FUNCTION Sequence-specific transcription factor (By similarity). Regulates multiple developmental processes including brainstem, inner and outer ear, abducens nerve and cardiovascular development and morphogenesis as well as cognition and behavior (PubMed:16155570). Also part of a developmental regulatory system that provides cells with specific positional identities on the anterior-posterior axis. Acts on the anterior body structures. Seems to act in the maintenance and/or generation of hindbrain segments (By similarity). Activates transcription in the presence of PBX1A and PKNOX1 (By similarity).SUBUNIT Interacts with OGT (via TPR repeats domain); the interaction takes place mainly in the nucleus (By similarity). Forms a DNA-binding heterodimer with transcription factor PBX1 (PubMed:9191052).INTERACTION The disease is caused by variants affecting the gene represented in this entry.DISEASE The disease is caused by variants affecting the gene represented in this entry.MISCELLANEOUS Lacks the homeobox domain.MISCELLANEOUS Lacks the homeobox domain.SIMILARITY Belongs to the Antp homeobox family. Labial subfamily.