Pair-rule protein that regulates embryonic segmentation and adult bristle patterning. Transcriptional repressor of genes that require a bHLH protein for their transcription (e.g. ftz). Transcription repression requires formation of a complex with a corepressor protein (Groucho). Interacts with gro (via WPRW motif) and Topors. 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. Ubiquitinated by Topors.