Sequence-specific transcription factor which is part of a developmental regulatory system that provides cells with specific positional identities on the anterior-posterior axis. May play a role in midgut regionalization. Restricted to the posterior 16 midbody segments. Expressed in the dorsoventral muscles, which arise from the septal mesoderm and lie in the groove of the intercaecal constrictions. Largest accumulation of transcripts is seen in the posterior 16 midbody segments of the leech embryo between days 7 and 14. Belongs to the Antp homeobox family.