Sequence-specific transcription factor which is part of a developmental regulatory system that provides cells with specific positional identities on the anterior-posterior axis. First detected in the posterior tail bud at around 16.5 hours post-fertilization (hpf), expression continuing through to 36 hpf. Expressed in the developing fin fold and neural tube from 48-72 hpf. Belongs to the Abd-B homeobox family.