Enables DNA-binding transcription repressor activity, RNA polymerase II-specific. Acts upstream of or within negative regulation of transcription by RNA polymerase II and regulation of telomere maintenance. Located in nucleus. Is expressed in several structures, including brain; early conceptus; genitourinary system; gut; and immune system. Orthologous to human YLPM1 (YLP motif containing 1). [provided by Alliance of Genome Resources, Apr 2022]