Two-Hybrid Protein-Protein Interactions

The two-hybrid system is an artificially constructed genetic system intended to facilitate the detection and assessment of protein-protein interactions. In the two-hybrid system a host organism, typically yeast or bacteria, is engineered so as to contain three components. These are a first protein fused to a DNA-binding domain of known specificity (hybrid 1); a second protein fused to a transcriptional-activation domain (hybrid 2), that can interact with the first protein, constituting a functional, albeit composite, transcription factor; and one or more reporter genes transcribed based on the binding of the composite transcription factor. Many permutations of the two-hybrid paradigm have been developed, and two-hybrid systems have become a mainstay of proteomic investigations.