Appears to be indispensable for the central nervous system development. May have a role in the neuronal differentiation of the ganglionic eminence and ventral thalamus. May also be involved in axonal guidance in the floor plate. Expressed in brain. Expressed at 10 hours and 12 hours in presumptive diencephalon. Expressed transiently at 12 hours in caudal telencephalon. Later expression in floor plate and somites, followed by rostral telencephalon and ventral thalamus. Expressed at 40 hours in hypothalamus. Belongs to the paired homeobox family. Bicoid subfamily.