Predicted to enable DNA-binding transcription factor activity, RNA polymerase II-specific and RNA polymerase II cis-regulatory region sequence-specific DNA binding activity. Involved in B cell differentiation and definitive hemopoiesis. Predicted to be located in nucleus. Is expressed in brain; genitourinary system; heart; liver; and thymus primordium. Human ortholog(s) of this gene implicated in T-cell acute lymphoblastic leukemia. Orthologous to human LYL1 (LYL1 basic helix-loop-helix family member). [provided by Alliance of Genome Resources, Apr 2022]