Enables DNA-binding transcription activator activity, RNA polymerase II-specific and RNA polymerase II transcription regulatory region sequence-specific DNA binding activity. Involved in positive regulation of cold-induced thermogenesis and positive regulation of transcription by RNA polymerase II. Is expressed in several structures, including central nervous system; genitourinary system; gut; heart; and sensory organ. Orthologous to human ESRRG (estrogen related receptor gamma). [provided by Alliance of Genome Resources, Apr 2022]