Enables HMG box domain binding activity; TBP-class protein binding activity; and transcription coactivator activity. Involved in positive regulation of transcription by RNA polymerase II. Located in nucleus. Is expressed in several structures, including early conceptus; embryo ectoderm; gonad; and limb mesenchyme. Orthologous to human UTF1 (undifferentiated embryonic cell transcription factor 1). [provided by Alliance of Genome Resources, Apr 2022]