Abstract: This invention relates to an improved method to modulate exogenous gene expression in which an ecdysone receptor complex comprising: a DNA binding domain; a ligand binding domain; a transactivation domain; and a ligand is contacted with a DNA construct comprising: the exogenous gene and a response element; wherein the exogenous gene is under the control of the response element and binding of the DNA binding domain to the response element in the presence of the ligand results in activation or suppression of the gene. The improvement resides in a select group of non-steroid ligands which show improved activity over known ligands.

Abstract: A hybrid polypeptide is disclosed, comprising a polypeptide for attachment of a prosthetic group to avidin fused to at least one polypeptide of interest, and a method of making the same. The hybrid polypeptide is produced by recombinant DNA techniques, using a DNA expression vector composed of a DNA fragment coding for the polypeptide for attachment to avidin fused to DNA coding for one or more polypeptides of interest. The hybrid polypeptide may also contain linking amino acid sequences for cleavage of the polypeptide of interest from the polypeptide for attachment using an appropriate proteolytic or chemical reagent. The hybrid polypeptide is expressed in appropriate host cells transformed with the DNA expression vector encoding the hybrid polypeptide, and may be recovered from crude cell extracts in high yield and high purity using avidin affinity chromatography.