Transcription factor probably involved in the development of the brain and the sense organs. Can bind to the bicoid/BCD target sequence (BTS): 5'-TCTAATCCC-3'. Expressed in the dorsal and basal telencephalon, in a subpopulation of proliferating neuroblasts, early in development (at least from 11.5 dpc). Up-regulated by FGF2 tretament in embryonic telencephalon primary cultures. Belongs to the paired homeobox family. Bicoid subfamily.