Some biological features of Candida albicans mutants for genes coding fungal proteins containing the CFEM domain

• Published in: FEMS yeast research Vol. 11; no. 3; pp. 273 - 284
• Main Authors: Pérez, Ana, Ramage, Gordon, Blanes, Rosario, Murgui, Amelia, Casanova, Manuel, Martínez, José P
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.05.2011; Oxford University Press
• Subjects: Animal models; Animals; Atomic force microscopy; biofilm; Biofilms; Biofilms - growth & development; Candida albicans; Candida albicans - chemistry; Candida albicans - genetics; Candida albicans - metabolism; Candida albicans - physiology; Cell surface; cell surface hydrophobicity; Cell viability; cells; Clonal deletion; Concanavalin A; confocal laser scanning microscopy; dyes; Extracellular matrix; fluorescence; Fluorescent indicators; Fungal cell surface proteins; fungal proteins; Fungal Proteins - chemistry; Fungal Proteins - genetics; Fungal Proteins - metabolism; Gene expression; gene expression regulation; Gene Expression Regulation, Fungal; genes; Genes, Fungal - genetics; glucose; Green Fluorescent Proteins; Hydrophobic and Hydrophilic Interactions; Hydrophobicity; Mannose; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - metabolism; Mice; Microscopy; Microscopy, Atomic Force; Microscopy, Confocal; Mutants; Mutation; Mycelia; mycelium; PGA10; pleiotropy; polypeptides; Promoter Regions, Genetic - genetics; Protein Structure, Tertiary; Proteins; RBT5 and CSA1/WAP1 genes; Reverse Transcriptase Polymerase Chain Reaction; Time Factors; Virulence; yeasts; Fungal cell surface proteins; atomic force microscopy; genes; cell surface hydrophobicity; biofilms; and
• ISSN: 1567-1356; 1567-1364
• DOI: 10.1111/j.1567-1364.2010.00714.x

Several biological features of Candida albicans genes (PGA10, RBT5 and CSA1) coding for putative polypeptide species belonging to a subset of fungal proteins containing an eight-cysteine domain referred as common in several fungal extracellular membrane (CFEM) are described. The deletion of these genes resulted in a cascade of pleiotropic effects. Thus, mutant strains exhibited higher cell surface hydrophobicity levels and an increased ability to bind to inert or biological substrates. Confocal scanning laser microscopy using concanavalin A-Alexafluor 488 (which binds to mannose and glucose residues) and FUN-1 (a cytoplasmic fluorescent probe for cell viability) dyes showed that mutant strains formed thinner and more fragile biofilms. These apparently contained lower quantities of extracellular matrix material and less metabolically active cells than their parental strain counterpart, although the relative percentage of mycelial forms was similar in all cases. The cell surface of C. albicans strains harbouring deletions for genes coding CFEM-domain proteins appeared to be severely altered according to atomic force microscopy observations. Assessment of the relative gene expression within individual C. albicans cells revealed that CFEM-coding genes were upregulated in mycelium, although these genes were shown not to affect virulence in animal models. Overall, this study has demonstrated that CFEM domain protein-encoding genes are pleiotropic, influencing cell surface characteristics and biofilm formation.