Implicated in the regulation of ecdysone-triggered gene hierarchies. Probably plays a key role in mediating the regulation of the larval molt by 20-OH-ecdysone. In mid instar larvae salivary glands, low basal levels are observed in puff stage 1. Levels increase in late larvae from puff stages 3-10, then decrease abruptly at stage 11. In prepupae, isoform C is the predominant form during the transition between puff stages 18-19. At puff stage 1, expression is also present in the gut. By stage 3 it is present in the wing disks, Malpighian tubules and the fat body. At stage 11, expression is only present in the gut and wing disks. The expression of this protein is developmentally regulated and is correlated with the 20-OH-ecdysone induced activity of puff 75B. Belongs to the nuclear hormone receptor family. NR1 subfamily.