Enables DNA-binding transcription factor activity. Acts upstream of or within transition between slow and fast fiber. Located in nucleus. Is expressed in several structures, including alimentary system; embryo mesenchyme; eye; genitourinary system; and nervous system. Used to study Williams-Beuren syndrome. Orthologous to human GTF2IRD1 (GTF2I repeat domain containing 1). [provided by Alliance of Genome Resources, Apr 2022]