Enables transcription corepressor activity. Involved in negative regulation of transcription by RNA polymerase II and protein sumoylation. Acts upstream of or within B cell differentiation; T cell differentiation; and negative regulation of gene expression. Located in nuclear body. Is expressed in several structures, including alimentary system; branchial arch; genitourinary system; nervous system; and sensory organ. Human ortholog(s) of this gene implicated in autism spectrum disorder; beta thalassemia; schizophrenia; and sickle cell anemia. Orthologous to human BCL11A (BAF chromatin remodeling complex subunit BCL11A). [provided by Alliance of Genome Resources, Apr 2022]