Patent ID: 7186505

Claim:
An expression system useful for the detection and isolation of a polypeptide capable of regulating a transduction pathway, the expression system comprising: (a) a first expression construct including a first coding region encoding a transactivator, said first coding region being under transcriptional control of a cis acting regulatory sequence element, said cis acting regulatory sequence element being regulatable by a trans acting regulator of the transduction pathway; and (b) an expression library including a plurality of second expression constructs, each second expression construct of said plurality of second expression constructs of said expression library including a second coding region encoding for one of a plurality of polypeptides, each of said plurality of second expression constructs of said expression library further including a third coding region encoding a reporter molecule, said second coding region and said third coding region being under a transcriptional control of at least one promoter being regulatable by said transactivator, such that when said first expression construct and a second expression construct of said plurality of second expression constructs of said expression library are introduced into a cell, said cell endogenously expressing said trans acting regulator of the transduction pathway, a level of expression of said reporter molecule in said cell is indicative of regulation of the transduction pathway by a specific polypeptide of said plurality of polypeptides expressed by said cell from said second expression construct when compared to a predetermined level of expression of said reporter molecule.