Figure 1.

Graphic representation of the yeast two-hybrid system. The two-hybrid system is based on the property of transcription factors that allows each domain to work independently of the other. (A) The DNA-binding domain (DBD) binds DNA, and the transcriptional-activation domain (TAD) stimulates the promoter complex. (B) In the two-hybrid system, the DBD and the TAD are separated and can be reconstituted only by a protein–protein interaction between a bait protein and a prey protein. This protein–protein interaction allows activated transcription of a reporter gene. In this diagram, the lacZ gene will give a phenotypic readout of blue color formation in yeast.