Sequence-specific transcription factor which is part of a developmental regulatory system that provides cells with specific positional identities on the anterior-posterior axis. Interacts with HOMEZ (By similarity). Forms a DNA-binding heterodimer with transcription factor PBX1 (PubMed:7791786). Initially found in all tissues of the posterior region in 8.5 and 9.5 dpc. Embryos, it eventually become specifically located in neural tissue. Belongs to the Antp homeobox family.