Patent ID: 8822754

Claim:
A transgenic, non-human animal whose genome comprises an ecdysone receptor-based gene expression modulation system comprising: (a) a first gene expression cassette that is capable of being expressed in a cell of said animal, said gene expression cassette comprising a polynucleotide sequence that encodes a first polypeptide comprising: (i) a DNA binding domain that recognizes a response element associated with a gene whose expression is to be modulated; and (ii) an ecdysone receptor ligand binding domain; and (b) a second gene expression cassette that is capable of being expressed in said animal, said gene expression cassette comprising a polynucleotide sequence that encodes a second polypeptide comprising: (i) a transactivation domain; and (ii) a retinoid X receptor ligand binding domain; and (c) a third gene expression cassette comprising; (i) a response element to which the DNA-binding domain binds; (iii) a promoter that is activated by the transactivation domain; and viii) a gene whose expression is to be modulated; wherein the ligand binding domains from the first polypeptide and the second polypeptide are different and dimerize wherein at least one of the first polypeptide and the second polypeptide does not contain the A and B domains of the corresponding ecdysone receptor or retinoid X receptor, wherein the gene expression modulation system is more sensitive to a diacylhydrazine ligand than to a steroid ligand.