Sequence-specific transcription factor which is part of a developmental regulatory system that provides cells with specific positional identities on the anterior-posterior axis. Binds the consensus region 5'-TTAAT[GT][GA]-3'. This homeotic protein controls development of the cells in the posterior thoracic and first abdominal segments. It activates the synthesis of the decapentaplegic (DPP) growth factor. The QA motif is able to mediate transcriptional repression. Belongs to the Antp homeobox family.