Enables DNA-binding transcription repressor activity, RNA polymerase II-specific. Involved in several processes, including nervous system development; positive regulation of signal transduction; and regulation of transcription, DNA-templated. Acts upstream of or within several processes, including nephron morphogenesis; nervous system development; and regulation of transcription by RNA polymerase II. Predicted to be located in nucleoplasm. Predicted to be active in nucleus. Is expressed in several structures, including central nervous system; paraxial mesenchyme; sensory organ; small intestine; and urinary system. Orthologous to human HES5 (hes family bHLH transcription factor 5). [provided by Alliance of Genome Resources, Apr 2022]