Patent ID: 7189506

Claim:
A method of producing a cell having a molecular switch for modulating gene expression, said method comprising: (i) transforming said cell with a nucleic acid construct having a DNA response element which binds a transcriptional regulatory protein operably linked to a promoter, a non-native compound-binding sequence which is the same as, overlapping, or adjacent to said DNA response element for binding to a DNA binding compound, and a transgene under the control of said first promoter, wherein the DNA binding compound is seperate and different from the transcriptional regulatory protein; and (ii) exposing said transformed cell to a DNA binding compound, wherein binding of the DNA binding compound to said compound binding sequence is effective to inhibit binding of a transcriptional regulatory protein to the DNA response element, thereby derepressing or deactivating expression of the gene, where the transcriptional regulatory protein is a repressor or activator protein, respectively.