Enables DNA-binding transcription factor activity, RNA polymerase II-specific and transcription cis-regulatory region binding activity. Acts upstream of or within several processes, including circulatory system development; regulation of transcription, DNA-templated; and stem cell fate specification. Located in nucleus. Part of transcription regulator complex. Is expressed in several structures, including alimentary system; brain; immune system; reproductive system; and urinary system. Human ortholog(s) of this gene implicated in hypotrichosis-lymphedema-telangiectasia syndrome and hypotrichosis-lymphedema-telangiectasia-renal defect syndrome. Orthologous to human SOX18 (SRY-box transcription factor 18). [provided by Alliance of Genome Resources, Apr 2022]