Filamentous growth of Candida albicans in response to physical environmental cues and its regulation by the unique CZF1 gene

Abstract

Hyphal growth in the opportunistic fungal pathogen Candida albicans is believed to contribute to the virulence of the organism by promoting penetration of fungal cells into host tissue. In this study, stimulation of hyphal growth by a feature of the physical environment was demonstrated. Specifically, growth of cells embedded within a matrix promoted the formation of hyphae. The CZF1 gene, encoding a putative transcription factor, was shown to be involved in the regulation of hyphal growth under certain conditions, including embedded conditions. Ectopic expression of CZF1 in embedded cells promoted the rapid formation of hyphae. Elimination of CZF1 and CPH1, encoding a homologue of the Saccharomyces cerevisiae Ste12p transcription factor, led to a pronounced defect in filamentous growth of embedded cells. Elimination of CZF1 alone led to a moderate defect in hyphal growth under some conditions, including embedded conditions. Hyphal morphogenesis in response to matrix embedding may occur in the opportunistic pathogen, C. albicans, to promote invasion of fungal cells into host tissue.

The Flo8 Transcription Factor Is Essential for Hyphal Development and Virulence inCandida albicans

“…Lee's and YPD ϩ 10% bovine serum media were used for hyphal induction (Lane et al, 2001b). YPS with 1% agar was used for colony morphology assay under embedded conditions (Brown et al, 1999).…”

Mutant alleles of the essential 14-3-3 gene in Candida albicans distinguish between growth and filamentation

“…This indicates the fine specificity and affinities of the ligand-binding pocket. Thus, the Czf1p-mediated matrix pathway (Brown et al, 1999;Giusani et al, 2002) is likely to involve different interactions of Bmh1p with ligands than the MAPK/cAMP pathways.…”

“…For all experiments, strains were either made prototrophic for URA3 or uridine was included in the media. For filamentation in matrix, studies were performed basically as reported by Brown and co-workers (Brown et al, 1999;Giusani et al, 2002). Briefly, 100 cells were plated onto YPS agar and then overlaid with a second layer of YPS agar, or approximately 100 cells were mixed with 25 ml molten YPS agar (2 %) and poured into a Petri dish.…”

“…Briefly, 100 cells were plated onto YPS agar and then overlaid with a second layer of YPS agar, or approximately 100 cells were mixed with 25 ml molten YPS agar (2 %) and poured into a Petri dish. The percentage of filamenting colonies was calculated by microscopically determining the number of colonies out of 100 which had at least 20 protruding filaments (Brown et al, 1999).…”

A conserved G protein (Drg1p) plays a role in regulation of invasive filamentation in Candida albicans

“…For selection of Ura 2 strains, CM-Ura medium was supplemented with 60 mg uridine ml 21 and 1 mg 5-fluoroorotic acid ml 21 (Kelly et al, 1987). For the colony morphology assay, YPS medium containing 1 % agar (Difco) was used (Brown et al, 1999). Synthetic low ammonium, Lee's, proline and GlcNAc media were prepared as described by Brown et al (1999).…”