Enables DNA-binding transcription activator activity, RNA polymerase II-specific and RNA polymerase II cis-regulatory region sequence-specific DNA binding activity. Involved in positive regulation of transcription by RNA polymerase II. Acts upstream of or within several processes, including adult behavior; animal organ development; and negative regulation of nitrogen compound metabolic process. Located in nucleus. Is expressed in several structures, including central nervous system; future brain; liver; thymus; and urinary system. Human ortholog(s) of this gene implicated in acute lymphoblastic leukemia. Orthologous to human PAX5 (paired box 5). [provided by Alliance of Genome Resources, Apr 2022]