Binds to direct repeats of the sequence 5'-AGGTCA-3'. Inhibits the ecdysone response. Plays an essential role in regulating molting of the tracheal cuticle during larval development. Homodimer. Highest expression in third instar larvae and prepupae. By 20-hydroxyecdysone (20HE) 106 hours after egg laying. Death during the larval stages, due to defects in tracheal development characterized by fluid filling of the second instar tracheae. Mutant larvae that survive into the third instar are smaller than wild-type larvae and fail to pupariate. May be due to a competing acceptor splice site. Belongs to the nuclear hormone receptor family. NR2 subfamily.