Transcription factor (PubMed:28056346, PubMed:29033363). Involved in motor neuron fate determination and maintenance, acting as a transcriptional repressor to counteract gene activation by transcription factor unc-3 in a subset of motor neurons (PubMed:28056346). Probably acts by binding to specific promoter elements (PubMed:28056346). Required for ventral D (VD) motor neurons to adopt their normal synaptic pattern (PubMed:7869081). Suppresses expression of flp-13 in VD motor neurons to ensure formation of the correct synaptic pattern (PubMed:15882588). Maintains low cAMP levels in VD motor neurons by enhancing expression of pde-4 which hydrolyzes cAMP and repressing expression of acy-1 which catalyzes cAMP formation (PubMed:29033363). This prevents respecification of synapses by VD neurons (PubMed:29033363). During copulation, required in males for correct movement of the spicules, a pair of prong-like structures which are inserted into the vulva of the hermaphrodite and anchor the male to the hermaphrodite (PubMed:18652814). Required for spicule prodding which allows detection of the vulva location and for spicule insertion into the vulva (PubMed:18652814). Required for normal locomotion. Expressed in spicule protractor and retractor muscles, and the male-specific neuron CP9 (PubMed:18652814). Expressed in the nerve ring, and preanal ganglion (PubMed:9852581). Expressed in asymmetric motor neurons (PubMed:9852581, PubMed:29033363). Expressed in ventral D motor neurons (PubMed:9852581, PubMed:7869081, PubMed:15882588, PubMed:29033363). Isoform a: Expressed in males and hermaphrodites (PubMed:18652814). Isoform b: Only expressed in males (PubMed:18652814). Expression in the asymmetric and ventral D motor neurons in the ventral nerve cord is restricted to the postembryonic stages L2 and L3. Belongs to the nuclear hormone receptor family.