Activation of the Cph1-dependent MAP kinase signaling pathway induces white-opaque switching in Candida albicans.

Depending on the environmental conditions, the pathogenic yeast Candida albicans can undergo different developmental programs, which are controlled by dedicated transcription factors and upstream signaling pathways. C. albicans strains that are homozygous at the mating type locus can switch from the normal yeast form (white) to an elongated cell type (opaque), which is the mating-competent form of this fungus.

White-opaque switching of Candida albicans allows immune evasion in an environment-dependent fashion.

Candida albicans strains that are homozygous at the mating type locus can spontaneously and reversibly switch from the normal yeast morphology (white) to an elongated cell type (opaque), which is the mating-competent form of the fungus. White-opaque switching also influences the ability of C. albicans to colonize and proliferate in specific host niches and its susceptibility to host defense mechanisms.

Tetracycline-inducible gene expression in Candida albicans.

In addition to gene inactivation, the manipulation of gene expression is another highly useful tool for the analysis of gene function. Several regulatable promoters are available that enable researchers to shut off or turn on the expression of a target gene in Candida albicans, usually by growing the cells in inducing or repressing media. In this chapter, we describe a tetracycline-inducible gene expression system (Tet-On) that allows forced expression of endogenous or heterologous genes in C.

The transcription factor Ndt80 does not contribute to Mrr1-, Tac1-, and Upc2-mediated fluconazole resistance in Candida albicans.

The pathogenic yeast Candida albicans can develop resistance to the widely used antifungal agent fluconazole, which inhibits ergosterol biosynthesis, by the overexpression of genes encoding multidrug efflux pumps or ergosterol biosynthesis enzymes. Zinc cluster transcription factors play a central role in the transcriptional regulation of drug resistance. Mrr1 regulates the expression of the major facilitator MDR1, Tac1 controls the expression of the ABC transporters CDR1 and CDR2, and Upc2 regulates ergosterol biosynthesis (ERG) genes.

Modulation of transcription affects mRNP quality.

Cotranscriptional loading of proteins onto nascent transcripts contributes to the formation of messenger ribonucleoprotein particles (mRNPs) competent for nuclear export. The transcription machinery is believed to play a pivotal role in mRNP assembly, which is at least partially linked to the function of the THO/TREX complex and the mRNA termination/polyadenylation apparatus. Here we demonstrate a prominent role for the rate of transcription in the production of export-competent mRNPs.