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Fig. 1. Domain structures of the ecdysone receptor components. The three isoforms
of Drosophila EcR and the single Drosophila USP are shown,
with the standard nuclear receptor regions indicated. Region C is the
DNA-binding domain (DBD); region E, the ligand-binding domain (LBD). The three
EcR isoforms are identical in sequence except in the A/B regions that are
unrelated. The number of isoform-specific residues is shown for each EcR. The
scale underneath (in residues) is aligned to EcR-B1. The residue mutated in
EcR-F645A is indicated.