Haploinsufficiency-based large-scale forward genetic analysis of filamentous growth in the diploid human fungal pathogen C.albicans

Abstract

Candida albicans is the most prevalent human fungal pathogen. Here, we take advantage of haploinsuf®-ciency and transposon mutagenesis to perform largescale loss-of-function genetic screen in this organism. We identi®ed mutations in 146 genes that affect the switch between its single-cell (yeast) form and ®lamen-tous forms of growth; this switch appears central to the virulence of C.albicans. The encoded proteins include those involved in nutrient sensing, signal transduction, transcriptional control, cytoskeletal organization and cell wall construction. Approximately one-third of the genes identi®ed in the screen lack homologs in Saccharomyces cerevisiae and other model organisms and thus constitute candidate antifungal drug targets. These results illustrate the value of performing forward genetic studies in bona ®de pathogens.

Evolution inCandida albicansPopulations During a Single Passage Through a Mouse Host

“…A large proportion of isolates with altered colony phenotypes also had undergone chromosomal changes via shortrange LOH events (11/17, or 65%) or chromosomelevel events (4/6, or 80%) (Table 4). Overall, our results show that the choice of isolates with altered colony phenotypes increased the detection of genome changes and are consistent with findings that LOH at many different loci influences filamentous growth in C. albicans (Uhl et al 2003).…”

The TRK1 Potassium Transporter Is the Critical Effector for Killing of Candida albicans by the Cationic Protein, Histatin 5

“…2A, gray bar; ⌬⌬Ct ϭ Ϫ7.0 Ϯ 1.6, n ϭ 3). Such lack of dominance of the wild-type allele is a common phenomenon found with many Candida genes (47,48). Complementation of the TRK1 gene, at the RP10 locus (trk1/TRK1/rp10:: TRK1), restored TRK1 transcripts in CaTK2 to the same level as in wild-type cells ( Fig.…”

Pathway analysis of Candida albicans survival and virulence determinants in a murine infection model

“…Consequently, a number of molecular genetic approaches have been developed in C. albicans to introduce targeted gene mutations, including the URA Blaster (2), SAT1 flipper (3), and other cassette methods (4) to construct viable homozygote deletions. Transposon heterozygosity (5) and regulatable antisense interference approaches to modulate gene expression (6) have also been described. However, these approaches are largely biased toward constructing nonlethal mutations; deletion analyses of essential genes (with the exception of conditional essential genes) and characterization of their resulting terminal phenotypes both in vitro and in the host milieu have been largely ignored despite their central role in cell growth and division of the pathogen.…”