SCREENING ASSAY

Disclosed are methods, kits and cells for screening for test compounds that are capable of inhibiting DNA-binding activity of a DNA-binding protein. The disclosed methods, kits and cells may include a reporter expression cassette that encodes a reporter expression product, wherein the reporter expression cassette comprises at least one binding site for the DNA-binding protein such that binding of the DNA- binding protein to the binding site inhibits expression of the reporter expression product. Also disclosed are methods for producing a helix-constrained peptide that may be used in the screening methods disclosed herein. The methods, kits and cells find application, for example, in the identification of antagonists that may be useful in the treatment of cancers involving the DNA-binding protein.