Sequence-specific transcription factor which is part of a developmental regulatory system that provides cells with specific positional identities on the anterior-posterior axis. At the 10-somite stage, expressed in the paraxial mesoderm with an anterior expression limit at somite 8. At the 20-somite stage, expressed in the developing CNS with an anterior expression limit adjacent to the somite 7/8 boundary. Belongs to the Abd-B homeobox family.