Detecting interactions between eukaryotic proteins in bacteria.

Few convenient genetic assays are available to study protein-protein interactions. This report describes a genetic scheme in E. coli to detect protein-protein interactions based on the concept of cooperative DNA binding of two interacting proteins. The yeast regulatory proteins GAL4 and GAL80, which are known to interact with each other, were used to test the scheme. A fusion protein, LexA-GAL80, was found to exert a cooperative effect on the DNA-binding activity of GAL4 as monitored by a bacterial repression assay.