Enables DNA-binding transcription activator activity, RNA polymerase II-specific; bHLH transcription factor binding activity; and cis-regulatory region sequence-specific DNA binding activity. Involved in several processes, including Sertoli cell development; cAMP-mediated signaling; and positive regulation of macromolecule metabolic process. Part of transcription regulator complex. Human ortholog(s) of this gene implicated in 46,XX sex reversal 2; 46,XY sex reversal 10; and campomelic dysplasia. Orthologous to human SOX9 (SRY-box transcription factor 9). [provided by Alliance of Genome Resources, Apr 2022]