Probable transcription factor (PubMed:11018016, PubMed:27341757). Binds to DNA sequence motif 5'-CTGTTTCA-3' (PubMed:22819322). Required for the migration of distal tip cells (DTC) and axonal growth-cones along the dorsal-ventral axis of the body wall, acting by cell autonomous repression of unc-129/TGF-beta expression in ventral body muscle during embyogenesis (PubMed:11018016, PubMed:27341757). Binds to the promoter region of the unc-129 gene (PubMed:11018016). Plays a role in dorsal-ventral patterning and fate specification of the postembryonic mesoderm (PubMed:29155044). Involved in male tail morphogenesis and in embryogenesis (PubMed:11018016). Plays a role in the development of sensory neurons and is required to repress AWA fate and promote ASG fate in the ASG chemosensory neurons (PubMed:11018015). Regulates expression of a class of small RNAs, known as 21U-RNAs. Expressed in ventral body wall muscle (PubMed:11018016). Expressed in the structural cells and two neurons of each ray in the male tail (PubMed:11018016). Expressed strongly in embryos and L1 larvae, but severely reduced or absent in later larval and adult stages (at the protein level) (PubMed:11018015). Expressed widely in embryogenesis, including ABp(l/r)aapapp cells, which are precursors to the AIB interneurons and the ASI chemosensory neurons, hypodermal cells hyp4, hyp5, hyp6, hyp7, H0, H1, and ABp(l/r)aapapa cells, which give rise to the AWA and ASG sensory neurons (at the protein level) (PubMed:11018015). Expression in the postembryonic M lineage is asymmetric; beginning at the 8-M stage and continuing through the 18-M stage, expressed in all the ventral, but not dorsal, M lineage cells (PubMed:29155044). Expressed dynamically during embryogenesis in head hypodermal cells, as well as in ventral body wall muscle (BWM) and intestinal precursor cells (PubMed:11018016, PubMed:27341757). Expression not detected in any dorsal BWM or its precursor during embryogenesis (PubMed:27341757). RNAi-mediated knockdown resulted in de-repression of unc-129 expression in ventral body wall muscle (BWM).