Transcription factor (PubMed:8700229, PubMed:16310763). Required to activate programmed cell death in the sister cells of the serotoninergic neurosecretory motor (NSM) neurons (PubMed:8700229). Negatively regulates the activity of ces-1 which in turn negatively regulates the activities of cell-killing genes (PubMed:8700229). Binds to the DNA sequence 5'-RTTACGTAAY-3' (PubMed:8700229). Involved in the development of the excretory duct cell, by positively modulating embryonic transcription of putative transcription factor lin-48, acting in concert with NFIL3 transcription factor homolog atf-2 (PubMed:16310763, PubMed:12231624). Positively modulates expression of neuropeptide pigment dispersing factor homologs pdf-1 and pdf-2 (PubMed:19686386). Interacts with NFIL3 transcription factor homolog atf-2. Expression begins in the embryo and diminishes in larvae (PubMed:16310763). Expressed in the excretory duct cell, as well as other cells, at larval L3 stage (PubMed:16310763). RNAi-mediated knockdown causes morphological defects in excretory duct cells. Reduces expression of transcription factor lin-48. Belongs to the bZIP family.