Galactose-Inducible promoters in Cryptococcus neoformans var. grubii.

Inducible promoters are invaluable tools for modulating gene expression (turning transcription on or off) and have been a key approach for ascertaining gene essentiality in Cryptococcus neoformans. Galactose-inducible promoters have been successfully used in Saccharomyces cerevisiae to manipulate heterologous gene expression. Utilizing S. cerevisiae galactose-inducible genes in a BLAST search of the sequenced C. neoformans var. grubii genome, we found three potential galactose-inducible promoters, P(GAL1), P(GAL7), and P(UGE2) that are induced by galactose and repressed by glucose in this variety. This chapter describes how to make a fusion of these promoters with heterologous genes, how to insert the fused gene back into the genome, and how to induce expression during asexual and sexual growth in C. neoformans var. grubii.