1. Mutation of CPH1 had no effect on HWP1 expression, suggesting that the positive regulators of hyphal development, CPH1 and EFG1, are components of separate pathways with different target genes. The expression of a second developmentally regulated gene, ECE1, was similarly regulated by EFG1. Since ECE1 is not required for hyphal development, the regulatory role of EFG1 apparently extends beyond the control of cell shape determinants. However, expression of ECE1 was not influenced by TUP1, suggesting that there may be some specificity in the regulation of morphogenic elements during hyphal development.
authors.affiliation: Department of Microbiology and Immunology, Georgetown University, Washington, D.C. 20007, USA.
authors.forename: L L
authors.initials: LL
authors.lastname: Sharkey
authors.forename: M D
authors.initials: MD
authors.lastname: McNemar
authors.forename: S M
authors.initials: SM
authors.lastname: Saporito-Irwin
authors.forename: P S
authors.initials: PS
authors.lastname: Sypherd
authors.forename: W A
authors.initials: WA
authors.lastname: Fonzi
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002176:Candida albicans / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D004271:DNA, Fungal; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009687:Nuclear Proteins; D010641:Phenotype; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D004271:DNA, Fungal; D004268:DNA-Binding Proteins; C082909:ECE1 protein, Candida albicans; C121438:EFG1 protein, Candida albicans; D005656:Fungal Proteins; C118102:HWP1 protein, Candida albicans; D008562:Membrane Glycoproteins; D009687:Nuclear Proteins; C104796:RBF1 protein, Candida albicans; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; C066502:TUP1 protein, S cerevisiae; D014157:Transcription Factors