Escherichia coli One- and Two-Hybrid Systems for the Analysis and Identification of Protein–Protein Interactions

Genetic methods based on fusion proteins allow the power of a genetic approach to be applied to the self-assembly of proteins or protein fragments, regardless of whether or not the normal function of the fused assembly domains is either known or amenable to selection or screening. The widespread adoption of variations of the yeast two-hybrid system originally described by S. Fields and O. Song (1989, Nature 340, 245–246) demonstrates the usefulness of these kinds of assays. This review describes some of the many systems used to select or screen for protein–protein interactions based on the regulation of reporter constructs by hybrid proteins expressed in bacteria, including recent implementations of generalizable two-hybrid systems for Escherichia coli.