Enables DNA-binding transcription repressor activity, RNA polymerase II-specific and RNA polymerase II cis-regulatory region sequence-specific DNA binding activity. Acts upstream of or within negative regulation of transcription by RNA polymerase II and positive regulation of cell differentiation. Predicted to be located in nucleus. Predicted to be part of transcription regulator complex. Is expressed in several structures, including central nervous system; dorsal root ganglion; foregut-midgut junction; and urinary system. Human ortholog(s) of this gene implicated in diabetic ketoacidosis; maturity-onset diabetes of the young type 9; type 1 diabetes mellitus; and type 2 diabetes mellitus. Orthologous to human PAX4 (paired box 4). [provided by Alliance of Genome Resources, Apr 2022]