Enables DNA-binding transcription activator activity, RNA polymerase II-specific; identical protein binding activity; and sequence-specific DNA binding activity. Involved in cellular response to corticotropin-releasing hormone stimulus; fat cell differentiation; and negative regulation of cell cycle. Acts upstream of or within several processes, including positive regulation of transcription by RNA polymerase II; regulation of apoptotic process; and skeletal muscle cell differentiation. Located in nucleus. Part of transcription regulator complex. Is expressed in several structures, including bone; genitourinary system; hemolymphoid system; nervous system; and submandibular gland primordium. Orthologous to human NR4A1 (nuclear receptor subfamily 4 group A member 1).