Enables DNA-binding transcription factor binding activity. Involved in several processes, including dorsal/ventral axis specification; negative regulation of transcription by RNA polymerase II; and regulation of signal transduction. Acts upstream of or within embryonic skeletal system morphogenesis and trophoblast giant cell differentiation. Located in nucleus. Is expressed in medulla oblongata basal plate mantle layer; placenta; sensory organ; skeleton; and trophectoderm. Orthologous to human MDFI (MyoD family inhibitor). [provided by Alliance of Genome Resources, Apr 2022]