Acts as a transcription factor required for formation of the pharyngeal primordium (PubMed:7607089, PubMed:18448117). Binds to the consensus sequence 5'-T[AG]TT[TG][AG][TC]-3' with variations of the sequence affecting onset of target gene expression (PubMed:18448117). Becomes associated with pharyngeal target promoters by the 8E cell stage, playing a role in inducing large-scale chromatin decompaction, prior to the activation of transcription (PubMed:20714352). Binding with target sequences in pharyngeal cells may be repressed by the nuclear lamina protein emr-1 (PubMed:20714352). Activates a wide array of pharyngeal genes including ceh-22, pax-1 and myo-2 and represses ectodermal genes lin-26 and elt-3, ensuring pharyngeal cell fate (PubMed:11823633, PubMed:20714352, PubMed:9584117, PubMed:14738885). Required for recruitment of htz-1 to a subset of pharyngeal promoters to ensure gene activation and also acts synergistically with tbx-2 in pharyngeal development. Acts in the regulation of diet-restriction-mediated longevity by increasing expression of sod-1, sod-2, sod-4 and sod-5 but not sod-3 (PubMed:17476212). Positively regulates the expression of the transcription factor hlh-6 in the pharyngeal gland (PubMed:17049341). May regulate gene expression in the intestine (PubMed:18448117). Interacts with elt-2. Present in nuclei of all cells of larval and adult pharynx but variable in neuronal nuclei. Strongly expressed in the embryonic pharynx, particularly pharyngeal primordium precursor cells. Expression less strong in the embryonic gut. Expressed in adult intestine (PubMed:17113066). Expression first seen at the 8E cell stage in the embryonic gut. After hatching, expression is almost diminished in the pharynx and gut. Expressed in L3/L4 larvae in cells of the developing gonad. At the 8-12E stage, expression is seen for the first time in the rectal precursors. Intestinal expression is down-regulated during the larval to adult transition. Worms are unable to form the pharyngeal primordium with the pharyngeal precursor cells, ABaraapapaa and ABaraapppaa showing arrested development prior to terminal cell division. Some mutants exhibit malformed rectal tissues and fail to undergo proper embryonic elongation. RNAi-mediated knockdown at the L1 larval stage reduces survival (PubMed:30965033).