Transcriptional repressor of genes that require a bHLH protein for their transcription (PubMed:1427077, PubMed:28899667, PubMed:24618901). In the larval brain, required to maintain the self-renewal and identity of type II neuroblasts by regulating the expression of the transcriptional repressor erm together with other self-renewal transcriptional repressors such as klu and E(spl)mgamma-HLH (PubMed:28899667, PubMed:23056424, PubMed:21262215, PubMed:24618901, PubMed:22357926). As part of its role in neuroblasts development, has been shown to be a direct target of the Notch signaling pathway, however might work also independently of N/Notch (PubMed:21262215, PubMed:22357926, PubMed:23056424). In the developing larval and pupal brain, required for mushroom body differentiation (PubMed:22357926). Involved in sex determination and SXL transcription repression when in complex with the corepressor protein Groucho (PubMed:8001118, PubMed:7651341). Homodimer (PubMed:22357926, PubMed:7651341). Heterodimer with E(spl)mgamma-HLH and E(spl) (PubMed:22357926). Transcription repression requires formation of a complex with the corepressor protein Groucho (PubMed:8001118). Interacts (via bHLH motif) with sisA (PubMed:7651341). Interacts with da (PubMed:7651341). In larvae, expressed in primary neural precursors (at protein level) (PubMed:1427077). In leg imaginal disks, expressed in stripes at the distal edge of each leg segment primordium (at protein level) (PubMed:1427077). In stage 9 embryo, detected in the first neuroblasts delaminating from the ectoderm (at protein level) (PubMed:22357926). In newly hatched larvae, detected in dividing neuroblasts (at protein level) (PubMed:22357926). First detected in preblastoderm cycle 12 in all nuclei (PubMed:1427077). During middle to late cycle 13, expressed in eight stripes that overlap those of the hairy protein (PubMed:1427077). Has a particular type of basic domain (presence of a helix-interrupting proline) that binds to the N-box (CACNAG), rather than the canonical E-box (CANNTG). The C-terminal WRPW motif is a transcriptional repression domain necessary for the interaction with Groucho, a transcriptional corepressor recruited to specific target DNA by Hairy-related proteins. Lethal at different developmental stages (PubMed:1427077). In late third instar larval brains, results in a complete absence of type II neuroblasts (NBs) and a reduction of type I NBs; after larval hatching, loss of neuroblasts in the ventral nerve cord and specific loss of type I neuroblasts within 48 hours; in the pupae, results in a premature loss of mushroom body NBs (PubMed:23056424, PubMed:21262215, PubMed:22357926). Escaper adult flies display weak motor activity, lethargic behavior, and shortened life span (PubMed:1427077). RNAi-mediated knockdown of the protein in type II neuroblasts lineage results in an increase in the number of type II neuroblasts (PubMed:28899667). Simultaneous RNAi-mediated knockdown of the ETS protein pnt or the transcriptional repressor Erm restores normal neuroblast numbers (PubMed:28899667).