A brief review of Yeast two-hybrid system

Protein interactions are essential to all cellular processes, such as replication, transcription, splicing, translation and metabolism. The yeast two-hybrid system utilizes the reconstitution of an active transcription factor for assay for protein–protein interactions. The active transcription factors are formed as a dimmer between two fusion proteins, one of which contains a DNA–binding domain (DB) fused to the first protein of interest (DB-X Bait) and the other, an activation domain (AD) fused to the second protein of interest (AD–Y Prey or Target protein). DB–X:AD–Y interaction reconstitutes a functional factor that activates chromosomally integrated reporter genes driven by promoters containing the relevant DB binding sites. When a selectable marker gene such as HIS3 is used as a reporter gene, two–hybrid dependent transcription activation can be monitored by growth of yeast cells on plates lacking histidine, thereby providing a tool for detection of protein–protein interactions. Nowadays, yeast two-hybrid system is considered as a suitable approach for mapping of protein interactions in cells. This map may consist of many possible protein interactions that occur during the entire lifespan of a cell. In this review, we are going to describe this system, its efficiencies and its approaches for protein-protein interactions.