Enables DNA-binding transcription activator activity, RNA polymerase II-specific and RNA polymerase II cis-regulatory region sequence-specific DNA binding activity. Acts upstream of or within several processes, including eating behavior; mammary gland involution; and positive regulation of transcription by RNA polymerase II. Located in cytoplasm and nucleus. Part of transcription regulator complex. Is expressed in brain; metanephros; and renal vasculature. Orthologous to human BSX (brain specific homeobox). [provided by Alliance of Genome Resources, Apr 2022]