Transcription factor (PubMed:28056346). Involved in cell fate determination; required to pattern the posterior hindgut (PubMed:10716947). 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). Required throughout development to repress transcription by unc-3, probably acting by binding to specific promoter elements (PubMed:28056346). Represses expression of VA and VB motor neuron-specific effector genes, such as DEG/ENaC channel del-1 and the innexin inx-12, in DA and DB motor neurons (PubMed:28056346). Represses expression of transcription factor bnc-1, perhaps acting directly, in DA and DB motor neurons (PubMed:28056346). First expressed during embryogenesis at the 1.5-fold stage, and in very few cells throughout development (PubMed:10716947). Expressed in L1 larvae in the posterior hindgut cells B and F and in later L1 stage in the B daughter cells B.a and B.p (PubMed:10716947). Also expressed in two posterior hypodermal nuclei of the large syncytial cell hyp7 and in the nervous system in two neurons of the lumbar ganglion (PubMed:10716947). RNAi-mediated knockdown by injection into the gonad results in male progeny with grossly abnormal tails with no spicules (PubMed:10716947). Hermaphrodite progeny are constipated and show backward uncoordination (PubMed:10716947).