Transcriptional regulator that plays a central role in lin-12/Notch and glp-1/Notch signaling, signaling pathways involved in cell-cell communication that regulate a broad spectrum of cell-fate determinations (PubMed:8625826). Binds directly to the 5'-[A/G]TGGGAA-3' DNA consensus sequence, which is present in the regulatory region of several genes (PubMed:8625826, PubMed:18706403, PubMed:23615264, PubMed:15297877). Acts as a transcriptional repressor when it is not associated with Notch proteins (By similarity). When in a complex with a Notch intracellular domain (NICD) product of lin-12/Notch and transcription regulator lag-3, it may act as a transcriptional activator that activates transcription of target genes (By similarity) (PubMed:18381292, PubMed:10830967). Probably represses or activates transcription via the recruitment of chromatin remodeling complexes containing histone deacetylase or histone acetylase proteins, respectively (By similarity). Involved in cell-fate specification during reproductive system development, by positively autoregulating its own expression, in response to lin-12/Notch signaling (PubMed:23615264, PubMed:32839181). May repress expression of hlh-6, in a lin-12/Notch-independent manner (PubMed:18706403).