Required for the establishment of head structures. Required to function as an early patterning gene in the anterior-most blastoderm head segment anlage and for the establishment of a specific head skeletal structure that derives from the non-adjacent intercalary segment at a later stage of embryogenesis. Binds the consensus DNA sequence 5'-[AG]TAAA[TC]A-3'. Expressed in early blastoderm embryos in anterior and posterior gut precursors, and, later in a subset of cells in central nervous system. Expressed throughout embryogenesis, maximally during the 5-12 hours period.