Patent ID: 7229766

Claim:
A method for detecting protein-protein interactions in a host cell cytoplasm, the method comprising: a. introducing a first recombinant expression construct encoding a first protein or protein-binding fragment thereof fused with the amino- or carboxyl-terminus of a transcriptional inhibitor; b. introducing a second recombinant expression construct encoding a second protein or protein-binding fragment thereof fused to a cytoplasm localization sequence, wherein the first or second protein or both is a protein encoded by a cDNA molecule or a member of a cDNA library, wherein said library comprises a plurality of fusion proteins in which the transcription inhibitor protein is fused to each of a plurality of members of said cDNA library in each species of fusion protein comprising said plurality of fusion proteins, wherein upon interaction of the first and second proteins in the cell cytoplasm, said transcriptional inhibitor is localized to the cytoplasm, wherein transcription of a gene operably linked to a promoter that is sensitive to or regulated by said transcriptional inhibitor is increased; and c. detecting said increased transcription of said gene, wherein said protein-protein interaction is detected thereby.