Transcription factor (By similarity). Required for the terminal differentiation of sensory- and motor-neurons, especially GABAergic neurons, and for morphological aspects of uterine development (PubMed:10068647). Plays a role in the cell-type-specific regulation of glutamic acid decarboxylase unc-25 (PubMed:10068647). Involved in promoting sleep-like behavioral quiescence, acting by modulating expression of transcription factor aptf-1 in the single sleep-active ring interneuron RIS (PubMed:26949257). Plays a role in regulation of RIS differentiation (PubMed:14568548). Required for the functional asymmetry of the ASER and ASEL chemosensory neuron pair, conferring the ability to discriminate sodium from chloride, perhaps by modulating expression of receptor-type guanylate cyclases, such as gcy-5 (PubMed:11287956, PubMed:21555395). Involved in regulating postembryonic axon maintenance in the ventral nerve cord, acting in concert with LIM homeobox protein ceh-14, via modulation of expression of immunoglobulin domain zig genes in the interneuron PVT (PubMed:12490565). May play a role in the functions of the excretory gland cell (PubMed:10068647). Expressed in a restricted set of neurons, and epithelial cells of the uterus and the excretory system, late in embryogenesis at about 300 minutes of development (PubMed:10068647). Expression in neurons continues throughout adulthood (PubMed:10068647). Expressed asymmetrically, only in the left neuron (ASEL), of the ASER and ASEL chemosensory pair (PubMed:10068647). Expressed in the interneuron PVT during embryogenesis (PubMed:12490565).