The assay described here is based on the classical Gal4-UAS system, a system broadly utilized for gene expression studies [26]. The yeast Gal4 protein represents a prototypic transcription factor consisting of two separate domains: an N-terminal DNA-binding domain (DBD: amino-acids 1–147) and a C-terminal transactivation domain (TAD: amino-acids 768–881). The Gal4 protein binds to the consensus Upstream Activation Sequences (UAS) via its DBD and activates transcription of downstream genes through its TAD. However, when the two Gal4 domains are separated, neither of them can function as a transcription factor by itself [27].