Functions as a transcriptional repressor. Required for brain development. Homodimer. In the embryo, expressed in the developing central nervous system and in other tissues including the developing digestive system (PubMed:12175514). At 9.7 dpc, expression is restricted to the midbrain and pretectum (PubMed:11731459). Expression detected from HH stage 4. Belongs to the paired homeobox family.