Transcription factor that binds to the consensus 5'-TGATNNAT(G/T)(G/A)-3' PBC/Hox motif of target genes to regulate gene expression (PubMed:21307099, PubMed:23784779). Binds to the consensus PBC/Hox motif lineage enhancer region of sem-2 to promote cell fate specification in the postembryonic mesoderm (also known as the M lineage) (PubMed:21307099). Regulates the expression of mig-13 which controls the asymmetric distribution of actin cytoskeleton-binding protein cor-1 in Q neuroblasts (PubMed:23784779). This in turn controls the polarity migration of Q neuroblasts and the subsequent mid-body region-specific development (PubMed:8101475, PubMed:23784779). Regulates vulval precursor cell (VPC) differentiation, in concert with orphan nuclear receptor nhr-25. Interacts with nhr-25. Expressed in Q neuroblasts during larval development with higher expression in migrating QR.ap neuroblast descendents than in QL.ap neuroblast descendents. Lin-39 and mab-5 double mutants have reduced sex myoblast specification-specific expression of sem-2 in the developing mesoderm. Belongs to the Antp homeobox family. Deformed subfamily.