Transcriptional repressor. Represses transcription from both N box- and E box-containing promoters (By similarity). Demarcates the prospective midbrain-hindbrain boundary (MHB) region in the neuroectoderm in early gastrulae embryos by repressing transcription of a number of target genes. Transcription repression requires formation of a complex with a corepressor protein of the Groucho/TLE family. Expressed in the presumptive midbrain-hindbrain boundary (MHB) as early as the early gastrula stage (stage 10.5). Expression in the MHB continues through to tailbud stage. Also transiently expressed in the eye anlage at late neurula stage. Not induced by Notch-signaling. Has a particular type of basic domain which includes a helix-interrupting proline. The C-terminal WRPW motif is a transcriptional repression domain necessary for the interaction with Groucho/TLE family members, transcriptional corepressors recruited to specific target DNA by Hairy-related proteins.