A Bacterial Two-Hybrid System Based on Transcription Activation

We describe the use of a bacterial two-hybrid system for the study of protein-protein interactions in Escherichia coli. This system is based on transcription activation and involves the synthesis of two fusion proteins within the bacterial cell whose interaction stimulates transcription of a reporter gene. Specifically, one of the fusion proteins can function as a transcription activator when its interaction partner is fused to a subunit of the bacterial RNA polymerase. This bacterial two-hybrid system has been used to study a number of interacting proteins from both prokaryotes and eukaryotes, and can be used to find interacting proteins from complex protein libraries.