Enables chromatin binding activity. Acts upstream of or within negative 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; genitourinary system; mesenchyme derived from splanchnopleure; retina; and spleen. Orthologous to human CBFA2T3 (CBFA2/RUNX1 partner transcriptional co-repressor 3). [provided by Alliance of Genome Resources, Apr 2022]