Enables DNA-binding transcription factor activity; single-stranded DNA binding activity; and transcription corepressor activity. Acts upstream of or within negative regulation of transcription, DNA-templated and positive regulation of transcription, DNA-templated. Located in nucleus. Is expressed in central nervous system; genitourinary system; hemolymphoid system; sensory organ; and tooth. Orthologous to human SPEN (spen family transcriptional repressor). [provided by Alliance of Genome Resources, Apr 2022]