Enables RNA polymerase II cis-regulatory region sequence-specific DNA binding activity; nuclear receptor activity; and protein heterodimerization activity. Involved in positive regulation of protein sumoylation. Acts upstream of or within several processes, including embryonic placenta development; positive regulation of transcription by RNA polymerase II; and response to hypoxia. Located in cytoplasm and nucleus. Part of transcription regulator complex. Is expressed in several structures, including alimentary system; central nervous system; genitourinary system; respiratory system; and sensory organ. Human ortholog(s) of this gene implicated in renal cell carcinoma. Orthologous to human ARNT (aryl hydrocarbon receptor nuclear translocator). [provided by Alliance of Genome Resources, Apr 2022]