Identification of genes differentially expressed in hyphae of Candida albicans

Abstract

The ability to switch from yeast to hyphal forms is essential for Candida albicans virulence. This morphological switch involves the expression of hyphal-specific genes under the control of transcriptional factors. To contribute to the discovery of hyphal-specific genes, we used a differential screening method where clones of a genomic DNA library were hybridized with yeast and hyphal cDNA probes. Two clones with increased expression in hyphae were selected for study. Sequencing these clones, we found that they encoded two important metabolic genes, CaHXT7 (high-affinity hexose transporter) and CaYLL34 (member of the AAA ATPase family). CaHXT7 and CaYLL34 ORFs were completely determined. Analyses of the putative proteins show that: (1) CaHxt7p has one hexose transporter domain and (2) CaYll34p has two AAA ATPase domains. These results show, for the first time, increased expression of metabolic genes in C. albicans hyphae. Also, because the proteins encoded by CaHXT7 and CaYLL34 may be necessary for the switching to hyphae, they could be new targets for antifungal drugs.

Phenotypic aspects of oral strains of Candida albicans in children with down's syndrome

“…Yeast-like aspects of Candida observed in genotypic characteristics through molecular biology by way of one-dimensional electrophoretic karyotyping and pulsed field electrophoresis with DNA probes, polymerase chain reaction (PCR), or also the combination of these techniques enables us to differentiate phenotypically undistinguishable strains, finding the genetic mapping sequence of these yeasts and showing the phenotypic aspect of each gene of the fungus (Fukazawa et al, 1997;Radford et al, 1997;López-Ribot et al, 2000;Melo et al, 2003).…”

“…group (children with Down's syndrome) is more exacerbated in vitro than in the control group, although all these yeasts are of colonizing type and originate from the oral mucosa of children with or without this chromosome disorder. Therefore, the presence of fringes in yeasts of Candida obtained from the mouth is possibly attributed to the virulence of this fungus, thus showing a higher tendency towards the development of the mycelial form by the yeast and favoring the adaptation to the oral cavity (Melhem, 1997;Radford et al, 1997;Melo et al, 2003). Patients with neoplasms or with AIDS have shown oral morphotypes of C. albicans with fringes more often than those obtained from the mouth of healthy individuals, which reinforces its association with yeast virulence (Melhem, 1997).…”