Involved in the transcriptional regulation of genes required for the development of pharyngeal muscles derived from the ABa lineage (PubMed:16701625, PubMed:23933492). Acts as a transcriptional repressor and binds to T-box binding sites in its own promoter to negatively autoregulate its own expression in neurons, seam cells and the gut in order to restrict its expression to certain tissues (PubMed:25873636). May function together with the nfya-1-NF-Y complex to repress its own expression (PubMed:25873636). Plays a role in neural fate specification in the hermaphrodite-specific neuron (HSN)/PHB neuron lineage, acting in concert with homeobox protein egl-5 and the asymmetric cell division protein ham-1. Expressed in body wall muscles and a subset of pharyngeal neurons. Expressed in head neurons and occassionally tail neurons (PubMed:23933492, PubMed:25873636). Not expressed in the pharynx (PubMed:23933492). First expressed in embryos at the 100-cell stage (PubMed:16701625). First expressed in pharyngeal precursors at the 100-200 cell stage and expression continues in the pharynx until near hatching, when expression becomes restricted to several neurons in the head (PubMed:23933492, PubMed:25873636). In larval stages, expressed in head neurons and occasionally tail neurons (PubMed:23933492). In L4 larvae, expressed in the gut and seam cells (PubMed:23933492). In larval stages, not expressed in the pharynx (PubMed:23933492). Sumoylated. RNAi-mediated knockdown results in 70% lethality at the larval stages (PubMed:23933492). RNAi-mediated knockdown enhances the larval lethality phenotype of the nfyb-1 cu13 mutant (PubMed:23933492).