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. albicans by the addition of the small-molecule inducer doxycycline in a growth medium-independent manner. The system is based on a cassette in which a gene of interest can be placed under the control of a Tet-inducible promoter in a single cloning step and integrated into the C. albicans genome with the help of a dominant selection marker. As the cassette contains all necessary components for Tet-inducible gene expression, it can be used to study the effect of forced gene expression on the phenotype of C. albicans cells in any strain without a requirement of additional genetic manipulations.