An inducible, tightly regulated, and growth condition-independent transcription factor in Saccharomyces cerevisiae

We constructed a synthetic transcription activator by fusing the bacterial LexA DNA-binding protein, the human estrogen receptor (ER), and an activation domain (AD). The activity of this chimera, called LexA-ER-AD, is tightly regulated by the hormone β-estradiol. We developed four versions of the transcription factor displaying different activation domains (AD) inducing transcription at different levels. By controlling the number of LexA binding sites in the target promoter, one can scale the expression levels up or down. As the system is heterologous in yeast, it can be used in different growth conditions.