The TATA-binding protein (TBP) from the human fungal pathogen Candida albicans can complement defects in human and yeast TBPs

Candida albicans is the major fungal pathogen in humans, yet little is known about transcriptional regulation in this organism. Therefore, we have isolated, characterized, and expressed the C. albicans TATA-binding protein (TBP) gene (TBP1), because this general transcription initiation factor plays a key role in the activation and regulation of eukaryotic promoters. Southern and Northern blot analyses suggest that a single C. albicans TBP1 locus is expressed at similar levels in the yeast and hyphal forms of this fungus. The TBP1 open reading frame is 716 bp long and encodes a functional TBP of 27 kDa. C. albicans TBP is capable of binding specifically to a TATA box in vitro, substituting for the human TBP to activate basal transcription in vitro, and suppressing the lethal Δspt15 mutation in Saccharomyces cerevisiae. The predicted amino acid sequences of TBPs from C. albicans and other organisms reveal a striking pattern of C-terminal conservation and N- terminal variability: the C-terminal DNA-binding domain displays at least 80% amino acid sequence identity to TBPs from fungi, flies, nematodes, slime molds, plants, and humans. Sequence differences between human and fungal TPBs in the DNA-binding domain may represent potential targets for antifungal therapy.