Transcriptional repressor. Represses transcription from both N box- and E box-containing promoters. May with HES1, cooperatively regulate somite formation in the presomitic mesoderm (PSM). May function as a segmentation clock, which is essential for coordinated somite segmentation. Transcription repression requires formation of a complex with a corepressor protein of the Groucho/TLE family. Dynamic expression in the presomitic mesoderm (PSM). At 8.5 dpc, expressed in two bilateral domains: rostral and caudal stripes. The rostral bands are located posterior to the newly formed somite, while the caudal bands extend to the most caudal tip. During 9.0 dpc-12.0 dpc stages, again specifically expressed in two domains of the PSM. 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 motif which is necessary for interaction with Groucho/TLE family members, transcriptional corepressors recruited to specific target DNA by Hairy-related proteins.